干旱-复水处理对寒富苹果光合特性的影响

Effect of Drought and Rehydrated Treatment on Leaf Photosynthetic Characters of Hanfu Apple

以自然光照和遮荫环境下生长的寒富苹果为材料,通过气体交换和叶绿素荧光等方法测定了寒富苹果在干旱-复水处理过程中的光合特性。结果表明:干旱胁迫及复水过程中,净光合速率(Pn)、气孔导度(Gs)、胞间二氧化碳浓度(Ci)、PSⅡ最大光化学效率(Fv/Fm)、光合性能指数(PI)等指标表现出先逐渐降低,极度干旱时达到最低值,复水后缓慢回升的趋势;处理结束后,其中全光照下建造的叶片Pn比处理前低41.4%,而遮荫低38.1%;随着干旱胁迫及胁迫解除,单位面积有活性的反应中心的密度(RC/CSo)、单位面积叶片吸收的能量(ABS/CSo)、热耗散的能量(DIo/CSo)均逐渐上升,达到最大值后缓慢下降,其中干旱胁迫7 d,不同光照环境下建造的叶片ABS/CSo和DIo/CSo达到差异极显著,这可能与前期叶片建造质量有较大关系。

The photosynthetic characters of Hanfu apple leaves under different light conditions were studied by analyzing the gas exchange and chlorophyll fluorescence parameters .The result showed that the net photosynthetic rate（Pn）,stomatal conductance（Gs）,intercellular corbon dioxide concentration （Ci）,maximal photochemical effi-ciency （ Fv/Fm ） and photosynthetic performance index （ PI ） all decreased gradually in dought condition , and reached the lowest in extreme drought , but recovered slowly after rehydration .At the end of the treatment , Pn of leaves under the full light and shading conditions was respectively 41.4% and 38.1% lower than that before the treatment.Along with the drought stress and drought relief ,the density of SPⅡ reaction per excited cross section （RC/CSo）,the energy absorbed per unit area （ABS/CSo） and the heat dissipation of energy （DIo/CSo） increased gradually ,and started to decline after they reached the highest .The differences of leaf ABS/CSo and DIo/CSo a-mong different lighting conditions reached a significant level after 7-days of drought stress ,which was probably relat-ed to the quality of leaves .