The effects of La3+ on inward K+ channels at plasma membrane in vicia guard cells are investigated using the whole-cell patch-clamp recording mode. It is shown that La3+ on both sides of plasma membrane blocks inward ...The effects of La3+ on inward K+ channels at plasma membrane in vicia guard cells are investigated using the whole-cell patch-clamp recording mode. It is shown that La3+ on both sides of plasma membrane blocks inward K+ currents in a concentration- dependent manner, indicating that La3+ binding sites may exist on both sides of plasma membrane in guard cells in vicia. The dose response is fitted by the Michaelis-Menten relation characterized by an inhibitor constant Ki of 2.56±0.25 μmol·L?1 (outside membrane) and (1.18±0.11)×10?15 mol·L?1 (inside membrane). Intracellular La3+ has much stronger inhibitory effect on inward K+ currents than ex- tracellular La3+ does, suggesting there may exist stronger binding sites inside membrane than outside membrane. Since ion channel activities of guard cells directly affect plant stomatal movement and water status, our results imply that rare earth elements might have potential practical values in regulating plant water status and strengthening plant drought endurance.展开更多
We explore nitric oxide (NO) effect on K+in channels in Arabidopsis guard cells. We observed NO inhib- ited K+in currents when Ca2+ chelator EGTA (Ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid) w...We explore nitric oxide (NO) effect on K+in channels in Arabidopsis guard cells. We observed NO inhib- ited K+in currents when Ca2+ chelator EGTA (Ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid) was not added in the pipette solution; K+in currents were not sensitive to NO when cytosolic Ca2+ was chelated by EGTA. NO inhibited the Arabidopsis stomatal opening, but when EGTA was added in the bath solution, inhibition effect of NO on stomatal opening vanished. Thus, it implies that NO ele- vates cytosolic Ca2+ by activating plasma membrane Ca2+ channels firstly, then inactivates K+in chan- nels, resulting in stomatal opening suppressed subsequently.展开更多
基金the National Natural Science Foundat ion of China(Grant No.20171031) the Shanxi Provincial Natural Science Foundation.
文摘The effects of La3+ on inward K+ channels at plasma membrane in vicia guard cells are investigated using the whole-cell patch-clamp recording mode. It is shown that La3+ on both sides of plasma membrane blocks inward K+ currents in a concentration- dependent manner, indicating that La3+ binding sites may exist on both sides of plasma membrane in guard cells in vicia. The dose response is fitted by the Michaelis-Menten relation characterized by an inhibitor constant Ki of 2.56±0.25 μmol·L?1 (outside membrane) and (1.18±0.11)×10?15 mol·L?1 (inside membrane). Intracellular La3+ has much stronger inhibitory effect on inward K+ currents than ex- tracellular La3+ does, suggesting there may exist stronger binding sites inside membrane than outside membrane. Since ion channel activities of guard cells directly affect plant stomatal movement and water status, our results imply that rare earth elements might have potential practical values in regulating plant water status and strengthening plant drought endurance.
基金Supported by the National Natural Science Foundation of China (Grant No. 20701028)
文摘We explore nitric oxide (NO) effect on K+in channels in Arabidopsis guard cells. We observed NO inhib- ited K+in currents when Ca2+ chelator EGTA (Ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid) was not added in the pipette solution; K+in currents were not sensitive to NO when cytosolic Ca2+ was chelated by EGTA. NO inhibited the Arabidopsis stomatal opening, but when EGTA was added in the bath solution, inhibition effect of NO on stomatal opening vanished. Thus, it implies that NO ele- vates cytosolic Ca2+ by activating plasma membrane Ca2+ channels firstly, then inactivates K+in chan- nels, resulting in stomatal opening suppressed subsequently.
