Incorporation of ¹³C into carbohydrates and translocation in peanut plant

Abstract

To investigate the translocation form of photo assimilates in the peanut (Arachis hypogaea L.) plant, the plants were individually supplied with ¹³CO₂ for 30 min. In the leaves, during the ¹³CO₂ feeding period, fructose was most strongly labeled with ¹³C, followed by glucose, whereas a small amount of ¹³C was incorporated into sucrose. Within 1 d after the end of the ¹³CO₂ feeding, the ¹³C abundances and ¹³C amounts of fructose and glucose rapidly decreased within 120 min, but increased from 120 to 240 min, and markedly decreased afterwards, while those of sucrose remained constantly low. In the petioles and stems, during the ¹³C labeling period, the ¹³C abundances and ¹³C amounts of fructose and glucose were also remarkably higher than those of other sugars and after the end of the ¹³CO₂ supply, they remained constantly higher than those of sucrose. In the leaves, a large quantity of ¹³C was incorporated into starch during the ¹³C labeling period and within 120 min after the end of the ¹³CO₂ supply, and thereafter, rapidly metabolized. Similar results were observed for the petioles and stems. The above results indicate that the carbon currently fixed in the leaves is rapidly exported from the leaves to the petioles and stems and translocated to other parts of the plant in the forms of fructose and glucose but not sucrose, in contrast to other crops in which sucrose is the major translocation form of photoassimilates.

Key Words:

• ¹³C-fructose
• ¹³C-glucose
• ¹³C-sucrose
• peanut plant
• translocation form