喀斯特石漠化地区土壤养分对泡核桃功能性状的影响

Effects of soil nutrients on functional traits of Juglans sigillata in karst rocky desertification areas

关键词:  泡核桃, 光合特性, 结构性状, 土壤养分, 石漠化, 喀斯特

Key words:  Juglans sigillata, photosynthetic characteristics, structural traits, soil nutrients, rocky desertification, karst

摘要:

为了探究喀斯特石漠化地区植物叶片功能性状及影响因素,以及揭示其对石漠化环境的适应机理,该文以中国南方喀斯特高原峡谷地区的泡核桃(Juglans sigillata)为对象,揭示土壤养分对叶片结构和光合性状的影响效应。结果表明:(1)泡核桃叶功能性状随石漠化等级增加,叶面积减小,比叶面积增大,叶干物质含量和叶组织密度先降后升,蒸腾速率、胞间CO₂浓度、气孔导度和光能利用率先下降后升高,其他性状变化趋势不显著。(2)冗余分析表明土壤养分能够解释37.4%的光合性状变异与53.4%的结构性状变异,其中全磷和溶解性有机碳对光合性状影响最大,而对结构性状影响最显著的是碱解氮和速效磷。(3)比叶面积分别与叶干物质含量极显著负相关,与净光合速率极显著正相关,叶厚度与叶组织密度极显著负相关,蒸腾速率与胞间CO₂浓度、气孔导度极显著正相关,水分利用速率与蒸腾速率、胞间CO₂浓度、气孔导度极显著负相关,光能利用率与净光合速率显著正相关。研究结果表明,泡核桃为适应喀斯特石漠化的特殊生境采取增强生长功能性状,同时提高资源获取能力的开拓型生长策略,以提高对环境胁迫的抵御和适应能力。

Abstract:

To explore the characteristics and influencing factors of leaf functional traits of plants in karst rocky desertification areas, and to reveal their adaptation mechanism to rocky desertification environment, this study reveals the effects of soil nutrients on leaf structure and photosynthetic traits in Juglans sigillata from the karstic plateau canyon areas of South China. The results were as follows:(1)The functional traits of blister J. sigillata leaves decreased with increasing rocky desertification grade, leaf area decreased, specific leaf area increased, leaf dry matter content and leaf tissue density decreased first and then increased, transpiration rate, intercellular CO₂ concentration, stomatal conductance and light energy utilization decreased and then increased, and the trends of other traits were not significant.(2)Redundancy analysis(RDA)showed that soil nutrients explained 37.4% of the variation in photosynthetic traits and 53.4% of the variation in structural traits, with total phosphorus and dissolved organic carbon having the greatest influence on photosynthetic traits, while the most significant effects on structural traits were alkali hydrolyzed nitrogen and available phosphorus.(3)Specific leaf area was highly significantly negatively correlated with leaf dry matter content and highly significantly positively correlated with net photosynthetic rate, leaf thickness was highly significantly negatively correlated with leaf tissue density, transpiration rate was highly significantly positively correlated with intercellular CO₂ concentration and stomatal conductance, water use efficiency was highly significantly negatively correlated with transpiration rate, intercellular CO₂ concentration and stomatal conductance, respectively, light energy utilization was significantly positively correlated with net photosynthetic rate. The results suggest that blister J. sigillata adapts to the special habitat of karstic desertification through a pioneering growth strategy of enhancing growth functional traits while improving resource acquisition capacity to improve resistance and adaptation to environmental stresses.