【作者】 杨洪建；

【导师】 王余龙；

【作者基本信息】 扬州大学 ， 作物栽培学与耕作学， 2005， 博士

【摘要】 大气CO₂浓度已从工业革命前的280μmol·mol^-1升高到现在的370μmol·mol^-1,目前正加速增高。据估计到2050年前后将达到450～550μmol·mol^-1。大气中CO₂浓度的不断升高将引起全球气候的明显变化,对水稻等农作物生产将产生重大影响。为了明确大气CO₂浓度升高对水稻根系的生长发育和根系活性的影响,及其与产量及其构成因素、物质生产与分配、养分吸收利用关系等,本研究利用我国唯一的农田开放式空气CO₂浓度增高（FACE）研究平台（无锡,31°37’N,120°28’E）,以武香粳14号为供试品种,设计比目前大气CO₂浓度（对照）高200μmol·mol^-1的FACE处理对其进行了比较系统地研究,以期为未来大气CO₂浓度升高环境下我国水稻高产栽培技术措施的制订提供试验依据。主要研究结果如下, 1.FACE处理使水稻有效分蘖临界叶龄期、拔节期和抽穗期每穴的不定根数、不定根总长度、根体积、根干重均显著或极显著大于对照;使有效分蘖期间和无效分蘖期间每穴的不定根发根数、不定根总长度和根体积以及根干重的增长量显著或极显著大于对照,对拔节长穗期这些根系性状的影响较小;FACE处理使水稻有效分蘖期间和无效分蘖期间发生的不定根粗度均显著大于对照,使拔节长穗期间发生的不定根粗度明显变细,从而使FACE处理水稻抽穗期每条不定根的平均粗度与对照无显著性差异。说明FACE处理水稻抽穗期每穴的不定根数、不定根总长度、根系体积和根干重均极显著大于对照主要是由于FACE处理使水稻有效分蘖期间和无效分蘖期间这些根系性状的生长量大幅度增加的缘故。 2.FACE处理使水稻单位干重根系的总吸收面积、活跃吸收面积的最大值比对照提早10d左右,使移栽后18d及其以后不同生育时期的单位干重根系的总吸收面积、活跃吸收面积、α-萘胺氧化量等根系活性指标均显著或极显著低于对照,但对不同生育时期每穴根系活性的影响相对较小。FACE处理使水稻生育前期根扬州大学博士学位论文系生长量大、植株含氮率低、碳氮比高等可能是造成其单位干重根系活性显著低于对照的重要原因。 3.FACE处理使2001一2003年水稻的穗数、结实率和千粒重分别比CK增加17.42%、4.16%和1.72%,使每穗颖花数比CK减少6.78%;FACE处理使2001年、2002年、2003年的水稻产量分别比对照提高1 1 .14%、1 5.80%、14.22%,均达到显著或极显著水平。FACE处理使水稻产量显著或极显著高于对照主要是由于穗数增加所致。水稻穗数、产量与抽穗期每穴的不定根数、不定根总长度、根体积和根干重关系密切,与其它根系性状关系不密切;多元回归和通径分析表明,抽穗期每穴不定根数和每穴根干重是影响水稻穗数多少和产量高低的主要根系性状。 4.FACE处理使2001一2003年水稻的生物产量比对照提高13.91%;其中抽穗前的干物质积累量比对照提高21.61%,抽穗后的千物质积累量比对照提高2.93%; FACE处理对经济系数的影响比较小,而且因年度而异;FACE处理使2001²003年水稻抽穗期、成熟期叶片占全株干重的比例显著下降,使茎鞘占全株干重的比例显著提高,对穗占全株干重比例的影响不大。水稻抽穗期和成熟期的干物质积累量与抽穗期每穴不定根数、每穴不定根长度、每穴根体积、每穴根干重关系密切,与其它根系性状关系不密切。多元回归和通径分析表明,抽穗期每穴不定根数、每穴根体积是影响抽穗期干物质积累量的主要根系性状:抽穗期每穴根干重、每穴不定根数是影响生物产量的主要根系性状。 5.FACE处理使水稻有效分集临界叶龄期、拔节期、抽穗期和成熟期的植株含N显著或极显著下降,使有效分集临界叶龄期、拔节期、抽穗期植株的N素积累量显著增加,但对成熟期N素积累量无显著影响;FACE处理使水稻有效分粟期间的N素吸收量极显著提高,对无效分集期间、拔节长穗期间和灌浆结实期间的N素吸收量无显著影响;FACE处理使水稻N素籽粒生产效率和收获指数显著提高。多元回归和通径分析表明,每穴根体积、每穴根干重和每穴不定根数是影响水稻有效分莫临界叶龄期N素积累量的主要根系性状,每穴不定根数、每条不定根粗度和每穴根系a一蔡胺氧化量是影响水稻拔节期N素积累量的主要根系性状,每条不定根粗度和每穴不定根数是影响水稻抽穗期和成熟期N素积累量的主更多还原

