“ Importance of seed, seed structure & function ”.pptx

Importance of seed, seed structure & function

1. Topic on Department of Plant Physiology “ Importance of seed, seed structure & function ”

2. IMPORTANCE OF SEEDS Seeds are fertilized, mature ovules, the result of sexual reproduction in plants. Seeds are of immense biological and economic importance. Seeds contain high protein, starch and oil reserves that help in the early stages of growth and development in a plant. Many cereals and legumes major food sources for a large proportion of the world’s inhabitants. Rice, barley, wheat and maize are all seeds. Seeds are the first determinant of future plant development. the seeds of the key to success in cultivation. Seeds are crucial & essential inputs to increase crop yields per unit area. Green revolution was only possible with the production of generally high quality seeds with other qualities, namely high germination , high vigor, high physical purity & sound health. S o the green revolution is actually the seed revolution.

3. 8. Only seed of assured quality can be expected to respond to fertilizers & other inputs in the expected manner, other wise the seed of hope may turn into a seed of frustration. 9. Among the inputs used by farmers for the cheapest input of seed . These are basic inputs & form a small part of the total cost of cultivation. 10.Quality seed eventually increase the performance of the crop production factor. 11.Fruits and their seeds as a primary food source. For example , the diet of many parrots consists predominantly of seed from native plants such as Banksia, Dryandra and Eucalyptus.

4. Importance of seeds :- Strong germination Rapid growth Increase crop yield per unit area. High vigor Tolerance pest & disease. Resistance to seed or soil born disease. Increase production Market value Good seed higher crop emergence. Good seed requried less seed rate Reduce replanting .

5. Structure of Seed Seeds of different plants may vary in many ways, but the basic anatomy remains the same. A typical seed consists of the following parts:

6. Testa :  It is the outer coat of the seed that protects the embryonic plant. Micropyle :  It is a tiny pore in the testa that lies on the opposite of the tip of the radicle. It permits  water to enter the embryo before active germination. Hilum :  Is a scar left by the stalk which attached the ovule to the ovary wall before it became a seed. Cotyledon :   In some plants, this contains high  quantities  of starch and will provide a  source of food   for the developing embryo prior to germination, in other plants this role is performed by an  endosperm . In  monocotyledons , there is just one cotyledon whereas in  dicotyledons  there are two. Depending on the type of germination (epigeous or hypogeous ) the cotyledons may remain below ground or be pulled above ground . Radicle: It is embryonic root which will develop into the primary  root  of the plant. It is usually the first part of the embryo to push its way out of the seed during germination. Plumule :  This is the embryonic shoot. It appears as a bud which will give rise to the shoot and the remaining structures in the plant. Endosperm :  In many plants, a separate part for storage of starch develops and this is called the endosperm. It is seen in maize and wheat .

7. Functions of Seeds They help in germination of the new plant. The   seeds  contain food reservoirs in the form of cotyledons and endosperm. The seed coat is protective in nature which protects the embryo inside. Dormancy during unfavorable condition. Embryo nourishment :- seed protect & nourish the embryo or young plant. It gives seedling as faster start than a sporting of spore, because larger food reserves in seed.  

8. Parts of Seed and Their Functions A seed is a structure that encloses the embryo of a plant in a protective outer covering. Under favorable conditions of growth, a seed gives rise to a new plant, using the nutrients stored in them.  The union of the male and female reproductive cells inside the ripened ovule of a  flower helps in the formation of seeds in a plant. Different seeds have different sizes, shapes, and colors that participate in the reproduction of flowering plants. A typical seed consists of three main parts : 1 ) seed coat   2 ) endosperm and   3 ) embryo.

9. 1. Seed Coat They are the protective outer covering of a seed that is usually hard, thick, and brownish in color. The seed coat is formed from the outer covering of the ovule called the integument. It usually contains two layers :   i )  testa – the thick outer layer ii )  tegmen – the delicate inner layer. A seed coat has the following four parts : Micropyle  – the small opening present at one end of the seed coat , Funiculus  – the seed stalk with which the seed is attached to the fruit body, the integument, Hilum  – the region from which the seed breaks off from the fruit, leaving a scar, and Raphe  – the base of the funiculus that is fused with the integument  Functions Protecting the seed from physical and mechanical damage. Preventing the seed from germination even under favorable  conditions of growth ( seed dormancy ). Acting as a physical barrier against the entry of parasites.

10. 2) Endosperm It is a tissue that is rich in oil, starch, and protein. Depending on the presence or absence of endosperm, seeds are of two types :- Non-endospermic or exalbuminous seeds  – Characterized by the complete absence of the endosperm, such as the seeds of the pea plant, groundnut, and gram . ii) Endospermic or albuminous seeds – Characterized by the presence of the endosperm, such as the seeds of millets, palms, and lilies . Functions:- Storing of reserve foods that provide nourishment to the developing plant. Protecting the embryo, the next part of the seed, by acting as the mechanical barrier.

11. 3 ) Embryo They are the young plant that is developing inside the seed coat. An embryo contains the underdeveloped tissues of  leaves, stem, and roots of a plant. What are the Parts of an Embryo of a Seed Epicotyl – The tiny shoot of an embryo, from which the entire shoot system develops. The tip of the epicotyl is called plumule . Hypocotyl – The stage of transition for the growing shoot and  root  of the embryo Radicle – The tiny root of the embryo Cotyledons   – They are the leaves of the embryo that provide nourishment to the developing plant. There are two types of cotyledons present in flowering plants:  monocotyledonous  or monocots  – embryo with one cotyledon dicotyledonous  or dicots  – embryo with two cotyledons.  Functions Giving rise to a new complete new plant Storing food and nourishing the baby plant

12. . Related Articles: Howard C . Potts (1971 ) SEEDS - DEVELOPMENT , STRUCTURE AND FUNCTION. Page.no. 37-51 . The Parts of a Seed and Their Functions in Seed and Plant Development –  Cropsreview.com