【作者】 郭玉春；

【导师】 林文雄；

【作者基本信息】 福建农林大学 ， 作物栽培学与耕作学， 2005， 博士

【摘要】 选育磷高效水稻品种,充分利用土壤中丰富的磷资源,对节约资源、防止污染和稻作的高效持续发展具有重要意义。 本研究在以往研究的基础上,选用不同磷效率基因型水稻为试验材料,从植株形态发生、生理生化机制和分子机理等角度出发,在个体、细胞与分子水平探讨在低磷胁迫下的磷高效的作用方式与内在机制,阐明磷高效水稻对低磷胁迫的响应及其分子机制。主要研究结果如下: 1、在较高浓度的低磷胁迫下,水稻能产生分蘖,采用相对分蘖干重这一指标能灵敏而准确地反映出不同水稻基因型耐低磷能力的差异。相对分蘖数及其干重、相对总生物量、相对地上部干重及相对根干重等指标是进行综合评价的理想指标。而在相对低浓度的低磷胁迫下,水稻分蘖受阻,相对地上部干重和相对总生物量是可靠的筛选指标。 2、低磷胁迫下植株的外部形态发生了较大的变化,而磷高效水稻各性状变化相对较小。从各供试材料的形态发生来看,磷高效水稻解剖特点如下:侧根原基的发生早,数量多,部分增加出现了根中根的现象;茎杆的壁薄,髓腔大,通气结构与维管束外内轮等机械组织的分化较为完善;叶片中的气室大,栅栏组织发达、气孔量多面广;分蘖原基数量虽有减少但均发生正常。 3、就磷效率而言,IR74表现出的磷高效是其较高的磷吸收率、运转率及利用率共同作用的结果,属磷高效综合型,磷中效IR71331吸收率突出,属磷高效吸收型,而IR71379为磷低效型。小的K_m和C_min,大的I_max及高的APase升幅和R/S是磷高效水稻固有的生理生化本质。 4、光合特性而言,各基因型水稻在低光强下的Pn、叶绿素和气孔导度变化较小,明显低于高光强下的降幅。在低磷和不同光强下,磷高效水稻的胞间CO₂浓度和Ca²⁺/Mg²⁺-ATPase均呈上升趋势,磷低效基因型的胞间CO₂浓度和Ca²⁺/Mg²⁺-ATPase均降低,磷高效水稻具有高光强的光合优势。 从抗性生理来看,不同基因型水稻叶片的丙二醛含量及增幅存在差异。磷高效水稻仅小幅增加,而磷低效水稻升幅较大,低磷下叶片膜脂过氧化程度远大于根系。更多还原

【Abstract】 Screening P-efficient rice variety may represent a more sustainable solution than sole reliance on fertilizer appliance. It is very important to economize resources and avoid pollution in rice cropping systems.34 different rice genotypes, were planted in pot and field , supplied with low(0.5mg/L P ) and high (10mg/L P ) phosphorus, to screen their phosphate efficiency (PE) at seedling and ripening stage respectively. After screening methodology was determined, IR74 (a high PE genotype) ,IR71331 (a moderate PE types) and IR71379 (a low PE genotypes) were planted at the low P deficiency of 0.5mg/L in hydroponic culture, to study the mechanism of PE discrepancy, which includes plant morphology and microstructure, physiological and biochemical properties, i.e. photosynthesis and resistance to low P characteristics, as well as its molecular mechanism. The results can be summarized as follows:It was showed that there were significant differences of tolerant indices to P deficiency in the tested rice genotypes. When rice cultivars were exposed to low P stress with the relative-higher P concentration (1mg/L P) to be screened, relative tiller dry weight (RTW) , relative shoot dry weight (RSW) and relative total plant dry weight(RPW ) could be used as the better screening criteria, especially RTW was considered a sensitive and reliable screening criterion based on the large coefficient of variation (CV) and variable range of data among the tested varieties. However, when rice genotypes were grown in the stress condition with the relative-lower P concentration (0.5mg/L P) , the screening criteria were different, and it suggested that relative shoot dry weight(RSW) or relative total plant dry weight (RPW) was the best single screening criterion. The differences in outside morphological and internal microstructure characters of rice varieties with different P efficiencies were further discussed. It could be showed that the efficient rice tolerant to low P stress resulted from the good development of lateral roots and tiller primordium, the thickness of palisade tissue, the denseness of stoma, moreover, the diameter stem and vessel increased.The genotypic differences in P efficiency of three rice varieties (IR74, IR71331 and IR71379) were studied under the P-deficiency controlled condition in hydroponic culture, and its adaptability to low phosphorus stress about physio-biochemical mechanisms were further studied. The results showed whether rice genotypes tolerated low P stress resulted更多还原