【作者】 宋艳霞；

【导师】 杨文钰；

【作者基本信息】 四川农业大学 ， 作物栽培学与耕作学， 2009， 硕士

【摘要】 在“麦/玉/豆”套作模式下,选用了4个耐荫性有差异的大豆品种为材料,通过与单作相比,研究了不同耐荫性大豆品种苗期叶片光合特性和氮代谢对套作遮荫的响应,并通过玉米收获前第15 d和复光后第15 d的对比,研究了恢复光照对套作下不同耐荫性大豆品种叶绿素荧光特性、氮代谢的补偿效应,并明确了套作遮荫对其最终产量、品质的影响。主要研究结果如下:1.套作遮荫提高了大豆叶片叶绿素含量;降低了叶绿素a与叶绿素b比值（Chla/o）及类胡萝卜素（Car）含量;叶片初始荧光（Fo）和实际光化学效率（ΦPSⅡ）呈增加趋势,PSⅡ最大光化学量子产量（Fv/Fm）呈减小趋势;净光合速率（Pn）、气孔导度（Gs）、气孔限制值（Ls）和蒸腾速率（Tr）呈下降趋势;胞间二氧化碳浓度（Ci）和水分利用效率（WUE）表现为增大趋势;套作遮荫显著降低了大豆地上部分干物质积累量。耐荫性相对较好的材料贡选1号和南豆12在套作遮荫下Pn下降较少,且有着相对较高的Chlb、Car分子组成比例、Fo和Fv/Fm。2.套作遮荫下大豆植株具有较高的全氮含量、相对较低的全碳含量,从而使C/N降低,其中,叶C/N要明显低于茎。同时,套作遮荫下大豆植株内硝态氮(NO₃^-1)含量升高,功能叶中硝酸还原酶（NR）、谷氨酰胺合成酶（GS）活性降低。套作遮荫抑制了大豆功能叶片可溶性蛋白的表达,而有利于叶片中氨基酸总量的增加。这些效应在不同耐荫性大豆之间表现出显著差异。耐荫性相对较好的贡选1号和南豆12在套作遮荫下C/N降低较多,并且能够保持相对较高的NO₃^-1和氨基酸含量,对套作遮荫适应性越强的品种其可溶性蛋白降低程度越小。3.套作大豆复光15d后,Fo和Fv/Fm较单作降幅明显缩小,ΦPSⅡ增幅也明显降低;茎、叶中全碳含量比单作仍低,但降幅减小,全氮含量由升高转变为降低,而C/N降低幅度明显减小;复光后套作大豆茎、叶中硝态氮含量和叶片中氨基酸含量变化较大,均由复光前的增加转变为降低,其中氨基酸含量贡选1号和南豆12分别降低了7.35%、7.01%,而南冬抗022-2、贡秋豆494-1为14.57%、13.67%;地上部分干物质增加迅速,显著缩小了与单作的差异。不同耐荫性大豆品种由遮荫转到相对强光下的恢复有明显的差异,贡选1号和南豆12恢复程度高于品种南冬抗022-2、贡秋豆494-1,耐性品种贡选1号和南豆12的Fo、Fv/Fm和C/N表现为超补偿现象。4.套作遮荫大豆荚粒数无显著变化,其主要受品种自身遗传特性因素所控制,而单株有效荚数、百粒重极显著、显著降低,从而引起最终产量的降低。较耐荫品种贡选1号、南豆12比耐荫性较弱的南冬抗022-2、贡秋豆494-1表现为相对较高的单株有效荚数、百粒重、荚粒数及产量,其中贡选1号、南豆12的产量分别降低了17.71%、19.74%,南冬抗022-2、贡秋豆494-1分别低了38.43%、37.49%。而套作大豆籽粒蛋白质、蛋脂总量表现为高于单作,而粗脂肪低于单作,其中耐性较强品种贡选1号、南豆12更易于蛋白质、粗脂肪和蛋脂总量的积累。更多还原

