【作者】 王永军；

【导师】 王空军； 董树亭； 李登海；

【作者基本信息】 山东农业大学 ， 作物栽培学与耕作学， 2008， 博士

【摘要】 我国长期面临“人多地少和粮食单产水平较低”的双重压力,而(超)高产是解决我国粮食问题的根本途径。系统研究超高产夏玉米的物质生产与产量形成规律及群体质量与个体功能特性,将有助于我们对玉米高产潜力的理解,可为夏玉米大面积高产与突破技术途径提供理论依据与技术支撑。本研究以采用强化栽培措施连续3年产量超过18000 kg?hm-2夏玉米(其中2005年创造了产量19348 kg?hm-2的夏玉米高产纪录)产量形成为平台,对超高产栽培模式(SYCS)和传统栽培模式(CCS)的夏玉米进行比较分析,较为系统地研究了超高产夏玉米的群体质量与个体光合、营养生理生态机制。本研究在国家玉米工程技术研究中心(山东)和作物生物学国家重点实验室进行,采用田间生理生态研究为主,室内生理生化分析为辅的方法,从群体和个体两个层面,系统研究了超高产夏玉米的群体质量与个体光合、营养生理生态机制。通过研究,明确了超高产夏玉米的群体质量与个体功能特征,建立了夏玉米超高产“群体结构与个体功能协同增益”理论模式与技术体系,构建了超高产玉米量化指标体系。主要研究结果与结论如下:1、超高产夏玉米的群体质量特征以单位生长积温衡量的SYCS玉米产量显著高于CCS,表现为SYCS玉米比CCS具有更高的光合效率和光合产物转化能力。SYCS玉米干物质生产速率优势明显,生长速率峰值在时间上表现出“早发”的特点;最大相对生长速率、达到最大生长速率的生长量以及起始势均显著高于CCS,尤其是活跃生长时间比CCS多15 d以上。SYCS玉米粒叶比均达0.25 kg?m-2以上,在提高粒叶比前提下增加密度,“扩库强源”使单位叶面积负荷更多籽粒来实现产量突破。SYCS玉米的收获指数高达0.532-0.542,说明其源库关系在较高密度群体内具有较好的协调性,群体质量较高。在保证较高密度前提下,提高群体整齐度可较好协调个体产量潜力与群体高产的关系,通过提高群体整齐度改善群体质量是今后超高产栽培的主攻方向之一。2种模式玉米农艺性状中,穗粒数变异最大,其次是茎粗,说明密度增加对个体茎穗发育影响较大,这也是造成高产田和生产田产量差异显著的主要原因。穗粒数的变异来源于穗行数和穗粒数的共同作用,对变异贡献较大的是行粒数。所以,在高密度群体中需要平衡碳氮代谢、减少籽粒败育,可提高行粒数的整齐度增加籽粒密度,进一步提高单位面积产量。玉米需要更高肥料投入。SYCS玉米产量是CCS的2.5-3.5倍,而肥料投入为其3倍以上。SYCS形成100 kg子粒N∶P 2O5∶K2O=2.10∶1.79∶3.74,而CCS则为2.00∶1.57∶1.92,表明超SYCS玉米对钾、磷肥的相对需求比例明显变大,氮肥需求则降低。2、超高产夏玉米的个体生理功能特征以单位生长积温衡量的SYCS玉米个体生物量显著高于CCS。SYCS玉米子粒灌浆表现出启动慢,降低慢,速率相对平缓,活跃灌浆时间长的特点。与CCS相比,SYCS玉米子粒产量形成并不具备灌浆速率上的优势,峰值具有“时滞”效应且下降慢,而活跃生长期长达60 d以上(比CCS高14 d以上),终极生长量高。SYCS玉米子粒灌浆时间长是实现高产的关键,前期高的灌浆速率并不是高产的性状,而可能是植株后期衰老加速的预示。壮株延衰,延长灌浆时间促粒重是实现超高产的关键。SYCS玉米群体中个体光合性能改善主要是光合高值持续期长,不在于灌浆前期光合强度高低。在高密度条件下,玉米的光竞争策略不是提高光合速率而是扩大个体叶面积并维持较长时间以截获更多光能。光合速率与气孔导度的显著正相关表明灌浆后期降低因肥水等非生物逆境造成的气孔限制有利于高产。于乳熟期和蜡熟期测定的光合日变化特性表明,SYCS玉米在粒重形成前期的光合与光能利用日变化单元并不高,其优势的凸显是在粒重形成后期,这表明光合强度与持续时间之间存在一种权衡关系,协调这二者乘积达到最佳范围是超高产栽培的重要内容。开花后叶片保持较高氮素含量,是延缓衰老,维持较高生理活性是实现超高产的重要原因之一。在高密度条件下,玉米的光竞争策略是在扩大个体叶面积并维持较长时间的同时保持叶片较高的氮素含量以同化更多光能。开花后30 d是SYCS和CCS玉米叶片氮素含量减少的界点,这可作为超高产玉米花后氮肥运筹的依据。超高产玉米花粒期叶片具有较强的抗氧化能力。花粒期植株叶片表现出较强的抗氧化能力,以CAT和POD活性氧清除机制为主,SOD途径不存在优势;特别是开花后50 d,超高产玉米的膜质过氧化程度显著低于常规生产处理的玉米。超高产玉米较高的抗氧化酶保护系统活性主要得益于叶片含较高的可溶性蛋,酶本身的比活力并不高,功能性蛋白在花粒期降解缓慢是超高产玉米延缓衰老的主要策略。3、超高产夏玉米的“群体结构与个体功能协同增益”理论模式的建立建立了夏玉米超高产“群体结构与个体功能协同增益”理论模式。其理论核心是:作物生产群体结构空间尺度上的生物学和生态学“超补偿”机制与个体功能时间尺度上的生物学和生理学“超补偿”机制相协同,即通过株行距科学配置,增加群体密度以补偿个体的功能性减产,通过肥水合理运筹,延长个体的生理功能高值持续期以超补偿群体的结构性增产,二者协同“扩库强源”,实现超高产。在实践中采用“以目标产量定品种,以紧凑株型保障高密度,大小行对角错株种植提高整齐度以优化群体,强化开花后肥水运筹,改善个体光合功能,壮株延衰提高粒重”的技术路线。主要挖潜途径包括2个方面:(1)以增加密度为保障的“群体结构性挖潜”;(2)以提高整齐度和强化开花后肥水运筹为保障的“个体功能性挖潜”。4、超高产夏玉米量化指标体系的构建构建了产量15 000 kg?hm-2以上夏玉米基本量化指标体系。在3年系统研究基础上,我们认为目前夏玉米实现超高产比较可取的产量结构模式是:有效穗数78000穗?hm-2,每穗600粒,千粒重340 g,穗粒重200 g以上;在倒伏风险小种植强抗倒品种的地区为,有效穗数90000穗?hm-2,每穗540粒,千粒重320 g,穗粒重接近200 g。集成了产量15000 kg?hm-2的技术规程。更多还原

【Abstract】 China is facing the problems of irreversible decrease in arable land, rapid population growth and stagnant output of crop. Fortunately, the super high-yielding crop breeding and production is put forward to improve the critical situation. However, the mechanisms of synchronous improvements on population quality and individual function of super high-yielding maize were not clearly understood. The goal of the paper is to help us to understand the potential of maize and provide the basal information and techniques for maize yield improvements in future.The field experiment was carried out from 2005 to 2007 in loam soil located at the National Maize Engineer and Research Center (Shandong province, China). In this experiment, the maize hybrids DH3719 was used to compare the yield of 21000 kg ha-1 via super-high yielding cultiviation system (SYCS) to the yield of about 9000 kg ha-1 via conventional cultiviation system (CCS). The population quality and individual items, including population uniformity, harvest index, grain/leaf area, photosynthetic parameters, anti-oxygen performances and mass nutrition elements (nitrogen, phophorus and potasium) uptake and utilization were investigated. The main results and significant conclusions were as follows:1. Population qualityThe yield per degree-day of DH3719 via SYCS was higher than that via CCS. The maximum crop grown rate (CGR), photosynthetic accumulation before maximum CGR and initiative filling potential of SYCS were significantly higher than CCS, and the peak of CGR in SYCS occurred earlier than CCS, accordingly, the active grown time of SYCS was 15 days longer than CCS. SYCS had higher capability to produce grain than CCS with the ratio of grain and leaf area of over 0.25 kg m-2, which showed it’s possible to improve the source by enhancing sink. The harvest index (HI) of SYCS was higher than that of CCS with 0.532-0.542, revealing the higher population quality, higher photosynthesis efficiency and stronger photosynthate partitioning capabilities under high planting density.It is one of the most important targets to improve the population uniformity and population quality in the future maize practices for super high yield. In our experiment, the variance on kernels per ear was the highest in the seven agronomy items (plant height, stem diameter, ear height, rows per ear, grains per row, ear diameter), then came the diameter of stem, so high planting density remarkably affected the ear and stem growth and development. The variance on kernels per ear was contributed by rows per ear and kernels per row, especially kernels per row, therefore, increasing uniformity of rows per ear by regulating the carbon-nitrogen metabolisms and decreasing grain abortion could increase density of kernels, and then increase the yield of maize.SYCS needs more fertilizers than CCS. The yield of SYCS was 2.5-3.5 times higher than CCS, while the fertlizers for SYCS should be more 3 times than CCS. When produced 100 kg grain, the absorption of N, P2O5 and K2O were 2.00 kg, 1.579 kg and 1.92 kg in CCS, respectively, but 2.10 kg, 1.79 kg and 3.74 kg in SYCS. Even more, among the 3 fertilizers, SYCS need more K2O and P2O5 than CCS, but less N than CCS.2. Individual physiological functionThe individual biomass per degree-day in SYCS was higher than that in CCS. Compared with CCS, SYCS was characterized with late grain filling, gentle change of grain-filling rate, and long active grain-filling period. Not grain-filling rate but long active grain-filling period contributed high yield for SYCS, which could be seen from over 14 days longer of active grain-filling period in SYCS than CCS. Prolonging the grain-filling time was essential to obtain super high yield in maize, while higher grain-filling rate may be the signal of rapid senescences in the anaphase of grain weight formation, not the symbol of high-yielding.Improvement in photosynthesis for SYCS was mainly by long high-photosynthesis duration, not