Chap 6: Life of a Plant Flashcards
two seed leaves
- dicotyledons
- two seed leaves
- frence bean, cotton, cucumber, peanut, tangerine
one seed leaf
- monocotyledons
- one seed leaf
- maize (corn), wheat, rice, sorghum, sugarcane
dicotyledon
french bean
- testa
- micropyle
- embryo: two cotyledon, plumule, hypocotyl, radicle
monocotyledon
maize grain
- pericarp & testa
- embryo: one cotyledon, plumule, hypocotyl, radicle
- endosperm
seed scar
hilum
testa
- tough, protects seed’s internal strusture
micropyle (only for dicotyledon)
- absorb water for germination
- only for dicotyledon
germination: beginning of growth
cotyledon from dicotyledon
- two, thick & fleshy
- seed leaf
- stores nutritious matter
cotyledon fron monocotyledon
- one, not thick and fleshy
- seed leaf
- absorbs nutrients fron endosperm
plumule
- young leaves are grown
- develops into the stem and leaves
hypocotyl
- connects plumule to radicle
- develops into part that connects the root and stem
radicle
- slender
- develop into the root
endosperm (only for monocotyledon)
- outside embryo
- stores nutrients (starch)
the cotyledon in the monocotyledon may not be enough, therefore endosperm is there
seed contain more starch
monocotyledon
seeds rich in proteins
french bean, soybean, green pea
seeds contain fats
pine nut, walnut
the fuller the seed
- more nutrients
- the stronger the young shoot grows from it
factors affecting the germination
- water
- air
- temperature
- light or darkness
- types of soil
before germination
- absorb water: testa can be softened or burst
- stored nutrients: dissolved in the water and transported to the radicle, hypocotyl and plumule
- germinate (start to grow)
during germination
- **radicle **elongates and burst out of the testa
- hypocotyl elongates so that plumule can come out of the ground
- plumule develop into stem and leaves grow out of it
- photosynthesis
elongates: grow
hypogeal germination
- cotyledon stay in the soil
- hypocotyl do no elongate
- wheat, pea and broad bean
epigeal germination
- cotyleden above soil
- hypocotyl elongates
- punpkin, soybean and cotton
delayed germination
- seed dormancy
- autumn, dormancy causes the seed not the germinate; will only germinate when spring
- avoids unfavourable factors like dryness and cold
don’t have dormancy or short periods of dormancy
- rice and wheat
- if weather is wet and warm for some time, buds will grow
fixed life spans
- can be extended under low temperature and dry condition
- shortened under high temperature and wet condition
- 2-3years: wheat, rice and maize
- 4-6years: cabbage, broad bean and pumpkin
the part of the root from the tip to the root hairs
root-tip, includes
* root cap
* division zone
* elongation zone
* differentiation zone
root cap
protects root tip
division zone
- meristematic region
- actively dividing, constant generation of new cells
elongation zone
lengthening the root