【作者】 陈传永；

【导师】 赵明；

【作者基本信息】 中国农业科学院 ， 作物栽培学与耕作学， 2010， 博士

【摘要】 为探明玉米高产群体叶层系统、茎秆系统、穗粒系统的结构与功能特点,2006,2008-2009年,在吉林省公主岭市,以先玉335、郑单958、吉单209为材料,设计了60000、75000、90000、105000株hm-24个密度梯度,测定了不同生育时期,主要以吐丝期为重点的冠层结构特征以及叶片叶绿素含量、可溶性糖含量、全氮含量与碳氮比的动态变化,测定并计算6个生育期的叶面积指数(LAI)、光合势(LAD)、净同化率(NAR)以及产量性能参数,平均叶面积指数(MLAI)、平均叶净同化率(MNAR)、收获指数(HI)、单位面积穗数(EN)、单穗粒数(GN)、千粒重(GW),并结合产量性能参数的变化特征对各品种进行了耐密性分析,结果表明:(1)玉米群体结构的密度效应不同,株高、穗位高、穗高系数、比叶面积、叶面积比率、粒数叶比均随密度增加而增加,粒重叶比、基部周长、吐丝后冠层内各层次茎叶夹角平均值、透光率均随密度提高而降低。(2)在产量形成过程中,不同品种各器官的籽粒贡献率不同,吐丝后叶片光合产物是籽粒干物质的主要来源,大约占82%~85%。对玉米全生育期干物质积累、吐丝后干物质增量,以及籽粒灌浆速率进行相对化模拟,其模拟方程均符合Logistic曲线y=a/(1+b*e-cx)对吐丝后对不同密度处理春玉米品种各器官干物质增量进行相对化模拟,叶片、叶鞘、茎秆、苞叶模拟方程均符合Polynomial曲线y=a+bx+cx2+dx3,穗轴模拟符合Rational方程y=(a+bx)/(1+cx+dx2)。(3)在10500~13500kg hm-2产量水平下,生产百公斤籽粒吸氮量变化范围是2.03~2.34 kg。各器官可溶性糖含量、全氮含量、C/N均随密度升高而降低,且在各生育期存在差异。玉米成熟阶段营养器官氮素转移量约占籽粒总含氮量的59.2~63.29%,增加种植密度可C/N比减小,高密度主要影响碳代谢,对氮代谢影响较小。(4)不同群体玉米叶片叶绿素含量均在灌浆期最高,可溶性糖含量在吐丝期最高,碳氮比分别在吐丝期与成熟期达到高峰;叶绿素含量、灌浆期光合速率、叶片可溶性糖、全氮、碳氮比均随密度增加而降低;吐丝后,光合速率呈下降趋势;吐丝后生育天数与叶绿素含量、光合速率、可溶性糖、C/N呈二次曲线关系,与全氮含量呈线性关系;叶片生理性状受密度影响的大小趋势表现为,光合速率>全氮>可溶性糖>叶绿素含量>C/N,叶绿素含量与C/N的变化顺序为郑单958>吉单209>先玉335,光合速率、全氮与可溶性糖变化顺序为先玉335>郑单958>吉单209。高密度主要影响叶片碳代谢;叶绿素含量不是影响吐丝后光合速率的主要因素。(5)通过产量性能方程分析表明,MLAI、EN与密度呈显著正相关,MNAR、HI、GN、GW与密度呈显著负相关;不同品种产量对密度大小的响应不同;先玉335、郑单958与吉单209产量呈一元二次方程关系,并具有良好的相关性;在试验密度范围内,品种耐密性表现为先玉335最好、郑单958次之,吉单209较差,其中,先玉335的适宜密度范围为90 000~105 000株hm-2,郑单958与吉单209的适宜密度范围为75 000 ~90 000株hm-2。更多还原

