PHOTOSYNTHESIS OF TWO WALNUT CULTIVARS AS INFLUENCED BY FRUITING

Net photosynthetic rate (P_N), chlorophyll content (Chl content), transpiration rate (E) and intercellular CO₂ concentration (C_i) of leaves on fruiting and vegetative shoots of J. hopeiensis Hu. (‘Yihe 1’) and J. regia L. (‘Qingxiang’) were measured using a CI-301PS open gas analysis system. The results indicated that the fruit affected the P_N rate, but the effect was inconsistent. From flowering to fruit oil pro¬duction period, the P_N of leaves on the fruiting shoots of the both cultivars was higher than that on the vegetative shoots. During the fruit maturity period, the P_N and Chl content of leaves on the fruit-bearing shoots of both cultivars were lower than that on the growing shoots. There was significant correlation between P_N and Chl content, E and C_i.