热消散法(TDP)在5种竹子蒸腾耗水测定中的适用性评价

Applicability Evaluation of Transpiration of Five Bamboo Species by Using TDP(Thermal Dissipation Probe) Method

为评价热消散法在竹子蒸腾耗水测定中的适用性,利用室内离体竹段注水变压法结合野外整株容器称重法对Granier公式进行了验证和系数校正,同时观察了5种竹子(毛竹Phyllostachys edulis、粉单竹Bambusa chungii、青皮竹B.textilis、茶秆竹Arundinaria amabilis、龙头竹B.vulgaris)的茎秆维管束结构。结果表明,茎秆维管束分布不均,维管束发育程度从竹壁外向内逐渐成熟,输水能力也逐渐增强。液流密度(Fd)和液流指数(K)呈幂函数关系,相关系数R2>0.83,说明热消散探针方法能较好地估算竹类的液流密度。用整株容器称重法对推导出的液流密度公式进行校正,校正后的液流密度公式与原始Granier公式中各系数均不同,尤其是α值。分别采用校正前后公式计算的竹子日蒸腾量差异显著,尤其是一天中液流高峰时段(午间)的差异最大。因此,只要对热消散探针方法准确验证、校正Granier原始公式系数,TDP技术是估计竹类植物水分利用的一种适宜方法。

In order to evaluate the applicability of TDP(Thermal dissipation probe) method used in transpiration measure of bamboo, the Granier empirical formula was verified and coefficients were revised by combining water-injection induced hydraulic pressure and sap flow changing device together with whole-plant container weighing menthods. In addition, the structure of vascular bundle in 5 bamboo species, including Phyllostachys edulis, Bambusa chungii, B. textilis, Arundinaria amabilis and B. vulgaris was observed. The results showed that the distribution of vascular bundles in culms were uneven. The development of vascular bundles become mature gradually from outside to inside of clum, and the transporting water capability also become strong. The sap fl ow density(Fd) and K value showed a power function relation with R2>0.83. It suggested that TDP method was an applicable technique for evaluating sap fl ow density in bamboo species. Furthermore, the equation coeffi cients were revised by using whole-plant container weighing method and new sap flow formula for every bamboo species were contained. The coeffi cients in new sap fl ow formula were different from those in Grnaier empirical formula especially α values. The daily transpiration had significant difference calculated by new equation and Granier empirical formula, especially the peak period(at noon) of sap flow in one day. Therefore, if the TDP method was carefully verifi ed and the coeffi cients in Granier empirical formula were revised, the TDP method could be an applicable technique for assessing water use in bamboo species.