格木不同种源光合作用光响应分析研究

摘要

以格木6个不同种源苗木为研究材料，通过测定其光合作用光响应曲线,分析光合生理指标光合速率(Pn)、胞间CO2(Ci)、气孔导度(Gs)、蒸腾速率(Tr)，计算水分利用率(RWUE)对光辐射梯度的响应变化；分析光饱和点（VLSP）、光补偿点（VLCP）、最大净光合速率（Pmax）、表观量子效率（RAQY）和暗呼吸速率（Rd）等光合特征参数。结果表明：南宁种源和浦北种源的Pn和Gs最大值较大，南宁种源的Ci最大值最大、Tr上升过程中一直较大，浦北种源RWUE最大；浦北种源VLSP、RAQY和Rd高，VLCP低，对光环境适应范围较广；南宁种源和大容山种源VLSP和VLCP高，阳性特征明显，有较好的适应强光能力；博白种源VLSP和VLCP低，利用弱光能力强；缅甸种源VLSP和VLCP均在中等，对光环境的适应生态幅窄；越南种源Rd和RAQY低，其利用光能能力不强；南宁种源和浦北种源的Pmax最大，具有较大的光合潜力。通过比较不同种源格木的光合作用差异性，以便在造林时根据环境、地形、地貌选择合适的种源。%By taking seedlings of Erythrophleum fordii Oliv from six provenances as the studied materials, theirs photosynthetic light response curves were recorded, the photosynthetic indexes such as photosynthetic rate (Pn), intercellular CO2 (Ci), stomatal conductance (Gs) and transpiration rate (Tr), as well as the responses of water use efifciency (RWUE) to radiation gradients were investigated;and the light saturation point (VLSP), light compensation point (VLCP), maximum net photosynthetic rate (Pmax), apparent quantum efifciency (RAQY) and dark respiration rate (Rd) were calculated. The results show that the maximum Pn and Gs were high in seedlings of Pubei and Nanning provenances, and Nanning seedlings had the highest maximum Ci and the Tr remained high state;and Pubei seedlings had the highest RWUE. As for the photosynthetic characteristics, Pubei seedlings had high VLSP, RWUE and Rd and low VLCP, suggesting an adaptation to a wide range of light sources;Nanning and Darongshan seedlings had high VLSP and VLCP, presenting a good acclimatization to bright light;Bobai seedlings had low VLSP and VLCP and high utilization of weak light;Burma seedlings had modest VLSP and VLCP, only adapted to a narrow range of light sources;Vietnam seedlings had low Rd and RWUE, and weak light utilization;Nanning and Pubei seedlings had highest Pmax and photosynthetic potential. The comparison on variations of photosynthesis of E. fordii seedlings of different provenances may inform the species selection for plantation in landscapes of different features.