13

Chapter II

REVIEW OF LITERATURE Introduction:

Till recently, very scanty attention is paid on the aromatic and essential oil

bearing plants with respect to their physiology, growth and yield. The literature

pertaining to Trachyspermum ammi and other related aromatic and medicinal plants

with respect to seed germination, physiology, biochemistry, growth, yield, essential

oil quality and changes in above mentioned attributes due to the applications of

PGRs, micronutrients and abiotic stresses like salinity and drought is briefly reviewed

in this chapter.

2.1. Seed germination and seedling growth:

Effect of PGRs

Application of GA3, NAA, IAA, IBA etc is well known practice in agriculture

and horticulture to improve the growth, yield and market quality of the produce, but

very few attempts are made for medicinal and aromatic plants. Many researchers like

Narra et al. (2010) reported enhanced seed germination, seedling elongation and dry

weight accumulation due to application of GA3 (10 ppm) in Trachyspermum ammi.

Similarly, Shetty and Rana (2012) reported that GA3 (100 ppm) had significantly

increased the germination percent and vigour index of Ajowan. Khoshvaghti et al.

(2013) and Hoseini et al. (2013) also claimed that seeds of Dill (Anethum graveolens)

and Fennel (Foeniculum vulgare) primed with GA3 showed enhanced germination

and seedling growth over control. Positive effects of GA3 on seed germination and

seedling growth of eleven different aromatic and essential oil yielding plants was

reported by Aglaia et al. (2011).

Dhoran and Gudadhe (2012) reported that seed germination, root and shoot

length, fresh and dry weight along with vigour index in Asparagus sprengeri was

significantly increased by different plant growth regulators like NAA, GA3 and IBA.

Borse (2004) noted enhanced germination and seedling growth in Solanum

khasianum due to PGRs treatments. Similarly, enhanced germination upto 80-95%

over control was recorded by Gupta (2003) using GA3 in Costus and Embelica. Bhatt

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14

et al. (2005) reported that application of GA3 and IAA had enhanced the seed

germination in Swertia angustifolia. Rajender et al. (2006) studied the positive effects

of GA3 on seed germination and seedling growth of different medicinal plants.

Kandari et al. (2008) had also reported maximum increase in seed germination with

GA3 in Arnebia benthamii Similar trend was noted in medicinal and aromatic plants

like Bacopa monieri (Mathur and Kumar 2001), Asparagus racemosa (Gupta et al.

2002), Trigonella (Gupta and Kumar 2003) and Cinamomum (Sakia and Nath 2003).

Effect of micronutrients

Applications of various micronutrients on seed germination and seedling

growth was worked out by many researchers. Micronutrients when applied in low

concentrations had beneficial impact but in higher doses cause metabolic disorders

and growth inhibition in most of the plant species (Claire et al. 1991). Renugadevi et

al. (2008) noted enhanced seed germination, root and shoot length, dry matter

accumulation, vigour index in Cyamopsis tetragonoloba due to treatments of MnSO4,

FeSO4 and ZnSO4. Similarly, Manivasagaperumal et al. (2011) recorded the effect of

zinc on the seed germination and seedling growth of Cyamopsis tetragonoloba.

The negative impact of higher doses of micronutrients on seed germination

was reported in various medicinal and crop plants like Lens esculenta (Ayaz and

Kadioglu 1997), Alyssum spp, Cuminum cyminum and Salvia officinalis (Ekaternia

and Lyle 1999), Medicago sativa (Peralta et al. 2001). Similar trend was recorded for

three medicinal plant species such as Boswelia volubillis, Eucomis autumnalis and

Merwilla natalensis in which seed germination was negatively affected by treatments

of micronutrients like Zn (Street et al. 2007). The decrease in seed germination and

seedling growth due to zinc application was reported in Leucaena leucocephala by

Shafiq et al. (2008).

Effect of salt stress

The abitic stress like salinity had adverse impact on all aspects of stressed

plants. Rohamare et al. (2014) reported significant reduction in seed germination,

root and shootlenght, fresh and dry weight of seedlings and reduced SVI in Ajowan

due to NaCl stress. Mehr (2013) studied the response of dill (Anethum graveolens) to

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15

salt stress and reported that germination percentage, radical, plumule length and dry

weight decreased significantly with the increase of salinity levels. Aglaia et al. (2011)

in their study on effect of NaCl in seed germination and seedling growth of different

aromatic and essential oil yielding plants like rosemary, dill, lavender, oregano,

spearmint, anise, coriander, parsley, sage, basil and cress indicated that higher

salinity levels significantly reduced all the parameters. Afzali et al. (2006) had

reported significant reduction in seedling growth of chamomile due to increasing

concentration of NaCl. Belaqziz et al. (2009) claimed that increasing salinity had

significantly reduced seed germination, seedling fresh and dry weights of Thymus

maroccanus. The adverse effect of salinity on seed germination and seedling growth

of medicinal and aromatic plants like Nigella sativa (Hajar et al. 1996), Ocimum

basilicum (Ramin 2005) were well documented.

Sosa et al. (2005) claimed that seed germination is one of the most salt-

sensitive stage severely inhibited with increasing salinity. This negative response of

seed germination under salt stress was reported by many researchers on Ocimum

basilicum, Eruca sativa, Petroselinum hortense (Miceli et al. 2003) as well as

chamomile and sweet marjoram (Ali et al. 2007). Ebru et al. (2004) studied the effect

of salt stress and reported decrease in seedling growth of Lens culinaris at higher

NaCl levels. Meratan et al. (2008) had also confirmed the adverse impact of NaCl on

seedling growth of three different species of Acanthophyllum.

Effect of water stress

The moisture or water stress is the major constrain for all crops resulting into

reduction in yield. Boroumand Rezazadeh and Kouchaki (2006) reported reduction in

germination with the increasing water stress in Ajowan, fennel and dill. Afzali et al.

(2006) had reported progressive decrease in the seed germination and seedling

growth of chamomile due to increased concentration of PEG 6000. Zeng et al. (2010)

noted that increasing water stress due to PEG 6000 had significantly reduced the seed

germination and seedling root length of various medicinal and aromatic plants.

Similarly, Asadi-Kavan et al. (2009) also noted reduced germination in Pimpinella

anisum due to PEG (6000) treatment.

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16

Several researchers observed decreased germination and seedling growth in

medicinal and crop plants like Plantago (Braga et al. 2009), Prosopis strombulifera

(Sosa et al. 2005), Portulaca oleraceae (Rahimi and Kafi 2009, Rahdari and Hoseini

2012), Phaseolus mungo (Pratap and Sharma 2010), Vigna radiata and Lens culinaris

(Kazerouni et al 2005), Cicer arietinum (Khakwani et al. 2011), Vicia faba (El-Tayeb

2006), Pennisetum glaucum (Radhouane 2007), Eucalyptus (Schutz et al. 2002) and

Medicago sativa (Safarnejad 2008).

2.2. Seedling physiology (Carbohydrates and Proteins):

Effect of PGRs

Not only seed germination but seedling physiology is also greatly affected by

PGRs treatments. Narra et al. (2010) noted that GA3 showed stimulatory effect on

reducing and total sugars as well as proteins in Ajowan seedlings. Similarly, Khinder

(1999) also reported increased reducing sugars and total sugars in GA3 treated seeds

of Capsicum annum. Gudhate (2008) concluded that starch and protein content was

significantly enhanced due to GA3 and IAA in seedlings of Androgaphis paniculata.

Acharya et al. (1990) reported the effect of GA3 on rice seedlings and found

increased growth of seedlings and enhanced hydrolysis of starch. Neelu et al. (2011)

reported that GA3 significantly increased total sugars in seedlings of Vigna radiata.