【Abstract】 Global atmospheric CO2 concentration is increasing from 280 to since pre-industrial times and it is projected to reach levels of 450~550μmol mol-1 within year 2050. The enhancement of atmospheric CO2 concentration commonly caused the climate change and affected the rice crops production. This study was carried out in the platform for FACE study, located in Wuxi (31°37’N, 120°28’E), China, using Wuxiangjing 14 as tested rice cultivar. The CO2 concentration in FACE treatment was 570μmol mol-1, with 370μmol-mol-l as ambient (AMB). The main purpose of the experiment was to study the effects of elevated CO2 concentration on root growth of rice and its relation with yield formation. Results showed as follows:(1)The number of adventitious roots per hole, the length of adventitious roots per hole, the roots volume per hole and the dry weight of roots per hole under FACE condition were significantly higher than those under AMB at tillering, jointing and heading stages; FACE treatment could significantly increase the diameter per adventitious root which were generated during effective tillering and unproductive tillering period, while the diameter per adventitious root generated during stem elongating and panicle bearing period became more and more thinner under FACE condition, which resulted in no significant differences existed between the diameter per adventitious roots under FACE and those at AMB at heading stage; The number of adventitious roots per hole, the length of adventitious roots per hole, the roots volume per hole and the dry weight of roots per hole under FACE were significantly higher than those at AMB at heading stage, which was chiefly resulted from the larger increment of those root traits stimulated by FACE during effective-tillering and unproductive-tillering period. While no obvious stimulation due to FACE were detectable for those root traits growth during stem elongating and panicle bearing period.(2)The peak value of total absorption area per unit dry weight of root and active absorption area per unit dry weight of root under FACE reached 10 days earlier than those at ambient air; and FACE treatment significantly decreased the total absorption area per unit dry weight of root, active absorption area per unit dry weight of root and the amount of a-NA per unit dry weight of root at 18 days after transplanting and its followed different stages, while little effects of FACE were detected on root activity per hole. Root activity per unit dry weight of root negatively correlated with the number of adventitious roots per hole, total length of adventitious roots per hole, roots volume and dry weight of root per hole at 28 days after transplanting and its followed different stages. The larger the root production, the lower the root activity per unit dry weight. For the most part, root activity per unit dry weight of root positively correlated with N content of rice plant, and negatively correlated with C/N ratio. According to available study results, the authors speculated that the largeness of biomass accumulated at early growth stages, lower N content in rice plant and higher C/N ratio appear to be the primary causes of significant decrement of root activity per unit dry weight of root under FACE condition.(3)In three year’s experiment, the number of panicles, filled grain percentage and 1000-grain-weight in FACE, average value of the data in 2001, 2002 and 2003, increased 17.42, 4.16 and 1.72 percent, respectively, while number of spikelets per panicle decreased in FACE treatment with 6.78 percent. Compared with AMB, Grain output in FACE treatment increased 11.14, 15.80 and 14.22 percent in 2001, 2002 and 2003, respectively, which was chiefly resulted from the larger increment of the number of panicles. The number of panicles and grain yields were significantly correlated with the number, the length of adventitious roots per hole and the roots volume, the dry weight of roots per hole. Among those root traits, the number of adventitious roots and the dry weight of roots per hole were the main traits which更多还原