湿地植物根系泌氧的特征

Characteristics of Radial Oxygen Loss from Root of Wetland Plants

研究了10种湿地植物的根系泌氧(radial oxygen loss,ROL)特征及其相关因素.泌氧不仅在物种间存在差异,而且在根系的不同部位也有明显不同.根据泌氧速率在根不同部位的变化趋势可将湿地植物的根部泌氧方式分为3种类型.类型Ⅰ为ROL在根的任意部位均较高,且沿氧传输方向逐渐降低;类型Ⅱ为ROL在根尖区域最高,之后沿根基部方向迅速降低;类型Ⅲ为ROL在根的任何位置泌氧速率非常低,且不随根的部位而变化.溶液培养条件下,缺氧胁迫能使植物根的直径增粗,根孔隙度提高,通气组织更加发达,诱导根基部泌氧屏障的生成,使泌氧速率和泌氧方式发生变化.

Characteristics of radial oxygen loss （ROL） from root of 10 wetland plants was studied in this paper. Root ROL varied with the distance from root tips,as well as with species. Spatial pattern of ROL was identified to show 3 types according to the trends of ROL rate along adventitious roots. Type Ⅰ showed a relatively high rate of ROL along the whole root, declining gradually from root apex to root basal part. Type Ⅱ was indicated by significantly high ROL in root apex but decreased greatly towards root base. As for Type Ⅲ ,ROL was similar but very low along the whole root. In nutrient solutions,deoxygenation caused a series of changes in root anatomy of some species, such as increased root diameter, root porosity and more developed aerenchyma,inducing a ROL barrier in root basal part and the consequent change of ROL profile.