高温胁迫下外源物质对颖花能量水平的影响及其与水稻耐热性关系分析

Effects of exogenous substances on the energy level of spikelets under high temperature stress and its relationship analysis with heat tolerance in rice

  • 摘要: 【目的】探究高温胁迫下喷施外源化学物质对水稻颖花能量水平的影响及其与水稻耐热性的关系,以期为水稻的耐热栽培提供理论依据。【方法】以常规籼稻高温耐性品种广陆矮15(GLA15)和高温敏感品种绵恢101(MH101)为试验材料,减数分裂期以叶面喷施清水为对照(CK),设5个外源物质喷施处理:0.15 mmol/L蔗糖(Suc)、25mmol/L阿卡波糖(Aca)、10mmol/L水杨酸(SA)、10mmol/L水杨酸+0.15mmol/L蔗糖(SA+Suc)、10mmol/L水杨酸+25 mmol/L阿卡波糖(SA+Aca)。喷施完毕立即利用日光型人工气候室进行高温胁迫(日最高气温/日最低气温为38.0℃/29.0℃)处理,分析高温胁迫下不同外源物质对颖花能量水平、花粉活力、颖花受精率、蔗糖代谢酶活性、抗氧化酶活性、碳水化合物含量、苯丙烷类代谢酶活性和次生代谢物含量的影响。【结果】喷施不同外源物质可构建不同的颖花能量水平,与CK相比,高温胁迫下2个水稻品种的ATP含量和ATPase活性均以SA+Suc处理最高,Aca处理最低,且GLA15颖花的ATP含量和ATPase活性总体高于MH101。高温胁迫下SA+Suc、Suc和SA处理的花粉活力和颖花受精率均较CK提高;Aca处理的花粉活力和颖花受精率则较CK显著降低(P<0.05,下同),MH101分别降低10.3%和35.6%,GLA15分别降低2.5%和8.0%,降幅MH101>GLA15。与CK相比,高温胁迫下SA、Suc和SA+Suc处理的蔗糖合酶、酸性转化酶、超氧化物歧化酶、过氧化物酶和抗坏血酸过氧化物酶活性增加,Aca处理的上述酶活性均降低;SA、Suc和SA+Suc处理的颖花碳水化合物含量增加,Aca处理的颖花碳水化合物含量降低(MH101的果糖和可溶性糖含量除外),SA可促进颖花的糖代谢水平,进而缓解Aca对可溶性糖、蔗糖和非结构性碳水化合物含量的抑制作用。高温胁迫下2个品种的苯丙氨酸解氨酶、肉桂酸-4-羟化和4-香豆酸辅酶A连接酶活性及木质素含量均以SA+Suc处理较高,总酚和总黄酮含量以Suc处理较高。【结论】外源化学物质主要通过影响碳水化合物含量和蔗糖代谢,调控颖花能量水平,维持较高抗氧化酶活性和次生代谢物水平,增强水稻花器官对高温胁迫的耐性。通过施用外源物质改善颖花能量起始水平可能是有效缓解水稻高温胁迫的一种潜在技术策略。

     

    Abstract: 【Objective】The purpose of the study was to investigate the effects of spraying exogenous chemicals on the energy level of rice spikelets under high temperature stress and its relationship with rice high temperature stress tolerance, in order to provide a theoretical basis for the cultivation of heat resistant rice. 【Method】Common indica rice high temperature tolerant variety GLA15 and high temperature sensitive variety MH101 were used as experimental materials. During meiosis, foliar spraying of clear water was used as a control(CK). Five exogenous substance spraying treatments were applied: 0.15 mmol/L sucrose(Suc), 25 mmol/L acarbose(Aca), 10 mmol/L salicylic acid(SA), 10 mmol/L salicylic acid+0.15 mmol/L sucrose(SA+Suc), and 10 mmol/L salicylic acid+25 mmol/L acarbose(SA+Aca). Immediately after spraying, a sunlight type artificial climate chamber was used for high temperature stress treatment(daily maximum temperature/daily minimum temperature being 38.0 ℃/29.0 ℃). The effects of different exogenous substances on the energy level, pollen vitality, spikelet fertilization rate, sucrose metabolism enzyme activity, antioxidant enzyme activity, carbohydrate content, phenylpropanoid metabolism enzyme activity and secondary metabolite content of spikelets under high temperature stress were analyzed. 【Result】Spraying different exogenous substances could construct different levels of spikelet energy. Compared with CK, under high temperature stress, the ATP content and ATPase activity of the two rice varieties were the highest in SA+Suc treatment and the lowest in Aca treatment. Moreover, the ATP content and ATPase activity of GLA15 spikelets were generally higher than those of MH101. Under high temperature stress, the pollen viability and spikelet fertilization rate of SA+Suc, Suc and SA treatments were all higher than those of CK, while the pollen viability and spikelet fertilization rate of Aca treatment were significantly reduced compared to CK(P<0.05, the same below). The pollen viability and spikelet fertilization rate of MH101 were reduced by 10.3% and 35.6% respectively compared to CK, while GLA15 was reduced by 2.5% and 8.0%, with a decrease of MH101>GLA15. Compared with CK, under high temperature stress, the activities of sucrose synthase, acid invertase, superoxide dismutase, peroxidase, and ascorbic acid peroxidase increased in SA, Suc, and SA+Suc treatments, while the activities of the above enzymes decreased in Aca treatment. The carbohydrate content in the spikelets treated with SA, Suc, and SA+Suc increased, while the carbohydrate content in the spikelets treated with Aca decreased(except for the fructose content and soluble sugar content of MH101). SA could promote the sugar metabolism level of spikelets, thereby alleviating the inhibitory effect of Aca on soluble sugar, sucrose, and non structural carbohydrate contents. Under high temperature stress, the activities of phenylalanine ammonia lyase, cinnamic acid 4-hydroxylation, 4-coumaric acid CoA ligase and lignin content of the two varieties were higher in SA+Suc treatment, while the total phenolic and flavonoid contents were higher in Suc treatment.【Conclusion】Exogenous chemicals mainly affect carbohydrate content and sucrose metabolism, regulate the energy level of spikelets, maintain high antioxidant enzyme activity and secondary metabolite levels, and enhance the tolerance of rice floral organs to high temperature stress. Improving the initial energy level of spikelets through the application of exogenous substances may be a potential technical strategy for effectively alleviating high temperature stress in rice.

     

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