光皮桦光合特性的研究

为揭示光皮桦光合特征,以浙江省的临安无性系、丽水无性系和广西壮族自治区的龙胜无性系3个光皮桦无性系幼株为试验材料,利用LI-6400P便携式全自动光合测定仪,于2010年10月测定了3种试验材料的光合日进程、光合-光响应过程、光合-CO2响应过程.结果表明,光皮桦净光合速率日变化呈单峰和双峰2种类型,临安无性系存在光合“午休现象“,临安无性系、丽水无性系的净光合速率均与龙胜无性系存在显著的差异(P＜0.05),而临安无性系与丽水无性系之间差异不显著(P＞0.05)；丽水无性系的气孔导度显著高于临安无性系与龙胜无性系(P＜0.05),而临安无性系和龙胜无性系之间的气孔导度值差异不显著(P＞O.05)；3个无性系的光饱和点变化范围在1 342.8～1 609.0μmol/(m2·s),光补偿点在18.1～27.2 μmol/(m2·s),表观量子效率在0.035～0.047；CO2饱和点变化范围在2 000.7～2 350.7μmol CO2/mol,CO2补偿点在61.5～76.7 μmol CO2/mol,羧化效率在0.027～0.040.逐步回归分析表明,临安无性系和丽水无性系净光合速率的主要影响因子是光合有效辐射,龙胜无性系则主要受蒸腾速率、气孔导度和胞间CO2浓度的影响.

Study on Photosynthetic Characteristics of Betula luminifera

In order to reveal the photosynthetic characteristics of Betula luminifera H.Winkl.,using three B.luminifera clones(clones in Lin’an and Lishui of Zhejiang province and Longsheng of Guangxi Zhuang Autonomous Region) as test materials,LI-6400P portable photosynthesis was adopted to determine the diurnal change of photosynthesis,photosynthesis-photoresponse process,photosynthesis-CO2 response process.The results showed that the diurnal change of photosynthesis rate of B.luminifera was unimodal and bimodal.The Lin’an clone had midday depression phenomenon;and the net photosynthetic rates of Lin’an clone and Lishui clone were significantly different from that of Longsheng clone(P<0.05),while there was no significant difference between Lin’an clone and Lishui clone(P>0.05).The stomatal conductance of Lishui clone was significantly higher than that of Lin’an clone and Longsheng clone(P<0.05);no significant differences was detected between that of Lin’an clone and Longsheng clone(P>0.05).The light saturation point,light compensation point,apparent quantum yield,CO2 saturation point,CO2 compensation point,carboxylation efficiency of the 3 clones was 1 342.8～1 609.0 μmol/(m2·s),18.1～27.2 μmol /(m2·s),0.035～0.047,2 000.7～2 350.7 μmol CO2/mol,61.5～76.7 μmol CO2/mol,0.027～0.040,respectively.Stepwise regression analysis showed that the main influence factor of net photosynthetic rate of Lin’an clone and Lishui clone was photosynthetic active radiation;while Longsheng clone was mainly affected by transpiration rate,stomatal conductance and intercellular CO2 concentration.