Plant Reproduction Flashcards
Describe angiosperm reproduction
An alternation of generations between a multicellular diploid sporophyte generation and multicellular haploid gametophyte generation.
What are flowers produced by and what are they used for?
Sporophyte, sexual reproduction
What are the four floral organs?
Sepals: protect the floral bud
Petals: help attract pollinators
Stamens: bear anthers (where haploid microspores develop into pollen grains, containing a male gametophyte).
Carpels: contain ovules (immature seeds) in their swollen bases
Ovules: embryo sacs (female gametophytes) develop here, from megaspores.
What is pollination?
Precedes fertilization, is the placing of pollen on the stigma of a carpel.
What happens after pollination?
The pollen tube discharges two sperm into the female gametophyte. Two sperm are needed for double fertilization.
What is double fertilization?
A process in which one sperm fertilizes the egg, forming a zygote and eventually an embryo, while the other sperm combines with the polar nuclei, giving rise to food-storing endosperm.
What does the seed coat do?
Encloses the embryo along with a food supply stocked in either the endosperm or the cotyledons.
What does seed dormancy do?
Ensures conditions are favorable for seedling survival. Breaking dormancy requires environmental cues, such as temperature or lighting changes.
What does the fruit do?
Protects the enclosed seeds and aids in wind dispersal or in the attraction of seed-dispersing animals.
What three mechanisms do plants have to avoid self-fertilization?
Having male and female flowers on different individuals (dioecious)
asynchronous production of male and female parts within a single flower
self incompatibility where pollen grains that bear an identical allele to one in the female are rejected
Can plants be cloned from single cells?
Yes
