Topic 6b - Plant repro. & dev. Flashcards
Re. alternation of generations…diploid mother cells develop from which structures? (male/female)?
Anthers (male)
Ovaries (female)
Re. alternation of generations…meiosis of mother cells in sporophyte produces…?
haploid spores
Re. alternation of generations…male (pollen) & female gametophytes produce…?
sperm & eggs
Go thru slide 5…
kill me now!
What structures make up the stamen?
anther & filament
What structures make up the carpel?
stigma, style, ovary
1st step in fertilisation of flower…When does pollination occur?
when pollen grain lands on the stigma of a carpel…see slide 13
2nd step in fertilisation of flower…What happens after pollination occurs?
pollen tube grows down thru style of carpel, tube cell nucleus & sperm follow…see slide 13
3rd step in fertilisation of flower…Double fertilisation…
pollen tube & sperm reach female gametophyte - one sperm fuses with central cell, the other sperm fuses with egg cell…see slide 13
Fruit develops from the …?
ovary
Seeds develop from the …?
ovule
What are the 6 major groups of plant hormones?
auxins gibberellins cytokinins ethylene absidic acid florigens
Charateristics of auxins…
promotes cell elongation in shoots
inhibits cell elongation in roots
stim. fruit dev.
Charateristics of gibberellins…
promotes stem elongation
stimulates - bud sprouting, flowering, fruit prod., seed germination…
Charateristics of cytokinins…
promote cell division
inhibits lateral root branch formation
stimulates lateral shoot branch formation
nutrient transport -> leaves
Charateristics of ethylene…
in most plant tissue
stress hormone
ripening of fruit
Charateristics of absidic acid…
throughout plant
helps with adaptive responses
Charateristics of florigens…
timing of flowering
identified in 2005
Which 2 plant hormones work together?
auxins & cytokinins
What is photoperiodism? What agent is responsible? 3 types…
changes in flowering of a plant in response to changes in day length agent - phytochrome (2 forms) - no change - long-day - short-day
What is the important variable in photoperiodism?
duration of uninterrupted darkness (not day length per se)
2 forms of phytochrome?
Pr - absorbs light in red wavelengths
Pfr - absorbs light in far red wavelengths
Phytochrome control of flowering in short day (long night) plants?
Pfr (inhibits flowering) gets converted -> Pr thus low Pfr -> removal of inhibition of flowering -> initiation of flowering
