以冬油菜品种“陇油6号”为材料，通过中性盐NaCl∶Na2 SO4（9 mol∶1 mol ）混合胁迫（浓度为40、80、120、160、200 mmol·L-1和240 mmol·L-1，Na＋浓度依次为44、88、132、176、220 mmol·L-1和264 mmol·L-1）和碱性盐NaHCO3∶Na2CO3（9 mol∶1 mol）混合胁迫（浓度为10、20、30、40、50 mmol·L-1和60 mmol·L-1，Na＋浓度依次为11、22、33、44、55 mmol·L-1和66 mmol·L-1）处理油菜种子和幼苗，研究不同盐、碱胁迫下油菜种子萌发特性并观察根尖细胞有丝分裂的形态变化。结果表明：对“陇油6号”种子萌发和幼苗生长无害的最大混合盐浓度为160 mmol·L-1（pH＝6．67， Na＋＝176 mmol·L-1），最大混合碱浓度为50 mmol·L-1（pH＝9．29，Na＋＝55 mmol·L-1）；随着盐、碱胁迫浓度增大，“陇油6号”幼苗根尖细胞有丝分裂指数逐渐降低，细胞微核率和染色体畸变率先上升后下降，碱性盐溶液胁迫下降幅度明显大于中性盐溶液胁迫；在同一盐、碱胁迫浓度时，处理时间越长，根尖细胞有丝分裂指数越低，染色体畸变率和微核率越高。这表明盐、碱胁迫对“陇油6号”种子萌发和幼苗生长是两种不同的胁迫，且碱性盐胁迫强于中性盐。%Using Longyou 6 as test material ,the characteristics of seed germination and morphological changes of mitosis of root apical cells of rapeseed ( Brassica campestris L .) were studied under the stresses of neutral salt NaCl∶Na2SO4 (9 mol∶1 mol) (concentrations of NaCl∶Na2SO4 were 40 ,80 ,120 ,160 ,200 mmol·L-1 and 240 mmol·L-1 , and concentrations of Na+ were 44 ,88 ,132 ,176 ,220 mmol·L-1 and 264 mmol·L-1 ) and alkaline salt NaHCO3∶Na2CO3 (9 mol∶1 mol) (concentrations of NaHCO3∶Na2CO3 were 10 ,20 ,30 ,40 ,50 mmol·L-1 and 60 mmol·L-1 , and concentrations of Na+ were 11 ,22 ,33 ,44 ,55 mmol·L-1 and 66 mmol·L-1 ) .The results showed that the maxi-mum concentration of NaCl∶Na2SO4 was 160 mmol·L-1 (pH=6 .67 ,Na+ =176 mmol·L-1 ) ,and that of NaHCO3∶Na2 CO3 was 50 mmol·L-1 (pH=9 .29 ,Na+ =55 mmol·L-1 ) under which the seed germination and seedling growth of rapeseed were not affected negatively .With the increase of salt and alkali concentration ,the mitotic index of root apical cells in rapeseed seedlings was gradually reduced ;the cell micronucleus rate and chromosome aberration went up firstly and then came down ;and the decrease rate under alkaline salt treatment was significantly greater than that under neutral salt treatment .Under the same concentration of salt and alkali stress ,the longer the treatment time lasted ,the lower was the mitotic index of root apical cells and the higher were the chromosome aberration rate and micronucleus rate .It could be concluded that salt and alkali stresses were different each other in affecting seed germination and seedling growth of rapeseed ,and the effects of alkaline salt were stronger than those of neutral salt .
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