In gymnosperms the ovules are unprotected, whereas in angiosperms they are protected by the megasporophyll which forms the carpel. One or several ovules may be contained in the carpel and each is attached to the carpel wall by a stalk funicle. When mature, the angiosperm ovule consists of a central mass of tissue, the nucellussurrounded by 1 or 2 protective layers, the integumentswhich eventually give rise to the seed coat.
Ovules contain the female gametophytes which are fertilized during pollination to initiate seed development. Thus, the number of ovules that are produced during flower development is an important determinant of seed crop yield and plant fitness. Mutants with pleiotropic effects on development often alter the number of ovules, but specific regulators of ovule number have been difficult to identify in traditional mutant screens.
Tomato plants belong to the plant group known as flowering plants or angiosperms. The tomato plant reproduces sexually, meaning that it requires both female and male organs to produce seeds. Every tomato seed has a tiny tomato plant inside.
Pollen grains from the greek palynos for dust or pollen contain the male gametophyte microgametophyte phase of the plant. Pollen grains are produced by meiosis of microspore mother cells that are located along the inner edge of the anther sacs microsporangia. The outer part of the pollen is the exinewhich is composed of a complex polysaccharide, sporopollenin. Inside the pollen are two or, at most, three cells that comprise the male gametophyte.
Lab 9 - Gymnosperms and Angiosperms. When mosses and liverworts first evolved, they dominated the terrestrial environment. But they were soon challenged by the more advanced tracheophytes.
Seed plant introduction: Origin and evolution of the seed habit The seed habit is the most complex and evolutionary successful method of sexual reproduction found in vascular plants. Today, seed plants, gymnosperms "Nacktsamer", ca. Most of this diversity is accounted for by the angiosperms and Charles Darwin described the rapid rise and early diversification within the angiosperms during the Cretaceous time as 'an abdominable mystery' see 'angiosperm seed evolution'.
This is a Passionflower. In the photos, the petals are brown and shrivelled at the top, and the dried stigma is at the bottom. The ovary is a small oval underneath the stigma, which in this species is divided into three.
Related to ovule: embryo sac. Botany A structure in seed plants that consists of the embryo sac surrounded by the nucellus and one or two integuments and that develops into a seed after it is fertilized. Botany a small body in seed-bearing plants that consists of the integument snucellus, and embryosac containing the egg cell and develops into the seed after fertilization. A small part in a seed-bearing plant that becomes a seed after its egg cell has been fertilized by a male cell.
Plant reproduction is the process by which plants generate new individuals, or offspring. Reproduction is either sexual or asexual. Sexual reproduction is the formation of offspring by the fusion of gametes.