【作者】 闫川；

【导师】 王绍华； 丁艳锋；

【作者基本信息】 南京农业大学 ， 作物栽培学与耕作学， 2009， 博士

【摘要】 本研究在大田和人工气候室条件下,通过对不同基因型品种穗叶体温、颖花结实及群体生理生态的测定,系统研究了气温与水稻体温的关系,以及大气湿度、品种株型、水稻器官生理年龄等对水稻体温与气温之关系的影响；此外,本研究探讨了不同基因型穗叶体温和颖花育性的差异机理,以及通过栽培措施调节群体结构,降低植株穗叶和冠层温度,提高水稻抗热害能力,揭示水稻在高温环境下正常结实的成因。主要研究结果如下：(1)水稻穗叶体温受大气温度、湿度、品种株型和器官生理年龄的影响。在大气湿度相同的条件下,水稻穗叶的体温随气温升高而提高,但提高的幅度逐渐变小；在气温相似的条件下,大气湿度提高,穗叶体温升高,大气温度与穗叶体温的差距缩小。不同基因型品种的穗叶体温及冠温也存在一定的差异,在大气温、湿度相同的条件下,水稻的穗叶体温直立穗型品种<弯曲穗型、“穗盖顶”型<“叶盖顶”型。器官生理年龄对穗叶体温也有一定的影响,表现为器官生理年龄越轻,体温越低。(2)水稻的颖花育性、结实率和千粒重与抽穗开花期和灌浆结实期的大气温、湿度有密切的关系。在高温、低湿环境下水稻的颖花育性、结实率和千粒重明显高于高温、高湿环境,较低的大气湿度可以部分缓解高温胁迫对水稻颖花育性和结实率的不利影响。研究表明：在高温环境中凡植株穗叶体温较低的基因型和栽培处理,其颖花育性、结实率和千粒重也较高；在环境温度为28-35℃条件下,穗温与颖花育性和结实率均呈显著负相关关系；不同基因型穗叶体温与剑叶光合特性和叶绿素含量、质膜透性和丙二醛含量、可溶性糖和脯氨酸含量、ABA与GA含量及热激蛋白表达有密切关系。因此,可以将植株穗叶体温纳入高温胁迫评价体系,作为选择抗高温育种材料的重要指标之一。(3)氮素穗肥对水稻穗叶体温和群体冠层温度具有明显的调节作用。在穗肥0-202.5 kg·hm-2(粳稻)或0-168.75 kg·hm-2(籼稻)范围内,随氮素穗肥水平的提高,水稻抽穗期的穗数、LAI、株高、单位株高LAI和比叶重等明显增加,群体内部温度、湿度、光照强度和CO2浓度等微气象因子产生了显著变化,致使水稻穗叶体温和群体冠层温度有明显的不同。研究表明：中肥处理(粳稻135.0 kg·hm-2,籼稻112.5 kg·hm-2)的群体LAI适宜、群体内部微气象较好,叶片净光合速率和蒸腾速率较高,穗叶体温和冠温较低,籽粒结实率较高。(4)行株距配置对水稻穗叶体温具有明显的影响。在密度相同条件下,行株距配置不同,水稻群体穗数、LAI、比叶重等差异显著,群体内部CO2浓度、光照强度、温度和湿度等微气象因子及其穗叶体温差异明显,结实率和产量显著不同。研究表明：中等行株距(30cm×13.3cm)配置能容纳更多的穗数和LAI,增加群体内部CO2浓度和光照强度,降低群体内部的湿度和穗叶体温,缩短节间长度,增大节间粗度、茎壁厚度及维管束数目,提高植株抗折力和抵抗外部高温胁迫的能力。(5)水分胁迫对水稻穗叶体温和群体冠层温度也具有明显的影响。在重度水分胁迫下,叶片蒸腾速率降低,穗叶体温和冠温明显升高,剑叶丙二醛含量提高,结实率和千粒重下降,籽粒产量显著降低。但在适度水分胁迫下,叶片蒸腾速率、叶绿素含量、净光合速率和气孔导度、剑叶可溶性糖和游离脯氨酸含量、CAT和POD活性等均未受到明显的影响,穗叶体温和冠温未明显升高,群体内部温度、湿度、光照强度和CO2浓度等微气象因子在一个良好的水平上,结实率和千粒重不仅未下降反而有所增加,产量显著提高。更多还原

