白芥和甘蓝型油菜属间杂种后代种子结构比较

白芥具有很多优良的农艺性状，从白芥和甘蓝型油菜属间体细胞杂种后代中筛选出多个具有黄籽或趋向黄籽性状的株系，利用光学显微镜和电子显微镜技术观察它们种子的结构。回交后代种皮解剖结构与甘蓝型油菜相似，而与白芥相差较远。种皮色素主要分布在栅栏层，甘蓝型油菜和部分后代株系中有色素分布，而白芥和部分黄籽后代株系中没有色素分布。栅栏层在甘蓝型油菜中最厚，在白芥中最薄，而后代介于两者之间。回交后代和甘蓝型油菜种皮表面纹饰为网-穴状，白芥为沟槽状或水疱状。胚子叶细胞面积以白芥最小，甘蓝型油菜最大，后代介于两者之间；而蛋白体面积指数以白芥最大，甘蓝型油菜最小，后代介于两者之间。超微结构观察表明，亲本和后代蛋白体均为球状晶体蛋白体，油体有大、小两种，其大小在亲本和后代间有差异。上述结果表明，回交后代株系种子解剖结构与甘蓝型油菜相近，种皮颜色、色泽深浅和栅栏层厚度，以及胚子叶细胞大小、油体和蛋白体等受亲本白芥的影响而发生变化。

Comparison of Seed Structure of Progenies from Intergeneric Hybrids between Sinapis alba and Brassica napus

Sinapis alba L. possesses desirable agronomic characters. The backcross progenies of intergeneric hybrids between S. alba and Brassica napus L. obtained the valuable agronomic traits from S. alba. Seed structure of some yellow and yellow-like seed lines, which were selected from backcross progenies, was observed under light microscopy and electronic microscopy. The morphologically anatomical structure of seed coat of backcross progenies resembled that of B. napus, but was different from that of S. alba. Seed coat of B. napus was composed of flattened epidermis, crushed subepidermis, U-shaped-a palisade layer and aleurone layer, while seed coat of S. alba was composed of intestine-shaped epidermis, ellipse subepidermis, U-shaped-b palisade layer and aleurone layer. The pigments of seed coat were mainly distributed in the palisade layer. There were pigments in seed coats of B. napus and some backcross progenies, but no pigments in those of S. alba and other backcross progenies. The palisade layer was thicker in B. napus, thinner in S. alba, and intermediate in hybrid progenies. Seed coat microsculpturing was observed with scanning electronic microscope. The reticulate-foveate pattern was the characteristics of B. napus and hybrid progenies, while the blister pattern of H₂O-immersed seed and the sulcate pattern of dry seed were the characteristics of S. alba. The area of cotyledon cell was larger in B. napus, smaller in S. alba, and intermediate in hybrid progenies. The area index of protein body in cotyledon cell was higher in S. alba, lower in B. napus, and intermediate in progenies. The observations of ultrastructure showed that protein bodies were heterogeneous with crystal globoids in parents and progenies. Oilbodies included large and small oilbodies, and their sizes were different from each other between parents and progenies. The above results showed that the anatomy of the progeny seeds was similar to that of B. napus, but the seed color, the thickness of palisade layer, cotyledon cell size, protein body and oilbody were affected by S. alba.