保水缓释肥对盐胁迫下水稻矿质元素分配的调控

研究了施加盐碱地保水缓释肥(ZL 2012 1 0400570.0)对盐胁迫水稻幼苗叶长、叶温、氮磷钾(NPK)及钠(Na)的吸收和转运的影响。结果表明:盐胁迫下,水稻植株最大叶长随基质肥配比(1%、2%和4%)的增加而增加,且随处理时间延长,其增加效应愈明显,而其叶温逐渐降低;随高盐(4.68 g kg~(-1)盐分)处理的进行,植株逐渐枯萎死亡。盐胁迫下,该肥料施用明显提高植株的NPK含量,降低Na含量。低盐(2.68 g kg~(-1)盐分)胁迫下,播种40 d,施肥显著增加N和K向植株地上部转运,但显著降低其P转运系数(P-TF)和Na转运系数(Na-TF),显著提高植株K~+、Na~+的选择性比率(S_(K,Na));而播种80 d,施肥导致植株N、P、Na转运下降,而K转运和S_(K,Na)显著上升。高盐胁迫下,施肥对植株氮转运系数(N-TF)无显著影响,而P和Na转运上升,钾转运系数(K-TF)和S_(K,Na)随肥施量增加而显著下降。综上所述,低盐胁迫下,施该颗粒状盐碱地保水缓释肥,可明显提高水稻幼苗植株的NPK吸收,降低植株Na的积累,显著提高了水稻幼苗植株对K的选择性运输,维持体内的离子稳态,从而显著提高水稻植株的耐盐性。高盐胁迫下,该肥短期内亦可明显促进植株矿质营养在体内的积累,降低植株Na含量,从而一定程度上缓解植株盐害。

Regulation of Water Retaining Controlled-Release Fertilizer on Distribution of Mineral Elements in Rice Plants under Salt Stress

Objective]Fertilizer,especially chemical fertilizer,contributes significantly to the modern agricultural production. However,in recent years,fertilizer consumption has been increasing exponentially throughout the world and,as a result,causing a series of serious environmental problems. The invention and use of water retaining controlled-release fertilizer(WRCRF)is a promising approach to improving utilization of the water resources and fertilizer nutrients,and pursuing sustainable development of the environment and agriculture. Some fertilizers can also be used to alleviate salt stress of crop plants,such as urea,manure,etc. However,little has been reported on application of WRCRF to plants under salt stress. Recently,a study has been done finding that application of WRCRF(ZL 2012 1 0400570.0)may improve salt tolerance of rice seedlings significantly,which may be attributed to its effects on root growth,content of leaf chlorophyll,photosynthesis and water use efficiency.Method]To validate the finding a pot experiment was carried out on effects of WRCRF on leaf length,leaf temperature,and absorption and translocation of N, P,K,Na of rice seedlings under salt stress for 20,40 and 80 d,separately. Rice seeds were sown in pots filled with natural soil,2.68 g kg-1 in salinity. Twenty days later,half of the pots were amended with sodium chloride(NaCl)through irrigation to make the soil up to 4.68 g kg-1 in salinity. WRCRF was applied at 0, 1,2 and 4 g kg-1,separately to the pots.Result]Results show as follows.(1)Maximum leaf length of the rice seedlings increased with application rate of WRCRF regardless of salt stress and duration of treatment. WRCRF application decreased leaf surface temperature of the rice plants under salt stress,and the higher the application rate of WRCRF,the higher the effect. However,the plants gradually died of high salinity. (2)The fertilizer increased the contents of N,P and K in the plants under salt stress,but lowered the content of Na. Besides,it increased the translocation factor(N-TF)of N and K from root to shoot in the plants,under low salt stress for 40 d,but lowered that of P and Na,which suggests that application of WRCRF significantly enhanced the plants’ability of selective adsorption of K and Na(SK,Na). However, in the plants under low salt stress for 80 d,the applicationsignificantly lowered N-TF,P-TF and Na-TF,but raised K-TF andSK,Na,while in the plants under high salt stress,it did not have much effect on N-TF,but raised P-TF and Na-TF and significantly lowered K-TF andSK,Na.(3)Na content in the roots was significantly higher than that in the shoot of the plants under salt stress,and Na content in the plants increased very markedly with rising salt stress,especially in the shoot of the rice,indicating that Na-TF increased with rising salt stress. Application of the fertilizer decreased Na content in the plants under salt stress,and Na-TF,too,which suggests that the fertilizer decreased not only Na content in the plants, but also Na translocation to the shoot. However,in the plants under high salt stress,the fertilizer increased Na-TF of the plants,which suggests that the fertilizer decreased Na content in the plants,but enhanced Na translocation to shoot of the plants. And(4)the application of WRCRF increased K and Na selective translocation coefficient(SK,Na)of the plants under low salt stress,andSK,Na increasing with rising fertilizer application rate,which suggests that the fertilizer enhanced selective K translocation to shoot under low salt stress. However,the application of WRCRF decreasedSK,Na of the plants under high salt stress,and it did with rising fertilizer application rate.Conclusion]To sum up,rice plants applied with WRCRF (ZL 2012 1 0400570.0)under low salt stress significantly increased N,P,K absorption,decreased Na accumulation,enhanced selective K translocation to shoot,and maintained better ion homeostasis,thus, improving their salt tolerance. However,the plants under high salt stress,though applied with WRCRF(ZL 2012 1 0400570.0),significantly lowered their selective K translocation to shoot,and ion homeostasis, and hence gradually withered.