油菜苗期的植株长势与抗性及后期产量密切相关。为探索甘蓝型黄籽油菜抗逆性较弱和产量较低的原因，以2对不同遗传来源的甘蓝型黄、黑籽油菜近等基因系为材料，研究了苗期植株的主要生理特性。结果表明，甘蓝型黄籽油菜苗期生长势弱，叶绿素含量和类胡萝卜素含量，光合速率和叶面积指数（LAI）均比相同遗传背景下的黑籽油菜低；与黑籽油菜相比，甘蓝型黄籽油菜无论是在不同的叶龄期，还是在植株的不同部位，均表现出“糖高氮低”的代谢特点，且越冬期叶片的硝态氮含量和硝酸还原酶活性也低；根颈粗和单株干物质重也明显小。甘蓝型黄籽油菜苗期生长势弱，冬前干物质积累偏少，进而影响其春后的生殖生长，这可能是其产量较低的重要原因之一。
Yellow-seeded rapeseed (Brassica napus L.) is characterized with thinner seed coat and lower hull percentage, which in turn is correlated with higher oil, protein and lower crude fiber contents compared to black-seeded rapeseed from the same genetic background. The breeding of yellow-seeded rapeseed has become one of the main objectives in rapeseed breeding. However the growth vigor, resistance and yield of yellow-seeded rapeseed are not so good as black-seeded rapeseed. The growth vigor of rapeseed plants during seedling stage is in connection with its yield significantly. Two pairs of different genetic near-isogenic lines of yellow-seeded and black-seeded rapeseed (Brassica napus L.) genotypes were used to study the physiological characters of yellow-seeded rapeseed in seedling stage, which included photosynthetic characters, characters on C/N metabolism and accumulation of dry matter. The results showed that the chlorophyll content and carotenoid content of yellow-seeded rapeseed were lower than those of black-seeded rapeseed, and its net photosynthetic rate was lower compared to black-seeded rapeseed from the same genetic background. The leaf area index (LAI) of yellow-seeded rapeseed was lower than that of black-seeded rapeseed. It was found that there were higher total sugar content and lower protein content in yellow-seeded rapeseed plants than in black-seeded rapeseed plants in every plant organs during seedling stage, and there were lower nitrogen content and activity of nitrate reductase in yellow-seeded rapeseed plants than in black-seeded rapeseed plants at overwintering stage. Width of root colla and dry matter per plant in yellow-seeded rapeseed plants were also lower than those in black-seeded rapeseed plants, indicating the weak growth vigor of yellow-seeded rapeseed. All those above were the important reasons leading to the lower yield of yellow-seeded rapeseed.
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