驼绒藜等8种耐旱灌木持水力分析

采用切枝自然脱水法测定了驼绒藜等8种耐旱植物的持水力及几个相关参数。结果表明,随着脱水时间的延续,植物间失水率的差异先是由小增大,后又趋于缩小,规律性十分明显。分析表明,个体间失水率差异与植物间失水率差异具有相同的消长模式,且二者峰值的时间进程基本吻合,从而导致植物间差异显著性峰值向右偏移。提出Logistic方程拟合法,认为方程拐点是植物种类间和个体间生理活性变化最大时期的客观标志之一。拐点是失水率曲线上多点信息的综合体现,且具有动态性质,因而相对于其他点状体系或静态标准,拐点用于持水力的判断表现出最高效率。依据以拐点为核心的失水率体系,将8种灌木的耐旱性分为3组。特别针对华北驼绒藜所表现出的超强的耐旱性参数,对华北驼绒藜与驼绒藜相对旱生地位的传统认识提出了质疑。

Analysis on water retention of 8 xerophyte shrubs including Ceratoides spp.

Water retentions and several related parameters on detached branches of 8 xerophyte shrubs including Ceratoides spp. were studied by the method of natural dehydration. The result showed that dehydration deviations between plants represented a obvious inerratic: going with the dehydration course, the deviations enlarged at the earlier period, then reduced at the following period to the end. Analysing made it clear that the deviations between individuals and between plants had the same ebb and flow mode, and it was about the same time when they reached to their curves' peaks, consequently resulted in the plant -deviation peak a right excursion. A suggestion of the quasi-curve by Logistic Equation was brought forward. The turning point(TP) of the equation could be consider as a impersonality indicator for the stage that physiological vigor changed the most between both plants and individuals. Each TP came from the multipoint data on its dehydration curve and possessed a dynamic feature, therefore it had the most efficiency, comparing with other's point or static criterion, in differentiating water retentions between plants. 8 shrubs was ranked as 3 main drought tolerance groups, according to the water loss system focusing on the TP. The traditional viewpoint on the relative position in drought tolerance of Ceratoides arborescens vs. C. latens was questioned, because the former had a unexpected super tolerant parameters than the latter one's.