| In this study, two new type rapeseed male sterile lines, a cytoplasmic male sterile line - 681A and a transgenic male sterile line - trans I , were used, and two tests were conducted. In the first test, cytologica] biological techniques were applied, cytological characters of abortion of 681A and trans I were observed, and the differences in cytological characters of abortion between two male sterile lines were compared. In another test, the effect of temperature on trace pollen of new type rape male sterile line-681A was studied by method of observation in field and temperature treatment by manpower.At the first, techniques of paraffin-embedded section and microphotograph were used. The main results are as follows: 1. The abortion stage of 681A was clinandrium stage. Due to effect of temperature, the differentiation of clinandrium began when bud were about 1.6-2 mm, after then all buds differentiated clinandriums, and one anther could differentiate to 1 ~ 4 clinandriums in which there were microspores which in stage from tetrad to mature pollen grains. The parts where hadn't differentiated clinandrium rested on archesporial cell stage, and there were only some palisade cells. 2. The properties of abortion of transgenic male sterile line -trans I were: From tetrad stage, many aberrances about tapetum could observed, such as hyperplasia, isolation and abscission with middle layer cells, abnormal disorganization, vacuolization, and so on. Because of these variability of tapetum, pollen grains of trans I were entire abortion, in despite of their figures were normal. Checked by microscope after be dyed by acetic acid magenta, we could found that all pollen grains were transparent straw yellow and no one was red. Other developmental characters of anther were the same as those of normal anthers.At the second time, number of pollen grains of 681A was observed. The test was conducted in Hunan Agricultural University in 2002. The flowers were fixed at the same day on which they flowered, and then were dyed by acetic acid magenta. By summarizing the relationship between number of pollen per visual field and according mean temperature in a day, results could be obtained: Because of fertile in low temperature condition and sterile in high temperature condition, 681A belonged to low-temperature-fertile type, and its critical temperature was about 10C. Significantcorrelation at the 0.01 level existed between the number of pollen per visual field and mean temperature in a day in flowering stage, and the relational coefficient between number of pollen per visual field and mean temperature in a day of 10 d before flowering was biggest. At the same time, the phenomenon was observed: the growth stage of a bud from about 2 mm to flowering was about 10 d. So we can deduce: the key stage of producing trace pollen is the stage when the size of buds is about 2 mm.In succession, the low-temperature (10C/7C) and high-temperature (20C/17C) treatments were conducted respectively in SANYO-SGC1700 type artificial climate chamber in 2003. When the first flower appeared on the main inflorescence, microscopic examination was conducted about three main inflorescences. Afterwards, when the biggest bud of first branching was 5 mm, chose 4 branching, retained one grade bud on a bruching respectively according to a classification criterion, four grades are <2 mm, 2.1~3 mm, 3.1~4 mm, 4.1~5 mm .respectively. Temperature treatment continued after choosing bud. When the 2 mm bud turned to 5 mm, microscopic examination about flowers or buds of 4 branching was conducted. The results of test approved more that: 681A belongs to low-temperature-fertile type, and the key stage of producing trace pollen is the stage when size of buds is about 2 mm.
|
PDF Full Text Request