海藻酸钠寡糖提高水稻幼苗对镉胁迫的抗性

通过水培试验,研究了海藻酸钠寡糖对水稻镉(Cd)毒害的缓解效果,并从Cd的吸收分布、非蛋白巯基(NPT)含量和抗氧化酶活性等方面,初步探讨了其可能的生理机制。结果表明,海藻酸钠寡糖预处理一定程度上可缓解水稻Cd毒害,其中20 mg/L处理的效果较明显,表现为促进了幼苗生长,提高了光合色素含量。进一步分析显示,海藻酸钠寡糖处理的水稻地上部和地下部Cd含量及转移效率均显著降低,Cd在根部细胞壁中的含量及所占比例则显著增加,叶片和根中NPT含量也分别提高了23.5%和14.9%,植物螯合肽(PCs)含量分别增加28.0%和15.0%,抗氧化酶活性和脯氨酸含量也有不同程度提高,丙二醛含量显著下降27.1%。这些结果初步说明细胞壁固持、巯基分子螯合和抗氧化系统均参与了海藻酸钠寡糖对水稻Cd毒害的缓解。

Alginate oligosaccharides enhanced the resistance of Oryza sativa L. to cadmium stress

Hydroponic experiments were conducted to study the effects of alginate oligosaccharides (AOS) on alleviating cadmium (Cd) toxicity in rice (Oryza sativa L.),and to explore the physiological mechanism.The results showed that the pretreatments of different concentrations of AOS alleviated Cd toxicity in rice,with the treatment of 20 mg/L AOS having obvious effect,characterized by promoted rice seedling growth and increased photosynthetic pigment contents.Moreover,Cd content in shoots and roots and Cd transfer efficiency were significantly reduced due to addition of AOS,compared to only Cd treatment.The contents and proportion of Cd in cell wall of root were significantly increased.The contents of non-protein thiols (NPT) in leaves and roots were increased by 23.5％ and 14.9％ respectively,and phytochelatins (PCs) contents were increased by 28.0％ and 15.0％.The activities of antioxidant enzyme and the content of proline were also improved by AOS in varying degrees,and malonaldehyde (MDA) content was decreased by 27.1％.These results preliminarily indicate that these several mechanisms,including cell wall binding,chelation with intracellular thiols and antioxidant systems are involved in the alleviation of AOS on Cd toxicity in rice.