【Abstract】 The main objective of this research was to analysis the high-yield population structure, functional characteristics and yield capability analysis of maize (Zea mays L.). Field experiments were conducted in Gongzhuling, Jilin Province in 2006,2008-2009. Three corn hybrids were cultivated at 60000 plants ha-1, 75000 plants ha-1, 90000 plants ha-1, 105000 plants ha-1.Treatments were arranged in a split-plot design with three replications. Plant population density was the main-plot and hybrids the subplot. The experiment was carried out to study the dynamic changes of the chlorophyll content, photosynthetic rate, soluble sugar content, nitrogen content, carbon-nitrogen ratio in corn leaf at different stages, especially after silking. The experiment was carried out to study the changes of the LAI, LAD, NAR, MLAI, MNAR,, HI, EN, GN, GW. And the main results were as follows:(1) This research indicate plant height, ear height, ear height/plant height, SLA, LAR, grain number to leaf area ratio increased and grain weight to leaf area, base circumference, MTA, transmittance rate decreased in all hybrids as plant density intensified. It showed that morphology structure was affected by density.(2) The dry matter distribution changes with the growth center transporting. The dry matter of different organ and its contribution to grains were different during the process of yield formation. It indicated that competition after silking was more detrimental to grain yield. And about 85-93% of grain yield was attributable to assimilates formed after silking. The dry matter proportion of different organ was changed as plant density intensified. Dry matter accumulation, dry matter accumulation after silking and grain-filling rate accorded with the logistic equation y=a/(1+be-cx).The dry matter accumulation of leaf, sheath, stem, bract conformed to Polynomial fitting y=a+bx+cx2+dx3.The dry matter accumulation of cob accorded with the Rational equation y=(a+bx)/(1+cx+dx2).(3) The soluble sugar content, nitrogen content, carbon-nitrogen ratio decreased in all hybrids as plant density intensified. The peak appeared at filling stage. The range of nitrogen uptake per 100kg grain were 2.03-2.34 kg. The soluble content, nitrogen content, carbon-nitrogen ratio of different organ decreased as plant density intensified, and were different in each growth stage. Nitrogen level of different organ is quite important in determining the final nitrogen content of grain, which ranged from 59.2 to 63.29% in different hybrids and experimental sites. Metabolism of carbon due to crowding stress was generally greater in high densities than low densities.(4) This research indicates the chlorophyll content, the photosynthetic rate in grain filling stage, soluble sugar content, leaf total nitrogen decreased in all hybrids increased competition pressure. It showed that transmission rate reduce, the leaf senescence accelerated, physical activity declined as plant density intensified. During the growth period, the changes chlorophyll content were single peak curve.The peak of chlorophyll content appeared at grain filling and the peak of Carbon-nitrogen Ratio appeared at silking and ripening respectively. The chlorophyll content, photosynthetic characteristics, soluble sugar content, carbon and nitrogen in corn leaf indicated a quadratic relationship with increasing days after silking. Total nitrogen in corn leaf decreased linearly in all hybrids as days after silking increased. High densities had great effect on carbon metabolism. The chlorophyll content had no or little effect on the photosynthetic rate after silking. The results showed the dynamic changes of photosynthetic characteristics, carbon and nitrogen were different as plant density intensified.(5) This research indicate LAI、LAD、MLAI、EN increased and NAR、MLAI、HI、GN、GW decreased in all hybrids as plant density intensified. It showed that transmission rate reduce, the leaf senescence accelerated, physical activity declined as plant density intensified. During the growth period, the changes of LAI, LAD were single peak curve. The peak of LAI appeared at silking, the peak of chlorophyll content appeared at grain filling and peak of high value duration of LAD appeared from full-grown to milky maturity. The peak of NAR appeared from seeding stage to jointing and from silking to grain filling respectively. The results showed the dynamics of photosynthetic characteristics were different as plant density intensified. The highest grain yield of xianyu335, zhengdan958, jidan209 was obtained from 90000 plants ha-1, 75000 plants ha-1, 90000 plants ha-1 respectively. Kernel yield per plant decreased in all hybrids as plant density intensified. The order of dense planting hybrid was xianyu335>zhendan958>jidan209.The suitable planting density range of xianyu335 is 90000plants ha-1-105000 plants ha-1, zhengdan958 and jidan209 were 75000plants ha-1-90000 plants ha-1.更多还原