油菜角果开裂区结构分化对果实开裂的作用

运用半薄切片技术、荧光显微镜技术, 观察不同开裂程度的两个油菜品种中双9号和中双11果实发育过程中“果实开裂区”的结构特征、发生发育规律, 探讨两品种油菜果实不同开裂程度的结构差异。结果表明, 油菜果实在发育过程中, 逐渐分化出由胎座框木化细胞、离区细胞、果瓣边缘木化细胞、紧靠果实内果皮的木化层enb细胞共同组成的开裂区; 易开裂的中双9号果实发育进程总体上比不易开裂中双11的早, 前者在15DAF (开花后第15天)时就已经能分辨出离区, 且胎座框细胞、果瓣边缘细胞、enb层细胞的壁都已经木化加厚, 而后者在25DAF才表现出这些特征；中双9号的离区在25DAF完全形成, 而中双11的离区在30DAF完全形成；中双9号离区部分细胞间在30DAF开始出现分离, 而中双11离区部分细胞间在35DAF开始出现分离。另外, 中双9号开裂区胎座框木化细胞间出现较多的裂缝有利于果实的开裂。这些结构和发育特征对于深入研究果实开裂的分子调控和抗角果开裂品种的选育具有理论指导意义。

Effect of Structural Differentiation of Fruit Dehiscence Zone on Pod Dehiscence in Oilseed Rape

Oilseed rape plants disperse their seeds by pod-shattering known as pod dehiscence, which causes yield loss. To inves-tigate the effect of structure differentiation on pod shattering, we studied the developmental process and structural characteristics of fruit "dehiscence zone" of two varieties with different pod shattering behavior Zhongshuang 9 and Zhongshuang 11 by semi-thin section and fluorescence microscopy. Our observations revealed that: (1) rape pod gradually differentiated to form "de-hiscence zone" in fruit development, which was composed of dehiscence zone (or separation layer), lignified valve edge, lignified endocarp b and replum cells; (2) The dehiscence zone of Zhongshuang 9 was found at 15DAF (day after flowering), and mean-while the walls of valve edge cells, endocarp b cells and replum cells were thickened, and that of Zhongshuang 11 did not show these features until 25DAF. The dehiscence zone was fully formed in Zhongshuang 9 at 25DAF, while in Zhongshuang 11 at 30DAF.The separation of dehiscence zone cells was observed at 30DAF in Zhongshuang 9, while this occurred in 35DAF for Zhongshuang 11. In addition, more cell separation sites occurring between lignified replum cells enhanced pod shattering in Zhongshuang 9. These results provide a theoretical guidance for molecular regulation of pod shattering and oilseed rape breeding for pod shattering-resistance.