【Abstract】 To study how air temperature and relative humidity (RH), genotypes, organ age and agronomic practice affect organs temperature and spikelet fertility of rice, we conducted a series of experiment in the field and plant growth chambers by measuring organs temperature, spikelet fertility and microclimate of rice. In addition, we investigated the effect of agronomic practices on TD and canopy temperature to assess the role of agronomic practices in enhancing the resistance of rice to avoid heat injury. The main results of the study are listed below(1) The panicle, leaf temperatures were affected by air temperature, air humidity, plant type and age of organs of rice. Under similar conditions of air humidity, the organ temperature was lower in the low air temperature than in the high air temperature. At the same air temperature, the organ temperature increased when the air humidity was high. The organ temperature was also affected by the plant type of the varieties. Under similar climatic conditions, the organ temperature of erect panicle varieties was lower than that of curved panicle varieties. Cultivars with panicle above the flag leaf showed lower organs temperature than cultivars with panicle below the flag leaf. After heading, there were significant differences between organ temperatures at different stages of rice growth, the more mature the organs, the higher the organ temperature.(2) The spikelet fertility, seed setting rate and 1000 grain weight were significantly affected by air temperature and humidity at heading stage of rice. Cultivars grown at a region with lower RH and higher temperature had higher spikelet fertility, seed setting rate and 1000 grain weight than those in higher RH under the similar air temperature during heading. Under ambient temperature of 28-35℃conditions, panicle temperature and spikelets fertility, seed setting rate showed a significant negative correlation. The lower temperature of rice organs during grain filling stage were positively correlated with spikelet fertility, seed setting rate and 1000 grain weight. Thus, it was suggested that temperature of panicle and leaf may be a potential methodology for screening physiologically superior lines in rice breeding programs. The differences in panicle and leaf temperature, and spikelet fertility of different cultivars were related with photosynthesis and chlorophyll content, the conductivity of the soak solutio and MDA, soluble sugar content and amino proline content, ABA and GA, and the expression of heat shock proteins. These differences could be the potential reasons for differences in heat resistance among the rice cultivars.(3) Panicle fertilizer application rate (PFAR) had a significant effect on organs and canopy temperature. Increasing PFAR resulted in the higher panicle number, LAI, plant high and specific leaf weight. It was also observed that air temperature, humidity, light intensity and content of CO2 were also affected by different PFAR treatments, medium PFAR was proved to be best for microclimate within rice population. Besides, there were felicitous leaf area index, length of second leaf, photosynthetic rate, transpiration and lower canopy temperature at medium PFAR. The temperature of plant organs was significantly affected by PFAR, the more the PFAR, the lower the temperature of panicle and leaf. This study clearly showed that medium PFAR has a significant effect on the temperature of plant organs and canopy, and also enhance the resistance to heat stress.(4) Row-spacing treatments has a significant effect on organ temperature. The panicle number, LAI, specific leaf weight and the yield of medium row-spacing treatments (30 cm×13.3 cm) was the highest, while the lowest values were observed under narrow row-spacing was the lowest with a significant difference at 0.05 level. Medium row-spacing treatments significantly diminished internode length and enhanced internode thickness, wall thickness, the number of vascular bundles, and lodging resistance at the 0.05 level compared to wide row-spacing and medium row-spacing. Significant differences were also observed in the CO2content, light intensity, air temperature and humidity among different row-spacing. These findings clearly showed that the medium row-spacing resulted in ideal microclimate and lower organs temperature reduced chances of heat injury and enhanced heat resistance.(5) Water stress has a significant effect on organ and canopy temperature. Increasing water stress caused increase in organs and canopy temperature. The lowest grain yield was observed under higher water stress treatment (W3). Lower seed setting rate and 1000 grain weight were the reasons for lowest yield of W3. Water stress significantly influenced physiological characteristics of flag leaf, soluble sugar content, amino proline content, CAT and POD activity of flag leaf and these values were the maximum under W2 treatment. In addition, water stress has a significant effect on chlorophyll content, photosynthetic rate (Pn), transpiration rate (Tr) and stomata conductance (Cs), W2 were highest. Significant differences existed in air temperature, humidity, light intensity and content of CO2 among different water stress, there was ideal microclimate within population of rice with W2. These results clearly revealed that the water stress treatment significantly influenced plant organs and canopy temperature increased risk of heat injury and ultimately caused reduction in yield.更多还原