Effect of local source-sink manipulations on fruits and leaves of young pear trees

The effects of modifying local source-sink relations on fruit and leaf characteristics of young pear trees were evaluated. The following treatments were applied: early spur ringing (ESR) from 27 days after full bloom (DAFB), late spur ringing (LSR) from 97 DAFB, early 15 % spur leaf area removal (ELAR) and late l5 % spur leaf area removal (LLAR). ESR and LSR significantly inhibited fruit gowth, suggesting that the fruiting spurs were not fully autonomous in their carbon economy. ELAR and LLAR had little effect on fruit size; sink strength was demonstrated here, since the presence of the fruit caused an efficient transfer of photoassimilates.