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甜橙净光合速率的季节性变化,春梢叶片呈双峰形,高峰出现在6月和9月,光合值为19.5953mgCO_2/dm~2·h 和25.1490mgCO_2/dm~2·h;秋叶净光合速率也呈双峰形,第一次高峰出现在10月上旬,第二次高峰在次年5月中旬,光合值分别是17.9051mgCO_2/dm~2·h 和17.4264mgCO_2/dm~2·h。叶片光合产物输出率的变化趋势与叶片的光合速率基本一致,一般占总光合量的30～50%左右。叶绿素含量的季节性变化与光合速率相似,春叶呈极显著相关,r=0.8937~(**)。甜橙密植果园树冠各部位的相对光照强度随树高的增加而增大,随叶幕层的加深而急剧减弱,栽植密度主要影响叶幕层的光照强度。
The seasonal changes of net photosynthetic rate of sweet orange showed that the leaves of spring shoot were bimodal in shape, the peak appeared in June and September, the photosynthetic rate was 19.5953mgCO 2 / dm ~ 2 · h and 25.1490mgCO 2 / dm ~ 2 · h. The net photosynthetic rate also showed a bimodal shape with the first peak appearing in early October and the second peak in the middle of May next year with photosynthetic rates of 17.9051 mgCO 2 / dm -2 · h and 17.4264 mgCO 2 / dm 2 · h The change trend of photosynthate output rate of leaves is basically the same with the photosynthetic rate of leaves, and generally accounts for 30 ~ 50% of the total photosynthetic rate. The seasonal variation of chlorophyll content was similar to photosynthetic rate, and the spring leaf showed a very significant correlation (r = 0.8937 ~ (**)). The relative light intensity of the crown of sweet orange orchards increased with the increase of tree height and sharply decreased with the deepening of leaf curtain. The planting density mainly affected the light intensity of leaf curtain.