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作者	单位
宋宇航，张孟寒，周瑞祥，陈新宜，华夏，齐学礼，汪月霞，李艳	(1.河南农业大学生命科学学院，河南郑州 450002； 2.河南省农业科学院作物分子育种研究院，河南郑州 450002)

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中文摘要:

为了解郑麦1860在灌浆前中期（花后15~21 d）旗叶叶绿体超微结构以及光合速率，选取百农207和周麦18为对照，通过光合仪测定三个小麦品种花后15~21 d叶片的光合参数，并利用实时荧光定量PCR对灌浆期蔗糖和淀粉合成相关基因的表达量进行分析，进一步通过透射电子显微镜观察叶绿体的超微结构。结果表明，花后15~21 d郑麦1860的净光合速率 (P_n)、细胞间隙CO₂浓度 (C_i) 和气孔导度 (G_s) 总体上显著高于百农207和周麦18，且保持较高的ATP酶活性、NADPH酶含量和叶绿素含量。与百农207和周麦18相比，郑麦1860花后15 d的淀粉含量也相对较高，但花后21 d的淀粉含量较花后15 d显著降低，而蔗糖含量却显著提高。实时荧光定量PCR分析表明，花后15~21 d郑麦1860旗叶蔗糖合成相关基因TaFBA、TaSS和淀粉合成相关基因TaSSⅡ均能保持较高的表达水平。透射电子显微镜观察发现，花后21 d郑麦1860叶绿体的类囊体片层排列清晰有序，堆砌紧密，嗜锇颗粒较少，也未观察到淀粉粒，表明该品种在灌浆前中期一直保持着较稳定的光合结构。这些结果表明，与百农207和周麦18相比，郑麦1860在灌浆前中期能够维持较完整的叶绿体结构，对光能的吸收和转化利用能力更强，可以捕获更多的光能进行光合作用；同时，可将旗叶中的光合产物更快地转运到籽粒中，降低旗叶中的光合产物浓度，从而维持较高的光合速率。

英文摘要:

To study the chloroplast ultrastructure and photosynthetic rate in flag leaf of Zhengmai 1860 during the early-middle period of grain filling stage (15-21 days after anthesis), Bainong 207 and Zhoumai 18 were used as control materials. The photosynthetic parameters of leaves were determined by a photosynthesis at 15-21 days after anthesis. The sucrose and starch content, and the related gene expression levels were determined. The results showed that the net photosynthetic rate(P_n), intercellular CO2 concentration(C_i) and stomatal conductance(G_s) of Zhengmai 1860 were significantly higher than those of Bainong 207 and Zhoumai 18 at 15-21 days after anthesis, and the ATPase acttivity, NADPH content and chlorophyll content of Zhengmai 1860 were also higher Meanwhile, the starch contents in flag leaves of Zhengmai 1860 at 15 days after antthesis were relatively higher, but the starch content of Zhengmai 1860 at 21 days after anthesis was obviously reduced, the sucrose content increased significantly. qRT-PCR analysis showed that the sucrose synthesis-related genes TaFBA,TaSS and starch synthesis-related gene TaSSⅡ could be maintained the high expression levels at 15-21 days after anthesis. As the results observed by a transmission electron microscopy, the chloroplast matrix sheets of Zhengmai 1860 kept arranging clearly and orderly, compactly stacking, exhibiting fewer osmium particles, which indicated that the variety can maintain a relatively stable photosynthetic structure during the early and mid-filling period. These results suggested that, compared with Bainong 207 and Zhoumai 18, Zhengmai 1860 had relatively complete the chloroplast matrix structure in the early and mid-filling period, which was benefit to absorb, transform and utilize light energy, as well as to transport the photosynthetic products from the flag leaves to the grain, and can redue the photosynthetic product concentration in the flag leaves and maintaining a high photosynthetic rate, and thus can increase the grain yield.

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