【摘要】 对青海高寒半干旱区2年生蒙古莸叶水势日变化、季变化进行了动态研究,并分析了其影响因子及SPAC水势梯度变异情况。结果表明,蒙古莸叶水势早晚高,通常13:00左右达到最低值,6月份蒙古莸叶水势日均值最低;在充分灌水条件下,蒙古莸叶水势日变化与气温、光辐射强度、大气相对湿度有显著的相关性,且三者综合因素对叶水势的影响要高于单因子对叶水势的影响;当土壤水受到限制时,叶水势与土壤含水量有显著正相关。SPAC中土壤水势<叶水势<大气水势,形成水势梯度。从蒙古莸整个生长季来看,叶水势与土壤水势的相关性较大,与大气水势的相关性次之。更多还原

【Abstract】 The effects of leaf water potential(LWP) and the variations of soil-plant-atmosphere continuum(SPAC) water potential gradient are analyzed by studying the dynamic changes of the LWP in Qinghai alpine semi-arid area.Results show that the pre-dawn and evening LWP is high,while the minimum peak value is observed at about 13 o’clock.The daily average LWP in June is the lowest during the whole growing season.The study also shows that the LWP has significant correlations to air temperature,photosynthetic active radiation,and humidity under the condition of full irrigation,while there is a remarkable positive correlation between the LWP and the soil water content(SWC) when soil water is restricted.With the ascendant order of soil,leaf,and atmospheric water potentials in SPAC system,a water potential gradient is created.Meanwhile,the correlation between the pre-dawn LWP and the SWC is higher than that between the LWP and atmospheric water potential in the whole growing season of Caryopteris mongolica Bunge.更多还原