Definition and Function of Seeds in Plants

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There are many functions of seeds in plants. Seeds are one part of the plant that has an important role. Without seeds, plants cannot reproduce.

What are the functions of seeds in plants? Check out the explanation below

Meaning of Seeds

Seeds are the main tool for reproduction. Agronomically, the fertilized seeds in plants become one of the cultivated products that can be used or used as human consumption material and can be used as feed for various types of livestock.

Seeds are the most important part of the plant. Seeds can be called plant embryos which are covered by a protective layer on the outside. Spermatophytes are part of the reproductive process in seed plants during the formation of seeds.

Almost all plants produce seeds. The quality of the growth and development of a plant depends on the spread of seeds. If the seed dispersal is correct then plant development will get maximum results, and vice versa.

Seeds that have good quality are seeds that are physiologically ripe. Characteristics of quality seeds such as yellow rice plants or yellow skin covering the seeds on soybeans.

Seeds are a very valuable part from the farmer’s point of view, because later these seeds can be replanted into new plants or plants.

Definition of seeds according to experts:

  1. Salisbury (1992), Seeds are radicle processes that produce embryonic roots which function as plant propagation due to the presence of carbohydrates and proteins.
  2. Kamil (1986), Seeds mean seeds that function as food or breeding with a water content of around 30 to 55 percent in them.

Seed plants are different from ferns or mosses because seed plants themselves produce seeds that go through a fertilization or fertilization process.

Types of Seeds in Plants

Based on the location of the ovule, the types of seeds in seed plants are divided into two, namely:

1. Open Seeds

Open seed plants commonly called Gymnosperms, are plants whose seeds are not covered by ovaries. In open seed plants, the seeds are located directly between the leaves that make up the conifers or strobilus.

Gymnosperms themselves have plant organs in the form of roots, leaves, stems, strobilus and vessels.

Open seed plants have a taproot system in which the type of stem is branched with stiff, thick and narrow leaves except for melinjo which has broad leaves and taproots.

The seeds themselves will be open and located on the surface of the fruit. The fruit will grow outside the megasporophyll.

Megasporophyll is the supporting part of the ovule which gathers together in the form of a woody strobilus. In addition, another feature of open seed plants is having true flowers and flower crowns.

a. Characteristics of Open Seed Plants

The characteristics of Gymnosperms include not having true flowers and no flower crowns. The seeds that are outside the surface and not protected by fruit leaves are called heterosporous plants, namely plants that produce two different types of spores, the megaspores themselves form female gametes. Moreover, microspores produce pollen grains and reproductive structures form inside the strobilus. So that there is a single fertilization.

Other characteristics as follows:

  1. It doesn’t have a true flower in the form of a strobilus
  2. There are no ovaries in the strobilus
  3. Stems do not have phloeterma
  4. Single fertilization
  5. The seeds themselves are not protected by fruit leaves
  6. Roots riding
  7. The leaves are narrow, stiff and thick
  8. Not a wide variety of leaf bones
  9. Has no true flower
  10. Cone-shaped breeding tool (cones or strobilus)
  11. The genitals are separate, the egg cell in the female strobilus and the pollen in the male strobilus

b. The Role of Seed Plants in Life

Gymnosperms are beneficial to human life, including the following:

  1. As an ornamental plant, examples of Hajj and cypress ferns
  2. As industrial materials, medicines and paints
  3. As a material for making matches and paper, for example, pine
  4. As vegetables, for example melinjo
  5. As a food source
  6. As a producer of paint oil or tepentine
  7. As a raw material for resin
  8. As an ingredient for medicine

2. Closed seeds

Closed seed plants or Angiosperms have a characteristic where all plants included in closed seed plants have flowers.

In closed seed plants, the plants that join are very diverse, such as soaring plants to climbing plants. Closed seed plants are divided into 2 parts, namely closed seed plants monocots (one piece) and dicots (two pieces).

Closed seed plants which are included in monocot plants usually have a single seed and are not plants that have wood because these monocot type plants usually do not have a cambium.

The size of monocot plant stems is usually small and unbranched with parallel leaf vein types, the number of flower crowns of plants is also a multiple of three and has a fibrous root system.

Therefore, closed seed plants with dicot plants usually have a physical form in the form of shrubs or trees and shrubs. This type of plant has a type of wood and stems that are hard, cambium and branched, a taproot system and the number of flower crowns is a multiple of two or five.

