不同家系马尾松维持水分平衡能力及综合评价

Ability to Maintain Water of Masson Pine from Different Family

在土壤干旱胁迫下,通过测定10个不同家系马尾松针叶保水力、蒸腾速率、气孔导度等指标,对不同家系马尾松维持水分平衡能力进行了研究。结果表明,各家系离体针叶在220h以上还未失水达到基本恒重,显示出很强的抗脱水能力。气孔导度随叶水势的下降而下降,变化趋势可用对数函数(y=a+blnx,b<0)拟合。各家系气孔完全关闭时的叶水势值较高,为-1.98～-2.99Mpa,有较强的维持水分平衡能力。苗木蒸腾速率随叶水势下降而变化的趋势可用指数函数(y=aebx,b<0)拟合,总体看各家系蒸腾速率都较小,表现出很强的控制蒸腾失水能力。蒸腾速率与气孔导度呈对数关系(y=a+blnx,b>0),表明轻度水分胁迫就使气孔导度下降,气孔阻力增加,蒸腾速率也随之下降。综合评价表明,不同家系马尾松都具有较强的维持水分平衡的能力,但家系间有所差异,其中以127、75、83、456家系维持体内水分平衡的能力最强,23、38、464家系次之,而186、20家系和台江(Taijiang)种源则相对较弱。

During soil drought stress, the authors studied on the adaptability to maintain water balance of Masson pine (Pinus massoniana Lamb) from ten families, by means of many aspects such as the ability to maintain water balance, transpiration rate and stomata conduction. The results showed each family could keep over 220 hours from dehydration to permanent weight, which showed strong ability to resist soil drought stress. With the descendant of leaf water potential the stomata conduction decrease, the trend could be fitted with logarithmic equation (y=a+blnx,b<0). When the stomata was entirely closed, leaf water potential was 1.98～ 2.99 Mpa. The descendant of transpiration rate with leaf water potential of different families could be fitted with exponent function( y=aebx, b<0). The relationship between the transpiration rate and the stomata conductance could be fitted with exponent function (y=a+blnx,b>0). The authors made a comprehensive appraisal to all families, the ability to maintain water of 127,75, 83 and 456 families were stronger than those of 23,38,464. Furthermore, 186,20 families and the families in Taijiang province were relatively weak.