The effects of NaCl stress on the H +-ATPase, H +-PPase activity and lipid composition of plasma membrane(PM) and tonoplast(TP) vesicles isolated from roots and leaves of two soybean cultivars(Glycine max L.) differ...The effects of NaCl stress on the H +-ATPase, H +-PPase activity and lipid composition of plasma membrane(PM) and tonoplast(TP) vesicles isolated from roots and leaves of two soybean cultivars(Glycine max L.) differing in salt tolerance(Wenfeng7, salt-tolerant; Union, salt-sensitive) were investigated. When Wenfeng7 was treated with 0.3%(W/V) NaCl for 3 d, the H +-ATPase activities in PM and TP from roots and leaves exhibited a reduction and an enhancement, respectively. The H +-PPase activity in TP from roots also increased. Similar effects were not observed in roots of Union. In addition, the increases of phospholipid content and ratios of phospholipid to galactolipid in PM and TP from roots and leaves of Wenfeng7 may also change membrane permeability and hence affect salt tolerance.展开更多
Under NaCl stress for 2 d, H+-ATPase activity increased, and H+-PPase activity decreased in the tonoplast of salt-tolerant barley ( Hordeum vulgare L. cv. 'Tanyin 2') roots. La3+ (1 mmol/L), an inhibitor of Ca...Under NaCl stress for 2 d, H+-ATPase activity increased, and H+-PPase activity decreased in the tonoplast of salt-tolerant barley ( Hordeum vulgare L. cv. 'Tanyin 2') roots. La3+ (1 mmol/L), an inhibitor of Ca2+ channel in plasma membrane, and EGTA (5 mmol/L), a Ca2+ chelator, inhibited this NaCl-induced increase in H+-ATPase activity but stimulated the H+-PPase activity. Treatment of barley roots with CaM antagonist (trifluoperazine, TFP, 20 mumol/L) also diminished the increase of H+-ATPase activity induced by NaCl. La3+, TFP or La3+ + TFP increased Na+ uptake and decreased K+ and Ca2+ uptake in barley roots under NaCl stress. These results suggested that the activation of tonoplast H+-ATPase and the regulation of Na+ and K+ uptake under NaCl stress may be related to Ca2+-CaM system.展开更多
Tonoplast-enriched vesicles were prepared from suspension-cultured Populus euphratica Oliv. cells by differential centrifugation and discontinuous sucrose density gradient centrifugation. The properties of the proton ...Tonoplast-enriched vesicles were prepared from suspension-cultured Populus euphratica Oliv. cells by differential centrifugation and discontinuous sucrose density gradient centrifugation. The properties of the proton pumping activity of H+-ATPases in tonoplast vesicles were studied by acridine orange fluorescent quenching measured at 22 degreesC. The proton pumping activity of ATPase was ATP-dependent with apparent Michaelis-Menten Constant (K-m) for ATP about 0.65 mmol/L. The optimal pH for H+-ATPases activity was 7.5. The proton pumping activity of H+-ATPase could be initiated by some divalent cations, Mg2+ being highly efficient, much more than Fe2+; and Ca2+, Cu2+ and Zn2+ were inefficient under the experimental condition. The proton translocation could be stimulated by halide anions, with potencies decreasing in the order Cl- > Br- > I- > F-. The proton pumping activity was greatly inhibited by N-ethylmaleimide (NEM), N, N'-dicyclohexylcarbodiimide (DCCD), NO3- and Bafilomycin A(1), but not by orthovanadate and azide. These results demonstrated that the H+-ATPase in the tonoplast of Populus euphratica belonged to vacuolar type ATPase. This work was the first time that tonoplast-enriched vesicles were isolated from Populus euphratica cells.展开更多
文摘The effects of NaCl stress on the H +-ATPase, H +-PPase activity and lipid composition of plasma membrane(PM) and tonoplast(TP) vesicles isolated from roots and leaves of two soybean cultivars(Glycine max L.) differing in salt tolerance(Wenfeng7, salt-tolerant; Union, salt-sensitive) were investigated. When Wenfeng7 was treated with 0.3%(W/V) NaCl for 3 d, the H +-ATPase activities in PM and TP from roots and leaves exhibited a reduction and an enhancement, respectively. The H +-PPase activity in TP from roots also increased. Similar effects were not observed in roots of Union. In addition, the increases of phospholipid content and ratios of phospholipid to galactolipid in PM and TP from roots and leaves of Wenfeng7 may also change membrane permeability and hence affect salt tolerance.
文摘Under NaCl stress for 2 d, H+-ATPase activity increased, and H+-PPase activity decreased in the tonoplast of salt-tolerant barley ( Hordeum vulgare L. cv. 'Tanyin 2') roots. La3+ (1 mmol/L), an inhibitor of Ca2+ channel in plasma membrane, and EGTA (5 mmol/L), a Ca2+ chelator, inhibited this NaCl-induced increase in H+-ATPase activity but stimulated the H+-PPase activity. Treatment of barley roots with CaM antagonist (trifluoperazine, TFP, 20 mumol/L) also diminished the increase of H+-ATPase activity induced by NaCl. La3+, TFP or La3+ + TFP increased Na+ uptake and decreased K+ and Ca2+ uptake in barley roots under NaCl stress. These results suggested that the activation of tonoplast H+-ATPase and the regulation of Na+ and K+ uptake under NaCl stress may be related to Ca2+-CaM system.
文摘Tonoplast-enriched vesicles were prepared from suspension-cultured Populus euphratica Oliv. cells by differential centrifugation and discontinuous sucrose density gradient centrifugation. The properties of the proton pumping activity of H+-ATPases in tonoplast vesicles were studied by acridine orange fluorescent quenching measured at 22 degreesC. The proton pumping activity of ATPase was ATP-dependent with apparent Michaelis-Menten Constant (K-m) for ATP about 0.65 mmol/L. The optimal pH for H+-ATPases activity was 7.5. The proton pumping activity of H+-ATPase could be initiated by some divalent cations, Mg2+ being highly efficient, much more than Fe2+; and Ca2+, Cu2+ and Zn2+ were inefficient under the experimental condition. The proton translocation could be stimulated by halide anions, with potencies decreasing in the order Cl- > Br- > I- > F-. The proton pumping activity was greatly inhibited by N-ethylmaleimide (NEM), N, N'-dicyclohexylcarbodiimide (DCCD), NO3- and Bafilomycin A(1), but not by orthovanadate and azide. These results demonstrated that the H+-ATPase in the tonoplast of Populus euphratica belonged to vacuolar type ATPase. This work was the first time that tonoplast-enriched vesicles were isolated from Populus euphratica cells.
