砷胁迫下水磷耦合对不同磷效率水稻农艺性状及精米砷含量的影响

Effect of Water Management and Phosphorus on Agricultural Traits and As Concentration in Polished Rice of Two Rice Cultivars Differing in P-Efficiency under As-stress Conditions

为探索缓解水稻砷毒害的农艺措施,选用耐低磷水稻99011和低磷敏感水稻99012,研究水分管理、磷用量及其交互作用对不同砷浓度酸性土壤上水稻生长发育、产量及稻米砷含量的影响。结果表明,节水灌溉(干湿交替)和增施磷肥都明显促进水稻生长(包括分蘖数、总穗数、有效穗、根系干重、生物量)和产量形成,缓解砷胁迫对水稻生长和产量的不利影响,且水、磷交互作用也表现出明显的正效应。50 mg kg 1砷处理时,节水灌溉显著降低精米砷含量,而增施磷肥提高了精米砷含量,水、磷交互效应明显比水分管理效应差,但比磷肥效应好得多;100 mg kg 1砷处理时,节水灌溉和增施磷肥都明显降低精米中的砷含量,且二者交互表现出正效应。土壤加砷后,相同处理的生物学性状均为耐低磷水稻明显大于磷敏感水稻,而精米砷含量则为耐低磷水稻显著低于磷敏感水稻。研究表明,可以根据砷污染程度采取干湿交替水分管理、调节磷用量以及选择吸收磷能力强的耐低磷水稻品种等措施缓解砷污染对水稻生长、产量和品质的不利影响。

To explore the agronomic measures for mitigating As toxicity to rice,we conducted soil culture experiments to investigate the effect of three potential practical methods,water management regime,phosphorus（P）fertilization and their interaction on plant growth,grain yield and As concentration in polished rice in P-efficient rice cultivar 99011 and P-inefficient rice cultivar 99012 in various As-stress acid soils.Results indicated that compared with flooded conditions and/or insufficient P application,water-saving irrigation（maintaining the soil moisture from 65% of the maximum field water capacity to flooded conditions）and/or sufficient P application significantly increased the number of tillers,total spike,productive spike,root dry weight,biomass and grain yield of two rice cultivars regardless of As levels.Both rice cultivars had the best agricultural traits under water-saving irrigation condition with sufficient P fertilization.So water management,P fertilization and their interaction all showed positive effect.At 50 mg kg 1of As level,water-saving management decreased the As concentration in polished rice markedly compared with flooded treatment,but sufficient P application increased the As concentration in polished rice significantly compared with insufficient P supply.Thus the effect of interaction of water management and P fertilization was worse than the independent effect of water management,but better than the independent effect of P fertilization.At 100 mg kg 1of As level,water-saving management and/or sufficient P supply reduced the As concentration in polished rice clearly compared with flooded conditions and/or insufficient P application,and their interaction effect was better than the independent effect of two factors.At the same treatment with As supply,all the investigated agricultural characteristics of low-P tolerant rice cultivar 99011 were better than those of low-P sensitive rice cultivar 99012,but the As concentration in polished rice was on the contrary.The study demonstrated that water management regime,P fertilization,and selection of P-efficient rice cultivars are effective measures that can be used to relieve the As stress to rice growth and the As accumulation in polished rice.