Question

Give reason
1. Plants that live in deserts are adapted to constant water stress.
2.Food is transported in the form of sucrose in plants.​

Answer 1

Plants that live in deserts are adapted to constant water stress.

• Think of a desert plant.

• Was it cactus?

• Cactus leaves are reduced to spines.

• Spines help in the loss of water through transpiration.

• They are also covered with a wax coating to prevent the loss of water.

• The stomatas of the plant remain closed both during day and night to avoid water loss.

• This is done to complete the process of photosynthesis.

                                                                     

Food is transported in the form of sucrose in plants.​

• Sucrose is water soluble.

• Hence, it can be easily transported to other parts of the plant body.

• Sucrose contains more energy.

• Sucrose has a low viscosity even at high concentrations.

                                                                     

Answer 2

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✒Desert plants have a shallow and extensive root system to collect water from very depth. Some plants possess an water efficient version of photosynthesis, known as CAM(Crassulacean Acid Metabolism).

✒ In the water stressed condition, the stomatas of the plant remain closed both during day and night to avoid water loss.

${ \sf{ \red{Answer2}}}$

✒Sucrose is formed in the cytosol of photosynthesizing cells from fructose and glucose and is then transported to other parts of the plant.

This process is favorable because

✒ Sucrose contains more energy than a monosaccharide, so it is more energy efficient, both in transport as in storage.

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${ \bf{ \underline{Main \: Points}}}$

◆Water stress :-

Plants experience water stress either when the water supply to their roots becomes limiting, or when the transpiration rate becomes intense. Water stress is primarily caused by a water deficit, such as a drought or high soil salinity.

◆Sucrose :-

Sucrose is the end product of photosynthesis and the primary sugar transported in the phloem of most plants. Sucrose synthase (SuSy) is a glycosyl transferase enzyme that plays a key role in sugar metabolism, primarily in sink tissues.

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