by the high photosynthesis rate during grain-filling. For maize, the strategy of capturing more light radiation under high planting density was by enlarging the leaf area, not by increasing the photosynthetic rate. The significantly positive relationship between photosynthetic rate and stomatal conductance revealed it was important for high yield to alleviate the abiotic stress, such as drought, nutrition deficiency, disease and insect pest etc. The diurnal trends of photosynthesis on 25 and 45 days after anthesis indicated the photosynthate accumulation unit in SYCS was not different from CCS in the prophase of kernel development, nevertheless, SYCS was significant higher than CCS in the phase of grain weight formation. So it is necessary to regulate the confliction between photosynthetic rate and photosynthesis duration for super high yield.One reason for higher yield of SYCS is the higher nitrogen concentration in leaves after anthesis, which would maintain the higher physiological function and delay the leaves senescence after anthesis. The 30th day after flowering was boundary for the difference of nitrogen concentration in leaves between SYCS and CCS. SYCS had high anti-oxygen capability during grain filling, the reactive oxygen cleaning was mainly through CAT and POD system, especially in the 50th day after anthesis. The degree of membrane lipid peroxidation was lower in SYCS than in CCS, especially the 50th day after anthesis. The high total ezyme activities in SYCS were not owed to its specific activity but to the high functional soluble protein amount.3. Synchronous improvement of population structure and individual functionThe theory of“Synchronous improvement of population structure and individual function”was established. The core of it was that: the over-compensation effects of biology and ecology occurred in crop population spatial structure, coinstantaneously the over-compensation effects of biology and physiology occurred in crop individual temporal scale.This theory integrates the planting density and row distance scheme, irrigation and fertilizer management. On one hand, planting density increment compensated the reduction of individual. On the other hand, individual function with high activity increment over-compensated the increase of population structure. The technological practices included choosing hybrids by intending goal yield, obtaining high density by plant type, ensuring the population uniformity by alternating row and diagonally sowing, and enhancing fertilizers and water inputs after anthesis, therefore, the photosynthesis and grain weight were improved and plant senescence were delayed. Two effective approaches of“structural exploration”and“functional exploration”for exploring crop yield.4. Quantitative items of super high-yielding maizeThe quantitative items of super high-yielding maize with yielding potential over 15000 kg ha-1 were explored in our experiment. The ideal system of yield components was: harvested ears≥78000 ear ha-1, kernels per ear≥600, 1000-kernel weight≥340 g, ear weight≥200 g. In the optimum zone planted anti-lodge hybrids and without lodge occurring, the ideal system of yield components was: harvested ears≥90000 ear ha-1, kernels per ear≥540, 1000-kernel weight≥320 g, ear weight≥200 g.更多还原