STUDENTS INDEPENDENT WORK ZHANABAY ZHANAT TPM Morphology of Flowering Plants. - презентация

1 STUDENTS INDEPENDENT WORK ZHANABAY ZHANAT TPM Morphology of Flowering Plants

2 The Root The Stem The Leaf The Flower The Fruit The Seed Medicine

3 MORPHOLOGY OF FLOWERING PLANTS The wide range in the structure of higher plants will never fail to fascinate us. Even though the angiosperms show such a large diversity in external structure or morphology, they are all characterised by presence of roots, stems, leaves, flowers and fruits

4 THE ROOT The root is underground part of the plant and develops from elongation of radicle of the embryo. In majority of the plants the direct elongation of the radicle leads to the formation of primary root which grows inside the soil. The main functions of the root system are absorption of water and minerals from the soil, providing a proper anchorage to the plant parts, storing reserve food material and synthesis of plant growth regulators.

5 Various types of root: Tap root: The primary roots and its branches constitute the tap root system.

6 Fibrous root: the primary root is short lived and is replaced by a large number of roots. These roots originate from the base of the stem and constitute the fibrous root system

7 Adventitious root: In some plants, like grass, Monstera and the banyan tree, roots arise from parts of the plant other than the radicle and are called adventitious roots

8 THE STEM Stem is the aerial part of the plant and develops from plumule of the embryo. The stem bears nodes and internodes. The region of the stem where leaves are born are called nodes. Internodes are the portions between two nodes. The main function of the stem is spreading out branches bearing leaves, flowers and fruits. It conducts water, minerals and photosynthates. Some stems perform the function of storage of food, support, protection and of vegetative propagation.

9 Modifications of stem for : storage The stem may not always be typically like what they are expected to be. They are modified to perform different functions. Underground stems of potato, ginger, are modified to store food in them. They also act as organs of perennation to tide over conditions unfavourable for growth.

10 Modifications of stem for : suppor t Stem tendrils which develop from axillary buds, are slender and spirally coiled and help plants to climb such as in gourds (cucumber, pumpkins, watermelon) and grapevines.

11 Modifications of stem for : protection Axillary buds of stems may also get modified into woody, straight and pointed thorns. Thorns are found in many plants such as Citrus, Bougainvillea. They protect plants from browsing animals.

12 THE LEAF The leaf is an expanded organ of a plant, produced laterally from a stem or branch.

13 Parts of a leaf: It develops at the node and bears a bud in its axil. The axillary bud later develops into a branch. The leaf is attached to the stem by the leaf base. The petiole help hold the blade to light. The lamina is the green expanded part of the leaf.

14 Types of Leaves A leaf is said to be simple, when its lamina is entire or when incised, the incisions do not touch the midrib. When the incisions of the lamina reach up to the midrib breaking it into a number of leaflets, the leaf is called compound. The compound leaves may be of two types : pinnately compound leaf palmately compound leaves

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16 THE FLOWER The flower is the reproductive unit in the angiosperms. It is meant for sexual reproduction. A typical flower has four different kinds of whorls arranged successively on the swollen end of the stalk or pedicel, called thalamus or receptacle. These are calyx, corolla, androecium and gynoecium.

17 Parts of a Flower

18 The calyx is the outermost whorl of the flower and the members are called sepals. Corolla is composed of petals. Petals are usually brightly coloured to attract insects for pollination. Androecium is composed of stamens. Gynoecium is the female reproductive part of the flower and is made up of one or more carpels.

19 THE FRUIT The fruit is a characteristic feature of the flowering plants. It is a mature or ripened ovary, developed after fertilisation. If a fruit is formed without fertilisation of the ovary, it is called a parthenocarpic fruit. Generally, the fruit consists of a wall or pericarp and seeds. The pericarp may be dry or fleshy. When pericarp is thick and fleshy, it is differentiated into the outer epicarp, the middle mesocarp and the inner endocarp.

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21 THE SEED The ovules after fertilisation, develop into seeds. A seed is made up of a seed coat and an embryo. The embryo is made up of a radicle, an embryonal axis and one (as in wheat, maize) or two cotyledons (as in gram and pea).

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