| To study the effect of environmental factors on oil and fatty acids accumulation,26 accessions of Brassica napus L.were planted in Nanjing,Wuhan,Xining and Lahsa respectively. A comparison of oil content of 26 lines in the four locations was made. Difference of amount of oil accumulation in developing seeds based on the date from two lines of Brassica napus L growing in three locations was compared. The main results from this research are as follows1. A positive correlation correlation between oil content and altitude(r=0.8001) as well as latitude. The oil content was less affected by latude compare to effect of altitude. The t-test value of regression coefficientswere 1.1095(altitude)>0.9158(latitude)2. Rate of oil accumulation in developing seeds from different locations showed a large difference. The oil rapid accumulation of seeds started on the 19th day after flowering(DAF) in Xining and lasted about 20 days. It started on 29 DAF in Lahsa with duration of 20 days and started on 24 DAF in Nanjing with duration of 15 days. However,the platform stage after oil content of seeds reaching the peak in Nanjing was longer than that in Xining and Lahsa. During the seeds developing of Brassica napus L,daily mean sunshine hours made a relatively small a affection on oil accumulation. Oil accumulation rate was positively correlated with daily mean temperature and daiy mean difference in temperature, negatively correlated with daily mean rainfall. The higher daily mean temperature, the greater daily mean difference in temperature and the less daily rainfall could promote oil accumulation. From 49 DAF,the affection of main climatic factors on oil accumulation were not obvious. In different ecological region, the climatic factors which affected on oil accumulation were different. The daily mean temperature and the daily mean sunshine hours were the major climatic factors which affected oil accumulation of seeds in Nanjing while daily mean difference in temperature and daily mean rainfall in Lahsa and daily mean difference in temperature and daily mean rainfall in Xining.3. By increasing of oleic acid (C18:1)content in developing seeds of Brassica napus L, linoleic acid (C18:2) content decreased. Oleic acid content was positively correlated with linoleic acid content. There was no obvious correlation existed between oleic acid content and linolenic acid (C18:3) content as well as linoleic acid content and linolenic acidcontent. The accumulation difference of the three fatty acids was found in developing seeds from different locations. The accumulation rate of oleic acid of the sample from Nanjing was the highest,from Xining was in middle while that from Lahsa was the lowest. The starting time of oleic acid rapid accumulation was 29 DAF in Lahsa which was 10 days later than in Nanjing and Xining. As seeds developing,linoleic acid content decreased slowly. And the rate of decreasing in the three location was almost equal. The starting time of linoleic acid decreasing was about 10 days earlier than the other locations. Linolenic acid content was not changed too much during the seeds developing. A great difference in linolenic acid content of seeds from 19 DAF to 39 DAF was found between the seeds from Lahsa and from the other two locations. Results showed that the relative activity of FAD2 decreased continuously during the seeds developing. The beginning time of the relative activity decrease of FAD2 in developing seeds was 29 DAF in Lahsa with 1 Odays later than that in Nanjing and Xining. The fastest decreasing rate was given from Lahsa while the decreasing rate from Nanjing was equal to from Xining. The difference of FAD2 relative activity might be resulted from the difference of the daily mean temperature and the daily difference of mean temperature from altitude locations.4. The oil content of seeds was signifcant negative correlation with hull ratio with a correlation coefficient of-0.856. It indicated the lower hull ratio was,the higheroil content was. |
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