Plant Transport and Physiology

Carbon dioxide from air is taken in through the tiny pores present on the surface of the leaves. These pores are surrounded by ‘guard cells’. Such pores are called stomata.

Adaptations are special features that allow a plant or animal to live in a particular place or habitat.

Yes, it is the correct answer. The process of preparation of food in plants does not take place with the help of osmosis. Photosynthesis takes place in the presence of sunlight with chlorophyll, water and air.

Stomata are the openings that are generally present on the lower surface of the leaves through which the gases and water vapour diffuse in and out easily. The oxygen diffuses in through the stomata and then enters the leaf cells. Similarly, the carbon dioxide produced by the leaf cells diffuses out through the stomata.

Condensation is the change of water from its gaseous form (water vapour) into liquid water. Perspiration, also known as sweating or diaphoresis, is the production of fluids secreted by the sweat glands in the skin of mammals. Respiration is defined as the movement of oxygen from the outside air to the cells within tissues, and the transport of carbon dioxide in the opposite direction. Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapour and is released in the atmosphere. 

When stomata are sealed or closed, transpiration and gas exchange (including CO2 intake for photosynthesis) are greatly reduced or stopped. However, guttation can still occur because it is driven by root pressure and takes place through specialized structures called hydathodes, not through stomata. Guttation typically occurs at night or early morning when transpiration is minimal.

Water movement up the xylem vessel is driven by transpiration pull and cohesion-tension mechanism, not osmosis. Osmosis is the movement of water across a semi-permeable membrane from low to high solute concentration. The other options (A, B, D) all involve water crossing cell membranes (root hair cells), which do involve osmosis.

 Excess water is excreted from plants through the stomata in leaves.  Plants can get rid of excess water by transpiration and guttation.

Resins and gums are the excretory products of plants that are stored in xylem (water and minerals conducting channel). Resin is a viscous, thick and sticky liquid, secreted by some plants especially by coniferous trees. Gums are mucilaginous substances secreted by the plants. Cellulose is the most abundant component of plant cell walls. Lignin is a component of cell walls, which binds cellulose fibres, confers strength and hardens the wood.

 Plants get rid off excess water by the process called transpiration. Transpiration is the loss of water in the vapour form from the exposed surfaces of plants like leaves, stem, etc. Waste products may be stored in leaves that fall off. Also, there are other waste products, which are stored as resins and gums in old xylem (water conducting system). Translocation is the means to transport food from leaves to other parts of the plant or transport of water from the roots to other parts of the plant.

Waste products are stored as resins in old xylem plants. Some plant wastes are very useful to human beings, e.g. rubber, latex, gum, resins and essential oils like eucalyptus or sandalwood oil. 

Metabolism will be adversely affected when the leaves are coated with wax on their upper surfaces in lotus. The reason is the upper surface is above the water and receives sunlight and air directly in contact with the atmosphere.

This option is correct. It is translocated in the form of sugar,  which on accumulating in tubers are enzymatically converted into starch.

Opening and closing of stomata in angiosperms is due to changes in turgor pressure of guard cells. As the turgor pressure of the guard cells changes, the opening and closing of stomata occurs.

Organic substances such as sugars translocated in the phloem, can be demonstrated by ringing the stem.