Effect of micronutrients

Micronutrients play vital role in plant metabolism and influence their growth,

yield and its quality. Shitole (2012) reported enhanced reducing sugars, total sugars

and starch along with proteins in seedlings of senna treated with different

micronutrients like Cu, Fe and Zn. Manivasagaperumal et al. (2011) recorded the

effect of zinc on the total sugars, starch and proteins in seedling of Cyamopsis

tetragonoloba and found that low level of zinc concentration caused increase,

whereas the higher concentrations induced decrease. Aly and El-Naggar (2009) also

observed increase in carbohydrate contents due to Cu, Zn and Fe on seedlings of

Dianthus. Similar trend was recorded by El-Khayat (1999), Gomaa (2001) and Samia

et al. (2009) in Antholyza aethiopica and Tritonia crocata due to application of Zn.

Shrinath et al. (2007) reported that application of Zn caused significant

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17

increase in reducing and non reducing sugars in onion bulbs. Bagali et al. (1992) also

reported that application of Zn caused increase in non-reducing sugars in guava.

Joshi et al. (2007) reported higher content of starch in Withania somnifera due to the

treatment of Zn. Verma et al. (2011) in Vigna radiata and Puneeth Raj et al. (2012)

in Phaseolus vulgaris. They also recorded enhanced protein content due to

application of Zn, Fe, Mn and Cu.

Effect of salt stress

Salinity stress usually induces accumulation of soluble sugars as it affords

tolerance. Rohamare et al. (2014) reported increased reducing and total sugars along

with reduction in protein and starch content in Ajowan seedlings treated with NaCl.

Prado et al. (2000) reported increase in soluble sugars of Chenopodium quinoa. Same

trend was noted by Besma and Mounir (2010) in Abelmoschus esculentus under salt

stress. They also reported decrease in starch content at higher concentration of NaCl.

Decrease in carbohydrate and protein content due to higher concentrations of NaCl

was reported in Pisum sativum (Dhingra and Sharma 1992), chickpea (Dhingra and

Verghese 1994, Dhingra et al. 1996) and Brassica (Sureena et al. 2001). Similarly, in

Sorghum, the NaCl stress caused decrease in starch and increase in sugars (Thakur

and Sharma 2005). Yan Li (2009) noted that soluble sugars were increased under

NaCl stress in Soja sieb (wild soybean). Progressive decrease in protein content with

increasing salinity was reported in Vicia faba (Gabbalah and Gomma 2004) and

mungbean (Kanta 2004).

Effect of water stress

The conditions of water stress cause highly adverse effect on plant

metabolism. It is well known that reducing and non-reducing sugars contribute to

turgor maintenance in plants subjected to water stress. Mohammadkhani and Heidari

(2008) noted that increasing concentration of PEG 6000 caused increase in soluble

sugars with decrease in starch in maize seedlings. Starch depletion in grapevine

leaves was noted by Patakas and Noitsakis (2001) in response to drought stress.

Enhanced soluble sugars due to water stress were reported by Al-Hakimi et al. (1995)

and Kameli and Losel (1993) in wheat.

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18

Deshmukh et al. (2001) reported enhanced reducing sugars with subsequent

decrease in total sugars, non-reducing sugars and proteins in Sorghum at seedling

stage subjected to water stress by PEG 6000. Kumar et al. (2011) also reported

enhanced protein content due to PEG 6000 in pigeon pea. Kaur et al. (2000) reported

that PEG 6000 induced water stress had caused significant increase in reducing

sugars and enhancement in carbohydrates in chickpea seedlings.

2.3. Antioxidants and antioxidant enzymes:

Effect of PGRs

Any biotic or abiotic stress is likely to generate free radicals in plants which

are scavanged by both antioxidants and antioxidant enzymes and protect the plants

under stress conditions. Narra et al. (2010) noted that GA3 showed stimulatory effect

on total amino acids in Ajowan seedlings. Increased proline content in dill due to the

treatments of GA3 and IAA was reported by Patel and Vyas (2007). Reda et al.

(2005) also noted enhancement in phenols due to GA3 in Thymus. Mahmood and

Saxena (1986) recorded increase in phenols due to the application of growth

regulators like IAA, IBA and IPA in tomato. Studies of Rychter and Lewak (1971)

confirmed the stimulation of isoperoxidases due to GA3. Gubler and Ashford (1983)

also claimed that GA3 was respomsible to increase peroxidase activity. Harmey and

Murray (1968) reported stimulation of POX activity due to GA3. The PPO activity of

Catharanthus roseus was increased significantly under GA3 treatment (Jaleel et al.

2010). GA3 caused a direct stimulatory effect on PPO activity in barley and wheat

(Jennings and Duffus 1977). Dendsay and Sachar (1982) reported increasing POX

activity in mung bean due to GA3. Kapchina and Foudouli (1991) noted that GA3,

IAA and BA caused increase in peroxidase activity, which helped for eliminating the

adverse effect of salt stress on pea seedlings. Senthil et al. (2005) reported that the

treatment of GA3 and IAA caused stimulation in POX activity of groundnut.

Effect of micronutrients

The higher concentration of various micronutrients cause increase in

antioxidants and stimulate the activities of antioxidant enzymes. Manivasagaperumal

et al. (2011) recorded the effect of zinc on proline contents of Cyamopsis

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19

tetragonoloba and noted maximum increase. Shitole (2012) also reported enhanced

proline, phenol and GB in seedlings of seena treated with micronutrients like Fe, Cu

and Zn. Enhanced activity of POX due to micronutrients was noted by Verma et al.

(2011) in seedlings of Vigna radiata. Similarly, Zhang et al. (2007) reported that

POD and SOD activity was stimulated under the influence of ZnSO4 in Perilla

frutescens. Shitole (2012) also recorded stimulated activities of POX, SOD and PPO

in senna seedlings treated with micronutrients. They are involved in several

physiological and biochemical processes, such as cell growth and expansion (Fang

and Kao 2000), auxin catabolism (Passardi et al. 2004), lignification (Brownleader et

al. 2000) etc.

Effect of salt stress

The abiotic stress like salinity induce increase in several antioxidant and

stimulate the activities of antioxidant enzymes that scavange the free radicals.

Rohamare et al. (2014) reported significant increase in the antioxidant contents of

Ajowan due to salinity stress. Agarwal and Pandey (2004) and Shitole (2012)

observed that NaCl treatments caused significant enhancement in proline contents of

senna seedlings. Similar results for enhanced proline and GB were reported by Jaleel

et al. (2007a,b) in Catharanthus roseus and by Ebru et al. (2004) in Lens culinaris.

Supporting findings were reported in Medicago sativa, soybean and pea (Tramontano

and Jouve 1997) and sugarbeet (Ghoulam 2002). With increasing concentration of

NaCl and duration, proline contents were increased in wheat (Sangeeta et al. 2007),

Ceriops roxburghiana (Rajesh et al. 1999), rice (Hsu et al. 2003) and Phaseolus

mungo (Dash and Panda 2001).

Khan et al. (1999 and 2000) have reported increased glycine betaine content

in shoots and roots of HaloxyIon recurvum and Halopyrum mucronatum under salt

stress. Saneoka et al. (1999), Muthukumarasamy et al. (2000) and Wang and Nil

(2000) reported enhanced glycine betaine content in wheat, Raphanus sativus,

Amaranthus tricolour respectively under salt stress. Enhancement in phenolics was

also reported by Besma and Mounir (2010) in Abelmoschus esculentus. They further

reported that phenols increased with increasing NaCl concentrations.

