不同水稻花粉育性耐高温的差异比较研究

Comparative Study on Fertility and High Temperature Tolerance of Different Rice Pollens

长江中下游一季稻的花粉发育和授粉受精极易受到盛夏高温的危害,是导致一季稻产量不稳定的主要自然因素。选育花粉发育耐高温的品种是提高一季稻稳产性的关键。本研究对190份水稻材料在高温条件下的花粉育性进行了比较,结果显示:MZQA8和MCQA2等花粉可染率高于80%、结实率高于70%的耐高温材料有36个;部分花粉染败、结实率比正常条件下低15%的高温敏感材料135个;花粉完全败育、结实率为0的高温极敏感材料19个,其中典败不育材料4个,无粉型不育材料15个。对响应高温表达且不利于花粉发育的UbL40基因的表达进行比较发现,在高温条件下耐高温水稻材料的花药中UbL401、UbL402b和UbL404c的相对表达水平明显低于不耐高温材料。本研究筛选出的花粉发育耐高温的MZQA8和MCQA2等材料可作为长江中下游一季稻耐高温育种的资源。UbL401、UbL402b和UbL404c在高温条件下的表达水平相对较低可能是水稻花粉发育耐高温的重要分子机制。

The pollen development,pollination and fertilization of one-season rice in the middle and lower reaches of the Yangtze River are extremely vulnerable to high midsummer temperatures,a main natural factor leading to unstable rice yields.Selecting and breeding varieties whose pollens are able to develop at high temperatures is the key to yield stability of one-season rice.In this study,190 rice materials were compared in their pollen fertility under high temperature conditions.The results showed that 36 materials,including MZQA8,MCQA2,etc.,were high temperature-resistant,with the stained pollen rates and seed-setting rates higher than 80%and 70%,respectively.There were 135 high temperature-sensitive materials,some of whose pollens were proved abortive by staining and seed-setting rates were 15% lower than those under normal conditions.Nineteen materials were extremely sensitive to the high temperature,with completely abortive pollens and 0 seed-setting rates,among which 4 belonged to the typical abortion type and 15 the pollen-free sterile type.Comparison of the m RNA expression levels of the UbL40gene,which expresses in re sponse to high temperatures and is adverse to pollen development,revealed that the relative expression levels of UbL401UbL402b and UbL404c in the anthers of high temperature-resistant rice materials were significantly lower than those of high temperature-sensitive ones.The screened-out materials in the study,such as MZQA8,MC-QA2,and so on,are rice varieties with pollens being able to develop under high temperature conditions,and can be used as resources for breeding high temperature-resistant one-season rice varieties suitable for cultivation in the middle and lower reaches of the Yangtze River.The relative low expression levels of UbL401UbL402b and UbL404c under high temperature conditions may be an important molecular mechanism underlying the high temperature tolerance of rice pollen development.