Guadua amplexifolia光合季节动态

Seasonal variation in photosynthesis of an introduced bamboo species Guadua amplexifolia

为了解国外引进的优良材用竹种Guadua amplexifolia在引种地福建省华安县的光合适应性,在自然条件下测定该竹种不同季节的光合及相关特征参数,并对不同季节的光合生理参数及其主要环境影响因子进行相关分析和通径分析。结果表明:其光响应特征参数具有明显的季节性差异,光饱和点(LSP)、光补偿点(LCP)、光下暗呼吸速率(Rd)、最大净光合速率(Pnmax)均是7月最高,4月和10月次之,1月最低;四个季节的净光合速率(Pn)日变化均呈双峰型,其中4月"午休"不明显;日均净光合速率4月>7月>10月>1月;除空气相对湿度(RH)外,蒸腾速率(Tr)、胞间CO2浓度(Ci)、气孔导度(Gs)、饱和水汽压差(VPD)、光合有效辐射(PAR)、叶片温度(Tleaf)等生理因子和环境因子均与净光合速率(Pn)显著相关;不同季节Pn的主要环境影响因子有所差异,1月Tleaf为Pn最大的环境影响因子,而10月RH的影响则明显增大。综合分析整个生长季节,各测定环境因子对Pn的影响大小顺序为VPD>PAR>RH>Tleaf。

Photosynthetic characteristics and main impact factors were measured in different seasons,and the data were analyzed by correlation and path coefficients,and different irradiances were measured in Hua’an County,Fujian Province,in order to study Guadua amplexifolia’s photosynthesis characteristic,CO2 assimilation rate on different times in one day. The results indicated that light saturation point （LSP）,light compensation point （LCP）,dark respiration rates（Rd）,and net photosynthesis at saturation light （Pnmax） all reached highest in July,lower in April and October,the lowest in January. In all seasons but April,daily course of net photosynthesis rate （Pn） had midday-depression pattern. The daily mean value of Pn was in the sequence AprilJulyOctoberJanuary. All environmental and physiological factors except for relative humidity （RH） had significant correlation with Pn,such as Tr,Ci,Gs,VPD,PAR,Tleaf and so on. The main environmental factors differed in every season. In January,leaf temperature （Tleaf） was the most important factor to Pn. But the effect of RH increased obviously in October. The effect of tested environmental factor to Pn was in the sequence VPDPARRHTleaf in the whole growth period.