【Abstract】 This experiment was carried out to study the effects of shading on relay-cropping soybean’s photosynthetic Characteristics、nitrogen metabolism、yield and seed quality,and the effects of restoration light intensity on fluorescent characteristics and nitrogen metabolism by using various varieties of late-maturing soybeans seedling in wheat/maize/soybean cropping system. （shade tolerant ’Gongxuan 1’、’Nandou 12’ and shade susceptible ’Nan dongkang 022-2’、’Gong qiudou 494-1’）.The main results showed as follows:1.Under relay-cropping system the total chlorophyⅡcontent of the four cultivars increased; while,the ratios of Chla/b and the content of carotenoids decreased.From the response data of ChlorophyⅡfluorescence,it was seen that with the decreasing of light intensity,there was a more increased in the minimal fluorescence（Fo） and the actual photochemical efficiency of PSⅡin the light（ΦPSⅡ）;and it indicated that soybean grow under Relay-cropping had lower maximal photochemical efficiency of PSⅡin the dark（Fv/Fm） as compared with those grown under monoculture.The net photosynthesis rate（Pn）、stomatal conductance（Gs）、stomata limitation（Ls） and transpiration rate（Tr） decreased;ratio of intercellular to ambient CO₂ concentration and water use efficiency increased.Poor light resulted in lower weight of dry matter accumulation in Maize/Soybean relay-cropping.Soybean with lower Pn decreasing higher Chlb、the molecular composition proportion of Car、Fo and Fv/Fm may possess potential low light-tolerance.2.The plants grown under relay-cropping had higher total nitrgen、relatively lower total carbon,thus C/N decreased.And more C/N was distributed into stem system compared with leafs.The nitrate nitrogen content increased,the activities of nitrate reductase（NR） and glufamine synthetase（GS） in functional leaves of soybean were significantly increased.The low light inhibited soluble protein expression of functional leaves,however,the amino acid contents slightly increased in leaves.These effects occurred significant differences among various varieties with those had different shade tolerance.More lower C/N and relative higher nitrate nitrogen content and amino acid contents were found in plants of ’Gongxuan 1’、’Nandou 12’ which have relatively better shade tolerantion,and the decreased extent of soluble protein content were smaller than shade susceptible. 3.Exposure of relay-cropping soybean to natural light intensity,the decreased degree of Fo、Fv/Fm and the increased extent ofΦPSⅡreduced significantly;total carbon were still lower than monoculture,but decreased degree reduced,total nitrgen turned to decrease,thus causing decreased degree of C/N reduced;after restoration light intensity 15 days,the nitrate nitrogen and amino acid contents of stems and leaves had a great change,which turned to decrease.In which the amino acid contents of ’Gongxuan 1’、’Nandou 12’ respectively decreased by 7.35%、7.01%,while ’Nan dongkang 022-2’、’Gong qiudou 494-1’ respectively decreased by 14.57%、13.67%;the dry matter accumulation enhanced rapidly,and reduced significantly with monoculture.When transfering from shading to relative strong light,various varieties soybean which had different shade-tolerant had obvious differences,the recovery degree of ’Gongxuan 1’、’Nandou 12’ were higher than ’Nan dongkang 022-2’、’Gong qiudou 494-1’,shade tolerant varieties’（’Gongxuan 1’、’Nandou 12’） Fo、Fv/Fm and C/N manifested as over compensation phenomenon.4.There was no significant change of soybeans’ seed number per pod under relay-cropping system,and the main factor affecting it was specie,that was,the genetic and physiological differences.The pod number per plant、100-seed weight of four various varieties was significantly lower than monoculture soybean,consequently reduced the final yield of relay-cropping soybean.Shade tolerant soybean ’Gongxuan 1’、’Nandou 12’ with higher pod number per plant、100-seed weight、seed number per pod and yield,in which the yield of ’Gongxuan 1’、’Nandou 12’ decreased by 17.71%、19.74%,’Nan dongkang 022-2’、’Gong qiudou 494-1’ decreased by 38.43%、37.49%.The grain protein、’total protein and oil’ were higher than monoculture soybean,and crude fat lower than that of monoculture treatment,shade tolerant soybean ’Gongxuan 1’、’Nandou 12’ were prone to the accumulation of protein、crude fat and ’total protein and oil’.更多还原