【作者】 李从锋；

【导师】 董树亭； 王空军；

【作者基本信息】 山东农业大学 ， 作物学， 2009， 博士

【摘要】 本试验于2007—2008年在国家玉米工程技术中心(山东)和作物生物学国家重点实验室进行。选用60年代以来生产上大面积推广玉米杂交种及其骨干亲本为材料,探讨我国玉米杂交种及其亲本更替过程中产量生理特性的演进规律,深入研究玉米品种及其亲本对群体密度响应的生理机制,以光合碳代谢为中心,系统探究我国杂交种及其亲本更替过程中源库生理特性的演进规律,主要研究结果如下:1我国不同年代玉米杂交种及其亲本更替过程中农艺性状的演进当代杂交种及其亲本的子粒产量显著高于1980s和1960s品系(P<0.05),分别平均提高25.7%、35.8%和7.6%、26.9%,表明当代F1杂交种在产量方面具有较高的杂种优势。随产量提高,不同年代杂交种及其亲本的穗长变化不明显,穗粗、穗粒数和百粒重均明显增加(P<0.05);F1杂交种株高、穗位高以1980s植株最高,而其亲本随年代更替不断升高。年代更替中,各品系的茎粗增大,雄穗分枝数减少,叶向值显著升高(P<0.05),且两密度条件下趋势基本一致。当代杂交种及其亲本的植株叶片数、叶面积指数、花后光合势和平均净光合速率均显著高于1980s和1960s品系(P<0.05),且在高密度条件下优势更明显。相关和通径分析表明,产量与穗粗、穗粒数、百粒重、叶面积指数和叶向值呈显著正相关(P<0.05),其中百粒重、叶面积指数和叶向值对其产量的贡献较大。2不同年代玉米杂交种亲本籽粒灌浆特性及物质运转产量较高的当代杂交种,其亲本灌浆速率呈先慢后快的趋势,籽粒灌浆的积累起始势(R0)较高,灌浆最大速率出现时间(Tmax)延迟,灌浆速率最大时生长量(Wmax)和最大灌浆速率(Gmax)明显较高。当代杂交种亲本具有较高的花前干物质积累和日增干重,其茎鞘物质输出率和茎鞘物质贡献率均高于早期的亲本。当代杂交种亲本的氮素积累量、转移量和氮素的利用效率明显较高。当代杂交种亲本较高的籽粒灌浆能力,这可能与当代杂交种亲本的物质积累能力强,对营养物质的运转效率高密切相关。3不同年代玉米杂交种亲本光合效率的演进规律当代杂交种亲本的籽粒产量随年代更替不断提高,其生物产量和收获指数共同提高,这主要是因为其花后具有较高叶面积、叶绿素含量和可溶性蛋白含量,维持叶片较好的保绿性,有效的延缓了植株衰老。与早期杂交种亲本相比,当代骨干自交系具有较高的光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Er),生育后期保持较高的光合性能,其光合速率的降低主要受非气孔因素限制。同时当代杂交种亲本具有较高的最大光化学效率(Fv/Fm)和实际光化学效率(ΦPSII),并且较多的天线色素用于捕获光能,促进了光合电子传递,这都有利于当代亲本提高光能利用效率和光合能力,获得较高的籽粒产量。4不同年代玉米杂交种亲本光合日变化特性及光合响应当代杂交种亲本在日变化中总比早期的亲本具有较高的光合效率,且在中午时优势更明显,各年代杂交种亲本都没有出现光合午休现象。当代杂交种亲本光系统II日变化中光化学效率(Fv/Fm)和量子产量(ΦPSII)都是比较高的,且具有较高的光化学猝灭系数(qP)和非光化学猝灭(NPQ),表明当代杂交种亲本光系统2反应中心开放比例增加,更多的天线色素吸收的激发能用于电子链传递。随光强度和CO2浓度的升高,表现出更高的光合潜势。当代杂交种亲本的光补偿点和CO2补偿点较低,表观量子效率和羧化效率显著高于早期的亲本,表明当代杂交种亲本在低光强和低CO2浓度条件下,可以维持相对较高的光合能力。5种植密度对不同年代玉米杂交种及其亲本光合特性的影响高密度条件下,当代杂交种及其亲本的光合高持续期明显延长,花后始终保持较高的叶面积指数、叶绿素及可溶性蛋白含量,有效维持植株叶片的功能期和延缓植株的衰老。当代杂交种及其亲本具有较高的PEPCase和RuBPCase活性,在籽粒灌浆期能够保持较高的光合效率,且对光能的利用效率明显高于早期的品系,从而使其生育后期能够维持叶绿体组分的结构性和功能性。6种植密度对不同年代玉米杂交种及其亲本光合特性的影响高密度条件下,减源疏库明显降低了不同年代杂交种及其亲本的籽粒产量,且疏库处理对其影响更大。当代杂交种及其亲本在减源疏库处理下具有较高的籽粒产量,且维持相对较高的穗位叶叶绿素和可溶性蛋白含量,有效延缓了其衰老的进程。当代品系具有相对较高的穗位叶光合效率,减源疏库对其影响并不显著,这主要由于其生育后期具有良好的叶绿体结构和较多的细胞器数目,使其维持相对较高光化学效率。更多还原

