The response of gas exchange parameters including net photosynthesis rate (<i>P</i>_n), stomatal conductance (<i>g</i>_s) and internal-to-ambient CO₂ concentration ratio (<i>C</i>_i/<i>C</i>_a) in bean source leaves to the treatment of low sink demand at 1300 h from the 1^st to 21^st day after removing the sink of roots and pods.

<p>Each value represents the mean of five replicates, and error bars represent ± S.E. The asterisks *, ** and *** indicate significant difference at <i>P</i><0.05, 0.01 and 0.001 between the control and treatment, respectively.