【摘要】 以小白菜(Brassicachinensis L.)为研究对象,为探明外源钙能否缓解镉胁迫对小白菜造成的生理毒害.实验以蛭石和珍珠岩(2∶1)混合为栽培基质,以改进的Hoagland营养液(用硝酸铵代替硝酸钙)为营养源,对比研究了不同质量浓度(0,200,400,800 mg/L)钙对镉胁迫下小白菜根系活力、硝酸还原酶(NR)活性、硝态氮含量、光合色素含量等生理指标的影响.结果表明:1)镉胁迫使小白菜根系活力下降,NR活性降低,而硝态氮含量明显上升,光合色素合成明显受到影响;2)在钙处理下,根系活力显著提高(p<0.05),NR活性普遍上升,光合色素含量有所上升但普遍低于对照组;3)低钙组的光合色素含量明显高于无钙组,但是总体呈现下降趋势.硝态氮含量与NR活性成负相关,呈现先降后升的趋势;高浓度钙抑制根系活力与NR活性.因此,适当钙质量浓度(200~400 mg/L)处理可以明显缓解重金属镉对小白菜造成的生理胁迫.本研究结果为外源钙在缓解植物重金属毒害方面的应用提供理论依据.更多还原

【Abstract】 In this research,Brassica chinensis L.was cultivated in mixed culture medium(vermiculite and perlite 2∶1) with improved Hoagland nutrient solution(substitute ammonium nitrate with calcium nitrate).The research mainly studied the effects of Ca with various concentrations(0,200,400,800 mg/L)on physiological property of Brassica chinensis L.under Cd stress.The physiological indexes included root activity,NR activity,NO3-N content and chlorophyll content.The results showed that:1) Under Cd stress,the NR activity and root activity declined,the synthesis of chlorophyll was inhibited obviously,but the content of NO3-N rised gradually.2) The root activity of plant got significantly increased under the treatment with Ca(p<0.05),the activity of NR also improved.The contents of chlorophyll in Brassica chinensis L.with Ca supply were higher than the treatment without Ca,but they were lower than the blank treatment.3) The contents of chlorophyll under low Ca treatment were higher than the treatment without Ca apparently,but they decreased gradually.The content of NO3-N first decreased then increased,and there was a significant negative correlation between NO3-N content and NR activity.The treatment of higher Ca concentration inhibited the activity of root and NR.In conclusion,appropriate concentration(200~400 mg/L)of exogenous Ca could relieve the stress of Cd to the Brassica chinensis L..更多还原