Often times, the term seed is used to describe a plant. The seed may be the fruit of an animal or it could be a part of a tree, but regardless of its origin, the seed plays a crucial role in the growth and life of the plant.
Origin of seeds
Whether or not seeds originated independently of plants is one of the biggest mysteries in plant biology. The question is important because the origin of seeds is linked to other major innovations in the plant kingdom, such as monocotyledons, angiosperms, and gymnosperms.
Traditionally, the origin of seeds has been studied using comparative morphology and paleobotany. However, more recent experiments with pteridophytes have provided a new perspective on this long-standing debate.
In pteridophytes, researchers have been investigating the role of the LEC1-like gene, which is believed to be involved in the function of the seed program. This gene is thought to be a key regulator of the seed program. It has been shown to play a central role in the emergence of spermatophytes.
During the germination phase, a young plant utilizes the endosperm, a collection of stored food. In turn, this process aids in improving the chances that the seed will survive a tough environment.
The endosperm of a seed contains a variety of different substances, some of which may be more significant than others. Among these are proteins, galactomannan, cellulose, and polysaccharides. Some of these substances are also subject to a derivatization process. The compositions containing these substances may have a higher viscosity than other compositions.
In addition to their edible properties, some seeds were used to manufacture alcohol, flour, starch, and other materials. These materials were often present in a husk, a fibrous protective cover.
During the early stages of a plant’s development, cotyledons are formed. They function as primary leaves, feeding the developing seedling until the plant has true leaves. They are also packed with reserve food material. These reserve materials are then used by the rest of the seedling.
Seeds are produced during the reproductive process of angiosperms. They contain the embryonic plant and a special covering. They are dispersed naturally by animals.
A number of cotyledons are required by all plants. The number of cotyledons is one of the characteristics used by botanists to classify flowering plants. For example, seeds of Jeffrey Pine (Pinus jeffreyi) have seven to thirteen cotyledons. The number of cotyledons in a plant depends on the growth habit and type of plant.
Shapes of ovules
During seed development, the shape of the ovules in seeds is important. Angiosperms are characterized by a number of different ovules. These can be classified based on the shape and orientation of the ovule body and the micropyle. In some species, the micropyle is curved while in others it is straight. These variations in the ovule phenotype affect the formation and development of the embryo sac.
The outer ovule integument of Arabidopsis is developed in a manner similar to that of leaves. The development of the integument requires the precise regulation of cell division. This explains why the outer ovule integument is a good model to study the morphogenesis of plant organs.
During the life cycle of plants, the term dormancy of seed refers to the inactive state of the seed. This condition is important in protecting the seed from the adverse environmental conditions. The availability of water, food, and air are some of the environmental factors that affect dormancy. These factors also influence germination.
The dormancy of seed is classified into two major types. Physical dormancy is defined as the lack of water and gas exchange in the seed. The hardness of the seed coat restricts the uptake of water and restrains its movement. In addition, the presence of inhibitors in the coat of the seed may also inhibit germination.
Dominant biomes in the world
Whether you call it a forest, jungle or prairie, these are the dominant biomes on the planet. These ecosystems are the largest and most stable on the planet. They are home to a huge diversity of plants, animals, and marine life. These biomes cover almost seventy percent of the Earth’s surface.
Tropical rainforests are the most biodiverse terrestrial biome. They are characterized by an emergent layer of tall trees, a ground layer of herbaceous vegetation, and a subcanopy of trees. The vegetation also produces large amounts of chemicals. The chemicals are produced by a huge diversity of organisms. The overstory of trees can reach up to 30 meters high.