水杨酸减轻水稻高温伤害的机理研究

发布时间：2018-08-18 20:23

【摘要】：近年来,极端高温气候频发,严重影响水稻产量的形成,研究水稻耐热性风险栽培技术可为我国粮食安全提供重要帮助。作为一种信号分子,越来越多的研究表明水杨酸(SA)可显著增强植物耐热性,然而有关水杨酸在水稻的应用效果的报道较少,且其作用机理还有待阐明。鉴此,本项研究将以耐热性差异较大的水稻品种为材料,于水稻颖花分化期,花粉母细胞减数分裂期及开花期高温胁迫10-15d,在比较花期高温对水稻叶片及颖花影响差异的基础上,研究(1)SA减轻高温抑制水稻颖花分化的作用途径;(2)高温下SA防止水稻颖花退化及花粉粒败育的作用机制。高温处理温度设计为39-43℃,水杨酸喷施浓度为0,10,100,1000,10000及50000μmol/L,均于高温处理前喷施。研究表明:1.花期高温胁迫对水稻颖花的伤害大于剑叶。高温下2个水稻品种N22和GT937结实率均大幅度下降,而剑叶净光合速率处理间差异不显著,甚至稍高于常温处理。水稻颖花及剑叶对高温响应的差异与其组织温度有关,40℃高温天气下水稻颖花的温度达38℃以上,而剑叶仅在35℃左右。高温下剑叶蒸腾速率比颖花高2倍以上,推测剑叶较高的蒸腾速率是剑叶温度较低的主要原因。2.耐热性差异较大的两个水稻品种N22和GT937,40℃高温下穗温分别为38.4℃和38.0℃,但N22的结实率下降幅度要明显小于GT937。笔者认为可能与颖花抗氧化酶活性的变化有关,高温下N22颖花抗氧化酶活性的下降幅度较小,而GT937出现大幅度下降的趋势。此外,N22高温处理的颖花MDA含量稍高于对照,而GT937则显著高于对照;3.水稻颖花分化期喷施适宜浓度水杨酸可有效减轻高温对颖花分化的影响。高温下100μmol/L SA处理的超级稻甬优12每穗实粒数比0μmol/L处理高近80粒,仅比常温处理少16粒。SA提高超级稻甬优12每穗粒数的原因主要有:(1)显著增强水稻颖花抗氧化酶活性,防止了丙二醛等伤害物质含量的增加;(2)促进颖花中IAA和BR含量的增加,尤其前者,差异达显著水平,从而有利于水稻光合产物向穗部转移,高温下100μmol/L处理的颖花可溶性糖含量显著高于0μmol/L就是很好的证明;4.SA可减轻水稻花粉母细胞减数分裂期高温对常优1号每穗粒数及结实率的不利影响。高温下,100μmol/L SA处理的每穗粒数比0μmol/L多10粒左右,但结实率高了近一倍。相对于0μmol/L处理,100μmol/L处理的花粉粒育性及二次枝梗数均有所增加,尤其是前者,差异达显著水平。此外,该处理的颖花抗氧化酶活性、可溶性糖、脯氨酸含量、IAA、BR及ZR含量均显著高于0μmol/L处理,而MDA及ABA含量显著低于0μmol/L处理;5.花粉母细胞减数分裂期喷施SA可减轻高温对常优1号花粉粒育性的伤害,除10μmol/L处理外,其余浓度处理的花粉粒育性均显著高于0μmol/L处理。高温下SA减轻花粉粒败育主要在于其可减缓花药抗氧化酶活性的下降,并有效防止花药中ROS及MDA含量的上升,从而减少花药绒毡层细胞程序性死亡(PCD)的产生。
[Abstract]:In recent years, extreme high temperature climate frequently occurs, seriously affecting the formation of rice yield, the study of rice heat tolerance risk cultivation techniques can provide important help for food security in China.As a signal molecule, more and more studies show that salicylic acid (SA) can significantly enhance plant heat tolerance, however, the application of salicylic acid in rice has been reported. In view of this, this study will take rice varieties with different heat tolerance as materials, at the spikelet differentiation stage, pollen mother cell meiosis stage and flowering stage of high temperature stress 10-15 days, on the basis of comparing the difference of high temperature at flowering stage on rice leaves and spikelets, study (1) SA reduces the inhibition of high temperature. The mechanism of SA preventing rice spikelet degeneration and pollen grain abortion under high temperature was studied. The temperature of high temperature treatment was 39-43 C, and the concentration of salicylic acid was 0,10,100,1000,10000 and 50 000 micromol/L, which were sprayed before high temperature treatment. Leaves. The seed setting rates of two rice varieties N22 and GT937 decreased significantly under high temperature, but the difference of net photosynthetic rate of flag leaves was not significant, even slightly higher than that under normal temperature. The difference of response of rice spikelets and flag leaves to high temperature was related to their tissue temperature. The temperature of rice spikelets was above 38 C under high temperature of 40 C, while that of flag leaves was only about 35. The transpiration rate of flag leaf was more than two times higher than that of spikelet at high temperature. It was speculated that the higher transpiration rate of flag leaf was the main reason for the lower temperature of flag leaf. 2. The panicle temperature of two rice varieties N22 and GT937 with different Heat-tolerance was 38.4 and 38.0 respectively at high temperature, but the seed setting rate of N22 decreased significantly less than that of GT937. In addition, the content of MDA was slightly higher than that of the control, while the content of GT937 was significantly higher than that of the control. 3. Spraying salicylic acid at the appropriate concentration at the spikelet differentiation stage could effectively reduce the high-temperature glume pairing in rice. The grain number per panicle of super rice Yongyou 12 treated with 100 micromol/L SA was nearly 80 grains higher than that of 0 micromol/L treatment, only 16 grains less than that of normal temperature treatment. The increase of IAA and BR contents in spikelets, especially in the former, was significant, which facilitated the transfer of Photosynthate to panicles. The soluble sugar content in spikelets treated with 100 micromol/L at high temperature was significantly higher than 0 micromol/L. 4. SA could alleviate the number of grains per panicle and the setting of Changyou 1 under high temperature. Under high temperature, the number of grains per panicle was about 10 more than 0 micromol/L, but the seed setting rate was nearly double. Compared with 0 micromol/L treatment, the fertility of pollen grains and the number of secondary branches of 100 micromol/L treatment increased, especially the former, the difference was significant. The contents of soluble sugar, proline, IAA, BR and ZR were significantly higher than those of 0 micromol/L treatment, while the contents of MDA and ABA were significantly lower than those of 0 micromol/L treatment. 5. Spraying SA at meiosis stage of pollen mother cells could alleviate the damage of high temperature to pollen fertility of Changyou No. 1. Except 10 micromol/L treatment, the fertility of other treatments was significantly higher than that of 0 micromol/L treatment. SA alleviates pollen abortion mainly by slowing down the decrease of antioxidant enzyme activity and effectively preventing the increase of ROS and MDA contents in anthers, thereby reducing the production of programmed cell death (PCD) in tapetum cells.
【学位授予单位】：中国农业科学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S511;S42

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