堇菜叶片草酸钙晶体与水分维持的关系

Relationship between calcium oxalate crystals and water maintenance in leaves of Viola verecumda

随着全球气候变化加重,干旱强度和持续时间逐渐增加,严重影响植物生长和作物产量。喀斯特为典型的干旱和高钙生境,植物叶片富集大量的草酸钙晶体,而该晶体与植物耐旱性之间的关系并不清楚。该研究以喀斯特适生植物堇菜(Viola verecumda)为材料,土壤进行自然干旱,分析堇菜叶片的草酸钙晶体变化特征与水分之间的关系。结果表明:在土壤自然干旱条件下,堇菜主要通过细胞内束缚水的释放,维持细胞内水分平衡;而在干旱后期,叶片通过关闭气孔,将部分自由水转变为束缚水,防止水分流失。此外,草酸钙晶体的密度与束缚水含量具有极其显著的强正相关线性回归关系(r=0.8253,P<0.0001),表明草酸钙晶体作为主要的束缚水物质。因此,堇菜植物在耐旱过程中可能协调草酸钙晶体和气孔的生理行为忍耐干旱胁迫。

As the global climate changes dramatically, the increasing intensity and duration of drought seriously affects plant growth and crop yield. Karst is a typical arid and high-calcium habitat, and plant leaves in karst areas contain a large amount of calcium oxalate crystals, while the relationship between the crystal and the drought tolerance of plants is not clear. In this study , we took Viola verecumda grown in karst area as material, and analyzed the relationship between the changing characteristics of calcium oxalate cyrstals and water in its leaves, by subjecting the leaves to natural dry soil. The results showed that in the early stage of drought stress, V. verecumda maintained the intracellular water balance mainly through the release of intracellular bound water. In the later stage of drought, the leaves mainly prevented water loss by closing the stoma and converting part of the free water into bound water. In addition, the density of calcium oxalate crystals had an significant positive correlation with the bound water content (r =0.825 3, P<0.000 1), suggesting that calcium oxalate crystals act as the main matter binding water. Therefore, V. verecumda may coordinate the physiological behavior of calcium oxalate crystals and stomatal during drought tolerance.