不同物候期土壤水热条件对云南箭竹水分状况及光合同化物贮存的影响OA

The study aims to explore the relationship between soil hydrothermal conditions(temperature,moisture content,water potential)and water content as well as photoassimilate storage of Fargesia yunnanensis during different phenological periods,and reveal the regulatory mechanisms of soil hydrothermal conditions underlying culm water use and photoassimilate allocation.By measuring soil hydrothermal indicators during 6 key phenological periods throughout the year,we simultaneously analyze the moisture content of various organs,stem sap flow,water potential,transpiration pull,and contents of soluble sugar,starch,and non-structural carbohydrates(NSC)in F.yunnanensis,and then conduct the correlation analysis.The results show that physiological indicators of various organs of F.yunnanensis respond significantly to changes in soil hydrothermal conditions.During the dry season,moisture content and sap flow rate in culms are extremely significantly negatively correlated with soil temperature,while its transpiration pull and carbohydrate content show a significant positive correlation with soil temperature.The moisture contents in branches,leaf sheaths,and leaves,as well as culm water potential,are significantly positively correlated with soil moisture content and water potential.However,the soluble sugar content in branches and leaves and NSC content in leaves are significantly negatively correlated with soil moisture.During the wet season,water-related indicators of all organs,soluble sugar content in branches,leaf sheaths and leaves,and NSC content in leaves are all positively correlated with soil hydrothermal conditions,and leaf photosynthetic capacity improves.The photoassimilate content in culm is significantly negatively correlated with soil moisture,mainly due to nutrient consumption by massive shoot sprouting.Correlation analysis indicates that sufficient soil moisture is conducive to leaf photoassimilate accumulation and culm carbohydrate transport.In general,soil hydrothermal conditions in different phenological periods significantly regulate water use and photoassimilate storage.Lower soil hydrothermal conditions lead to insufficient water storage in bamboo clumps and affect leaf photosynthesis,while appropriate soil temperature is beneficial for photoassimilate accumulation.The results provide a scientific basis for water management and nutrient regulation of F.yunnanensis in different phenological periods,and have important practical significance for improving its cultivation efficiency and resource utilization value.