State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan 430074, China.
Sci Total Environ. 2022 Dec 10;851(Pt 1):158189. doi: 10.1016/j.scitotenv.2022.158189. Epub 2022 Aug 19.
Renewed interest in phosphite, an analog of phosphate, has increased due to its widespread distribution and increasing abundance in many waterbodies. However, up until recently very little is known about their ecological effects on aquatic organisms. Herein we studied the effects of phosphite via root and foliar exposure on the growth responses of the dominant pioneer macrophyte V. natans. Overall, both exposures of phosphite to V. natans resulted in significant reductions in the leaf length, root length, relative growth rate (RGR) and photosynthetic pigments, suggesting phosphite had an inhibitory effect on the plant growth. Our results further confirmed phosphite could induce the oxidative stresses in the V. natans cells, as indicated by the significantly increased intracellular enzyme activities i.e. superoxide dismutase activity (SOD) and malondialdehyde (MDA). Microscopic evidence also showed phosphite penetrated the cell membrane and destroyed membrane integrity under high phosphite stress. Besides, V. natans leaves exhibited intuitive deterioration symptoms, which seemed to be more sensitive to phosphite toxicity than roots. It is concluded that the increased abundance of phosphite in waterbodies cannot be utilized as a bioavailable P source but impose adverse physiological and metabolic limitations to plant growth, which should be receive more attention in the ecological risk assessment. Our result is necessary to build a comprehensive understanding of phosphite biogeochemical behaviors in aquatic ecosystems.
由于亚磷酸盐在许多水体中广泛分布且丰度不断增加，人们对其作为磷酸盐类似物的兴趣重新燃起。然而，直到最近，人们对其对水生生物的生态影响知之甚少。在此，我们通过根和叶暴露研究了亚磷酸盐对优势先锋水生植物水鳖生长响应的影响。总的来说，亚磷酸盐对水鳖的这两种暴露都导致叶片长度、根长度、相对生长率（RGR）和光合色素显著减少，表明亚磷酸盐对植物生长有抑制作用。我们的结果进一步证实，亚磷酸盐可以诱导水鳖细胞产生氧化应激，这表现为细胞内酶活性（如超氧化物歧化酶活性（SOD）和丙二醛（MDA））显著增加。显微镜证据还表明，在高亚磷酸盐胁迫下，亚磷酸盐穿透细胞膜并破坏膜的完整性。此外，水鳖叶片表现出直观的恶化症状，似乎比根对亚磷酸盐毒性更为敏感。因此，可以得出结论，水体中亚磷酸盐含量的增加不能作为可利用的 P 源，反而会对植物生长造成不利的生理和代谢限制，在生态风险评估中应予以更多关注。我们的研究结果对于全面了解水生生态系统中亚磷酸盐的生物地球化学行为是必要的。
