炭化苹果枝通过减少土壤DTPA-Cd降低苹果砧木镉积累和镉伤害

Carbonized Apple Branches Decrease the Accumulation and Damage of Cadmium on Apple Rootstock by Reducing DTPA-Cd in Soil

为探究炭化苹果枝对苹果砧木镉积累和镉伤害的影响,以盆栽苹果砧木(平邑甜茶)实生苗为试材,在施有0.5%和1%(质量分数)的炭化苹果枝的盆土中灌入含镉(CdSO4)营养液,分析盆土中二乙烯三胺五乙酸(diethylenetriamine pentaacetic acid,DTPA)所提取镉(DTPA-Cd)及根茎叶镉含量,检测根系和叶片抗氧化酶活性和根系细胞死亡情况以及叶片光合速率.结果表明,施用炭化苹果枝的盆土DTPA-Cd含量显著低于未施用炭化苹果枝的,其中施用0.5%和1%的炭化苹果枝使盆土DTPA-Cd含量在处理第12 d分别比未施的降低17.50%和25.55%;施入炭化苹果枝明显降低苹果砧木根茎叶镉积累量,提高根系和叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,降低根系和叶片·O_(2)^(-)生成速率、H_(2)O_(2)和MDA含量,还降低根系细胞死亡比率,提高叶片光合速率,其中施用(ω)0.5%和1%的炭化苹果枝使根系镉含量在处理第12d分别比未施的降低29.49%和37.18%,使根细胞死亡比率分别比未施的降低22.73%和29.09%.这些说明施用炭化苹果枝可通过降低土壤DTPA-Cd含量,减少苹果砧木对镉的吸收和积累,减轻根系细胞以及叶片光合性能所受到的伤害,施用1%的比施用0.5%的效果更显著.

To explore the effects of carbonized apple branches on cadmium(Cd)accumulation and its damage to apple rootstock,the rootstocks of apple(Malus hupehensis Rehd.)in pots containing soil together with 0.5%and 1%(ω)carbonized apple branches were irrigated by a nutrient solution containing CdS04.The content of DTPA-Cd(cadmium extracted by diethylenetriamine pentaacetic acid)in the potting soil,and the accumulation of Cd in the roots,stems,and leaves of apple rootstocks,were subsequently monitored.The activities of antioxidant enzymes in roots and leaves,root cell death,and the net photosynthesis rate were further analyzed.The results showed that the concentration of DTPA-Cd in the potting soil with carbonized apple branches was significantly lower than that without carbonized apple branches(Cd-only).Compared with the Cd-only treatment,the concentration of DTPA-Cd in the potting soil decreased by 17.50%and 25.55%in the treatment with 0.5%and 1%(ω)carbonized apple branches for 12 days.The Cd accumulation in roots,stems,and leaves;the accumulations of superoxide anions(·O_(2)^(-)),hydrogen peroxide(H202),and malondialdehyde(MDA)in roots and leaves;and the amount of cell death in the roots of apple rootstock treated by carbonized apple branches were significantly lower compared to the Cd-only treatment.However,the activities of superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT)in the roots and leaves,and the net photosynthesis rate of apple rootstock treated by carbonized apple branches,were significantly higher than under the Cd-only treatment.Compared with the Cd-only treatment,Cd accumulation in roots decreased by 29.49%and 37.18%in the treatment with 0.5%and 1%(ω)carbonized apple branches for 12 days,and the amount of cell death decreased by 22.73%and29.09%,respectively.Our results show that carbonized apple branches reduce the uptake and accumulation of Cd in apple rootstock by reducing the content of DTPA-Cd in the soil,thereby alleviating the damaging effect of Cd on cells and photosynthesis.Moreover,the use of 1%(ω)carbonized apple branches was more effective than0.5%(ω).