Agarwal and Pandey (2004) and Dash and Panda (2001) noted stimulated

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20

activities of SOD, POX and PPO under the influence of NaCl stress in Cassia

angustifolia and Phaeseolus mungo. Ezatollah et al. (2007) and Sangeeta et al. (2007)

also reported stimulation in SOD activity with increasing salt stress in wheat

seedlings. Stimulation in the activity of different antioxidant enzymes was reported

under salinity in Amaranthus viridus (Bhattacharjee and Mukherjee 2006), wheat

seedlings (Meneguzzo et al. 1999, Sairam and Srivastava 2002) and pea (Hernandez

et al. 1999). Ghoulam and Fares (2001), Yan Li (2009) and Demir and Kocaliskan

(2001) noted stimulation in POX and PPO activities due to salt stress in sugar beet,

Soja sieb and bean.

Effect of water stress

Water stress is highly influencive to enhance the antioxidants and stimulate

antioxidant enzyme acitivities. Kumar et al. (2011) noted enhanced proline content in

pigeon pea subjected to water stress by PEG 6000. Enhanced proline (upto 10 folds)

in tomato subjected to PEG 6000 was noted by Zgalli et al. (2005). Similarly,

accumulation of proline under drought stress condition was reported in Abelmoschus

esculentus (Sankar et al. 2007a). Fumis et al. (1993) observed higher proline and

amino acids in wheat seedlings subjected to water deficit. Chen and Kao (1993) also

detected proline accumulation in rice leaves subjected to water stress. Hanson (1980)

recorded proline accumulation in rice, sorghum, maize, wheat and barley under water

stress. Deshmukh et al. (2001) also noted enhanced proline and phenol contents due

to water stress (PEG 6000) in sorghum at seedling stage. Mohammadkhani and

Heidari (2008) observed the same trend in maize seedlings subjected to drought

stress.

Kumar et al. (2011), Pan et al. (2006), Lai et al. (2007) and Fazeli et al.

(2007) reported stimulated activities of SOD and POD in various plants subjected to

water stress by PEG 6000. Aktas et al. (2007) also reported increased activities of

SOD, PPO and POX during drought stress in Laurus nobilis seedlings. Pratap and

Sharma (2010) also reported similar trend in different plants under osmotic stress.

The stimulation in antioxidant enzymes under drought was noted by Tanaka et al.

(1990), Moran et al. (1994), Zhang and Kirkham (1996) and Sgherri et al. (2000) in

different crops.

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21

2.4. Physiology of field grown plants:

Effect of PGRs

The application of various PGRs has positive as well as negative impact on

physiology of treated plants depending on concentrations used. Rohamare et al.

(2013a) claimed improvement in photosynthetic pigments (chl a, b and total chl) in

Ajowan due to foliar application of GA3 and NAA. Similarly, Aftab et al. (2010)

noted significant enhancement in total chlorophyll contents, net photosynthetic rate,

stomatal conductance, internal CO2 and activity of enzyme NR in Artemisia annua

treated with GA3. Kanjilal and Singh (1998) also studied the effect of IAA and NAA

on Chamomilla recutita and reported enhanced chlorophyll content. Misra (1995)

noted enhanced photosynthetic pigments (chl a and chl b) due to application of GA3

to patchouli. Hassanpouraghdam et al. (2011) reported that foliar application of GA3

caused enhanced chlorophyll content in Lavendula officinalis.

Similarly, enhanced chlorophyll content and NR activity due to application of

PGRs in Mentha spicata was reported by Singh and Misra (2001). Similar was the

trend in jasmine (Gowda and Gowda 1990). Srivastava and Sharma (1991) noted

increased net photosynthetic rate and chlorophyll content in Mentha due to PGRs.

Enhanced chlorophyll content due to application of NAA and GA3 was noted by

Verma and Sen (2008) in coriander. They further noted that GA3 improved vegetative

growth and NAA improved the quality of herb.

The enhancement in photosynthetic pigments due to the application of

different concentrations of NAA, GA3 and KIN in many medicinal plants like

Pogostemon cablin (Bate et al. 2003), Enicostemma littorale (Gajaria 1998),

Anthurium Spp (Beena and Mercy 2003), Cymbopogon winterianus (Mohanty and

Kar 2003), coriander (Meena et al. 2006) and black cumin (Shah et al. 2006) is well

documented.

Effect of micronutrients

Foliar applications of micronutrients cause improvement in morpho-

physiological attributes in treated plants. Rohamare et al. (2013b) reported that foliar

application of micronutrients was responsible for significant increase in chlorophyll

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22

contents (chl a, b and total chlorophyll) of Ajowan. Abd El-Wahab and Mohamed

(2007) also reported enhanced photosynthetic pigments due to application of Mg to

Ajowan. Similar trend was noted due to the application of Zn by Nahed et al. (2007)

in Salvia. Khalifa et al. (2011) and Aly and El-Naggar (2009) reported increase in

photosynthetic pigments due to the foliar application of micronutrients in Iris and

Dianthus respectively. Similarly, Manivasagaperumal et al. (2011), Pandey and

Gautam (2009) and Ismail and Azooz (2005) reported that application of Zn showed

increase in chlorophylls in Cyamopsis, Lens, Carthamus and Helianthus. The

enhancement in chlorophylls due to micronutrients like Fe, Zn and Mn was reported

by Misra et al. (2011, 2012) in Khus-khus, Srivastava et al. (2006) in turmeric,

Youssef et al. (2004a) in Ocimum sanctum.

Effect of salt stress

There is strong evidence that salt stress affects biosynthesis of chlorophylls

and carotenoids (Stepien and Klobus 2006). Jelali et al. (2011) noted reduction in

chlorophylls in marjoram subjected to salt stress. Mehr (2013) reported reduction in

chlorophyll a, b and total chlorophyll due to salt stress in dill. El-Danasoury et al.

(2010) also recorded reduced chlorophylls due to NaCl in spearmint. Increased

salinity levels caused reduction in chlorophyll a, b and total chlorophylls of Centaury

(Siler et al. 2007), Teucrium polium, Thymus vulgaris, Zataria multiflora, and

Ziziphora clinopodioides (Koocheki et al. 2008), Satureja hortensis (Najafi et al

2010), Withania somnifera (Jaleel et al. 2008a) and Rosmarinus officinalis

(Kiarostami et al. 2010). Similarly, Azooz et al. (2004), Dagar et al. (2004), Mannan

et al. (2009), Agastian et al. (2000) and Parida et al. (2002) reported that salinity was

responsible to reduce chlorophylls in Sorghum, Salvadora persica, soybean, mulberry

and Bruguiera parviflora respectively. It was attributed both to the increased

degradation and the inhibited synthesis of chlorophyll pigments (Garsia-Sanchez et

al. 2002), or due to the disturbance of ions involved in chloroplast formation and

protein synthesis and/or plastide breakdown (Abd El-Wahab 2006).

Effect of water stress

The water or drought stress usually affects the photosynthetic pigments.

Azhar et al. (2011) reported that water stress caused significant reduction in

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23

transpiration rate and stomatal conductance, but internal CO2 concentration was

increased in Ajowan. They further reported that photosynthetic rate showed non-

significant reduction at 80% field capacity but it was highly increased at 60% field

capacity. A similar reduction in transpiration rate with increased drought stress was

also reported by Saefi et al. (2006) in Olea europaea. Kumar et al. (2011) recorded

reduced RWC, chlorophyll a, b and total chlorophyll in pigeon pea as a result of

water stress. Similarly, decrease in RWC and chlorophylls due to water stress was

reported in rice by Hsu and Kao (2003), tomato (Zgalli et al. 2005) and sesame

(Hassanzadeh et al. 2009). Many researchers like El-Tayeb (2006), Barathi et al.

(2001), Fu and Huang (2001), Egert and Tevini (2002) and Thalooth et al. (2006)

reported reduction in photosynthetic pigments in Vicia faba, mulberry, grasses,

Allium schoenopasum and Vigna radiata due to water stress.