【Abstract】 The experiment was carried out in national maize engineering technology center (Shandong) and State Key Laboratory of Crop Biology from 2007 to 2008. We investigate the evolution of yield and physiology traits in china with maize hybrids and their parents which was popularized in production after 1960s, and analyze the physiology machanism of reponse to plant density of maize hybrids and their parents. This paper focused on photosynthetic carbon metabolism, study source-sink traits of maize hybrids and their parents released in different years. The main results as followed:1 Evolution Characteristics of Main Agronomic Traits with Genetic Improvement of Maize Hybrids and their Parents in ChinaCompared with 1980s and 1960s hybrids and their parents, the modern varieties had higher grain yield with the times evolution (P<0.05), accompanied with biomass and harvest index under two planting densities, indicating that the modern F1 hybrids had higher heterosis in their yields. The ear length of hybrids and their parents had less change, and greatly increased in ear diameter, kernel numbers per ear and 100-kernel weight with grain yield enhancing (P<0.05). Plant height and ear position height of hybrids was highest in 1980s, and those of their parents were heightened released in different years. The stem diameter increased, tassel branches reduced, and leaf orientation value (LOV) significantly enhanced of hybrids and their parents in different years (P<0.05). The individual leaf numbers, leaf area index(LAI), leaf area duration after anthesis and average net photosynthetic rate of 2000s hybrids and their parents were higher than those of the earlier varieties (P<0.05), especially at high density condition. The correlation and pathway analysis indicated that yield was positively correlated with ear diameter, kernel numbers per ear, 100-kernel weight, leaf area index and leaf orientation value (P<0.05), and 100-kernel weight, leaf area index and leaf orientation value of elite inbred lines showed more contribution in their yield.2 The grain filling traits and matter transportion of maize hybrids parents released in different yearsThe modern hybrids with higher grain yield had higher initiation potential(R0), and the appeared time of the highest rate delayed, the biggest production(Wmax) and the highest grain filling rate(Gmax) were higher than those of the earlier parents. Also, the modern hybrids parents maintained higher nutrient matter accumulation, stem-sheath matter exportation rate, stem-sheath matter contribution and higher nitrogen translocation efficiency. The modern hybrids parents maintained higher grain filling ability, which was closed correlated with stronger matter accumulation ability and higher nutrient matter translocation efficiency of modern maize parents.3 The evolution of photosynthesis efficiency in maize hybrids parents released in different yearsThe grain weight in the recently lines gradually increased released in different years, which was accompanied with the common enhancement of plant weight and harvest index. Also, the recently released lines had a better stay-green character, prolonging effective photosynthesis duration during leaf senescence owing to their higher chlorophyll content, soluble protein content, and larger leaf area at late growth stage. In recently released lines, photosynthetic rate (Pn), intercellular CO2 concentration (Ci) and stomatal conductance (Gs) showed higher values, and declined slowly at late growth stage obviously. Synchronously, Chlorophyll fluorescence parameters such as the maximal photochemical efficiency (Fv/Fm), the actual photochemical efficiency (ΦPSⅡ), photochemical quenching coefficient (qP) and non-photochemical quenching coefficient (NPQ) of recently released lines were higher than those of earlier released lines. We analyzed plant light energy partition indicated that more percentage energy partition was allocated to photo reaction center in recently released lines, but had a lower themal-dissipation of antenna pigment. These suggested recently released lines showed great advantages in photosynthetic performance, electron transfer, and light energy transform at the late growth stage, so the higher grain yield of recently released lines resulted from the common improvement of leaf physiological activity and photosynthetic efficiency in grain filling period.4 The photosynthetic diurnal Change traits and photosynthetic responses of maize hybrids parents released in different years. The modern maize hybrids parents maintained higher photosynthetic efficiency than those of earlier parents in diurnal Change, especially showed great advantages at noon. Three maize hybrids parents were not appeared photosynthetic midday depression. With the increase of light intensity, the modern parents showed higher photosynthetic potential. The modern hybrids parents had lower light compensation points and CO2 compensation points, and showed higher apparent quantum efficiency and carboxylic efficiency. These indicated that the modern hybrids parents maintained higher photosynthetic ability under low light intensity and low CO2 concentration.5 Effect of plant density on photosynthetic traits of maize hybrids and their parents released in different yearsThe modern hybrids and their parents maintained longer photosynthetica higher duration, and had higher leaf area index, chlorophyll content and soluble protein content, which delayed the process of senescence in maize plant. The modern hybrids and their parents had higher photosynthetic key enzymes activity, and showed higher photosynthetic efficiency, moreover, light energy utilization efficiency of the modern maize was higher than those of earlier maize, which could maintained the excellent structure and function of chloroplast components at the late of stage.6 Effect of source-sink change on yields and photosynthetic traits of maize hybrids and their parentsSource-sink change distinctly decreased grain yield and 100-grain weight of maize hybrids and their parents, and significantly at reduced sink treatment. The modern hybrids and their parents maintained higher chlorophyll content and soluble protein content, which prolonged the function of maize leaf and delayed the process of senescence in plant. The modern maize hybrids and their parents had higher photosynthetic efficiency and photochemistry efficiency, but not significant change by source-sink change, which was mainly caused by better chloroplast structure and more organelle numbers to sustain higher photochemistry efficiency.更多还原