祁连山青海云杉叶片δ~(13)C特征及其与生理指标关系

以祁连山青海云杉叶片为研究对象,通过测定叶片稳定碳同位素比率(δ13C)、叶片含水量(LWC)、脯氨酸含量、灰分含量、碳含量、氮含量、碳氮比、土壤含水量(SWC)等指标,探讨不同水分梯度下叶片δ13C的控制因子.结果表明,祁连山青海云杉叶片δ13C值在-28.9‰～-25.4‰之间变化,平均值为-27.3‰.沿河西走廊从东到西的干旱梯度(降水量逐渐减少),叶片δ13C表现出偏正的趋势.叶片δ13C与LWC和脯氨酸含量呈显著正相关关系,与灰分含量、SWC显著负相关.叶片δ13C值在青海云杉种内分布稳定,主要是由自身的遗传特性所决定,同时与生长环境条件也有一定的关系,其中土壤可利用水分是最主要的限制因子.叶片灰分含量是δ13C值的可选择性替代指标.

Relationship between Foliar Stable Carbon Isotope Composition and Physiological Factors in Picea crassifolia in the Qilian Mountains

In this paper, a comprehensive investigation on leaf water content, proline concentration, ash content, carbon content, nitrogen content, the ratio of carbon to nitrogen and soil water content in the Qilian Mountains are presented, as well as foliar stable carbon isotope composition of Qinghai spruce (Picea crassifolia). The results show that the leaf carbon isotope values range from -28.9‰ to-25.41‰, with an average of (-27.3±1.0)‰. Along the Hexi corridor from east to west, with precipitation decreasing, the δ~(13)C values become more positive. Foliar δ~(13)C values are positively and significantly correlated to leaf water content and proline concentration. In contrast, negative and significant correlations are found between foliar δ~(13)C values and ash content and soil water content. The results indicate that available water plays an important role in the growth of Picea crassifolia in the Qilian Mountains. In addition, foliar δ~(13)C values are mainly affected by the inherent genetic traits. Furthermore, leaf ash content may be an alternative selection criterion for leaf δ~(13)C values.