Reduced photosynthesis in terms of Pn, Gs and/or int CO2 and Fv/Fm under

water stress was reported by Slama et al. (2007) in Sesuvium portulacastrum, Xing

and Wu (2012) in Pharbitis nil, Lonicera japonica and Parthenocissus tricuspidata.

Drought stress was found to decrease the RWC of Citrus (Sanchez-Blanco et al.

2002), Festuca novae-zelandia (Abernethy et al. 1998), coriander (Farahani et al.

2007, 2008), marjoram (Baatour et al. 2010) and Artemisia (Guenaoui et al. 2008).

2.5. Biochemical constituents:

Effect of PGRs

Various types of PGRs induce biochemical changes in treated plants.

Rohamare et al. (2013a) reported enhanced total carbohydrates in Ajowan when

treated with NAA and GA3. Mostafa et al. (2005) noticed enhanced soluble sugars,

polysaccharides, total carbohydrates and proteins in Hibiscus subdariffa due to GA3.

The positive effect of GA3 on total sugars, reducing sugars and proteins was reported

by Gudhate and Dhumal (2007) in kalmegh. Similar findings were reported by

Guinchard et al. (1997), Todic et al. (2005), Muthukumar et al. (2005) and Sivakumar

et al. (2001) in different plants like white clover, grapes, babycorn and pearl millet.

The highest level of total sugars was recorded in GA3 treated rice and Pisum sativum

was reported by Gogoi and Baruah (2000) and Prasad and Prasad (1998). The work

of Gadil et al. (2006) and Sritharan et al. (2005) supported the above findings.

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Rai et al. (2002) had also recorded increase in sugars due to IAA, NAA and

GA3 in different crop plants. Many researchers recorded significant increase in

reducing sugars due to the treatments of GA3, in dill, banana, Spinacia, Capsicum,

and baby corn (Patel 2006, Anitha et al. 2005, Ratnakar and Rai 2011, Khinder 1999,

Vani et al. 2004). Dhar and Majumdar (2003) noted that the treatments of NAA were

responsible to cause the increase in carbohydrates in Capsicum annum. Similarly,

Shitole (2012) noted enhanced reducing sugars, total sugars, starch and proteins in

Senna treated with different PGRs. Joshi et al. (2007) noted that PGRs in

combination with the micronutrients in Withania somnifera caused higher increase in

starch. The enhancement in starch and total sugars of Podophyllum due to GA3 was

observed by Kushwaha et al. (2007). Borse (2004) have noted significant

enhancement in proteins due to IAA as well as NAA in Solanum khasianum.

The positive influence of NAA and IAA on protein was reported by

Sivakumar et al. (2002), Dey and Srivastava (2003) and Purbey and Sen (2005) in

pearl millet, Vigna radiata and fenugreek. Song-ZhiRong (2001) and Ratnakar and

Rai (2011) also reported increased proteins in Capsicum and spinach respectively due

to GA3. Increase in protein content due to PGRs treatment was recorded in medicinal

and aromatic plants like Pogostemon (Bate et al. 2003), Dolichandron, Eugenia and

Terminalia (Naidu and Swamy 1995), Ocimum sanctum (Dayal 1996), Anthurium

(Beena and Mercy 2003), black cumin (Shah et al. 2007a) and Chamomilla recutita

(Kanjilal and Singh 1998).

Effect of micronutrients

Applications of micronutrients induce positive changes in biochemical

constituents of treated plants. Rohamare et al. (2013b) reported enhanced proteins

and total carbohydrates in Ajowan due to foliar applications of micronutrients. Abd

El-Wahab and Mohamad (2008) reported that foliar application of Fe, Zn and Mn had

caused significant improvement in total carbohydrates of Ajowan. Khalid (2012) also

noted enhanced total carbohydrates, sugars and proteins due to micronutrients in

anise, coriander and sweet fennel. Hendawy and Khalid (2005) noted enhanced total

carbohydrates in Salvia officinalis due to Zn treatment. Aziz et al. (2010) reported

enhanced soluble sugars in Cymbopogon citratus due to foliar spray with Zn and Fe.

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Similar observations for carbohydrates and starch content in Withania somnifera was

noted by Joshi et al. (2007).

Pandey and Gautam (2009), Shrinath et al. (2007), Leithy (1998) and Bagali

et al. (1992) reported increase in total sugars, reducing and non-reducing sugars in

Lens culinaris, onion, Nigella sativa and guava due to application of Zn. El-Naggar

(2009) studied the effect of foliar application of Cu, Zn and Fe and noted increase in

carbohydrates in Dianthus caryophyllus. Same trend was observed by Khalifa et al.

(2011) in Iris. Significant increase in proteins due to application of micronutrients

like Fe, Mn and Zn was reported by many researchers like Tarraf et al. (1999) in

lemon grass, Karima and El-Din (2005) in fenugreek, Bedour et al. (1994) in Ocimum

basilicum, Youssef et al. (2004a) in O. sanctum and Ravi et al. (2008) in Carthamus

tinctorius.

Effect of salt stress

The abiotic stress like salinity had profound effect on metabolism of plants

leading to induce changes in various biochemical constituents. Mehr (2013) noted

significant increase in total soluble carbohydrates and proteins in dill due to salt

stress. Hendawy and Khalid (2005) noted enhanced total carbohydrate content in

Salvia officinalis due to salinity stess. In fennel, total carbohydrates were adversely

affected due to salinity (Abd El-Wahab 2006). Garg et al. (2002) reported that starch

contents were decreased under salt stress during vegetative stage but at flowering

stage there was accumulation of starch in Cuminum cyminum.Significant increase in

both reducing and non-reducing sugars under salt stress was reported in Bruguiera

parviflora by Parida et al. (2002). Salt stress had induced increase in reducing sugars

in wheat (Kerepesi and Galiba 2000, Khatkar and Kuhad 2000). Jose et al. (2003)

noted that salt stress was responsible to induce significant increase in total sugars in

cowpea. Similar trend was noted in Soja sieb (Yan Li 2009). Abd Monem and Sharaf

(2008) reported that soluble carbohydrates in both shoots and roots were increased at

lower level of NaCl in Lentil.

Reduction in protein due to NaCl was observed in Catharanthus roseus

(Osman et al. 2007), chamomile and sweet marjoram (Ali et al. 2007), Achillea

fragratissima (Abd El-Azim and Ahmed 2009). Stimulation of protein synthesis

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26

under salinity stress was noted by Singh et al. (1987), which might be helping in

osmotic adjustments. Decrease in proteins under NaCl treatments was reported in

Ammi (Hala and Mona 2008). Similarly, Gururaja et al. (2001) noted decreased

proteins with increasing salt concentrations in Salvadora persica and mungbean.

Wang and Nil (2000), Muthukumarasamy et al. (2000), Parida et al. (2002) and Garg

et al. (2002) reported significant decrease in proteins under salt stress in various

crops.

Effect of water stress

The moisture stress had significant impact on various metabolic reactions in

stressed plants. Ghasemzadeh et al. (2010) noted the accumulation of carbohydrates

in medicinal plants. Guo et al. (2011) observed increased sucrose contents in

broccoli. Mohsenzadeh et al. (2006) in Aeluropus lagopoides and Guenaoui et al.

(2008) in Artemisia noticed accumulation of soluble sugars as a result of water stress.

Similar trend was noted by El-Tayeb (2006) in Vicia faba and Akinci and Losel

(2010) in cucumber.

2.6. Antioxidants and antioxidant enzymes

Effect of PGRs

Many researchers have noted strong correlation between PGRs and

antioxidants as well as antioxidant enzymes in medicinal and aromatic plants (Jaleel

et al. 2007a). Jaleel and Mohammed (2010) reported increase in proline and glycine

betaine in Catharanthus roseus due to GA3 treatments. As suggested by Maiti et al.

