Question 1 Name the two conducting tissues of plants?
Question 2 What is the function of transpiration?
Question 3 What is transpiration?
Question 4 Name the two kinds of cells of xylem?
Question 5 Name the various cells through which water moves upwards to reach the leaves?
Question 6 What is translocation?
Question 7 How does transpiration help in upward movement of water from roots to leaves?
Question 8 Explain the mechanism of transport of minerals in plants?
Question 9 Name 4 types of xylem cells?
Question 10 Name 4 types of phloem cells?
Transportation in Plants
Transport system is less elaborate in plants because they are comparatively less active and require less supply of materials either from outside or synthesised by plants themselves.
In plants during respiration there is intake of oxygen and release of carbon dioxide. They obtain gases from atmosphere through roots, stomata in leaves, lenticels in woody roots and stems.
Exchange of gases between cell and environment take place by the process of diffusion.
In plants, water and minerals are absorbed mainly from the soil and then transported upward through specific tissues called xylem.
Organic food which are synthesised in green leaves and hormones are transported through special tissue called phloem.
Transport of Water
Xylem is made up of 4 kinds of cells : Tracheids, vessels, xylem parenchyma, xylem fibres.
It involves 3 interconnected processes:
1) Absorption of water and mineral
The water and minerals are absorbed by plants from the soil through root hairs and root apex.
There is difference in concentration between soil solution and root hairs.
Water molecules moves from higher water potential to lower water potential and then to xylem vessels and tracheids.
There is steady movement of water from soil to roots to xylem vessels and tracheids, creating a column of water that is steadily pushed upwards.
2) Upward movement of water and minerals
Movement of water and minerals is due to root pressure(root absorb water and exerts a pressure which pushes the water upward)or transpiration pull(transpiration pull generated in leaves pull the water column filled in xylem vessels and tracheids)
3) Transpiration ie loss of water in the form of vapours
The loss of water in the form of vapours from the living tissue of aerial parts is called as transpiration.
It occurs mainly by the process of diffusion through stomata (Tiny pores, present at lower side of leaf, kidney shaped guard cell surrounding them, they regulate opening and closing of stomata)
Transpiration helps in the absorption and upward movement of water and minerals dissolved in it from roots to leaves in temperature regulation)
Transport of Food
Phloem is made up of Sieve tubes, companion cells, phloem parenchyma and phloem fibres.
The hormones required for growth and development are synthesised at shoot and root tip.
Phloem is a complex permanent tissue running parallel with xylem strands.
Transport of soluble products of photosynthesis is called translocation.