【作者】 梁艳丽；

【导师】 梁颖； 王三根；

【作者基本信息】 西南农业大学 ， 植物学， 2002， 硕士

【摘要】 在相同的遗传背景下，甘蓝型油菜(Brassicanapus L)黄籽与黑籽相比黄籽具有含油量高、蛋白质含量高、皮壳率低、油质清澈透明、饼粕饲用价值高等一系列优点，受到油菜育种家的普遍重视。但甘蓝型油菜黄籽性状遗传不稳定，大大制约了黄籽油菜的育种进程，弄清甘蓝型黄籽油菜种皮特性的形成机理，将对黄籽油菜的育种具有重要意义。本文以3对不同来源的甘蓝型油菜作为试验材料，每对材料包括具有近等基因系的黄籽和黑籽两种材料，对甘蓝型黄籽油菜种皮特性形成的机理进行了研究，主要结果如下： 1．种子发育进程中种皮所含色素的动态研究和方差分析表明，遗传背景对种皮色素含量的影响不大。种皮叶绿素、多酚、花色素、黑色素含量在黄、黑籽之间均存在极显著差异：叶绿素含量在种子发育后期黄籽极显著高于黑籽；多酚、花色素、黑色素在黑籽中的含量极显著地高于黄籽：在黑籽种皮颜色不断加深的过程中，多酚、花色素含量有明显的下降，而黑色素含量却迅速上升。认为叶绿素不是产生黑籽种皮色泽的直接原因，多酚、花色素含量对种皮色泽的形成有重要影响，而黑色素含量是决定成熟种皮色泽的主要因素。 2种子发育进程中种皮厚度相关指标的动态研究和方差分析表明，遗传背景对种皮纤维素含量有极显著的影响，对皮壳率及种皮木质素含量的影响却不大。在种子发育进程中，种皮纤维素含量在黄、黑籽间的差异不显著，而皮壳率及种皮木质素含量在黄、黑籽间的差异达显著水平。认为造成黄籽皮壳率低的原因可能是黄籽种皮木质素含量明显低于黑籽所致，而不是纤维素含量的差异造成的。 3．种子发育进程中与种皮色素及木质素合成相关的酶活性的动态研究和方差分析表明，PAL、PPO、POD在种子发育进程中酶活性均是先上升再下降，黑籽的PAL、PPO及POD活性均极显著地高于黄籽，说明PAL、PPO、POD活性对种皮特性的形成均有重要影响。其中，PPO及POD的活性高峰出现在开花后41天左右，PAL活性高峰出现在开花后34天左右，认为PPO及POD在种子呈色过程中可能起了重要作用，而PAL对种皮特性形成的影响，不是直接产生颜色物质或使种皮加厚的物质，而是以产生前体物质为主。 4．以多种酶抑制剂和蛋白质合成调节剂在种子发育进程中处理植株，并对处理植株成熟种子的相关指标进行测定，结果表明，抑制PAL、PPO活性，促进蛋白质合成、抑制氧化反应，均可使种皮色素及木质素含量降低，皮壳率下降、蛋白质含量和含油量有所上升；抑制蛋白质合成使种皮色素及木质素含量有所上升，蛋白质含量、含油量有所下降。说明甘蓝型黄籽油菜种皮特性的形成与莽草酸——苯丙氨酸途径有关，受到PAL、PPO活性及体内氧化反应的影响，这与 甘鱼型黄籽必莱升友甘佐形戍机o研允 戈要 动态测定的结果是相符的。 5．对酯酶、PPO、POD的同工酶分析表明，在相同的遗传背景下，酯酶的同 工酶数在黄、黑籽间没有差异；黑籽的PPO同工酶带均比黄籽多，且黑籽具有1 条虹值为0．41的特异谱带＿带；黑籽的POD同工酶均比黄籽多一条谱带伪 带或。带）。在不同品种间，酯酶、PPO、POD的同工酶谱差异均较大。可能黄 籽缺失的某些同工酶对种皮特性的形成产生了影响。 以上2、3、4、5结论在甘蓝型黄籽油菜的研究中均属首次报道。更多还原

【Abstract】 Yellow seeds in Brassica species are characterized with thinner seedcoat and lower hull percentage which in turn are correlated with higher oil and protein and lower crude fiber contents compared to black seeds under the same genetic conditions. But the widespread application of yellow-seeded species in Brassica napus L. is limited seriously owing to it’s genetic instability.Therefore,the search of the mechanism on the formation of distinctive seedcoat features is meaningful for both rapeseed breeding and plant genetics.Many studies were on the pigments in the seedcoatUp to now, rare researches were reported of the reason on the lower hull percentage in yellow-seeded rape.Three pairs of different genetic near-isogenic lines of black- and yellow-seeded Brassica napus as experimental materials were used in my study. The results are as follows:1 .The changes in pigments in seedcoat were investigated with the development of rape seed.The results of experiments and variance analysis showed that there was no significant difference in pigments contents among the three pairs of materials.Butjthe contents of chlorophyll,polyphenols,anthocyanin and melanin in seedcoat were different between black- and yellow-seeded lines and the differences were up to highly significant level. The results showed that chlorophyll content in yellow-seeded lines was much higher than that in black ones when seeds are nearing mature.The contents of polyphenols,anthocyanin and melanin in seedcoat of black-seeded lines were significantly higher than those of yellow-seeded ones.The contents of polyphenols and anthocyanin declined and the content of melanin increased rapidly in the late stage of seed development. So it was speculated that polyphenols and anthocyanin contents might influence the colour of seedcoat,but melanin content might be the mam factor to influence the colour of seedcoat.2.The indexes related to thickness of seedcoat were measured with the seedgrowth.The results of experiments and variance analysis showed that the difference of cellulose content in seedcoat reached highly significant level, but the content of lignin and hull percentage nearly had no difference among the three pairs of materials.The difference in cellulose content between yellow- and black-seeded lines was not obvious during the growth of seed,but the differences in lignin content and hull percentage was up to highly significant level.So it could be concluded that the lower lignin content might be the reason for the lower hull percentage in yellow-seeded lines.3.some enzymes related to pigments and lignin in seedcoat were studied.The results of experiments and variance analysis showed that the activities of PAL,PPO,POD increased gradually in the early stage and decreased in late stage during the period of seed development.The activities of PAL,PPO,POD in black-seeded lines were much higher than those in yellow ones.lt was suggested that the activities of PAL,PPO and POD might have great effect on the formation of distinctive seedcoat features.The activities of PPO and POD reached climax at 41 DAF.The activity of PAL reached climax at 34 DAF.lt was indicated that PAL activity might mainly influence the content of some precursor.4.Some enzyme activities were repressed and formation of protein was modulated during the seed growth.The results indicated that the formation of distinctive seedcoat features was related to the shikimic-phenylalanine pathway and influenced by PAL activity,PPO activity and oxidation.5.The isozyme patterns of esterase,polyphenol oxidase(PPO) and peroxidase(POD) in seedcoat were investigated. Same or similar esterase isozyme bands were observed between black- and yellow-seeded lines under same genetic conditions;There were more PPO isozyme bands in black-seeded lines than in yellow ones and there was 1 special band in black-seeded lines;Black-seeded lines had 1 more POD isozyme band (b or c band) than yellow ones under same genetic conditions. Owing to different genetic background,the isozyme patterns of esterase.PPO an更多还原