Effects of salt and alkali stress on seed germination and mitosis of root apical cells of Brassica campestris L.
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DOI:10.7606/j.issn.1000-7601.2014.04.003
Key Words: rapeseed  salt-stress  alkali-stress  seed germinati on  root apical cell  mitosis
Author NameAffiliation
XU Yao-zhao1, ZENG Xiu-cun1,2, FANG Yan2, SUN Wan-cang2 (1.河西学院, 甘肃 张掖 734000
2.甘肃农业大学 甘肃省油菜工程技术研究中心, 甘肃 兰州 730070) 
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Abstract:
      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 maximum concentration of NaCl∶Na2SO4 was 160 mmol·L-1 (pH=6.67, Na+=176 mmol·L-1), and that of NaHCO3∶Na2CO3 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.