(2000) the increased proline accumulation might be helping to tolerate abiotic stress

as it avoids the cellular damage by ROS. Foliar applications of GA3 in Catharanthus

rosens showed significant stimulation in POX, SOD and PPO activity over control

(Jaleel et al. 2007a). The stimulation in POX and PPO activity was also reported in

IAA treated plants of Datura stramonium by Kady et al. (1980). Similarly Zaidi and

Singh (1993) had also noted stimulation in activity of peroxidase due to application

of GA3 and IAA in Glycine max. Reda et al. (2005) reported stimulation in PPO

activity in Thymus vulgaris due to GA3. Patel (2006) had also reported stimulated

activity of polyphenol oxidase in PGRs treated Anethum graveolens. Similarly, Singh

and Misra (2001) noted increased POX activity in Mentha due to PGRs.

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27

Effect of micronutrients

The higher as well as lower concentrations of micronutrients induce changes

in different types of antiodixants and antioxidant enzymes. Hendawy and Khalid

(2005) noted enhanced proline content in Salvia officinalis due to Zn treatment.

Manivasagaperumal et al. (2011) recorded the effect of zinc on the proline contents

of Cyamopsis tetragonoloba. It is well known that micronutrients induce

enhancements in antioxidants like phenols and glycine betaine of plants (Shaukat et

al. 1999). Aziz et al. (2010) also reported enhanced phenolic contents in

Cymbopogon citratus due to foliar spray of Zn and Fe.

Pathak et al. (2009) reported that Zn application caused maximum

enhancement in antioxidants enzymes like SOD and PPO activity in Vicia faba.

Pandey et al. (2002 a, b) in maize, Pathak et al. (2005) in Vigna radiata, Zhang et al.

(2007) in Perilla frutesceins reported similar results due to application of

micronutrients. Muriel et al. (2000) stated that SOD activity was increased with the

increased concentration of zinc. Muriel et al. (2000) recorded stimulation in SOD

activity with the treatments of Cu and Zn. Hema morab et al. (2003), reported the

effect of foliar applications of micronutrients like Fe, Cu and Zn on the activity of

different antioxidant enzymes in soybean and reported significant stimulation.

Effect of salt stress

Salt stress had great impact on stimulation of antioxidant enzymes and

antioxidants. Ashraf and Orooj (2006) reported enhanced proline content as a result

of salt stress in Ajowan. Mehr (2013) also noted significant increase in proline and

catalase (CAT) activity in dill due to NaCl stress. Baatour et al. (2012) recorded

enhanced phenolic contents in Origanum majorana under salinity. Jelali et al. (2011)

noted same trend for phenols under salt stress. The work of El-Danasoury et al.

(2010) regarding the proline and phenol supported the above trend for spearmint.

Accumulation of proline in response to salt stress is very common, which was

confirmed by Ali et al. (2007), Hendawy and Khalid (2005), Al-Amier and Craker

(2007), Zaki et al. (2009), Abd El-Azim and Ahmed (2009) and Najafi et al. (2010)

reported the influence of salt stress on antioxidant enzymes and recorded their

stimulation in various aromatic plants. Increase in proline due to salinity stress was

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28

well documented for several medicinal plants like black cumin (Hajar et al. 1996),

Coriander (Zidan and Elewa 1995), lentil (Abd El-Monem and Sharaf 2008),

Cuminum (Garg et al. 2002), Rosmarinus officinalis (Mannan et al. 2009) and

Kiarostami et al. (2010). Khan et al. (2000) reported that content of glycine betaine

was enhanced under the salt stress in Haloxylon recurvum. In Catharanthus roseus

and Matricaria chamomila increase in total free amino acids due to salt stress was

reported by Osman et al. (2007) and Cik et al. (2009).

Maximum stimulation in POX, SOD and PPO activity under NaCl stress in

Senna was reported by Agarwal and Pandey (2004) and Shitole (2012). The

enhancement in POX, SOD and PPO activities due to salt stress in Raphanus sativus

was recorded by Muthukumarasamy et al. (2000). The higher constitutive and/or

induced activity of SOD was reported in wild beet species (Bor et al. 2003).

Lekshmy et al. (2011b) reported that SOD activity was increased under NaCl stress

in wheat and Pisum sativum.

The medicinally important plant Acanthophyllum sordidum showed very high

increase in POX and PPO activity due to salinity (Meratan et al. 2008). Mondal et al.

(2004) and Meloni et al. (2003) recorded similar trend in salt affected plants. Greater

stimulation in SOD and POX activities was reported in shoots of soybean and rice

(Demiral and Turkan 2004, Ghorbanli et al. 2004) under salt stress. Enhanced PPO

activity by the treatments of NaCl in Catharanthus roseus was reported by Jaleel et

al. (2008b) and in Arachis hypogaea by Sankar et al. (2007b). On the contrary Jaleel

et al. (2008a) noted retardation in SOD activity in Withania somnifera under NaCl

stress.

Effect of water stress

Enhanced proline under water stress was reported by Farahani et al. (2008,

2009) in coriander, El-Tayeb (2006) in Vicia faba, Guenaoui et al. (2008) in

Artemisia, Safarnejad (2008) in alfalfa, Abernethy et al (1998) in Festuca novae-

zelandiae, Slama et al. (2007) in Sesuvium portulacastrum, Baher et al. (2002) in

Satureja hortensis and Sundaresan and Sudhakaran (2006) in Manihot esculenta.

Similarly, enhanced phenol content due to water stress was reported by Bettaieb et al.

(2011, 2012) in Cumin. Accumulation of total phenols has been reported by Gray et

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29

al. (2003) in Echinacea purpurea, De Abreu and Mazzafera (2005) in Hypericum

brasiliense, Azhar et al. (2011) in Ajowan and Chen et al. (2011) in Prunella vulgaris

subjected to drought stress. El-Tayeb (2006) reported stimulation in POX activity in

drought stressed Vicia faba. Similarly Acar et al. (2001) noted enhanced POX and

SOD activities in Hordeum vulgare under drought stress.

2.7: Mineral nutrition:

Effect of PGRs

The uptake of various essential nutrients in plants showed significant increase

due to PGRs treatments. Aftab et al. (2010) noted enhanced leaf N, P and K contents

in Artemisia annua treated with GA3. Hassanpouraghdam et al. (2011) reported that

foliar application of GA3 caused enhanced N and P contents in Lavendula officinalis.

Alam et al. (2012) reported that the leaf N, P and K content was highest in GA3

followed by NAA and KIN treatments in C. roseus. Ahmed et al. (2000) recorded

enhanced N, P, K, Fe, Mn and Zn content due to foliar application of Kinetin in

Rocket plants. Levent (2008) reported that GA3 treatments had enhanced the N, P,

Ca, Mg, Mn and Zn contents of maize. Similarly Khan et al. (1996) also reported that

accumulation of N in mustard, when treated with GA3. Foliar application of GA3 had

enhanced K and Ca uptake in maize and cotton (Ashraf et al. 2002b). Improved

macro-element content due to application of PGRs was also reported by many

researchers like Rawia et al. (2010) in tuberose, Al-Humaid (2003) in rose and Raifa

et al. (2005) in Hibiscus Sabdariffa and Ashraf et al. (2002a) in wheat.

Effect of micronutrients

Foliar application of various micronutrients caused increase in uptake of

different essential nutrients required by plants. Rohamare et al. (2013b) reported

increased N, P and K content in Ajowan treated with mutli-micronutrient fertilizers.

