Effect of Fruit Removal on Net Gas Exchange of Avocado Leaves

Abstract

Abstract All but 10 current-year leaves were removed from girdled branches of avocado ( Persea americana Mill.) trees having one remaining fruit or all fruit removed. Removing all fruit resulted in increased leaf dry weight per area (W a ), a 250% increase in the number of starch grains in leaves, and a reduction in leaf conductance (g l ) and net CO 2 assimilation (A). Internal CO 2 concentration (C i ) was lower for leaves of branches with fruit than for leaves of branches without fruit. The results suggest that the accumulation of starch in defruited, girdled branches results in an inhibition of A. The data suggest that the increased g l associated with the presence of avocado fruit is possibly a result of increased A and reduced C i levels.