A seed is an organ that grows into a plant. There are many different kinds of seeds. They are classified into different categories, including angiosperms and gymnosperms.
Angiosperm
Angiosperms are one of the most highly evolved groups of plants on Earth. Besides flowers, angiosperms also have fruits. These fruits can protect seeds and promote seed dispersal. They are most commonly found in tropical regions. There are more than a hundred living species, most of which are trees. Some are valuable to humans for timber and paper.
In angiosperms, a fertilized egg develops into an endosperm, which is an embryo-nourishing tissue. The endosperm is formed through double fertilization. It is a specialised structure, containing rich cytoplasm and tannins. It is recognised by its prominent, radially extended cells.
Endosperms in angiosperms are arranged synchronously post-fertilization. Most angiosperms retain an endosperm layer in their mature seeds. However, the exact functions of this specialised tissue in living angiosperms are not completely understood.
Angiosperms can be divided into two groups: basal angiosperms and gymnosperms. Basal angiosperms have small embryos and have been referred to as B1 seeds. Gymnosperms, on the other hand, are seed-producing non-flowering plants. A common feature of gymnosperm seeds is the presence of a female gametophyte.
A recent study has revealed an unusual feature of the development of seeds. Endothelium has been discovered in early angiosperm seeds. This discovery provides new insights into the evolution of angiosperms.
Genetic studies have identified peptides that play critical roles in the regulation of seed development. Several signalling peptides are seed-specific, meaning they are expressed in the reproductive tissues of seed producing plants. These signalling peptides are implicated in host recognition and reproductive tissue development.
Gymnosperm
A gymnosperm seed is a spore that grows on a plant’s leaf or stem and forms a cone. Gymnosperms belong to a division of plants called angiosperms. They are also part of the subkingdom Embophyta.
Angiosperms are flowering plants that produce flowers and fruits. They are believed to be the earliest vascular plants to live on land. These plants have larger xylem cells, which improve the efficiency of their vascular system. In addition, they are usually aquatic. Consequently, they are pollinated by insects. However, some gymnosperms are pollinated by wind.
There are four main divisions in gymnosperms. The Coniferophyta division includes conifers. Cycads are the largest gymnosperm group. Cycads are evergreen and can live for many years. Moreover, they have feather-like leaf structures. Their sporophytes are monoecious, meaning they produce both male and female cones.
The sporophyte is the bulk of the plant, and it consists of two complete sets of chromosomes. It spends most of its life in the sporophyte phase, also known as sporophyte generation.
The sporophyte phase is followed by the gametophyte phase. Gametophytes are smaller, and their lifespan is relatively short. Unlike angiosperms, gymnosperms do not produce true fruits. Instead, they produce seeds.
Seeds develop on the leaves and scales of the plant, and they are exposed on the plant’s bracts. Usually, they are modified to form a cone.
Non-albuminous
A non-albuminous seed is a type of seed that doesn’t contain any endosperm. In fact, it lacks the protective layer of the endosperm, the enzymatic process of converting the sugars in the seed to a protein called globulin, and the reproductive organs that surround it.
The name “non-albuminous” has a number of meanings. It can refer to a type of food that is not consumed by a developing embryo, or a seed with no endosperm, but is still an important part of the plant’s life cycle.
An albuminous seed is a type of seed containing a large quantity of the masticatory organ, which provides the food for the plant’s development until it germinates. This organ is also known as the endosperm, and it is the part of the seed that is responsible for storing the nutrients required for the growth and reproduction of the plant.
During the development of the plant, the endosperm is the primary source of energy for the seed, but as the seed matures, the endosperm is used less and less. On the other hand, the endosperm is also the primary storage medium for the plant’s reserve food, and it is this food that enables the seeds to last for longer periods of time.
There are two types of endospermic seeds: monocot and dicot. Monocots are composed of one cotyledon, while dicots have two.
