Studies On The Influence Of Different Stages Of Flower Bud Differentiation Under Low-temperature Stress In Rapeseed (Brassica Napus L.)

Flower bud differentiation is the basis of flowering plants. In this paper, we have been used the early maturity oilseed line and medium maturity oilseed cultivation as materials, discussed the low temperature stress on the flower bud differentiation in different stages of the flower bud number, the influence of the blossom and the change of the physiological and biochemical indexes in the process of the flower bud differentiation. The main results were as follows:1、 Different maturity of Brassica napus varieties of flower bud differentiation phase responsed to low temperature differences。 The Sensitive temperature of the flower bud differentiation in different stages of1358line were≤10℃、≤7℃、5℃and<10℃; and Sensitive temperature of Xiangyou15were4℃、<0℃、<0℃and<10℃.This meant that when the temperature was lower than these values, these tested materials were suppressed in flower bud formation and differentiation process slows down. Both materials in flower bud differentiation stage, bud primordium differentiation stage、 ovule pollen mother cell differentiation stage than bud primordium differentiation stage、 female flower petal primordium and stamen primordium differentiation stage are more sensitive to temperature.2、 Different low temperature stress, with the extension of stress time, there were differences in their physiological and biochemical indexes content. In the first flower bud differentiation phase, the soluble protein content、 malondialdehyde (MDA) and proline contents were all showed a trend of increase.These changes may help to alleviate the low-temperature injury to1358line and Xiangyou15.With the increasing of stress, the soluble protein content of1358line declined in the second and third flower bud differentiation phase, and the same as the proline content in the fourth phase. For Xiang-you15, in the third and fourth phase the contents of soluble protein and proline were reduced, while MDA content was significantly increased in treatments with lower temperature and longer stress. Comparison between the two rapeseeds, the cold resistance indexes of Xiangyou15are all higher than1358line and showed stronger cold resistance.3、 Each stage of flower bud differentiation which is under different low temperature treatment, the ending flowering time are differences in apparent. The beginning flowering time was delayed, and the ending flowering time was ahead of time. Under—5℃、0℃and10℃,for1358line different differentiation stage of flowering phases showed minimum in bud primordium differentiation stage, sepal primordium differentiation stage takes second place and female flower petal primordium and stamen primordium differentiation stage is the longest. For Xiangyou15, in the same differentiation stage, the processing temperature is lower, the later flowering, and the ending flowering time earlier; same temperature conditions, the ending flowering time showed earlier in bud primordium differentiation stage, sepal primordium differentiation stage is latest.4、 After low temperature treatment on the flower bud differentiation period, influenced by low temperature conditions, the correlation of economic characters to yield were showed that:The number of effective pods per plant>The number of first effective branches> Plant height> Seeds per pod> Main inflorescence pod number> First flowering node.