海水胁迫下CoCl_2对油菜生长和抗氧化生理指标的影响

Effect of CoCl_2 on the Growth and Antioxidant Physiological Indexes of Rape Seedling under Seawater Stress

以‘高油605’油菜品种为材料,通过室内水培实验考察了不同浓度CoCl2处理对海水胁迫下油菜种子的萌发、幼苗生长及相关生理指标的影响。结果表明：（1）Hoagland＋30%海水（CK3）处理的油菜种子萌发和生长受到显著抑制,但添加50-100μmol.L-1 CoCl2处理的油菜种子发芽率比CK3显著提高31.98%-32.91%,发芽势极显著增加54.17%-59.03%（P〈0.01）,鲜重显著增加25.49%-50.98%;而添加150-1000μmol.L-1 CoCl2则对油菜遭受海水胁迫的缓解作用减弱,抑制了油菜幼苗的根系生长。（2）CK3幼苗的抗坏血酸和叶绿素含量显著降低;但添加10-100μmol.L-1 CoCl2处理的抗坏血酸含量比CK3极显著提高1.26-1.87倍,添加30、50和100μmol.L-1CoCl2处理的叶绿素含量比CK3显著提高;但200-1000μmol.L-1 CoCl2使油菜幼苗抗坏血酸含量显著降低,1 000μmol.L-1 CoCl2使幼苗叶绿素含量显著下降。（3）10μmol.L-1 CoCl2处理幼苗的POD和SOD活性分别比对照显著增加60.2%和18.19%,APX活性却降低6.20%;10-70μmol.L-1 CoCl2使油菜幼苗POD活性降低,SOD和APX活性增加,MDA含量降低,显著缓解了海水胁迫压力;而100-1 000μmol.L-1 CoCl2使POD先升后降,SOD和APX活性降低,MDA含量增加。研究发现,适宜浓度CoCl2能够显著提高海水胁迫下油菜幼苗的抗氧化酶活性,增强其清除活性氧能力,降低膜质过氧化作用,从而有效缓解海水胁迫伤害,诱导增强其耐盐性,促进幼苗生长;10-100μmol.L-1 CoCl2对30%海水胁迫的缓解效果最好,更高浓度的CoCl2反而对油菜幼苗产生毒害作用。

Rape variety ＇High oil 605＇ as material,effects of different concentration CoCl2 on the growth and physiological characters of rape seedling under seawater stress were carried out.The results showed that：（1）Seed germination and growth of rape were significantly inhibited in 30% seawater.Treatment with 50-100 μmol·L-1 CoCl2 compared with 30% seawater treatment could significantly improve the seed germination and growth of rape seedling.Rape seed germination rate increased by 31.98%～32.91%,significant difference（P〈0.05）.Rape seed germination potential increased by 54.17%～59.03%,extremely significant difference（P〈0.01）.Fresh weight increased by 25.49%-50.98%,but treatment with 150-1 000 μmol·L-1 CoCl2 the seawater stress relief effect was abate,inhibited the growth of root length.（2）Ascorbic acid content and chlorophyll content were significantly inhibited in 30% seawater.Ascorbic acid content of rape seedling increased by 1.26-1.87 times with 10-100 μmol·L-1 CoCl2 treatment.The chlorophyll content has greatly increased with 30 μmol·L-1 and 50 μmol·L-1 and 100 μmol·L-1 CoCl2 treatments,but treatment with 200-1 000 μmol·L-1 CoCl2 reduced Ascorbic acid content,and treatment with 1 000 μmol·L-1 CoCl2 reduced chlorophyll content.（3）POD and SOD activity of treatment with 10 μmol·L-1 CoCl2 significantly increased by 60.2% and 18.19% compared with CK1 but APX activity reduced by 6.20% with no significant difference.Treatments with 10-70 μmol·L-1 CoCl2 decreased POD activities and MDA content,but increased SOD and APX activities,which alleviated seawater stress;while treatments by CoCl2 with 100-1 000 μmol·L-1 decreased SOD and APX activities,and POD had a curve of increased,then decreased and increased MDA content.Therefore,high concentration of CoCl2 is harmful to rape seedling.The result showed that treatment with optimum concentration of CoCl2 could significantly increase antioxidant enzyme activities of rape seedlings,enhance its scavenging reactive oxygen species,reduce lipid peroxidation under seawater stress,in order to effectively alleviate the seawater stress injury induced increase their salt tolerance,and promote rape seedling growth;The optium concentration was 10-100 μmol·L-1.