Abd El-Wahab and Mohamed (2007 and 2008) noted that foliar application of

micronutrients in Ajowan had caused significant improvement in N, P, K, Fe, Zn, Mn

and Mg. Khalid (2012) recorded significant enhancement in N, P and K due to foliar

application of micronutrients in Pimpinella anisum, Coriandrum sativum and

Foeniculum vulgare. Hendawy and Khaild (2005) noted enhanced Zn content due to

micronutrient application. Khalifa et al. (2011) reported that foliar spray of Zn

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30

significantly increased P and K content of Iris. Similarly, Erdal et al. (2004) reported

positive effect of foliar applications of Fe in Fragaria vesca on P, K and Mg

contents. Misra et al. (2012) reported that supply of increased Fe, Mn and Zn in khus-

khus plant due to micronutrient applications. Similar results were recorded by Yadav

et al. (2002) and Samia et al. (2009), Nahed et al. (2007), Rawia et al. (2010) in

different plant species due to the application of micronutrients.

Foliar spraying of onion plants with Fe, Mn and Zn resulted into highest N

content (Abd El-Samad et al. 2011). Zeidan et al. (2010) reported that foliar

application of Fe and Zn increased N, P, K, Zn and Mn contents in wheat. Foliar

application of mixture of various micro elements caused increased in the contents of

N, P, K, Cu and Zn content in Dianthus (Aly and El-Naggar 2009). Similar results

were obtained by Sharaf and El-Naggar (2003) in carnation, Mahgoub et al. (2006)

for Iris, El-Tohamy et al. (2007) in snap beans. Odiaka and Obasi (2003) reported

that foliar application of Cu and Zn significantly improved Cu and Zn content in

tomato. Aly and El-Naggar (2009) reported that foliar application of micronutrient

fertilizers showed enhancement in Cu and Zn. Said-Al Ahl and Omer (2009) noted

increased Fe and Zn content in coriander due to foliar micronutrient sprays. The work

of Aziz and El-Sherbeny (2004) in Sideritis montana, Said-Al Ahl (2005) in Anethum

graveolens indicated similar trend. Derakhshani et al. (2011) reported that Zinc

application has increased the Mn and Zn uptake of Chrysanthemum balsamita.

Effect of salt stress

Many researchers like Ashraf and Orooj (2006) reported reduced K and Ca

contents in Ajowan treated with NaCl stress. Harrathi et al. (2012) and (2013) also

noted that NaCl caused increased concentrations of Na but reduced K contents in

Carthamum tinctorius. Hendawy and Khaild (2005) reported reduced Zn content

under salt stress in sage. The reduction in macro-element contents due to salinity

stress was reported by Abd El-Hady (2007). Reduced N content as a result of salt

stress has been previously reported in medicinal and aromatic plants like marjoram

(Baatour et al. 2010) and Melissa officinalis (Khalid and Cai 2011). Similarly,

Othman et al. (2006) showed that K concentration in barley was reduced with

increasing salinity. Decreased N, P, K and Mn content due to salt stress was reported

by many workers such as Jaleel et al. (2008b) in Catharanthus roseus and Levent et

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31

al. (2008) in maize. Inhibition of Mn due to salinity stress was reported by Parida et

al. (2004) in Bruguiera parviflora. Alpaslan and Gunes (2001) stated that salinity

reduces nutrient uptake and accumulation as well as partitioning within the plant.

Increased NaCl concentration has been reported to induce increases in Na and Cl as

well as decreases in N, P, Ca, K and Mg level in fennel (Abd El-Wahab 2006),

peppermint and lemon (Tabatabaie and Nazari 2007), Matricaria recutita (Baghalian

et al. 2008), Achillea fragratissima (Abd El-Azim and Ahmed 2009). Levent (2008)

reported that N, P, K, Ca and Mg contents were reduced under salinity in maize.

Similarly, Lekshmy et al. (2011b) noted that NaCl stress caused reduction in Fe, Mn,

Mg and Zn in wheat. Othman et al. (2006) reported that K content was reduced with

increasing salinity in pigeon pea.

Effect of water stress

The work of Rahdari and Hoseini (2012) indicated that water stress had

caused decrease in P concentrations in Portulaca oleraceae. Niakan and Ghorbanli

(2007), Abdalla and El-Khoshiban (2007) and Singh and Singh (2004) noted

decreased K content in soybean and wheat subjected to water stress. Drought stress

caused decrease in Ca and/or Mg in various plants and it was supported by Akhondi

et al. (2006) in Medicago sativa and Kirnak et al. (2003) in bell pepper. Pirzad et al.

(2011) noted reduction in the contents of Fe and Zn in Matricaria chamomilla treated

with different irrigation regimes. Hu et al. (2007) noted reduced Ca, Mg and Mn

levels in maize due to drought stress. Dogan and Akinci (2011), Singh and Singh

(2004) noted that availability of varius nutrients to plants was decreased with

increasing water stress.

2.8. Growth and yield attributes:

Effect of PGRs

Phytohormones are known to influence the growth and yield attributes in

treated plants. Rohamare et al. (2013a) reported that foliar application of PGRs like

NAA and GA3 had caused significant improvement in growth parameters like plant

height, number of primary branches and leaf area in Ajowan. They also noted

improvement in yield attributes like number of umbels, seed yield and dry biomass.

Similarly, Shetty and Rana (2012) also reported that GA3 application showed

significant improvement in number of umbellets/umbel, number of umbels/plant,

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32

number of seeds/umbel, number of seeds/umbellet, seed yield, biological yield and

1000 seed weight of Ajowan. Same trend was recorded by Krishnamoorthy and

Madalageri (2000) in Ajowan treated with GA3. They recorded increase in plant

height, number of secondary and tertiary branches.

Foliar application of GA3 at vegetative and flowering stage to Ocimum

sanctum enhanced the biomass (Dayal et al. 1998). Yaseen and Tajuddin (1998)

reported the increase in growth and dry yield of Artemisia annua due to application

of IAA. Similarly, Fathonah and Sugiyarto (2009) reported that foliar application of

IAA and GA3 increased plant height, number of leaves, leaf area, plant fresh and dry

weight in Pimpinella alpine.

Verma and Sen (2008) reported that PGRs like IAA, NAA and GA3 caused

significant enhancement in plant height, number of leaves and fresh weight of leaves

in coriander. Abbas (2013) reported that GA3 and NAA caused significant

enhancement in growth attributes like plant height, number of leaves and branches

and dry weights in Anethum graveolens. Aftab et al. (2010) reported the application

of GA3 to plants of Artemisia annua caused significant enhancement in growth

attributes like shoot and root length, fresh and dry weight. Hassanpouraghdam et al.

(2011) reported that foliar application of GA3 caused enhanced growth and yield

attributes in Lavendula officinalis.

Mohanty and Kar (2003) and Singh and Govind (2000) reported that foliar

application of GA3 caused significant increase in the growth parameters of

Cymbopogon and citrus. Similar results for enhanced plant height and number of

branches/plant were also noted by Shah et al. (2006) in black cumin, Bhat et al.

(2011) in Iberis umbellate, Singh and Misra (2001) in Mentha spicata, Bate et al.

(2003) in Pogostemon cablin, Singh et al. (2008) in Salvia and Godha et al. (2000) in

Chrysanthemum. Singh (2003) reported that GA3 had significantly increased fresh

weight of leaf, diameter of flower, fresh and dry weight, leaf area index, number and

weight of flowers per plant in Calendula officinalis.

Effect of micronutrients

Rohamare et al. (2013b) reported increase in plant height, number of branches

and dry biomass as well as yield attributes in Ajowan due to micronutrient

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treatments. Abd El-Wahab and Mohamed (2007, 2008) reported that application of

Mg, Fe, Mn and Zn to Ajowan caused increase in plant height, number of branches,

fresh and dry weight, number of umbels and seed yield of Ajowan. Abbas (2013) in a

study on dill noted that micronutrient sprays of Fe, Mn, Zn, Cu and B caused

significant improvements in all the growth attributes. Similarly, El-Sawi and

Mohamed (2002) also noted that application of Zn and Mn had significantly

increased plant height, number of branches, dry weight and seed yield in cumin.

