Organic substances are translocated in upward and downward directions

Organic substances are translocated in upward and downward directions through phloem. Answerthe following
(i) What is the effect of blocking the phloem?
(ii) What do you find in chemical analysis of phloem sap?

(i) The blocking results in the stoppage of translocation of organic solutes.
(ii) The phloem sap contains three major classes of organic compounds-organic acids, amino acids and sucrose besides some cations, anions and hormones. Sucrose is the major metabolite, which is supplied from leaves to other parts of the plant. Of total solute content in the phloem, sucrose content ranges from 50-85 %.