Life Processes Test - 11

For plants, soil is richest and nearest source of raw materials as it is rich in minerals such as Nitrogen, Phosphorus, Potassium, etc., also, it has one of the important raw materials water.

Plants do not move and have a large proportion of dead cells in many tissues. Therefore, their energy needs are low and hence they can afford to have a slow transport system as compared to animals.

A plant absorbs water and minerals from soil through roots and transports it other parts like stem, leaves, flowers etc. It is through the xylem tissue that it does so. The xylem vessels and tracheids move water and minerals from roots of a plant to its leaves.

The phloem (tissue) transports products of photosynthesis from the leaves (where they are synthesized) to other parts of the plant.

ÂTranslocation is the movement of materials from leaves to other tissues throughout the plant.

ÂPlants produce carbohydrates (sugars) in their leaves by photosynthesis, but non-photosynthetic parts of the plant also require carbohydrates and other organic and nonorganic materials.

ÂFor this reason, nutrients are translocated from sources (regions of excess carbohydrates, primarily mature leaves) to sinks (regions where the carbohydrate is needed). Some important sinks are roots, flowers, fruits, stems, and developing leaves.

ÂIn xylem tissue, vessels and tracheids of the roots, stems and leaves are interconnected to form a continuous system of water-conducting channels reaching all parts of the plant.

ÂThe water which is lost through the stomata is replaced by water from xylem vessels.

The transpiration rate increases when the temperature increases. Water evaporates more quickly at higher temperatures.

As temperature increases, the rate of evaporation and transpiration increases.

Transpiration increases because at warmer temperatures plants open up their stomata and release more water vapor.