低温胁迫下钼对冬小麦光合作用特性的影响

Effects of Molybdenum on Photosynthetic Characteristics in Winter Wheat under Low Temperature Stress

研究了低温胁迫下施钼对冬小麦钼高效品系97003和钼低效品系97014叶片光合参数的影响。结果表明，低温胁迫下施钼显著提高2个品系叶片的净光合速率（Pn）和气孔限制值（Ls），显著降低叶片气孔导度（Gs）、胞间CO2浓度（Ci）和蒸腾速率（Tr）。随着低温处理时间的延长叶片Pn下降，施钼处理Ci降低、Ls升高，说明其Pn下降主要由气孔限制因素引起；不施钼处理低温胁迫前期（0～4d）Ci下降、Ls升高，而后期（4～6d）Ci升高、Ls下降，说明不施钼处理Pn下降在低温胁迫前期可能主要由气孔限制因素引起，而低温胁迫后期可能主要由非气孔因素引起。钼对冬小麦叶片光合参数的影响存在基因型差异，低温处理前后钼低效品系施钼处理叶片Pn上升幅度和Tr下降幅度均显著高于钼高效品系。

Effects of molybdenum （Mo） on several photosynthetic parameters in winter wheat were investigated under low temperature stress using Mo-efficient line 97003 and Mo-inefficient line 97014. The results indicated that the net photosynthetic rate （ Pn ） and stomatal limitation （ Ls ） increased significantly （ P 〈 0.05 ）, while stomatal conductance （ Gs ）, intercellular CO2 concentration （ Ci ） and transpiration rate （ Tr ） decreased significantly （ P 〈 0.05） in Mo-fertilized treatment of both wheat lines under low temperature stress. From 0 to 6 days of low temperature stress in Mo-fertilized treatment, with the decline of Po, decrease of Ci and increase of Ls , indicating that stomatal limitation was the main factor to P, decline. In Mo-deficient treatment, with the decline of Pn, Ci was decreased and Ls was increased at earlier stage of low temperature stress （0 to 4 days）, whereas Ci was increased and Ls was decreased at later stage （4 to 6 days）, implying that the probable main factors for Pn decline were stomatal limitation at earlier stage of low temperature stress, and nonstomatal limitation at later stage. Genotypic differences in response to the effects of molybdenum on the photosynthetic parameters exist between Mo-efficient line 97003 and Mo-inefficient line 97014. The changing rates of P, and Tr of 97014 were significantly higher than those of 97003 in Mo-fertilized treatment.