BIO 210- 01
Plant sexuality has a wide range of topics about sexual reproduction systems found across the plant kingdom. Flowers, which are the reproductive units of angiosperms, amongst all living things are physically varied the most. They also show the greatest diversity in methods of reproduction of all biological systems. The system for classifying flowering plants was proposed by Carolus Linnaeus, which is based on plant structures. Plants employ several different morphological adaptations that involve sexual reproduction. Christian Konrad Sprengel studied plant sexuality, which brought understanding to the pollination process. This process involved both biotic and abiotic …show more content…
Ovules begin life as a small projection into the cavity of the ovary. Still remaining attached to the ovary wall by a placenta, the ovule bends as it grow and develop. In the beginning, the ovule is a group of similar cells that is called the nucellus. The nucellus contains the embryo sac. As development continues, the mass of cells differentiates to form the inner and outer integument that surrounds and protects the nucellus, but leaves a small opening called the micropyle. This opening is to allow male gametes to pass and interact with the female gamete (haploid egg cell) located in the embryo sac. Each anther contains four pollen sacs. Pollen grains develop inside each pollen sac that begins with a mass of large pollen mother cells in each sac that are all diploid. The wall thickens in each pollen grain and forms an inner layer called the intine and an outer layer called the exine. Surface patterns are different on pollen grains from different species. After pollen grains have matured, the anther dries out and splits open, which releases the pollen. This process is called …show more content…
The zygote divides multiple times by mitosis in order to produce an embryo. The embryo then differentiates to become a plumule, radicle, and/ or one or two cotyledons, which is attached to the wall of the embryo sac by a suspensor. Endosperm tissue is produced by the primary endosperm nucleus dividing multiple times by mitosis. This endosperm stores food for later use by the seed in some cases. It may gradually disappear as the cotyledons develop in others. The embryo sac expands to support growth, and the nucellus is crushed out of existence, which in return give nutrients to the embryo and endosperm. The integuments that surround the embryo sac become a tough, protective seed coat called testa. The micropyle is not removed to continue the intake of oxygen and water at germination. The water content of the seed decreases to prepare the seed for dormancy. The wall of the ovary becomes the pericarp, which is the fruit wall with the entire ovary now being fruit. The fruit protects the seeds and aid in