摘要
树干木质部中树液流密度的变化会引起树干局部电位差的变化,通过测定这种局部电位差来研究液流密度的变化过程是一种可行的方法.本次研究通过测定倾斜黄杨加水前后树干的局部电位差,同时借助小波变换方法,探讨了这种局部电位差对根系吸水过程的响应.结果表明:加水前树干液流密度相对稳定,而在加水后树干部分区域的树液便开始了明显的流动;加水后树液优先从树干的向阳面流动,而树干侧面的树液流动则明显滞后于向阳面;干旱状态下局部电位差对根系吸水过程响应的变化幅度要明显大于湿润条件;电位差的变化在短时间条件下反映树干液流的变化过程,并可据此测定液流速度,但在更长的时间尺度条件下则可能更多地反映了树干的生理变化过程.
Variation of sap flux density gives rise to the change of xylem local electric potential of trunk. Therefore, the variation of sap flux density can be investigated by measuring the local electric potential difference, which is considered as a feasible method. Using this method and wavelet transform, we study the response of local electric potential difference of a tilted boxtree trunk to the water absorption of the root. The results indicate that sap flux density keeps relatively stable before watering, but there is obvious sap flow in the partial zone of the trunk after watering. Sap flows through the dominant path which is the sunny part of the trunk and sap flows through sunny part ahead of side part obviously. The amplitude of response of local electric potential difference is larger in drought condition than the amplitude in moist condition. The change of electric potential difference on a small time scale reflects the variation of sap flow in trunk and the velocity of sap can be measured according to it, but it may reflect the physiological change of the trunk on a large time scale.
出处
《地球物理学进展》
CSCD
北大核心
2010年第2期721-727,共7页
Progress in Geophysics
基金
国家自然科学基金项目(40771038)资助
关键词
局部电位差
优势通道
小波变换
树液
液流密度
local electric potential difference
dominant path
wavelet transform
sap
sap flux density
