As the name implies, a seed is the embryo of the plant. It has an endosperm and a cotyledon. The cotyledon is a ring of cells that surround the seed. It has genetic control and a root meristem identity.
Endosperm
The endosperm of a seed is a collection of stored food. The endosperm is used by a young plant during germination, when the embryo begins to develop. The endosperm may be made of proteins and polysaccharides, such as cellulose.
The endosperm of a seed contains the embryo, nutritive tissue, a protective coat, and an embryonic root. The endosperm of a seed may be a dry solid or a wet liquid. Some seeds may remain dormant for months or even years, depending on the variety and the conditions. Some edible seeds include coconut, wheat, walnut, sunflower, oats, and rice.
Some seeds, like walnut and coconut, contain nutritional reserves surrounded by a fibrous protective husk. Some seeds may weigh as much as 60 pounds. These grains are an excellent source of protein, carbohydrate, and dietary fiber. Some seeds, such as oats, can be ground and turned into flour or oil.
Ectopic ovule primordia
The ectopic ovule primordium is an organ that replaces a mature ovule. It is shaped like a finger, although it is not fully developed. It is formed from the flanks of the proximal chalaza. It is connected to the placenta by a short funiculus. It contains a number of cells that are striated and irregular. It has interspersed stomata and is covered by integuments.
The ectopic ovules can be classified into three groups based on their morphological features. These are: the small/young ovule primordium (O1), the large/old ovule primordium (O2), and the intermediate ovule primordium (O3). The O2 is dome-shaped, while the O1 is a small bump. Besides, the sepals in the former group are often branched and contain abundant stigmatic papillae. Moreover, the carpels in the latter group are often flattened and show sepal-like mixed characteristics.
Cotyledons
A cotyledon seed is a leaf-like structure that forms inside the embryo of a plant seed. These structures have various functions including storing food, providing photosynthesis, and aiding in metabolizing nutrients found in the rest of the seed.
The first leaves formed by a germinating plant are usually cotyledons. However, a cotyledon is not the only type of seed leaf. Other plant embryonic leaves include the hypocotyl and the scutellum. A cotyledon seed is generally small and undeveloped, but it can grow if it is provided with ample reserves of food.
A cotyledon may have some short-term or even long-term function during seedling development or germination. The cotyledon has several components, including a plumule, radicle, and a pedicel.
A cotyledon can be found in both monocot and dicot plants. A cotyledon can be used by a dicot plant to help with the process of photosynthesis. A cotyledon is the primary leaf of a plant, and the stipule (part of the cotyledon) is a shield-shaped structure.
Root meristem identity
One of the most important features of plant meristems is the ability to regulate cellular differentiation. This is a necessary feature of the meristem as it must balance specification of determinate tissues (such as a cotyledon or leaf) with the function of indeterminacy, which requires retention of pluripotent cells that could remain undifferentiated.
A number of different factors are responsible for maintaining the identity of a root or shoot meristem. These include the genes encoding the CLV3-like effector proteins. These molecules are part of a set of peptides that act as extracellular signals to regulate the development and maintenance of a meristem.
The function of the PRC2 gene is also known to affect meristem identity. The PRC2 gene encodes a protein that has tissue-dependent effects during hormone-induced organogenesis.
Genetic control
Several mechanisms have been proposed to explain observed differences in genetic control of seed performance, and the relationship between seed weight and length, and seed coat color in common bean. However, the complexity of the relationships between these traits is apparent when the response of lots from different genotypes to temperature is analyzed.
The interactions between the genotype and environment are common in nature. They result in large changes at the molecular level. The thesis presented here provides insight into how these interactions may be facilitated by the use of genetic tools.
The research presented here connects the phenotypic changes to changes at the metabolome. This is a systems genetics approach to studying genetic control of seed performance.
Seed germination was tested in two runs for the 2007/08 and 2008/09 seasons. The ap2-10 (+/-) genotype showed a higher germination percentage and larger seeds than wild-type. The average seed weight produced by the cross was intermediate between the homozygous ap2 mutant and the wild-type plant.
