外源钙对模拟酸雨胁迫下水稻质膜组分和钙形态的调节

Regulation of exogenous calcium on plasma membrane compositions and calcium forms of rice roots under simulated acid rain stress

为了探寻减轻植物酸致伤害的有效方法,采用水培法研究了外源钙(Ca,5 mmol·L^(-1))对模拟酸雨(SAR,pH 4.5/3.0)胁迫下水稻根系质膜稳定性、质膜组分以及钙形态的影响。结果表明:低强度SAR(pH 4.5)对水稻根系膜稳定性无显著影响,而高强度SAR(pH 3.0)显著降低水稻根系膜稳定性,且水稻根系质膜磷脂(磷脂酰胆碱和磷脂酰甘油)、膜蛋白和非水溶性钙含量显著减少,胞内水溶性钙含量显著增加,恢复5 d后仅SAR(pH 3.0)组上述指标仍显著低于对照。与单一SAR和单一Ca^(2+)处理组相比,pH 4.5+Ca^(2+)组水稻根系膜稳定性无显著变化。pH 3.0+Ca^(2+)组水稻根系质膜稳定性、磷脂(磷脂酰胆碱和磷脂酰甘油)、膜蛋白和非水溶性钙含量显著低于对照但高于单一SAR(pH 3.0)组,水溶性钙含量仍显著高于对照但低于SAR(pH 3.0)组,且恢复5 d后上述指标均达到对照水平。外源Ca^(2+)增强水稻根系质膜耐受SAR胁迫能力与其维持水溶性钙-非水溶性钙平衡及缓解磷脂和膜蛋白的降解有关,且缓解效果受酸雨强度限制。

To explore effective ways to reduce damage on plants caused by acid rain,the effect of exogenous calcium(Ca,5 mmol·L^(-1))on the membrane stability,plasma membrane compositions,and calcium forms in rice roots under simulated acid rain(SAR,pH 4.5/3.0)were studied through hydroponic experiments.Low intensity SAR(pH 4.5)had no significant effect on membrane stability in rice roots.High intensity SAR(pH 3.0)decreased the membrane stability,contents of phospholipids(phosphatidylcholine and phosphatidylglycerol),and membrane protein in rice roots and increased the content of water-soluble calcium.After a 5-day recovery,the above indicators in rice roots treated with pH 3.0 SAR were still lower than the control.Compared with rice treated with single SAR or Ca^(2+),pH 4.5+Ca^(2+)treatment had no effect on the membrane stability in rice roots.pH3.0+Ca^(2+)decreased the membrane stability as well as the contents of phospholipids,membrane proteins,and non-water-soluble calcium in rice roots,and these parameters were higher than those treated with pH 3.0 SAR.Water-soluble calcium in rice roots treated with pH 3.0+Ca^(2+)was increased and lower than the pH 3.0 SAR treatment.After a 5-day recovery,the above indicators in rice roots treated with pH 3.0+Ca^(2+)were close to the control.Briefly,exogenous Ca^(2+)enhance the tolerance of rice to SAR stress and that is related to maintaining the balance of water-soluble calcium and non-water-soluble calcium as well as alleviating the degradation of phospholipids and membrane proteins.The alleviating effect is limited by the intensity of acid rain.