保水剂对作物生长的不利影响及发生机制  

Adverse effects of superabsorbent polymers on crop growth and the underlying mechanisms

作　　者：司徒艳结 卫尤明 杨俊颖 毛小云[1,2] 廖宗文 陈娴[1] SITU Yan-jie;WEI You-ming;YANG Jun-ying;MAO Xiao-yun;LIAO Zong-wen;CHEN Xian(College of Resource and Environment,South China Agricultural University,Guangzhou,Guangdong 510642,China;Guangdong Provincial Key Laboratory of Eco-Circular Agriculture,Guangzhou,Guangdong 510642,China)

机构地区：[1]华南农业大学资源环境学院,广东广州510642 [2]广东省生态循环农业重点实验室,广东广州510642

出　　处：《植物营养与肥料学报》2022年第7期1318-1328,共11页Journal of Plant Nutrition and Fertilizers

基　　金：国家自然基金项目(42007084);广东省科技计划项目(2019B030301007)。

摘　　要：施用保水剂是提高作物抗旱能力的有效措施,但其用量稍多即导致种子发芽率下降、产量减少、根系生长受阻等不利影响。究其原因,既可能是保水剂与作物竞争“土壤水分”、降低土壤“通气性”等间接影响,也可能是保水剂对作物生长的直接抑制作用。农用保水剂中不可避免地残留着丙烯酸、钠等水溶性成分,丙烯酸对动物具有生物毒性,其在正常水分条件下,可以很快降解。但是,如果保水剂在土壤中吸水形成凝胶,就会大大降低丙烯酸的降解速率,可能对作物造成伤害。由于绝大多数研究都是在常规土壤水分条件下进行得到的结果,因此,在干旱条件下安全有效使用保水剂还需从机理和技术两方面开展研究,主要研究内容包括:不同保水剂在干旱条件下的安全阈值研究;聚合物单体成分在干旱条件下的降解特征及其降解产物对动植物的生物毒性;保水剂中有害组分在不同土壤条件下的降解、稀释扩散特征,有害组分对作物生长不同时期不利影响的发生与其降解动态的关系。另外,在应用技术方面,现行“农林保水剂”行业标准对单体残留量尚无限制,还缺乏对安全使用保水剂的指导。在以上研究基础上,今后应筛选单体生物毒性低的聚合物,优化单体合成参数,减少单体残留,以实现保水剂的安全高效使用。Application of superabsorbent polymers(SAPs)is an effective measure to improve drought resistance of crops.However,slightly excessive application rate will lead to adverse effects,such as decline of seed germination rate,yield decrease,poor root growth and so on.The indirect causes of the adverse effects could be the competition for soil moisture by crops and reduced soil aeration.The direct cause of the adverse effects is the inhibition of crop growth caused by the residual water-soluble components in SAPs,such as acrylic acid and sodium.Acrylic acid is toxic to animals,but its quick degradation under normal moisture conditions lessens its danger.However,if SAPs absorb water and form gel in soil,the half-life of acrylic acid in the gel will be greatly elongated,and might damage the crops.Most studies on the possible direct damage of monomers in SAPs were conducted under normal soil moisture conditions.Therefore,the safe and effective application of SAPs still needs to be studied under drought conditions.The safe concentration and threshold for crop growth,the degradation kinetics of monomer components under drought conditions,and the toxicity of degraded monomers to soil,plants under drought conditions need to be extensively studied.The degradation,dilution and diffusion characteristics of harmful components in SAPs under different soil conditions and the risk in different crop growing periods are also unclear.The limitations of the residual quantity of monomer should be considered in current industrial standard of SAPs,so as to provide guidance for the safe use of SAPs.In general,the safe and efficient application of polymers relies on the screening of SAPs with low biotoxicity of monomers,the optimized synthesis parameters to reduce the residue of monomers,and the specified application methods.

关 键 词：保水剂 抗旱机理 不利影响 生物毒性 降解特征 安全阈值 

分 类 号：S482.99[农业科学—农药学]