核桃果实发育初期的水分状况

Water Potential in Different Parts of Walnut Tree During Early Period of Fruit Development

对在不同土壤水分条件下核桃枝条、叶片和果实水分含量动态与生长发育关系的研究结果表明,土壤供水不足时,树体水分亏缺,影响枝条生长和果实发育,降低坐果率.对有关水分生理指标测试表明,不同品种核桃叶水势(φW)日变化虽有差别,但相似,呈双峰型,叶φw愈低,晚上回升愈缓慢.叶φw日变化还受枝条上着生果实的影响,未着生果实枝条叶φw高于有果枝的.叶φw降低抑制光合产物的形成和累积.核桃蒸腾作用的日变化也呈双峰曲线,并与环境因子有密切关系.叶组织水分亏缺时,抗脱水能力强,具有一定的抗旱性能,晚熟品种优于早熟品种.

The water content in branches, leaves and fruits of walnut tree and fruit development at various soil water conditions during the early period of fruit development were studied. The results showed that though the diurnal variations of leaf water potential among different species of walnut were different, a similar pattern was found. The leaf water potential was also affected by the fruit existed. The decrease of leaf water potential inhibits the accumulation of dry materials. The transpiration of leaf showed double peaks in a day, which was closely related to environmental factors. The critical and natural saturation deficit measurements showed that the walnut leaf texture had stronger ability to resist dehydration, hence it could resist drought. Meanwhile , when water deficit occurs, late ripening species has a higher drought resistant ability than that of early ripening species.