Hendawy and Khalid (2005) noted that application of Zn caused enhancement in

plant height, number of branches, herb fresh and dry weight in sage.

Khalid (2012, 1996), Maurya (1990), Khattab and Omer (1999), Chaudhary

and Jat (2007) and Kalidasu et al. (2008) reported that foliar application of

micronutrients caused significant improvement growth attributes like plant height,

number of branches and leaves/plant, herb fresh and dry weights along with the yield

attributes like number of umbels, number of seed per umbel and seed yield as well as

essential oil content in anise, coriander, and sweet fennel due to the applications of

Zn, Fe, Cu and Mn. Application of zinc as foliar spray on fenugreek had showed a

favourable effect on yield and yield attributes (Meena and Singh 2007). The influence

of foliar spray with Zn and Fe in Cymbopogon citratus has been studied by Aziz et al.

(2010) and reported increased the fresh and dry weights. Positive effect of Zn supply

on growth and yield was recored by Grejtovsky et al. (2006) and Said-Al Ahl and

Omer (2009). Similar was the finding of Nahed et al. (2007) and Tarraf et al. (1994)

in sage and Rosmarinus officinalis. Further, Jirali (2001) noticed that the foliar

application of FeSO4 and ZnSO4 caused increase in leaf length, number of leaves and

plant height in turmeric.

Effect of salt stress

Adverse impact of salt stress on growth and yield attributes is well

documented. Ashraf and Orooj (2006) reported that NaCl stress had caused

significant reduction in fresh and dry weights of shoots and roots as well as yield of

Ajowan. Nabizadeh et al. (2003) showed that salinity has a meaningful negative

effect on yield and yield components of cumin. Khorasaninejad et al. (2011) noted

that salt stress caused reduction in growth parameters like stem and root length, fresh

and dry weight, total biomass of Mentha piperita. Aziz et al. (2008) noted reduced

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34

growth attributes like plant height, fresh and dry weights in peppermint, pennyroyal

and applemint due to NaCl stress. Razmjoo et al. (2008) recorded reduction in plant

height, number of branches and flowers, fresh and dry flower weight of Matricaria

chamomile due to NaCl stress. Ozturk et al. (2004) also showed significant reduction

in growth attributes such as plant height, number of branches, fresh and dry biomass

of Melissa officinalis under salt stress.

Harrathi et al. (2012, 2013) recorded that application of NaCl reduced the

fresh and dry weights of shoots and leaves, leaf area, number of leaves/plant and

shoot dry matter of Carthamum tinctorius. Similarly, Hendawy and Khaild (2005)

and Ben Taarit et al. (2009) reported that salinity significantly reduced the vegetative

growth attributes in sage. Jelali et al. (2011) reported reduction in plant height, fresh

and dry weight in Origanum majorana treated with NaCl. Ghassemi-Golezani et al.

(2011) reported that the plants of dill treated with NaCl showed reduction in dry

matter. El-Danasoury et al. (2010) noted that NaCl stress caused significant reduction

in growth and yield attributes of spearmint. Several investigators reported reduction

in growth and yield of aromatic and essential oil yielding plants like Foeniculum

vulgare (Abd El-Wahab 2006), Majorana hortensis (Shalan et al. 2006), Matricaria

recutita (Baghalian et al. 2008), Thymus maroccanus (Belaqziz et al. 2009), geranium

(Leithy et al. 2009), Thymus vulgaris (Najafian et al. 2009), sweet fennel (Zaki et al.

2009), Mentha pulegium (Queslati et al. 2010) and Mentha piperita and Lipia

citriodora (Tabatabaie and Nazari 2007).

The growth parameters such as plant height, number of leaves per plant,

number of capitula per plant and its diameter was reduced with salinity in milk thistle

(Ghavami and Ramin 2008). Same trend was noted for Satureja hortensis in which

leaf area, leaf and stem fresh weight, as well as dry weight of leaves, stems and roots

was decreased under different levels of NaCl (Najafi et al. 2010). Increasing salinity

of irrigation water significantly decreased vegetative growth and green yield of sweet

fennel (Zaki et al. 2009). Alireza et al. (2008) studied the effects of salinity on

medicinal plants like Zataria multiflora, Ziziphora clinopodioides, Thymus vulgaris

and Teucrium polium and reported that NaCl stress was responsible to decrease the

fresh and dry weight of leaves. Salinity caused reduction in yield of mentha (Ozturk

1997), and Ocimum basilicum (Said-Al Ahl and Mahmoud et al. 2010). In fennel,

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35

cumin and Ammi majus increasing salt concentrations caused a significant reduction

in number of umbels, fruit yield/plant and weight of 1000 seeds (Abd El-Wahab

2006, Nabizadeh 2002, Ashraf et al. 2004 and Hala and Mona 2008).

Effect of water stress

It has adverse impact on growth as well as yield attributes. Moussavi-Nik et

al. (2011) reported that increasing irrigation interval had caused significant decrease

in yield contributing parameters such as umber of umbels/plant, 1000 seed weight

and seed yield in Ajowan. Similarly, Azhar et al. (2011) noted that plant height, fresh

and dry weight of plants was reduced significantly with increasing water stress levels

in Ajowan. Same trend was also noted by Ardakani et al. (2007) in Melissa

officinalis. Bettaieb et al. (2011) reported that Cuminum cyminum exposed to water

stress caused reduction in growth attributes like plant height, number of branches,

fresh and dry matter as well as yield components like number of umbels/plant and

umbellets per umbel. Ozturk et al. (2004) indicated that water stress was responsible

for reduction of growth and yield attributes in Melissa officinalis. Laribi et al. (2009)

noted that caraway (Carum carvi) under water deficit showed reduction in plant

height, number of branches, fresh and dry matter, seed yield and yield components

like number of umbels, umbellets, 1000 seed weight and seed yield/plant. Ghassemi-

Golezani et al. (2008) reported that plant height, fresh and dry biomass and seed yield

of dill (Anethum graveolens) decreased with decreasing water availability.

Ade-Ademilua et al. (2013) reported that water stress significantly reduced

plant height and total leaf area in Ocimum gratissimum. Razmjoo et al. (2008)

recorded same trend in chamomile. Farahani et al. (2009) reported that water deficit

significantly affected growth and yield parameters like plant height, leaf and stem

yield, biological yield and number of tillers in lemon balm. Dunford and Vazquez

(2005) reported that moisture stress caused reduction in plant height, fresh and dry

weights and total dry matter in Mexican oregano. Kochaki et al. (2006) showed that

by increasing irrigation intervals there was reduction in number of umbels and

subsidiary branches, number of umbellate/umbel and 1000-seeds weight in

Foeniculum vulgare. Farahani et al. (2008) found same trend in Coriandrum sativum

and recorded reduction in biological yield, EO yield, seed yield and EO percentage.

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36

2.9. Essential oil yield and its quality:

Effect of PGRs

The treatments of PGRs also influence the oil yield and its constituents along

with the growth parameters. Rohamare et al. (2013a) reported enhanced essential oil

content and yield/plant of Ajowan when treated with NAA and GA3. They further

noted increase in Thymol content of Ajowan oil. Aftab et al. (2010) reported

enhanced essential oil in Artemisia due to application of GA3. Hassanpouraghdam et

al. (2011) noted that foliar application of GA3 caused enhanced EO percent and EO

yield/plant in lavender. Enhanced essential oil percent and yield/plant due to

application of PGRs was reported in various aromatic plants like Chrysanthemum spp

(Kataria et al. 2003), Cymbopogon writeranus (Mohanty and Kar 2003), Coriandrum

sativum (Verma and Sen 2003) and Salvia sclarea (Singh et al. 2008).

