Study On The Grape Root Physiology And Cytology Response To Copper And Cadmium Stress

The experiment was carried out with the one-year cutting seedlings of two grape cultivars(‘Muscat Hamburg’ and ‘Ze Xiang’) under hydroponics and pot culture, studied copper sulfate, cadmium chloride stress and its combined stress on root activities and root physiological and biochemical characteristics, the absorption and accumulation of mineral elements in grape organs, meanshile, with the analysis of caspase3/7 activity, Evans blue solution and flow cytometry(FCM) technique, studied the induction of PCD on grape root and the changes of mitochondria characteristic.The main results were as follow:Root activity presents downward trend under copper, cadmium and its combined stress of ‘Muscat Hamburg’ and ‘Ze Xiang’grapes, super oxygen anion producing rate, hydrogen peroxide, malondialdehyde and proline contents are on the rise; Under low copper stress(0.5,1mmol/L), the accumulation of reactive oxygen species induced the rising of antioxidant enzymes activities, CAT and POD activities were highest when copper concentration is1mmol/L,otherwise, the corresponding copper concentration is 1.5mmol/L when SOD activity is highest,then with copper stress increasing, the three kinds of enzyme activity decreased,SOD,POD activities are still higher than control significantly,but CAT activity below or flat with contrast, two varieties present basic consistent.With the copper, cadmium and its combined treatment, ‘Muscat Hamburg’ and ‘Ze Xiang’ grapes’ root activity and NO generation are on the falling, the production rate of O2·-,H2O2 contents, relative electric conductivity,malondialdehyde,and proline contents are on the rise;the malondialdehyde contents induced by 0.5mmol/L Cd Cl2 treatment are more than1.5mmol/L Cu SO4 treatment,showed that the damage of root membrane induced by cadmium treatment is greater than copper,root ROS production induced by combined stress significantly higher than copper and cadmium treatment alone;It is worth noting that the NO contents of root induced by 1.5mmol/L Cu SO4·5H2O are significantly higher than other treatments, the concentration of copper induced the synthesis of NO, that is to say 1.5mmol/L Cu SO4·5H2O promote root NO.With the Copper, cadmium and its combined treatment,SOD,POD,CAT enzyme activities in grape roots decreased significantly,mitochondrial permeability transition pores increased,mitochondrial membrane potential and cytochrome c/a decreased significantly;Antioxidant enzymes activities,under combined treatment, mitochondrial permeability transition pores and cytochrome c/a increased significantly than copper, cadmium treatments;10mmol/L Ca(NO3)2 greatly alleviated the SOD,POD,CAT enzyme activities, mitochondrialfunctions induced by copper, cadmium and its combined treatment; Copper, cadmium and its combined treatment can damage antioxidant enzymes activities and mitochondria,but10mmol/L Ca(NO3)2 greatly alleviated the damage.The results showed that, cell death number under 1.5mmol/L Cu SO4·5H2O and0.5mmol/L Cd Cl2 treatments were significantly higher than control, Caspase-like3/7 activities elevated,the apoptotic rate increased,mitochondrial permeability transition pores increased,mitochondrial membrane potential and cytochrome c in roots decreased,the roots of‘Ze Xiang’ grape were induced to PCD; Cell death number, Caspase-like3/7 activities,apoptotic rate and mitochondrial permeability transition pores induced by combined stress were significantly higher than copper, cadmium treatments, combined stress intensified cell death of roots.Under the copper, cadmium and its combined stress,the absorption of Ca in different parts of grape plants is Cu+Cd>Cu>Cd>Ck, each treatment promote the Ca absorption in different parts; The absorption of Mg in stem and petioles are: Cd>Cu+Cd>Cu>Ck, there is no significant difference in the contents of Mg between toor and branch,surpress the absorption of Mg in leaf; Promote the absorption of Fe in stem,leaf and petiole,copper treatment of root and branch are highest in Fe; The absorption of Zn in stem,leaf and petiole were surpressed,the rules were: Ck > Cd > Cu+Cd > Cu,the absorption rules of root and branch were opposite;Each treatment inhibit the absorption of K in organs, the rules were: Ck>Cu>Cd>Cu+Cd,the inhibition of combined treatment is greater than individual treatment;Each treatment promote the absorption of Na,the order were: Cu+Cd>Cd>Cu>Ck,but no influence for Na contents in the stem;Ehe absorption of Cu in different organs were: Cu>Cu+Cd>Ck>Cd,cadmium treatment surpress the absorption of Cu;The order of Cd in root,stem,branch and leaf were: Cu+Cd > Cd > Cu > Ck, inhibit the absorption of Cd in petiole.