Sexual reproduction in plants. Group three(3) members: Petrina bailey Tavoy Campbell Teacher: Mrs. Haughton. What Is SEXUAL REPRODUCTION?. Plant reproduction is the production of new individuals or offspring in plants, which can be accomplished by both sexual or asexual means.
Group three(3) members:
Surrounding the mother cells is the tapetum which provides nutrition to the mother cells
Each microspore mother cell undergoes meiosis to produce a tetrad of haploid cells
Each haploid cell undergoes mitosis to become a pollen grain (microspore)
The two cells produced by this mitotic division are:
pollen tube nucleus
The generative nucleus is the gametophyte - it will undergo a mitotic nucleus to produce two male gametes (exactly when this occurs depends on the species)
Surrounding the nuclei are two walls; the inner intine and the outer exine
When the pollen grains mature the anther will burst releasing the pollen grains
Dehisced (pollen grains released) anther
The eight cells arrange themselves with:
three cells at the micropylar end - these are the egg apparatus. The middle cell is the female gamete (the egg cell) while the other two are the synergids
two cells in the middle - the polar nuclei
three cells at the other end - the antipodal cells (these have no known function)
Because of the fusion of two gametes, the zygote may have some genetic consequences.
Some of these genetic consequences with sexual reproduction by self pollination may include:
GENETIC CONSEQUENCES WITH SEXUAL reproduction BY CROSS FERTILIZATION MAY INCLUDE:
This is the process by which two gametes; both of the n number of chromosomes, come together, whether of the same plant as in self fertilization, or of two different plants as in cross fertilization, to produce a zygote with the 2n number of chromosomes.
one fuses with the egg cell to form a diploid zygote - this will give rise to the embryo
the other fuses with the two polar nuclei to form a triploid endosperm nucleus - this will give rise to the endosperm that will nourish the developing embryo.
This process is known as a double fertilization because two fusions occur.
Double fertilization was first discovered by a Russian scientist namely; S. G. Navashin in 1898 in two species of plants – Lily Lilum martagon and the Fritillaria Orientalis.(both are sperm making plants).
Double Fertilization is the process by which, two sperms all enter the pollen tube where one sperm fertilizes the mature egg/ovule and the other the embryo sac. The nucleus of both sperm fuses with the respective nucleus of the ovule and the nuclei of the embryo sac.
As growth of the embryo continues the surrounding nucellus breaks down supplying nutrients for growth.