Fig. 8.7

Structure of Flowers

• Outermost whorl typically consists of three to five sepals. Sepals (calyx) may be fused together.

• Next whorl consists of three to many petals (corolla). Calyx and corolla form the perianth.

Structure of Flowers

• Several to many stamens are attached to the receptacle around the base of the pistil. Each stamen consists of a filament with an

anther at the top.- Pollen grains developed and

disseminated in anthers.

Structure of Flowers

• Pistil consists of Stigma, Style, and Ovary. Superior Ovary - Calyx and corolla are

attached to the receptacle at the base of the ovary.

Inferior Ovary - Receptacle grows up and around the ovary.

- Calyx and corolla appear to be attached at the top.

• Inflorescences - Group of several to hundreds of flowers.

Generalized Flower

Fruits

• Fruit is an ovary and its accessory parts that have developed and matured. Usually contains seeds. All fruits develop from flower ovaries and

accordingly are found exclusively in flowering plants.

Fruits

• Fruit Regions Exocarp - Skin Endocarp - Inner boundary around seed(s). Mesocarp - Fleshy tissue between exocarp

and endocarp.- Three regions are collectively called the

pericarp.

Regions of a Mature Peach

Fruits

• Fleshy Fruits Simple fleshy fruits develop from a flower

with a single pistil.- Drupe - Simple fleshy fruit with a single

seed enclosed by a hard, stony endocarp, or pit. Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display

Fig. 8.9

Fruits

• Berry - Usually develops from a compound ovary and often contains more than one seed. True berry is a fruit with a thin skin and a

relatively soft pericarp. Pepos - Relatively thick rinds (Pumpkins). Hesperidium - Leathery skin containing oils

(Citrus). Copyright © McGraw-Hill Companies PermissionRequired for Reproduction or Display

Fig. 8.10a

Fruits

• Pomes - Bulk of flesh comes from enlarged floral tube or receptacle that grows up around the ovary. (Apples)

Copyright © McGraw-Hill Companies PermissionRequired for Reproduction or Display

Fruits

• Dry Fruits That Split at Maturity (Dehiscent) Follicle - Splits along one side or seam. Legume - Splits along two sides or seams. Silique - Splits along two sides or seams,

but seeds are borne on central partition exposed when the two halves separate.

Capsules - Consist of at least two carpels, and split in a variety of ways.

Copyright © McGraw-Hill Companies PermissionRequired for Reproduction or Display Copyright © McGraw-Hill Companies Permission

Required for Reproduction or Display

Copyright © McGraw-Hill Companies PermissionRequired for Reproduction or Display

Copyright © McGraw-Hill Companies PermissionRequired for Reproduction or Display

Fig. 8.12

Fig. 8.14b

Fig. 8.14a

Fig. 8.15

Fruits

• Dry Fruits That Do Not Split at Maturity (Indehiscent) Achene Nut Grain Samara Schizocarp

Copyright © McGraw-Hill Companies PermissionRequired for Reproduction or Display

Fig. 8.16

Fig. 8.17

Fruits

• Aggregate Fruits Derived from a single flower with several to

many pistils.- Individual pistils mature as a clustered

unit on a single receptacle Raspberries, Strawberries.

• Multiple Fruits Derived from several to many individual

flowers in a single inflorescence. - Pineapples, Figs

Fig. 8.19

Fig. 8.19b

Fig. 8.20

Fig. 8.21

Fruit and Seed Dispersal

• Wind Dispersal Small and Lightweight seeds.

• Animal Dispersal Seeds pass through digestive tract. Fruits and seeds catch in fur or feathers. Oils attract ants.

• Water Dispersal Some fruits contain trapped air.

• Mechanical Ejection of Seeds

Fig. 8.22

Fig. 8.23

Seeds

• Structure Cotyledons - Food storage organs that

function as first seed leaves. Plumule - Embryo shoot. Epicotyl - Stem above cotyledon. Hypocotyl - Stem below attachment point. Radicle - Stem tip developing into a root.

Dormancy

• Coat Imposed Dormancy Prevention of Water Uptake Mechanical Constraint Interference with Gas Exchange Retention of Inhibitors Production of Inhibitors

Dormancy

• Embryo Dormancy High levels of GA and ABA

Dormancy

• Primary vs Secondary dormancy

• Release from Dormancy Afterripening Chilling (stratification) Light

Germination

• Germination is the beginning or resumption of seed growth. Seed must be viable.

- Favorable Environmental Factors- Imbibe water

Fig. 8.28b

Fig. 8.29

Longevity

• Viability of most seeds is significantly extended when the seeds are stored under conditions of low temperatures and kept dry. A few species produce seeds with no

period of dormancy.- Vivipary

Box Fig. 8.1

Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display