科尔沁沙地樟子松能否发生冬季“生理干旱”伤害

在内蒙古东部半干旱地区分别测定了春、秋两季栽植的樟子松苗越冬期间针叶含水量和蒸腾强度的变化，测定了针叶的致死临界含水量并在室内模拟了生理干旱伤害症状以探讨发生冬季生理干旱伤害的可能性．结果表明秋植苗针叶含水量１月份就已降到初始致死含水量以下而春植苗针叶含水量始终显著高于初始致死含水量并顺利越冬．含水量与蒸腾强度的对比表明甚至在冻土期内，针叶仍有某种水分补充来源．模拟实验中出现的针叶伤害症状和秋植苗野外伤害症状一致．结论认为该地区已正常成活的春季造林苗不大可能发生冬季生理干旱伤害．

Whether winter desiccation injuries of Pinus sylvestris var. mongolica occur on Keerqin sandy land

To know whether winter desiccation injuries of Pinus sylvestris var. mongolica occur in the semi -arid region of eastern Inner-mongolia,dynamics of needles'water content and transpiration rate of its seedlings planted in Spring and Autumn are monitored during overwintering period,and needles critical water content and symptoms of winter desiccation injuries are determined and simulated in laboratory.The results show that the needles'water content of seedlings planted in Autumn becomes significantly lower than their critical water content since January, while that of seedlings planted in Spring has a significantly higher water content than the critical value through the winter,which is beneficial to overwintering.The comparison of water content and transpiration rate indicates that there must have some water incomes for needles even in the soil frozen period.The simulated winter desiccation injury symptoms are similar to those occured on Autumn -planted seedlings in the field,but not observed on Spring-planted ones.It'S concluded that in this region,winter desiccation injuries may not occur in living seedlings planted in Spring.