核桃光合特性的研究

Studies on the Photosynthetic Characteristics of English Walnut

核桃的光补偿点为0.7klx,光饱和点为60klx;在60klx光照条件下,核桃光合作用的最适温度为27℃;核桃光合强度的年周期变化呈一双峰曲线,主峰出现在5月中旬,次峰出现在7月中旬;在6月下旬晴天和晴转多云天气,测得的光合强度日变化,均呈一单峰曲线,高峰出现在11时左右;结果枝叶片光合强度高于发育枝,生长后期结果枝上发出的果前枝叶片光合强度较高;不同品种间光合强度有明显差异,但早实核桃与晚实核桃之间无明显差异。

In this experiment, the photosynthetic characteristics of English walnut ( Juglans regia L. ) were studied. The main results were as follows : 1. The light compensation point of photosynthesis in English walnut was 0.7 klx, and the light saturation point was 60 klx. The optimum temperature for photosynthesis in English walnut was 27℃ when light intensity was 60 klx. 2. The seasonal changes of net photosynthetic rate ( Pn) presented a two-peak pattern, the first (bigger) ]peak reached in mid-May, and the second (smaller) in mid-July. 3. In a sunny day and a sunny turning to cloudy day of mid-June, the diurnal changes of Pn all showed a single-peak curve, the maximum peak appeared at 11 o' colck in the morning. 4. The Pn of fruiting shoot leaves was higher than that of developmental shoot leaves. In late growing season, the Pn of apical slender branchlets leaves (which appear on the apical partof a bearing branch) was high. 5. There was signi-ficant difference in Pn of the leaves among English walnut varieties, but the difference between early-bearing type and late-bearing type of English walnut was not significant.