F. Answer the following questions:
1. What is the importance of water to plants?
What are the three main characteristics of roots for absorbing water?
3. State two significance of transpiration.
4. Name the forces that contribute to the ascent of sap.
5. How is transpiration pull set up in the plant?
6. Describe an experiment to demonstrate osmosis.
7. State the functions and deficiency symptoms of the following nutrients-Magnesium, iron,
manganese, nitrogen.
8. Describe the structure and function of phloem tissue.
9. State the relation between transpiration and absorption of water.
10. List the external factors affecting transpiration.
Answers
Ans 1 Water is used for transpiration carrier of nutrients from the soil to green plant tissues. ... Water is essential for the germination of seeds, growth of plant roots, and nutrition and multiplication of soil organism. Water is essential in hydraulic process in the plant. It helps in the conversion of starch to sugar.
Ans 2 The characteristics of roots for absorbing water are as follows:
Surface area of roots is enormous.Root hair contain cell sap, of a higher concentration than that of the surrounding water.Root hairs have thin walls.
Ans 3 Cools the surface of the leaves. Helps in growth and development. It controls the temperature of the plants. Allows the movement of minerals from the soil to different parts of the plant.
Ans 4 Forces Contributing to Ascent of Sap water movement is regulated by root pressure and transpiration. ...High temperature, atmospheric pressure, wind velocity and low atmospheric humidity influence the ascent of sap as that of transpiration.
And 5 The Role of Transpiration Pull in PlantsDuring transpiration process, water molecules get evaporated from the stomata. ... This results in upward pull of water from the root to the mesophyll cells by generating a negative pressure in xylem vessels to pull the water from the soil.
Ans 6 The level in the capillary tube increases because of the fact that osmotic pressure of the sugar solution is higher than that of the water, and the water moves through the semipermeable membrane of potato from petri-dish into the cavity. So the experiment shows that the phenomenon of osmosis.
Ans 8 Phloem is the vascular tissue in charge of transport and distribution of the organic nutrients. The phloem is also a pathway to signaling molecules and has a structural function in the plant body. It is typically composed of three cell types: sieve elements, parenchyma, and sclerenchyma.
Ans 9 Transpiration is the loss of water from a plant in the form of water vapor. Water is absorbed by roots from the soil and transported as a liquid to the leaves via xylem. In the leaves, small pores allow water to escape as a vapor. Of all the water absorbed by plants, less than 5% remains in the plant for growth.
Ans 10
Factors affecting transpirationAtmospheric humidity. When the atmosphere is humid, the rate of transpiration is reduced. ...Temperature. An increase in temperature brings about an increase in the rate of transpiration by lowering the relative humidity and wider opening of stomata.
Wind. ...
Light. ...
Available soil water. ...
CO2.