Explain the translocation of food molecules in plants.

Asked by abhinav_1995 | 26th Dec, 2009, 03:57: PM

Expert Answer:

Translocation is the movement of nutrients and other materials from leaves to other tissues throughout the plant. Plants produce carbohydrates (sugars) in their leaves by photosynthesis, but nonphotosynthetic parts of the plant also require carbohydrates and other organic and nonorganic materials. For 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.

Translocation occurs within a series of cells known as the phloem pathway, or phloem transport system, with phloem being the principal food-conducting tissue in vascular plants. Nutrients are translocated in the phloem as solutes in a solution called phloem sap. The predominant nutrients translocated are sugars, amino acids, and minerals, with sugar being the most concentrated solute in the phloem sap.

Translocation occurs in both upward and downward directions. Ascent of sap occurs largely using simple physical forces like transpiration and root pressure, but translocation is achieved by utilising energy.

 

Answered by  | 28th Dec, 2009, 07:42: AM

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