磷对苦草种子及幼苗生长和根系泌氧的影响

Effects of Phosphorus on the Growth and Radial Oxygen Loss of Vallisneria natans Seeds and Their Seedling Stage

[目的]了解不同浓度富磷水体对苦草种子及其生长发育的影响。[方法]以苦草为模式植物,采用原位根系泌氧图像分析(平面光极技术)的方法,研究不同浓度富磷水体对苦草种子和植株生长发育以及根系泌氧的影响。[结果]不同浓度的富磷水体对苦草种子发芽均有促进效果,苦草幼苗根长生长随富磷水体中磷酸盐浓度的增加而加快。当磷酸盐浓度在50~200 mg/L时,苦草中叶绿素含量变化稳定;当磷酸盐浓度超过200 mg/L时,苦草中叶绿素含量波动显著,后期呈现出升高趋势。当磷酸盐浓度超过200 mg/L时,苦草累积MDA速度较快,此浓度下,苦草对磷酸盐吸附量最多,去除率达67.6%。植物根系的养分吸收程度会直接影响植物中叶绿素的合成以及MDA的释放,苦草根系泌氧研究表明,磷酸盐胁迫下根系pH降低,活性氧含量呈增加趋势。[结论]该研究结果为富磷水体对苦草生长发育的影响机制提供了科学的数据支撑,对湿地植物修复不同程度的富磷水体具有借鉴意义。

[Objective]To understand the effect of different concentrations of phosphorus-rich water on the growth and development of Vallisneria natans seeds.[Method]Using Vallisneria natans as model plants,the effects of different concentrations of phosphorus-rich water on the growth and development of Vallisneria natans seeds and radial oxygen loss were studied by radial oxygen loss image analysis(planar optode technology).[Result]Different concertratons of phosphorus-rich wate promoted the germination of Vallisneria natans seeds,and the root length growth of Vallisneria natans seedlings was accelerated with the increase of PO 43--P concentration in phosphorus-rich water.When the PO 43--P concentration was 50-200 mg/L,chlorophyll changes in Vallisneria natans were stable.When the PO 43--P concentration exceeded 200 mg/L,the chlorophyll concentration fluctuated significantly and showed an increasing trend in the later stage.When the PO 43--P concentration exceeded 200 mg/L,Vallisneria natans accumulated MDA at a faster rate.When the PO 43--P in water was 200 mg/L,Vallisneria natans adsorbed the most phosphate,and the removal rate of phosphorus-rich water reached 67.6%.The degree of nutrient uptake in plant roots would directly affect the synthesis of chlorophyll and the release of MDA in plants.Th radial oxygen loss of Vallisneria natans showed that the pH of the roots was decreased and the reactive oxygen content tended to increase under phosphate stress.[Conclusion]The results of this study provide scientific data to support the mechanism of phosphorus-rich water on the growth and development of Vallisneria natans,and have implications for wetland plant remediation of phosphorus-rich water at different levels.