Why sucrose and not glucose is the main carbohydrate translocated in phloem?
glucose is more readily soluble ,so cannot be stored
Carbohydrates are moved about plants in the sieve tubes of the phloem. This movement of materials from one part of a plant to another is called translocation. Carbohydrate is normally translocated as sucrose. If you inject glucose or fructose into a plant, it will probably be converted into sucrose before translocation.
Vegetables are obtained from a variety of plant parts eg roots, leaves, stems. What they have in common the the use of starch as a way of storing food. Starch is made by the plant from glucose (sugar). Glucose is made in the leaves by the process of photosynthesis. The glucose is turned into sucrose and then transported through cells called phloem to other parts of the plant. When it reaches its destination the sucrose…
In a flowering plant, the glucose is formed during photosynthesis is stored in the form of starch(insoluble)...but when it is needed, it is converted to sucrose(soluble) which flows through the phloem and is utilized, while rest is again converted to starch and stored hence, it is transported in the form of sucrose
Water is transported through the plant in Xylem vessels, these begin in the roots and end in the leaves of the plant; water is translocated through a combination of "transpirational pull" and capillary action. Xylem is one of two "conductive" tissues responsible for moving water and the products of photosynthesis (glucose) through the plant, the tissue responsible for moving the "food" around is Phloem.
C12H22O11 Sucrose and starch are the end products of photosynthesis. Sucrose, formed in the leaf cytosol, is transported through the phloem to the sink tissues where it is metabolized or stored in the vacuole. During the night, sucrose is formed from starch, produced and stored in the chloroplasts during the day.