Science, asked by kashish4040, 1 year ago

what are the various part of a plant explain giving necessary diagrams

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Answered by curioussoul
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Plant Parts – Root, Stem, Leaf, Transpiration, Respiration in Plants, F

Plant Parts and Their Functions – Structural Organization in Plants



The Root

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.In majority of the dicotyledonous plants, the direct elongation of the radicle leads to the formation of primary root which grows inside the soil. It bears lateral roots of several orders that are referred to as secondary, tertiary, etc. roots. The primary roots and its branches constitute the tap root system, as seen in the mustard plant.In monocotyledonous plants, 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, as seen in the wheat plant.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.



The root is covered at the apex by a thimble-like structure called the root cap. It protects the tender apex of the root as it makes its way through the soil.Tap roots of carrot, turnip and adventitious roots of sweet potato, get swollen and store food.Hanging structures that support a banyan tree are called prop roots. Similarly, the stems of maize and sugarcane have supporting roots coming out of the lower nodes of the stem. These are called stilt roots.In some plants such as Rhizophora growing in swampy areas, many roots come out of the ground and grow vertically upwards. Such roots, called pneumatophores, help to get oxygen for respiration.

The Stem

The region of the stem where leaves are born are called nodes while internodes are the portions between two nodes.Some stems perform the function of storage of food, support, protection and of vegetative propagation.Underground stems of potato, ginger, turmeric, zaminkand, colocasia are modified to store food in them.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.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.Some plants of arid regions modify their stems into flattened (Opuntia), or fleshy cylindrical (Euphorbia) structures. They contain chlorophyll and carry out photosynthesis.Underground stems of some plants such as grass and strawberry, etc., spread to new niches and when older parts die new plants are formed.

The Leaf

Leaves originate from shoot apical meristems. Leaf develops at the node and bears a bud in its axil. The axillary bud later develops into a branch.A typical leaf consists of three main parts: leaf base, petiole and lamina.The petiole help hold the blade to light. Long thin flexible petioles allow leaf blades to flutter in wind, thereby cooling the leaf and bringing fresh air to leaf surface.The lamina or the leaf blade is the green expanded part of the leaf with veins and veinlets. There is, usually, a middle prominent vein, which is known as the midrib. Veins provide rigidity to the leaf blade and act as channels of transport for water, minerals and food materials.

Leaf Venation

The arrangement of veins and the veinlets in the lamina of leaf is termed as venation.When the veinlets form a network, the venation is termed as reticulate. When the veins run parallel to each other within a lamina, the venation is termed as parallel.Leaves of dicotyledonous plants generally possess reticulate venation, while parallel venation is the characteristic of most monocotyledons.



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