In botany, a seed is a plant embryo and food reserve enclosed in a protective outer covering called a seed coat (testa). More generally, the term "seed" means anything that can be sown, which may include seed and husk or tuber. Seeds are the product of the ripened ovule, after the embryo sac is fertilized by sperm from pollen, forming a zygote. The embryo within a seed develops from the zygote and grows within the mother plant to a certain size before growth is halted.
Fertilisation or fertilization, also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. While processes such as insemination or pollination which happen before the fusion of gametes are also sometimes informally referred to as fertilisation, these are technically separate processes. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation.
In botany, apomixis is asexual development of seed or embryo without fertilization. However, other definitions include replacement of the seed by a plantlet or replacement of the flower by bulbils.
Sweet corn, also called sweetcorn, sugar corn and pole corn, is a variety of corn grown for human consumption with a high sugar content. Sweet corn is the result of a naturally occurring recessive mutation in the genes which control conversion of sugar to starch inside the endosperm of the corn kernel. Sweet corn is picked when still immature and prepared and eaten as a vegetable, rather than field corn, which is harvested when the kernels are dry and mature. Since the process of maturation involves converting sugar to starch, sweet corn stores poorly and must be eaten fresh, canned, or frozen, before the kernels become tough and starchy.
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 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.
Field corn, also known as cow corn, is a North American term for maize grown for livestock fodder, ethanol, cereal, and processed food products. The principal field corn varieties are dent corn, flint corn, flour corn which includes blue corn, and waxy corn.
The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid in most species, which may be auxin-driven. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein. This can make endosperm a source of nutrition in animal diet. For example, wheat endosperm is ground into flour for bread, while barley endosperm is the main source of sugars for beer production. Other examples of endosperm that forms the bulk of the edible portion are coconut "meat" and coconut "water", and corn. Some plants, such as orchids, lack endosperm in their seeds.
An F1 hybrid (also known as filial 1 hybrid) is the first filial generation of offspring of distinctly different parental types. F1 hybrids are used in genetics, and in selective breeding, where the term F1 crossbreed may be used. The term is sometimes written with a subscript, as F1 hybrid. Subsequent generations are called F2, F3, etc.
Aleurone is a protein found in protein granules of maturing seeds and tubers. The term also describes one of the two major cell types of the endosperm, the aleurone layer. The aleurone layer is the outermost layer of the endosperm, followed by the inner starchy endosperm. This layer of cells is sometimes referred to as the peripheral endosperm. It lies between the pericarp and the hyaline layer of the endosperm. Unlike the cells of the starchy endosperm, aleurone cells remain alive at maturity. The ploidy of the aleurone is (3n) [as a result of double fertilization].
Corn kernels are the fruits of corn. Maize is a grain, and the kernels are used in cooking as a vegetable or a source of starch. The kernel comprise endosperm, germ, pericarp, and tip cap.
Waxy corn or glutinous corn is a type of field corn characterized by its sticky texture when cooked as a result of larger amounts of amylopectin. The corn was first described from a specimen from China in 1909. As this plant showed many peculiar traits, the American breeders long used it as a genetic marker to tag the existence of hidden genes in other maize breeding programs. In 1922 a researcher found that the endosperm of waxy maize contained only amylopectin and no amylose starch molecule in opposition to normal dent corn varieties that contain both. Until World War II, the main source of starch in the United States was tapioca, but when Japan severed the supply lines of the U.S., they forced processors to turn to waxy maize. Amylopectin or waxy starch is now used mainly in food products, but also in the textile, adhesive, corrugating and paper industry.
Double fertilization is a complex fertilization mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte with two male gametes (sperm). It begins when a pollen grain adheres to the stigma of the carpel, the female reproductive structure of a flower. The pollen grain then takes in moisture and begins to germinate, forming a pollen tube that extends down toward the ovary through the style. The tip of the pollen tube then enters the ovary and penetrates through the micropyle opening in the ovule. The pollen tube proceeds to release the two sperm in the embryo sac.
A seedless fruit is a fruit developed to possess no mature seeds. Since eating seedless fruits is generally easier and more convenient, they are considered commercially valuable.
Plant reproduction is the production of new offspring in plants, which can be accomplished by sexual or asexual reproduction. Sexual reproduction produces offspring by the fusion of gametes, resulting in offspring genetically different from either parent. Asexual reproduction produces new individuals without the fusion of gametes, resulting in clonal plants that are genetically identical to the parent plant and each other, unless mutations occur.
Cytoplasmic male sterility is total or partial male sterility in hermaphrodite organisms, as the result of specific nuclear and mitochondrial interactions. Male sterility is the failure to produce functional anthers, pollen, or male gametes. Such male sterility in hermaphrodite populations leads to gynodioecious populations.
Maize, also known as corn in North American and Australian English, is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant gives rise to inflorescences which produce pollen and separate ovuliferous inflorescences called ears that when fertilized yield kernels or seeds, which are botanical fruits. The term maize is preferred in formal, scientific, and international usage as the common name because it refers specifically to this one grain whereas corn refers to any principal cereal crop cultivated in a country. For example, in North America and Australia corn is often used for maize, but in England and Wales it can refer to wheat or barley, and in Scotland and Ireland to oats.
Gynodioecy is a rare breeding system that is found in certain flowering plant species in which female and hermaphroditic plants coexist within a population. Gynodioecy is the evolutionary intermediate between hermaphroditism and dioecy.
Mutation breeding, sometimes referred to as "variation breeding", is the process of exposing seeds to chemicals, radiation, or enzymes in order to generate mutants with desirable traits to be bred with other cultivars. Plants created using mutagenesis are sometimes called mutagenic plants or mutagenic seeds.
Macapuno or coconut sport is a naturally occurring coconut cultivar which has an abnormal development of the endosperm. The result of this abnormal development is a soft translucent jelly-like flesh that fills almost the entire central cavity of coconut seeds, with little to no coconut water.
Corn silk is a common Stigma maydis, the shiny, thread-like, weak fibers that grow as part of ears of corn (maize); the tuft or tassel of silky fibers that protrude from the tip of the ear of corn. The ear is enclosed in modified leaves called husks. Each individual fiber is an elongated style, attached to an individual ovary. The term probably originated sometime between 1850 and 1855.
