When the anther, mature the speed open and the pollen grains are set free.
Answers
Answer:
Ooops! The sentence is incorrect.
Explanation:
When the ovary matures the ovules are set free...
Answer:
Explanation:
A pollen tube is a tubular structure produced by the male gametophyte of seed plants when it germinates. Pollen tube elongation is an integral stage in the plant life cycle. The pollen tube acts as a conduit to transport the male gamete cells from the pollen grain—either from the stigma (in flowering plants) to the ovules at the base of the pistil or directly through ovule tissue in some gymnosperms. In maize, this single cell can grow longer than 12 inches (30 cm) to traverse the length of the pistil.Pollen tubes are unique to plants and their structures have evolved over the history of plants. The pollen tube formation is complex and the mechanism is not fully understood, but is of great interest to scientists.[1] Pollen tube formation is important for sexual reproduction to occur in seed plants. Wind, water or pollinators transport pollen grains to the female gametophyte. One such method of transport involves traveling through the style from the stigma. Once a pollen grain has implanted on a compatible stigma via self-incompatibility mechanisms, the germination process is initiated.[2] During this process, the pollen grain undergoes a conformational change whereupon a given section begins to protrude outwards to form a tube-like structure, known as the pollen tube.[3] This structure rapidly descends down the length of the style via tip-directed growth, reaching rates of 1cm/h, whilst carrying two non-motile sperm cells. [2] Upon reaching the ovule the pollen tube ruptures, thereby delivering the sperm cells to the female gametophyte, ultimately resulting in a double fertilization event. [4] The first fertilization event produces a diploid zygote and the second fertilization event produces a triploid endosperm.