外源S^(2-)抑制水稻生长及土壤微生物活性的半效应浓度研究  

EC_(50) of soil S^(2-)inhibiting rice growth and soil microbial activities

作　　者：谢晓梅[1,2] 廖敏[1,2] 张楠[1,2] 徐培智[3] 徐昌旭[4] 刘光荣[4] 

机构地区：[1]浙江大学环境与资源学院,杭州310058 [2]浙江省亚热带土壤与植物营养重点研究实验室,杭州310058 [3]广东省农业科学院土壤肥料研究所,广州510640 [4]江西省农业科学院土壤肥料与资源环境研究所,南昌330200

出　　处：《植物营养与肥料学报》2015年第5期1286-1293,共8页Journal of Plant Nutrition and Fertilizers

基　　金：国家公益性行业(农业)专项(201003059)资助

摘　　要：【目的】S2-是冷浸田类低产稻田中水稻生长的重要限制因子,探讨S2-对土壤-水稻生态系统的生态毒性特征,可为揭示冷浸田土壤S2-毒害临界值及其机理研究提供理论依据。【方法】以单季常规晚粳稻秀水134为材料,采用盆栽试验模拟冷浸田土壤S2-毒害,设外加S2-0、10、50、100、300、600和1200 mg/kg,在水稻苗期和分蘖期调查水稻生长,叶片叶绿素含量、脯氨酸和抗氧化酶系统活性,土壤微生物活性。【结果】在含一定S2-本底(12.08mg/kg)的正常稻田土壤中,随外源S2-的加入量增加,对水稻生长的抑制逐步增强。当外源S2-浓度超过50 mg/kg后,水稻的株高、干物质积累量显著降低;水稻叶片生理指标叶绿素含量(SPAD值)、脯氨酸含量、抗氧化酶系统活性则显著增加,表明50 mg/kg是本研究条件下外源S2-对水稻生长产生显著毒害影响的临界点;随外源S2-浓度的增加土壤微生物量碳、微生物三大基础菌系总量、功能菌系总量和微生物总量都随外源S2-处理水平的增大而降低,硫化细菌总量随之增加,土壤S2-浓度40 mg/kg(含本底)为多数土壤微生物活性指标(微生物基础菌系总量、功能菌系总量、微生物总量)EC50变化的临界值;体系中土壤微生物活性指标和水稻生长存在显著相关,表明供试土壤S2-对水稻生长的影响是S2-对土壤-植物-土壤微生物系统同步影响的综合结果。可见,供试土壤S2-浓度40 mg/kg为导致土壤-水稻-土壤微生物系统受到显著负效应的临界值。【结论】土壤中S2-超过一定浓度将对土壤-水稻-土壤微生物系统产生显著负效应,S2-浓度40 mg/kg(含本底)为导致供试土壤-水稻-土壤微生物系统受到显著负效应的临界值,当供试土壤中S2-含量超出该浓度时,需采取合理的农艺措施控制其负效应。[Objectives]S2- is one of the important limiting factors for rice growth in cold waterlogged paddy fields which are typical low yield paddy fields. Characteristics of ecological toxicity of S2-to system of soil-rice under S2-stress were investigated in order to provide a theoretical basis for future research to reveal the dose critical value of S2- toxicity and its toxic mechanism in cold waterlogged paddy soil. [Methods] Effect of exogenous S2- treatment on rice physiological indices （ rice physiological growth, chlorophyll, proline and the activities of the antioxidant enzyme system in the rice leaves） , soil microbial activities and their bioecological characters at the seedling and tillering stages in the interactive system of soil-rice-S2- and microbe were studied by a greenhouse pot experiment which is set to simulate S2- toxicity in waterlogged paddy soil. A single season conventional late japonica rice＆amp;nbsp;Xiushui 134 was selected as crop material, and S2-was applied at seven different levels in one paddy soil, namely 0, 10, 50, 100,300, 600 and 1200 mg/kg. [Results] The addition of exogenous S2-gradually inhibits the growth of rice and decreases soil microbial activities in the normal tested paddy soil in which the background S2-concentration is 12. 08 mg/kg. The plant height and dry matter accumulation of rice decrease sharply when the exogenous S2-concentration exceeds 50 mg/kg. However, SPAD value of chlorophyll content in rice leaves, proline accumulation and activities of antioxidant enzyme systems are increased significantly. These results suggest that exogenous S2-of 50 mg/kg is the critical concentration under the tested condition to poison rice growth. Meanwhile, soil microbial activities are declined rapidly with the increase of the concentration of exogenous S2-. The turning point of decreasing soil microbial activities can be presumed as 40 mg/kg of soil S2- concentration by analyzing its toxicant concentration that inhibits a microbe-mediated ecological process by 50%（ EC50 ）

关 键 词：硫离子 水稻生理指标 土壤微生物量 土壤微生物活性 

分 类 号：S511.22[农业科学—作物学] S154.3