本研究以白纹阴阳竹( Hibanobambusa tranquillans f. shiroshima H. Okamura )、鼓节竹( Bambusa tul doides‘Swolleninternode')、花秆早竹( Phyllostachys violascens f. viridisulcata P. X. Zhang et W. X. Huang)和美丽箬竹(Indocalamus decorus Q. H. Dai)4个观赏竹种为供试材料,分析了各竹种的光响应和CO2响应曲线及参数、光合和气体交换参数以及相关环境因子的日变化规律,并通过相关性分析、逐步多元回归分析和通径分析探讨了影响4个竹种叶片净光合速率( Pn)的主要因子。测定结果表明：随光合有效辐射强度( PAR)或胞间CO2浓度( Ci)的提高,各竹种叶片的Pn值均逐渐增大,但增幅有一定差异；各竹种的光响应和CO2响应参数均有较大差异,其中,白纹阴阳竹叶片的表观量子产量( AQY)最低,CO2饱和点( CSP)和CO2补偿点( CCP)也较低,其他参数均最高；而花秆早竹叶片的AQY和CCP值均最高,而其他参数总体上均最低。4个竹种的光合及气体交换参数日变化曲线均有一定差异；美丽箬竹叶片Pn值日变化曲线呈“双峰型”；白纹阴阳竹、鼓节竹和花秆早竹叶片的Pn值日变化曲线均呈“单峰型”,峰值分别出现在14：00、10：00和12：00；总体上看,4个竹种叶片的气孔导度( Gs)、Ci、蒸腾速率( Tr)和水分利用效率( WUE)总体上具有相似的日变化趋势。分析结果表明：按照总影响效应由高至低进行排序,对白纹阴阳竹叶片Pn值的主要影响因子为PAR、Tr、大气CO2浓度( Ca)、Ci,对鼓节竹叶片Pn值的主要影响因子为PAR、Tr、Ca、Gs,对花秆早竹叶片Pn值的主要影响因子为PAR、Tr、Gs、气温( Ta)、Ci,对美丽箬竹叶片Pn值的主要影响因子为PAR、空气相对湿度( RH)、Ta、Ca、Tr、Gs。综合分析结果显示：4个竹种中,白纹阴阳竹光合能力最强,但对弱光的适应和利用能力较弱,CO2同化能力强且适应范围广；鼓节竹和美丽箬竹对光和CO2的利用能力和适应范围均居中；花秆早竹光合能力和CO2同化能力最差,但对弱光的适应和利用能力较强,CO2适应范围较窄。%Taking four ornamental bamboo species of Hibanobambusa tranquillans f. shiroshima H. Okamura, Bambusa tuldoides ‘Swolleninternode', Phyllostachys violascens f. viridisulcata P. X. Zhang et W. X. Huang and Indocalamus decorus Q. H. Dai as materials tested, light response and CO2 response curves and parameters, and diurnal change laws in photosynthetic and gas exchange parameters and related environmental factors related were analyzed, and the main factors affecting net photosynthetic rate ( Pn ) of leaf of four bamboo species were discussed by correlation analysis, stepwise multiple regression analysis and path analysis. The determination results show that with enhancing of photosynthetically active radiation intensity ( PAR) or intercellular CO2 concentration ( Ci) , Pn value of leaf of each bamboo species increases gradually, but there is a certain difference in their increasing ranges. There are great differences in light response and CO2 response parameters of each bamboo species. In which, apparent quantum yield (AQY) of leaf of H. tranquillans f. shiroshima is the lowest, CO2 saturation point ( CSP) and CO2 compensation point ( CCP) are also lower, and other parameters all are the highest, while both AQY and CCP values of P. violascens f. viridisulcata are the highest, other parameters are the lowest generally. There are some differences in all diurnal change curves of photosynthetic and gas exchange parameters of four bamboo species. Diurnal change curve of Pn value of leaf of I. decorus is “double-peak type”. That of H. tranquillans f. shiroshima, B. tuldoides‘Swolleninternode' and P. violascens f. viridisulcata is “single-peak type”, their peak values appear at 14:00, 10:00 and 12:00, respectively. Overall, diurnal change trends of stomatal conductance (Gs), Ci, Transpiration rate ( Tr) and water use efficiency ( WUE) of leaf of four bamboo species are similar. The analysis results show that according to total influence from high to low, main factors affecting Pn value of leaf of H. tranquillans f. shiroshima are PAR, Tr, air CO2 concentration ( Ca) , Ci;those of B. tuldoides ‘Swolleninternode' are PAR, Tr, Ca, Gs, those of P. violascens f. viridisulcata are PAR, Tr, Gs, air temperature ( Ta) , Ci, and those of I. decorus are PAR, air relative humidity ( RH) , Ta, Ca, Tr, Gs. The comprehensive analysis results indicate that among four bamboo species, H. tranquillans f. shiroshima has the strongest photosynthetic ability, while it has a weak ability to adapt and use to low light, and its CO2 assimilation ability is also strong with a wide adaptability; B. tuldoides‘Swolleninternode' and I. decorus are at the middle both in utilization ability and in adaptation range of light and CO2; P. violascens f. viridisulcata is the worst both in photosynthetic ability and in CO2 assimilation ability, while it has a strong ability to adapt and use to low light, and has a narrow CO2 adaptation range.
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