In Salvia officinalis, application of GA3 application caused significant

reduction of β-Tujone and α-Humulene in relation to the control plants (Povh and

Ono 2007). Similarly, Stoeva and Iliev (1997) by applications of cytokinnins in mint

noted increased 1, 8-Cineole with decrease in Carvone content. Compositionally,

Isomenthone, Linalool, Citronellol, Geraniol, Citronellyl formate and Geranyl

formate levels were significantly higher in the oil from PGRs treated plants

(Bhattacharya and Rao 1996). Oil content and yield and Citronellol and Geranyl

acetate in the oil, were higher due to KIN (Farooqi et al. 1994). Essential oil content

and their constituents in Mentha piperita was changed in response to the application

of IAA and GA3 (Ibrahim et al. 1992). Positive increase in Pyrethrin content of

Chrysanthemum cinerariaefolium due to the application of different PGRs was

reported by Farooqi et al. (1999).

Effect of micronutrients

Significant improvement in essential oil and Thymol content was reported in

Ajowan seeds treated with micronutrient like Cu, Fe, Mn and Zn (Rohamare et al.

2013b). Abd El-Wahab and Mohamed (2007) reported enhancement in essential oil

percent and yield/plant of Ajowan treated with micronutrients. Abd El-Wahab and

Mohamed (2008) reported that foliar application of Fe, Zn and Mn had caused

significant improvement in EO percent and yield/plant of Ajowan. Yassen et al.

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37

(2010) observed that application of micronutrients like Fe, Cu, and Zn wassuitable

for improvement of biomass, yield. El-Sawi and Mohamed (2002) claimed that foliar

applications of micronutrients had caused improvement in EOyield/plant in cumin.

They further noted increase in main constituents of oil such as Cumin aldehyde, p-

Cymene, α-Terpineol, Thymol and Acoradiene. On the other hand, β-pinene content

was reduced. Nasiri et al. (2010) reported that foliar application of micronutrients like

Fe and Zn had significantly enhanced the essential oil percent and yield in Matricaria

chamomile. Khalid (1996 and 2012) reported that application of micronutrients Fe,

Zn and Mn had caused enhancement in essential oil content of anise, coriander and

sweet fennel. Hendawy and Khalid (2005) reported enhanced essential oil percent

and yield/plant due to Zn in sage plant. Gerjtovsky et al. (2006) reported that soil

based Zn application only slightly affected the essential oil constituents like

Chamazulene and (E)-β-Farnesene content of chamomile.

Fatima et al. (2007) reported that application of micronutrients had enhanced

the oil content of Cupressus. Khalifa et al. (2011) reported that Zn treatments had

significantly increased the oil content of iris. Hamza and Sadanandan (2005) reported

increase in piperine contents of black pepper due to the foliar applications of ZnSO4.

The stimulatory effects of iron and zinc on growth and secondary metabolites were

recorded by Said-Al Ahl and Mahmoud (2010) in Ocimum basilicum. Significant

increase in essential oil content in coriander was also reported by application of Fe,

Zn and Mn by Khattab and Omer (1999). The influence of foliar spray with Zn and

Fe in Cymbopogon citratus was studied by Aziz et al. (2010) and they reported that

micronutrients had increased the content of essential oil. Essential oil of Mentha

piperita was increased due to foliar application of Zn (Akhtar et al. 2009).

Effect of salt stress

Salt stress greatly influences the yield as well as its quality in various plants

including medicinal and aromatic plants. Ashraf and Orooj (2006) reported reduction

in essential oil yield/plant due to NaCl. Khorasaninejad et al. (2011) noted that NaCl

significantly decreased the essential oil percent and yield in peppermint. Neffati and

Marzouk (2008) reported that essential oil yield of coriander was increased

significantly due to low NaCl stress but it was decreased significantly under high

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38

salinity. They further noted that at low stress, (E)-2-decenal, (E)-2-dodecenal and

dodecanal contents increased. However, high salinity significantly decreased the

content of all above compounds. Belaqziz et al. (2009) claimed that increasing

salinity had no marked effect on essential oil content of Thymus maroccanus. Aziz et

al. (2008) noted reduced essential oil yield/plant in peppermint, pennyroyal and

applemint due to salt stress. They further noted increased Menthone percentage in

peppermint with decrease in other constituents. Razmjoo et al. (2008) and Ozturk et

al. (2004) reported that NaCl stress caused reduction in essential oil content of

Chamomila matricaria and Melissa officinalis.

Similar was the findings of Hendawy and Khaild (2005) reported that salinity

enhanced essential oil percent and reduced the EO yield/plant of sage. They further

noted that soil salinity had enhanced V Thujone and Camphore but induced decrease

in 1, 8 Cineol and $- Thujone. Jelali et al. (2011) noted that marjoram showed

increased EO yield under salt stress. Ben Taarit et al. (2009) noted that in sage plants

moderate to high concentrations of NaCl enhanced the essential oil production in

sage. Harrathi et al. (2012, 2013) reported that NaCl treatment in Carthamus

tinctorius resulted in enhanced EO yield at lower salt stress and showed decrease

under higher levels. Salt stress had significant effect on EO constituents of

Carthamus. Ghassemi-Golezani et al. (2011) noted that essential oil yield/plant in dill

was linearly increased with increasing salinity. El-Danasoury et al. (2010) observed

that salt stress caused significant reduction in essential oil yield of spearmint. But, the

essential oil percent was enhanced. Baatour et al (2010) reported similar results in

marjoram. The reduced EO content and yield/plant due to salt stress was also

reported by Eman et al. (2008).

Ashraf and Akhtar (2004) in Foeniculum vulgare reported decreased EO with

increase in NaCl concentration. Salt stress enhanced EO yield of M. pulegium and

increased the levels of Menthone, Pulegone, and Neomenthol (Karray-Bouraoui et al.

2009). The chemical composition of EO in Salvia sclarea was strongly affected by

NaCl treatments (Taarit et al. 2010). It was also demonstrated that essential oil yield

was significantly increased by soil salinity (Said-Al Ahl and Mahmoud

2010).Changes in essential oil constituents due to salinity were also reported in

literature by various researchers. Salinity decreased the essential oil yield and

Review of Literature

39

Anethole percentage in fennel (Abd El-Wahab 2006). While, in Matricaria recutita,

the main essential oil constituents showed increase under saline conditions

(Baghalian et al. 2008). Also, in Origanum vulgare it was found that the main

essential oil constituent Carvone was decreased under salt stress (Said-Al Ahl and

Hussein 2010). Said-Al Ahl and Mahmoud (2010) noted increased Linalool and

decreased Eugenol content due to salinity. The essential oil yield was increased

significantly with increasing NaCl concentrations in coriander roots (Neffati and

Marzouk 2009), turnip-rooted and leaf parsely (Petropoulos et al 2009).

Effect of water stress

The impact of water stress on oil yield and its quality is has been also well

documented in the literature. Bettaieb et al. (2011) reported increase in essential oil of

Cuminum cyminum due to water stress as well as change in its chemotype. Ade-

Ademilua et al. (2013) also noted reduced essential oil percent and yield/plant in

basil. Razmjoo et al. (2008) reported similar trend in Matricaria chamomilla.

Similarly, Ozturk et al. (2004) noted that essential oil yield/plant was reduced under

water deficit but essential oil percent was increased in Melissa officinalis. The main

essential oil constituents Carvone and Limonene showed increase under water deficit

(Laribi et al. 2009). Ghassemi-Golezani et al. (2008) indicated that essential oil

content was increased under moderate water stress but reduced under severe water

defict. Dunford and Vazquez (2005) reported that moisture stress caused significant

reductions in Thymol and Carvacrol percentages in essential oil of Mexican oregano.

The review of literature clearly indicated that very scanty work has been done

in past on Ajowan and other aromatic plants. Therefore the present investigation was

undertaken to fulfill the lacuna.