The dicot seed parts have their respective functions, namely:

  1. The plumule is the upward growing embryonic axis which will later grow into the first leaves
  2. Radiculo is the axis of the embryo that grows downwards, then it will become the primary
  3. The seed coat is a thin membrane that protects the seed from physical damage and prevents excessive evaporation of moisture
  4. The hypocotyl is the part of the embryo that is below the embryonic axis
  5. The epicotyl is the part of the embryo that is above the embryonic axis
  6. The embryo is a candidate for a new plant/plant that unites two separate cotyledons, the embryo itself has a part attached to the cotyledons which is called the embryonic axis.
  7. The cotyledon is the largest part of the seed which contains food reserves for the embryo

Monocot seed parts have their respective functions, namely:

  1. Coleorhiza is a structure that has a function to protect the radicle
  2. The radicle is the lower end of the embryo which will develop into a root
  3. The coleoptile is a structure that has the function of protecting the plumula
  4. The plumule is the upper end of the embryo which will develop into a leaf
  5. Embryo is a candidate for a new plant or plant that is ready to develop
  6. The scutellum is a combination of cotyledons which will form a special structure and have the function of absorbing food from the endosperm to be given to the embryo.
  7. The endosperm is the largest part of the monocot seed which has a function as a food reserve for the embryo

a. Characteristics of Closed Plants

Angiosperms have the characteristics of having seeds covered by fruit leaves, having true flowers, generally plants in the form of shrubs, shrubs, lianas, herbs and trees.

Other characteristics as follows:

  1. Have flowers
  2. Various kinds of flat leaves and wide bone arrangement
  3. The ovary is not visible because it is wrapped in one body, namely the pistil
  4. There is double fertilization
  5. Has true flowers in the form of petals, crowns and their breeding tools are pistils and stamens

b. The Role of Open Seed Plants for Life

Angiosperms are beneficial to human life, including the following:

  1. As ornamental plants, such as roses, cacti, sunflowers etc
  2. As ingredients for spices, such as cloves, nutmeg, hazelnut, pepper etc
  3. As a food source in the form of vegetables
  4. As a fruit ingredient
  5. As a source of protein
  6. As a raw material for household appliances or furniture industry
  7. As an ingredient for medicine
  8. As a producer of aromatic oil
  9. As a producer of vegetable oil
  10. As a producer of biodiesel such as palm oil
  11. As a producer of sugar
  12. As a source of carbohydrates, such as wheat, rice, potatoes and others

Seed plants have other names, namely:

  1. Flowering plants (Anthophyta)
  2. Plants whose mating process is visible (Phanerogamae)
  3. Plants whose marriage process is through vessels and institutionalized (Embriophyta sifonogama)

Seed Function For Plants

1. As a place to store reserves for plants

Seeds can be used to store food reserves for plants where the results of plant photosynthesis will be stored in the form of food reserves. Food reserves are used to survive, especially when food on the ground is running low.

This often occurs during the dry season, when the condition of plants is unable to make food, then the food reserves are used to survive. Several types of plants whose seeds can be used as storage for food reserves include peanuts, rice, soybeans and green beans.

Seeds that are small and grow fast usually do not contain much endosperm. Whereas for seeds that can last a long time and are hard, the endosperm content has seeds and seeds to survive.

Like, plants or plants on the coast. Coconuts, will survive by floating over thousands of miles to reach the coast, they take long or months to germinate. Thus, the coconut seed provides a rich endocarp in the form of coconut meat.

2. As a breeding tool/genetic information source

Seeds have a function as a breeding tool because they can produce new plants. The embryo of the plant is known as the seed. Propagation through seeds can produce plants with uniform growth and is easier to do

3. As a forming of new plants

Seeds can be used to form new plants. By planting it in the ground, the seeds will develop and grow into new plants that have the same characteristics as their parents.

The formation of new plant candidates by mating between egg cells and sperm nuclei is called amphimixis, while apomiksis (apomixis) is the formation of institutions without prior mating events.

Characteristics of Seeds in Plants

Quality seeds or not can be seen from the characteristics, as follows:

  1. Seed plants have a more complex sporophyte generation compared to ferns and mosses. Breeding tool in the form of strobilus. Meanwhile, in sporophyll ferns, flowers have not yet formed.
  2. Quality seeds do not contain bacteria or fungal pathogens, so these seeds are safe to be replanted or consumed again.
  3. Quality seeds have a water content of not more than 25%.
  4. Quality seeds have a perfect shape, round or oval, not deformed and smooth.
  5. Male gametes or sex cells are found in pollen grains and female gametes are found in the embryo sac. Merging of the two cells through a pollen tube.
  6. Seed plants can be clearly distinguished from their stems, leaves and roots.
  7. Has a multicellular nature with a macroscopic body size and has a variety of heights
  8. It has a diverse vascular network consisting of xylem which functions as a carrier for minerals and water from the soil, while phloem as a carrier for food materials from leaves throughout the plant body.
  9. It is autotrophic or synthesizes its own food through photosynthesis except for parasitic plants. Thus, seed plants are called photoautotrophic organisms.
  10. In general, seed plants have a habitat on land. For example, guava, mango and rambutan. In addition there are also those that have floating habitats such as water hyacinth.
  11. There are 2 types of seed plant reproduction, namely asexually or sexually

Parts – Parts of Seeds in Plants

In general, seeds have 3 important parts, namely the outer shell, embryo and food reserves. However, some types of seeds also form an inner layer after the outer shell which is called the sarcotesta.

