不同菌根类型木本植物叶片光合及其与叶片特性和环境因子的关联

Leaf photosynthesis in different mycorrhizal types of woody plants and its associations with leaf characteristics and environmental factors

摘要:

叶片光合作用构成了植物能量和物质循环的基础。菌根真菌(mycorrhizal fungi)作为植物根系共生体系的关键组成部分，在调节植物营养吸收、水分利用以及抗逆性等方面发挥着重要作用，是影响森林生态系统功能和稳定性的关键生态因子。目前，对于不同菌根类型对木本植物光合能力及其对环境变化响应的影响还缺乏足够的认识。目的 探讨不同菌根类型木本植物光合能力的差异，及其对叶片特征和环境因子变化的响应。方法 基于中国植物性状数据库，并结合文献资料，确定了木本植物的菌根类型，共包括3种：丛枝菌根(arbuscular mycorrhiza, AM)、外生菌根(ectomycorrhiza, ECM)，以及受AM和ECM这2种菌根共侵染的双菌根(AM+ECM)。在此基础上，建立了中国不同菌根类型木本植物性状数据库，每个样本均包含叶片光合能力、光合生理特征、叶片结构和养分特征，以及相关的环境因子等数据。结果 在木本植物中，ECM植物叶片的光合能力显著高于AM植物。此外，菌根类型显著影响着植物叶片特征与光合能力之间的关系。木本植物的光合能力主要受叶片气孔导度和蒸腾速率的影响。AM植物的光合能力还受叶面积、比叶面积和氮磷含量的影响；AM+ECM植物则受比叶面积、比叶重和碳磷含量的影响；而ECM植物则受最大蒸汽压亏缺的影响。在环境因子方面，ECM植物的最大净光合速率和最大电子传递速率相较于AM和AM+ECM更容易受到温度和降水的影响。结论 菌根类型对木本植物的光合能力具有显著影响，叶片特征主要通过调控最大电子传递速率来影响叶片的最大净光合速率。此外，环境因子对木本植物叶片形态和生理特征的影响也因菌根类型的不同而存在差异。

关键词:菌根类型;光合能力;环境因子;叶片特征;最大净光合速率

Abstract:

Leaf photosynthesis forms the foundation of plant energy and material cycles. Mycorrhizal fungi, as a crucial component associated with roots, play a significant role in regulating the nutrient absorption, water utilization, and stress resistance of plants and are key ecological factors affecting the function and stability of forest ecosystems. However, at present, knowledge is limited regarding the effects of different mycorrhizal types on the photosynthetic capacity of woody plants and their responses to environmental changes.Objective To explore the differences in photosynthetic capacity among woody plants with different mycorrhizal types and their responses to changes in leaf characteristics and environmental factors.Methods According to the China Plant Trait Database and available articles, we identified three mycorrhizal types of woody plants, which included arbuscular mycorrhiza (AM), ectomycorrhiza (ECM), and AM+ECM. On this foundation, a database of woody plant traits for different mycorrhizal types in China was established, with the data of each sample encompassing photosynthetic capacity, photosynthetic physiology, leaf structure, nutrient characteristics, and environmental factors.Results The woody plants with ECM had higher photosynthetic capacity than those with AM. Mycorrhizal types significantly influenced the relationship between leaf traits and photosynthetic capacity. The photosynthetic capacity of woody plants was primarily affected by the stomatal conductance and transpiration rate of leaves. In addition, the photosynthetic capacity of plants with AM were influenced by leaf area, specific leaf area (SLA), and nitrogen and phosphorous content. The photosynthetic capacity of plants with AM+ECM were affected by SLA, specific leaf weight, and carbon and phosphorous content, while that of plants with ECM was influenced by the vapor pressure deficit. The maximum net photosynthetic rate and maximum electron transport rate of plants with ECM were more susceptible to temperature and precipitation than plants with AM and AM+ECM.Conclusion Mycorrhizal types significantly affect the maximum net photosynthetic rate of woody plants, and leaf characteristics primarily influence the maximum net photosynthetic rate by regulating the maximum electron transport rate. Moreover, the effects of environmental factors on the morphological and physiological traits of woody plant leaves depend on mycorrhizal types.

Key words:mycorrhizal type;photosynthetic capacity;environmental factors;leaf characteristics;maximum net photosynthetic rate