Post on 18-Nov-2014
Conditions For Germination
• Conditions required for germination are the presence of:
(a) water
(b) air
(c) suitable temperature (heat)
WATERWater - is required for germination. • Mature seeds are often extremely dry and
need to take in significant amounts of water, relative to the seeds dry weight, before cellular metabolism and growth can resume.
• Most seeds respond best when there is enough water to moisten the seeds
but not soak them.
2. Temperature – • warmer temperatures enable
enzymes to work.
3. Air (Oxygen) - enables seeds to respire
aerobically to supply energy for growth
Vegetative organs are stems, leaves, and
Roots.– Modification of vegetative organs make
vegetative reproduction (asexual) possible
How Do Angiosperms (flowering plant) Reproduce
Asexually?
Vegetative Reproduction• Is a type of asexual reproduction that produces
a new plant from a certain part of the parent plant without involving seeds.
• Occurs through certain parts such as:
~ Rhizome ( Rizom)
~ Leaf ( Daun)
~ Tuber ( Tuber)
~ Stem ( Batang)
~ Runner ( Batang Rayap)
~ Bulb ( Bebawang)
~ Corm ( Umbisi)
~ Sucker ( Anak Pokok)
TubersTubers are underground food stores which stores food over the winter and provides a new plant with food until it can make its own.
Food made by the new plant is sent to make new tubers. Thereby reproducing itself.
Examples: potato, artichoke, yam, cassava, water chestnut, arrowroot
Taro- Japanese potato
• Some form enlarged underground stems called tubers (e.g., potatoes).
• They develop when specialized stem branches grow down into the ground and swell up with starch containing cells. Buds on the tubers will grow into new plants. Examine the potato tuber and note the buds which are commonly termed "eyes" (Figure 7).
Bulbs • Onions, chives and lilies over-winter in the form of a bulb.
• Each bulb has a very short stem which is surrounded by fleshy leaves.
– Bulbs and corms are short, vertical, underground stems.
• Bulbs have fleshy, modified leaves for food storage — a large, underground bud. These can give rise to new plants, (lilies, onions).
Bulb of Hippeastrum lily
Bulbs
• E.g. daffodils, lilies
Runners- Stolons
Runners are side shoots which grow out from the parent plant.
Buds form at points along the runner and eventually these buds form roots and grow into new plants.
Examples: spider plant (Anthericum), strawberry (Fragaria x ananassa)
Runner
Runners (Stolons)
• These are horizontally growing stems that produce few, if any, leaves.
–horizontal stems that form roots –at intervals and can develop into new plants
– Rhizomes are horizontal underground stems that give rise to new shoots.
www.texasbamboosociety.net
Corms
• This structure is similar to bulbs except that there are no storage leaves.
• The nutrients are, instead, stored in the swollen stem.
• Corms – disc-like underground stems that consist primarily of stem tissue.
www.backyardnature.net/pix
Corms of crocuses (left) and gladiolus (right)
– Leaves can also be source of new plantlets, as in Kalanchoe.
Vegetative reproduction: Plantlets form at edge of leaf
of Kalanchoe daigremontiana.
– Suckers • are shoots produced by
roots. • Many grasses and trees,
such as aspens form interconnected stands of genetically identical individuals.
Application of Vegetative Reproduction
• vegetative reproduction technology includes:
(a) cutting (keratan)
(b) marcot (tut)
( c) Layering ( tut lentur)
(d) tissue culture ( Kultur tisu)
Cuttings
• Cuttings: Cuttings are part of the plant that is cut off of the parent plant. Shoots with leaves attached are usually used. New roots and leaves will grow from the cutting. The shoot is cut at an angle. A growth promoter may be used to help with the growth of the roots.
Cutting
They can be placed in moist
soil or water (and sometimes
dipped in rootingpowder).
Cuttings are small pieces of stem with some leaves attached, the new plant grows from this.
MARCOT (TUT)
Layering
• Layering: In layering a shoot of a parent plant is bent until it can be covered by soil. The tip of the shoot remains above ground. New roots and eventually a new plant will grow. These plants can then be separated.
Cutting
They can be placed in moist
soil or water (and sometimes
dipped in rootingpowder).
Cuttings are small pieces of stem with some leaves attached, the new plant grows from this.
Researchers are investigating ways to reproduce plants by tissue culture.– Many plant cells are tot potent — undifferentiated
cells can give rise to entire plants– Culturing tiny bits of apical meristem can eliminate
plant viruses
www.ppm4plant-tc.com/ http://members.tripod.com/~rsauleda/
Cattleya orchid
– Treatment with hormones can cause apical meristems to produce millions of plants in a year
– Used for strawberries and potatoes to produce virus-free plants
http://www.noursefarms.com/images/staticPages/tour/tissueCulture.jpg
Tissue culture of commercial strawberries
Recombinant DNA also used with tissue culture to produce plants with disease resistance, increased nutritive value, etc.
www.goldenrice.org/image/
Golden Rice (right) is bioengineered to produce and accumulates pro-vitamin A (β-carotene) in the grain, often in short supply in developing countries.