Plant Transport and Physiology

This is the correct option. Water vapour is given out by the plants by the process of transpiration.

The intermixing of particles of two substances on their own is known as diffusion. Here, the particles of perfume spray mix in the air in the room and the whole room begins to smell nice. This is diffusion.

Plants eliminate some waste through diffusion. During the day, excess oxygen gas produced by photosynthesis is released through the stomata. Carbon dioxide produced by respiration is normally used up during photosynthesis. At night, however, as photosynthesis slows, carbon dioxide is not used up as fast as it is produced, and it is released as a waste product. Plants also produce oxygen as a by-product of photosynthesis. The oxygen that is not used for respiration is also excreted through the stomata.

 Waste products are stored as resins in old xylem plants. Plants also excrete some waste substances into the soil around them.

This is the correct answer. Plants also use stomata in leaves to excrete gaseous wastes. 

Sunken stomata are present in xerophytes.

In the old and woody stems and roots gaseous exchange occurs through lenticels.

In plants, water and minerals are moved upward through suction pull via xylem from the roots to all parts of the plant. Food synthesised in the leaves is transported to all parts of the plant by phloem.

Option 2 is correct. It is due to imbibition that the seeds absorb water and swell up.

The loss of water from the aerial part of the plant during day time is known as transpiration. So, option 2 is correct.

This is the correct answer as the small thick leaves minimise water loss from the plant through evaporation.

Water that remains in the soil after gravitational water is drained out.

Transfusion tissue serves the function of veins in cycas.

Xylem is one of the two types of transport tissue in vascular plants. Almost all plant cells produce primary cell walls. The major component of most primary walls in xylem is a disorganized network of cellulose fibrils, which allows the wall to stretch and expand as the cell grows. The secondary wall is deposited on the inner side of the primary wall during and after the cell has elongated or enlarged. The cellulose fibrils in the secondary wall are arranged in a regular fashion with alternating layers at fixed angles to the main axis of the cell. This reinforces the plant cell, while preserving the elastic nature of the primary wall. Most of the cell types in xylem can be distinguished based on the shape and features of the secondary cell wall. The walls of tracheids are made up of lignin. Xylem parenchyma cells store water, mineral nutrients and carbohydrates, and respond to wounding. Sclerenchyma cells of xylem provide mechanical support, defence and water transport.

Ans - 4