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pollen stigma interaction - stigmathe stigma after landing on the stigma pollen grain germinates and produces a pollen tube that carries the male
self- vs cross-pollination a major advantage of self-pollination is its certainty continued self-pollination over many generations however results in
benefits of cross-pollinationbecause of the specific benefits of cross-pollination flowering plants have evolved many devices to prevent
chiropterophily - cross-pollinationpollination brought about by bats is called cheiropterophily bats which feed at night and do not see very well are
ornithophily - cross-pollinationin tropical areas the birds dominate over insects as important pollinators the most common among them are
entomophily - cross-pollinationit involves insects to carry the pollen to achieve pollination salvia exhibits a specialised tumapipe floral mechanism
hydrophily - cross-pollinationall hydrophytes are not necessarily pollinated by water in fact most of the aquatic plant are anemophilous eg alisma
anemophily - cross-pollinationit is also commonly referred to as wind pollination ie the pollen grains are carried through wind currents to ensure
cross-pollination - types of pollinationin this kind of pollination the pollen from anther of one individual is transferred to the stigma of another
self-pollination - types of pollinationself-pollination refers to the transfer of pollen grains from the anther to the stigma of the same flower in
anther dehiscence and pollen transferanther dehiscenceanther dehiscence simply means the release of pollen grains from dry and mature anthers it
pollination pollination refers to the transfer of pollen from dehiscing anthers to the pistil unlike animals plants cannot move to their mates for
nutrition of embryo sac the morphology of the ovule suggests that the chalazal end is the main route for the entry of nutrients the funicular
haustorial behavior of embryo sac there are instances in which the entire embryo sac may grow beyond the ovular tissue the central cell may also form
central cell - synergidsit is the largest cell of the embryo sac and the mother cell of the endosperm the enlargement of the embryo sac after the
egg - synergidsthe three cells of the egg apparatus are arranged in triangular fashion with the egg sharing a common wall with the two synergids and
functions of synergidsultra structurally the structure and concentration of cell organelles reveals that synergids are metabolically active the
tetrasporic embryo sacs in this group neither of the meiotic divisions is accompanied by wall formation so that at the end of meiosis all the four
polygonum type - monosporic embryo sacsthe embryo sac is formed from the chalazal megaspore in the tetrad and is eight-nucleate the development of
female gametophytethe development of a female gametophyte is initiated with the enlargement of one of the megaspores usually the one close to the
pollinia and massulaein most cases the pollen grains of each tetrad become separated from one another and they lie freely in the pollen sac in some
sterility in angiospermssterility in angiosperms may arise due to several causes either the anther may not be formed or anthers are formed but
pollenkitt - pollen wallthe lipoidal layer found on the outside of the mature pollen grains of many insect pollinated species is known as the
difference between vegetative and generative cell the cytoplasm of the vegetative cell and the generative cell is distinctly different the generative
endothelium - ovulein plants bearing unitegmic ovules the nucellus degenerates during early stages of ovule development and the embryo sac comes in