Sarkotesta itself is divided into 2 parts, namely Endotesta and sklerotesta. Endotesta itself is the innermost layer with a fleshy and thinner structure, while the sclerotesta is the middle layer with a thick and hard structure.

The parts of the seed are as follows:

1. The outer shell of the seed

The testa, also called the outer shell of the seed, is formed from the joining of the ovule interguments during the process of seed formation. A layer of cells resembling or nearly pallidase-like without intercellular spaces is called malpighi cells. These cells can be found in several types of seed cults. The seed coat itself is composed of lignin, chitin and cellulose substances.

2. Embryo

The embryo is the part of the seed which is the starting point for the growth of a plant or plant. The embryo itself is formed from the meeting between male gametes and female gametes.

The embryo has its own position inside the seed, precisely at the core of the seed and is surrounded by existing food reserves. The development of the embryo into the radicle or root candidates and cotyledons or ovaries.

4. Food reserves

All seeds have food reserves, even some plants or plants make seeds the main food reserve. The function of the food reserve itself is to strengthen the seed’s absorption of water and nutrients for plant growth.

In addition to being a food source in the reserve, the embryo itself will also develop until the seeds form roots.

Structure of Plant Seeds

Explanation of the structure of the seeds include the following:

1. Seed coat or Spermodermis

The seed coat is the outermost layer of the seed that covers all parts of the seed. The first part of the seed is the seed coat. Seed coat in closed plants / angiosperms consists of two layers, namely:

  • Outer layer of skin/testa. Serves as a protector of the inside of the seed. The shape of this layer varies, some are stiff like leather, some are thin or some are hard like stone and wood.
  • Inner layer of skin/tegmen. This thinner layer is known as the epidermis.

While the seed coat in open plants / gymnosperms consists of three layers, namely:

  • The outer skin or sarcotesta is thick and fleshy skin and in certain situations changes color from light to dark color.
  • The middle skin or sclerosta is a hard and strong skin, and woody and resembles the inner skin/endocarpium on a stone fruit.
  • The inner skin or endotesta is a layer of skin that is attached to the part of the seed that has a shape like a thin membrane

2. Umbilical cord or Funiculus

The umbilical cord or funiculus is the part of the seed that is shaped like a stalk that connects the seed to the seed. When the seeds are cooked, they will be separated from the umbilical cord and only the scars are visible, commonly known as the seed navel.

3. Core seeds or Nucleues Seminis

Is the core of the seed. The seed core itself consists of:

4. Institution or Embryo

Embryos are individual candidates for new plants that grow from seeds in favorable or favorable environmental conditions. Inside the embryo consists of leaves or cotyledons, root candidates or radicles, stems or cauliculus and albumen or white institutions.

5. Institute Leaves

Institutional leaves or cotyledons are the first leaves to grow during germination after the emergence of institutional roots. Its function is as a place to store food. In addition, as a tool for sucking food from pistils for institutions and tools for photosynthesis.

6. Radicle

Institutional roots or radicles are root candidates that originate from seeds. Usually seen in dicot plants, whose roots grow continuously to form a taproot.

7. Stem of the institution

The institute stem or cauliculus is divided into two, namely the segment of the stem that is under the leaf of the institution called the internodium hypocotylum, while the segment of the stem that is above the leaf of the institution is called the internodium epicotylum.

8. Albumen

The white body or albumen is the part of the seed that contains food reserves for initial growth before it can make its own food. Because, not all seed plants have white institutions. The existence of white matter is divided into two, namely white outside/perispermium and white inside or endospermium.

Characteristics of Seed Plants

Seeds will be produced by flowers after pollination and fertilization. Other characteristics are:

  1. Breeding is obtained by seeds produced by conifers or flowers
  2. Male sex cells to female sex cells through the pollen tube
  3. Tissues in seed plants have complex vessels
  4. In general, seed plants have chlorophyll for photosynthesis, which is the basic process of making food in plants.

Reproduction of Seed Plants

Sexual or generative reproduction by forming seeds which begins with the formation of gametogenesis, then pollination or pollination, fusion occurs between male and female gametes which produce embryos.

There are several stages, among others, gametogenesis is the formation of sex cells or gametes. The gametes occur in the flower. Pollination or pollination is the attachment of pollen to the stigma or the attachment of pollen to the ovary.

While asexual or vegetative propagation is carried out with vegetative organs such as rhizomes, shoots or solon.

Vegetative reproduction is carried out by means of reproduction without going through marriage between male and female gametes. Thus, it will produce offspring that are the same as its parent.

Well, that’s an explanation of the definition of seeds, types, functions, characteristics, parts, structure, characteristics and reproduction of seed plants in everyday life. Hope it is useful.