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What is a Seed?

A seed is the embryonic stage of a plant’s life cycle. It is surrounded by a protective coating called the seed coat.

Seeds are essential for plant survival, and they serve several important functions. These include nourishment, dispersal, and dormancy during unfavorable conditions.

Origin

The seed is the product of the ripened ovule of gymnosperms (flowering plants) and angiosperms. This small embryonic plant is surrounded by a protective coat called the seed coat and may contain an endosperm.

The development of the seed in higher plants depends on processes of sexual reproduction. In seed plants, fertilization requires a viable pollen grain and a receptive stigma to produce a zygote.

Once the zygote develops, it forms a seed coat around the ovule and grows within the mother plant to a certain size before growth is halted.

The seed program is one of the key evolutionary innovations that allowed the gymnosperms and angiosperms to dominate terrestrial environments. It enables dispersal of species over wide areas and provides a source of food for animals in a long-term storable form.

Function

Seeds serve several key functions for the plants that produce them. These include nourishment of the embryo, dispersal to a new location and dormancy during unfavorable conditions.

Most seeds are composed of three parts: the seed coat, endosperm and embryo. The seed coat is a protective covering that helps the seed to remain viable.

It also protects the embryo from physical, mechanical, temperature-related and water damage. It also serves as a channel to transmit environmental cues to the interior of the seed.

The outer seed coat varies from thin and papery to rock-hard. Inside the seed is the embryo plant and usually some sort of nutritive tissue called endosperm, which stores food. There are also accessory structures attached to the seed, including cotyledons, which are leaves that can hold a food supply for the growing sprouting seedling.

Structure

In botany, a seed is an undeveloped plant embryo and store of food enclosed in a protective outer covering. It is the product of a mature ovule in gymnosperm and angiosperm plants, following fertilization by pollen.

A seed has two layers, the outer layer known as the testa and the inner layer known as tegmen (see figure 18.3.118.3.1). The testa is thick and protects the ovule from moisture and sunlight.

The inner tegmen separates the embryo and endosperm tissue by a proteinous membrane called the aleurone layer. The embryo may be small (as in buttercups), or it may fill the entire seed as in roses and some mustards.

The developing seed consists of an embryo, which is linear with one or more seed leaves or cotyledons (one in flowering plants, several in Pinus and other gymnosperms), a radicle, and a hypocotyl. The radicle and plumule are covered with sheath-like structures called coleoptile and coleorhiza.

Variation

The seed size and number of a plant are among the most important life-history traits for both its fitness and yield. Thus, understanding the genetic architecture of these traits is critical to both conservation and agroforestry.

In this study, we mapped quantitative trait loci (QTLs) that affect 12 life history traits related to seed size and fruit size. We identified eight QTL on chromosomes 1, 3, 4, and 5, with the largest located at the bottom of chromosome 1 (21.6 Mb) and explaining 15% of phenotypic variation in seed size.

The QTL affecting seed number colocated with QTLs for other traits, suggesting that it controls seed size via maternal components affecting ovule number or carpel development, or reproductive resource allocation in the mother plant. The remaining six putative QTL did not explain any of the phenotypic variation in seed number.

By Weed Smoker

Rastafarianism is an African religion and there is a great deal of people in the world that follow its teachings. In fact, there are even people that have embraced the lifestyle that is closely associated with Rastafarianism in the past such as musician and entertainer Bob Marley and Rastafarian clothing designer Larry Lloyd.

As the name implies, the Rastafarian lifestyle includes wearing clothes and accessories that are made out of beads, feathers, and other natural materials. The clothing in the Rastafarian tradition often includes animal skin, such as a horse's hide. The hair of the Rastafarian man is also usually long.

The lifestyle of Rastafarians is largely based on traditional ways of living in their native countries, as well as the African traditions and rituals that are passed down. Rastafarians have a great deal of respect for the animals that are part of their diet. Most people that follow this type of lifestyle believe that they have a direct link to the animals that they eat. In fact, in some cases, the animals may be eaten during the ceremony that follows the ceremony.

In addition to having a great deal of respect for the animals, Rastafarians also have a great deal of respect for their hobbies and pastimes. They often dress in clothes that are similar to that of the animals that they eat. Rastafarians also have a great deal of respect for the clothing that they wear and the clothing that is used to decorate their home. The color of the clothing and accessories that are worn by Rastafarians is often very similar to that of the animals that they eat.

Although Rastafarians follow a lifestyle that is based on a natural way of life, some of them do have to be in the workplace. For example, many Rastafarians work as musicians or entertainers. In order to do so, the musician may have to give up some of his or her time in order to become successful. In addition, some musicians choose to work for other musicians, such as Bob Marley and the Wailers. However, other musicians choose to work for themselves, like Bob Marley.

Although the Rastafarian lifestyle is different from that of other people, the Rastafarian lifestyle is also a life of peace and harmony. The Rastafarian people live a simple life where they eat animal meat, live in their own homes, and do not engage in much of the materialistic activities of society.