| Rape is one of oil crops in the wold, which are mainly soybean, sunflower, rape and peanut. With the hard work of so many researchers, a series of yellow- seeded Brassica napus L. with good quality have been bred and used in practice since the first was discovered by proIssor Liu in 1975. Yellow rapeseed in Brassica napus is characterized with thinner seed coat and lower hull percentage, which in turn are correlated with higher oil and proteins and lower crude fiber contents compared to black seeds. Under the same genetic conditions, the oil content in yellow seeds is 2% higher than that in black ones, or even more than 5%. Previous results showed that the color of seed coat has apparently negative correlation to oil content. But, the widespread application of yellow- seeded napus L. in Brassica napus L. was limited seriously owing to low and unstable yellow- seeded percentage and poor external characters of seeds in yellow- seeded rapedseed (Brassica napus L.). Up to now, rare studies on pigments or color difference in seed coat of Brassica napus L. are reported. The objective of the present study was to go into the mechanism on the color difference between yellow- and black- seed coat. Therefore, we chose three pairs of different genetic near- isogenic lines (NILs) of black- and yellow- seeded Brassica napus L. as experimental materials to identify the type of pigments in seed coat of rapesecd and further investigate the changes in the contents of pigments, amino acid and related enzymes. Three pairs of black- and its near isogenic yellow- seeded materials (4B and 4Y, 7B and 7Y, 8B and 8Y), coming from cross combination descendants (Brassica napus X Brassica juncea, B. napus X Brassica campestris, and Brassica napus X Brassica carinata) respectively were used to materials. The results are as follows: 1. This study adapt steps as follows: acetone extracting chlorophyll and lutein桯CI.- ethanol solvent extracting polyphenolics and anthocyanidin and flavonoid桸aOfl extracting melanin until seed coat had no color. After extract solution identified by UV- spectrometer and HPLC, it was discovered that Pigments extracted from seed- coal included chlorophyll a, chlorophyll b, lutein, polyphenols, anthocyanidin, flavonoid, and melanin so on, and that melanin was the main factor affecting seed coat color of rape. 2 Changes in six types of pigments in seed coat of rape was investigated with the seed growth. (1) Changes in content of chlorophyll a and b in seed coat The results of experiment and variance analysis showed that changes in the content o~ chlorophyll a and b was very obvious during the growth of seed and the difference was iii to highly significant level. however, the difference hetween yellow- and black- seeded wa not obvious, except that the content of chlorophyll a and b in yellow - seeded was higher than that of black one. It was concluded that chlorophyll didn't influence the seed coat color of rapeseed. (2) Changes in lutein The content of lutein in seed coat of strains tested changed obviously with the development of seed and the difference was up to the highly significant level. Difference between yellow- and black- seeded and that caused difference genetic background of materials were not obvious. It was speculated that the content of lutein could not influence the color of seed coat. (3) Changes in polyphenols content in seedcoat No significant difference of polyphenols content in three pairs of NILs had been indicated, but the difference between black- and yellow-...
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