Cd胁迫对高、低积累白菜生理生化特性的影响

Effects of Cd Stress on Physiological and Biochemical Characteristics of Chinese Cabbage With High and Low Accumulation

以白菜品种"北辰"(高积累)和"金峰"(低积累)为试材,通过盆栽试验法,探讨不同程度Cd胁迫下2个白菜品种的生物量、光合呼吸系统、抗氧化防御系统的变化,研究了Cd胁迫对Cd高、低积累白菜品种生理生化特性的影响,以期为白菜全生产提供参考依据。结果表明:当Cd胁迫浓度为1.0 mg·kg^(-1)时,2个白菜叶绿素含量、生物量的积累受到抑制,叶片的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)以及气孔抑制率(Ls)明显下降,胞间CO_(2)浓度(Ci)增加。随着Cd胁迫浓度升高至5.0 mg·kg^(-1),"北辰"和"金峰"中丙二醛(MDA)含量、过氧化物酶(POD)活性也呈上升趋势(分别增加169.7%、100.6%),且低积累品种"金峰"的叶片中过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、谷胱甘肽酶(GR)、脱氢抗坏血酸还原酶(DHAR)的活性在各个Cd浓度胁迫下较"北辰"高。综上所述,Cd胁迫对高、低积累白菜生理生化特性的响应程度不同,低积累品种由于CAT、POD、APX、GR、DHAR的活性较"北辰"高,尤其在5.0 mg·kg^(-1)Cd胁迫下"金峰"GR活性高出"北辰"63.7%,不易受到Cd的毒害,导致地上部分积累较少的Cd,同时叶片中较高的抗氧化水平可抵抗Cd胁迫。

Taking‘Beichen’(high accumulation)and‘Jinfeng’(low accumulation)as test materials,pot experiments were conducted to explore the changes in biomass,photosynthetic respiratory system,and antioxidant defense system of two cabbage varieties under different degrees of Cd stress.The effects of Cd stress on the physiological and biochemical characteristics of cabbage varieties with high and low accumulation of Cd were studied,in order to provide reference of Chinese cabbage production.The results showed that when Cd stress concentration was 1.0 mg·kg^(-1),chlorophyll content and biomass accumulation were inhibited,net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr)and stomatal inhibition rate(Ls)were significantly decreased,and intercellular CO_(2)concentration(Ci)was increased.With the increase of Cd stress concentration to 5.0 mg·kg^(-1),MDA content and POD activity in‘Beichen’and‘Jinfeng’also showed an increasing trend(169.7%and 100.6%,respectively),and the activities of CAT,POD,APX,GR and DHAR in leaves of‘Jinfeng’with low accumulation were higher than that in‘Beichen’under various Cd concentration stress.To sum up,high and low Cd stress on accumulation cabbage physiological and biochemical characteristics of different response,low accumulation variaty because of CAT,POD,APX,GR,DHAR,high activity of‘Beichen’,which under the stress of 5.0 mg·kg^(-1)Cd‘Beichen’63.7%higher than that of GR activity,less susceptible to Cd poisoning,lead to less Cd part is accumulated on the ground,at the same time,the higher antioxidant levels in blade can be resistant to Cd.