Influence of sink competition on peduncle histogenesis in kiwifruit

Abstract

Just before flowering, inflorescences with one terminal and two lateral flowers were thinned according to the following treatments: (1) no thinning (control); (2) inflorescence with a main and one lateral flower, (3) inflorescence with only the main flower, and (4) inflorescence with only a lateral flower. The terminal fruit grew at the same rate in all conditions. A single lateral fruit did not grow more than the controls. At harvest the main fruit showed higher weight Histo-anatomical observations showed that primary xylem differentiation on the main flower peduncle appeared earlier than in laterals. When just a lateral flower was maintained, there was formation of secondary xylem only in distal parts of the peduncle. The removal of the main fruit did not change the vascular differentiation of lateral peduncles. The terminal peduncle showed a radial arrangement which did not develop in lateral ones when the main flower was cut off. Therefore, in the inflorescence, fruit growth may be partly limited by the anatomical features of the fruit peduncle which is established early during flower development Removal of sink competition within the inflorescence did not change xylem conductivity and fruit growth. © 1991 Crown copyright.