Plant Transport and Physiology

The pulvinus is a joint-like thickening at the base of a leaf or leaflet that facilitates leaf movement in response to stimuli, such as in the 'Touch-me-not' (Mimosa pudica) plant.

Mimosa pudica's leaf folding response (thigmonasty) occurs due to rapid turgor pressure changes in pulvini cells - specialized motor cells at leaf bases. When touched, potassium ions exit these cells, water follows, and turgor drops.

Xylem is the specialized plant tissue responsible for the upward transport of water and dissolved minerals from the roots to the rest of the plant.

Transpiration is the biological process by which plants release water vapor from their leaves into the atmosphere.

Xylem conveys water and dissolved minerals from the roots to the rest of the plant.

vaporization in case of plants is known as transpiration.

Like all other living cells of the plants, the root cells also need oxygen to generate energy. Roots take up air from the air spaces present between the soil particles.

Desert plant prevent water loss by less transpiration.

Air helps in the dispersal of seeds and pollen of flowers of several plants. Air is not the source of nitrogren for plants which they take from soil alone.

The plants and animals depend on each other for exchange of oxygen and carbon dioxide from air. Plants use up large amounts of carbon dioxide and give out oxygen during photosynthesis and hence they help to maintain the level of gases in the air. 

Hydrilla is an aquatic plant i.e. it lives in water. Function of roots is to fix the plant in the soil and to absorb water from the soil both these requirements get reduced in aquatic plants so hydrilla has got poorly developed roots. Its function is to hold the plant in its place against the water currents.

Aquatic plants are the plants living in water. These plants have to face the water current that is why their leaves are narrower and ribbon like so as they can easily bend against the water flow without being broken down. Conduction of water is the function of internal xylem tissue and has nothing to do with leaf structure.

Plants are the living organisms which stay fixed at one point, do not move as a whole from one place to another rather show differential movement of its parts like leaves, flower etc. food and water are being transported within the pant from one to another part. Flower is closed in the initial stage but opens out when grow fully. Stomata keeps on opening and closing depending upon the requirements.

Cactus is a plant which grow in deserts. Thus to avoid the loss of excess water through stomata its leaves are reduced to spine like structures and it is the stem in these plants which is green in colour and performs the functions of photosynthesis.