干旱对兴安落叶松枝叶非结构性碳水化合物的影响

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 干旱对兴安落叶松枝叶非结构性碳水化合物的影响 DOI: 10.5846/stxb201401260198 作者: 作者单位: 东北林业大学,东北林业大学生态研究中心,东北林业大学生态研究中心 作者简介: 通讯作者: 中图分类号: 基金项目: 国家"十二五"科技支撑项目(2011BAD37B01); 长江学者和创新团队发展计划(IRT1054) The influence of drought on non-structural carbohydrates in the needles and twigs of Larix gmelinii Author: Affiliation: Northeast Forestry University,Northeast Forestry University, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:降水格局的变化以及极端干旱的频繁发生是全球气候变化的重要特征之一.为了揭示干旱对树木碳代谢的影响,通过控雨试验研究兴安落叶松(Larix gmelinii Rupr.)枝叶的非结构性碳水化合物(NSC)及其组分(可溶性糖和淀粉)的浓度对降水减少的响应,探索枝叶NSC浓度与土壤含水率的关系.控雨试验包括减雨100% (100%RE)、减雨50% (50%RE)和对照 (CK) 3个处理;控雨时期为2012年生长季(6月至8月).结果表明,叶NSC浓度对干旱处理的响应比枝更显著.控雨处理对枝叶总NSC浓度影响不显著(P > 0.05),试验期间叶总NSC平均浓度变化在9.45-14.12 mg/g范围内;枝总NSC平均浓度变化在7.72-9.26 mg/g之间.然而,不同处理之间的叶片可溶性糖浓度差异显著.100%RE最高(8.98±0.31)mg/g、50%RE次之(8.45±0.13)mg/g、CK最低(7.73±0.32)mg/g.相反,叶淀粉浓度以CK最高(2.99±0.22)mg/g、50%RE次之(2.68±0.32)mg/g、100%RE最低(2.63±0.17)mg/g.叶可溶性糖与淀粉浓度的比值的大小顺序为:CK (2.27) < 50%RE (2.51) < 100%RE (3.70).叶可溶性糖浓度、可溶性糖浓度和淀粉浓度的比值与土壤含水率呈显著的负相关关系(P < 0.05),而叶淀粉浓度有随土壤含水率升高而增高趋势,但相关关系不显著(P > 0.05).叶NSC总浓度、枝NSC及其组分浓度与土壤含水率的关系均不显著(P > 0.05).研究表明,短期干旱对兴安落叶松树体内总NSC浓度的影响不显著,树木可以通过将淀粉转化成可溶性糖的方式维持其正常的呼吸作用等生理活动. Abstract:Global climate change is characterized by variations in precipitation patterns and frequency of drought events. Extreme drought events may lead to large-area tree death and thus changes in the geographical distribution of vegetation, of which the underlying mechanisms are still unclear. It has been postulated that carbon starvation may be responsible for the drought-induced tree death, which, however, needs to be tested with a well-designed controlled experiment. In this study, we conducted a rainfall exclusion experiment on Dahurian larch (Larix gmelinii Rupr.) plantation during the growing season of 2012 and examined the concentrations of non-structural carbohydrates (NSC) in twigs and needles of the larch. The experiment included three treatments: 100% rainfall exclusion (100% RE), 50% rainfall exclusion (50% RE) and control (CK, i.e., ambient rainfall). Our objectives were to (1) compare the concentration of NSC components in the needles and twigs among the treatments; and (2) explore relationships between NSC concentrations in needles or twigs and soil moisture. Three trees were randomly selected for each treatment. The twigs and needles from upper, mid and lower crowns in the southern direction were monthly sampled and mixed, respectively, for each tree from early June to late August of 2012. A modified phenol-sulphuric method was used to determine the concentrations of soluble sugars and starch. For a specific sample, the total concentration of NSC was obtained by by summing the concentrations of the sugars and starch. There was no significant effect of the treatments on the total NSC concentrations in both needles and twigs (P > 0.005). The mean concentrations of total NSC in needles varied from 9.45 mg/g to 14.12 mg/g, and those in twigs ranged between 7.72 mg/g and 9.26 mg/g. However, the concentration of soluble sugars in needles differed significantly among the treatments (P < 0.05). The sugar concentration in needles was highest for the 100% RE treatment (8.98±0.31)mg/g, followed by the 50% RE treatment (8.45±0.13)mg/g, and the lowest for the CK (7.73±0.32)mg/g. In contrary, the starch concentration in needles ranked as the CK (2.99±0.22)mg/g > 50% RE (2.68±0.32)mg/g > 100% RE (2.63±0.17)mg/g. The ratio of soluble sugars to starch in the needles ranked as the CK (2.27) < 50% RE (2.51) < 100% RE (3.70). There was a significant negative relationship between soil moisture and concentration of soluble sugars or ratio of sugar to starch in needles (P < 0.05). The concentration of starch in needles tended to increase with soil moisture increasing, but their correlation was insignificant (P > 0.05). There were no significant correlations between soil moisture and the total NSC concentration in needles, and between soil moisture and the concentrations of total NSC or component concentrations in twigs (P > 0.05). This study illustrated that the short-term drought stress had no significant effect on the total NSC concentration, but resulted in a transfer of starch into soluble sugar that maintained tree metabolic activities and survival during the drought event. 参考文献 相似文献 引证文献