不同水分管理下优质稻花后植株碳氮流转与籽粒生长及品质的相关性

以桂华占、八桂香为材料,在干湿交替灌溉、亏缺灌溉、淹水灌溉3种水分条件下,研究优质稻花后植株碳氮流转与籽粒生长及品质的相关性。结果表明:不同水分管理下,桂华占和八桂香花后碳氮流转与籽粒的生长间存在密切相关。主要表现在:(1)茎鞘和叶片干物质转运对籽粒干物质积累的贡献率为16.86%～25.68%,花后茎叶干物质运转速度和运转率与籽粒起始灌浆势呈显著甚至极显著正相关;籽粒最大灌浆速率、活跃灌浆期、持续灌浆时间与叶片干物质运转速度和运转率呈极显著正相关,与茎鞘干物质运转速度和运转率呈极显著负相关;(2)茎鞘碳同化物转运对籽粒的产量和淀粉产量的贡献率则为干湿交替灌溉>亏缺灌溉>淹水灌溉;但叶片碳同化物转运对籽粒的产量和淀粉产量的贡献率则为淹水灌溉>亏缺灌溉>干湿交替灌溉;茎叶可溶性糖积累量的减少和籽粒直链淀粉含量和积累量增加是同步的,且茎叶可溶性糖积累量快速递减期(花后3～12d)与直链淀粉含量和积累量快速递增期(花后6～12d)同步;(3)茎鞘和叶片氮素转运对籽粒氮素积累的贡献率为44.05%～117.66%,叶片总氮转运对籽粒氮素积累的贡献率大于茎鞘,茎鞘和叶片氮同化物对籽粒氮素的贡献率以淹水灌溉处理的最大,亏缺灌溉处理的次之,干湿交替灌溉处理的最小。     

Much Improved Water Use Efficiency of Rice under Non-Flooded Mulching Cultivation

Water shortage is increasingly limiting the luxury use of water in rice cultivation. In this study, non-flooded mulching cultivation of rice only consumed a fraction of the water that was needed for traditional flooded cultivation and largely maintained the grain yield. We also investigated the growth and development of rice plants and examined grain yield formation when rice was subjected to non-flooded mulching cultivation. One indica hybrid rice combination was grown in a field experiment and three cultivation methods, traditional flooding （TF）, non-flooded straw mulching cultivation （SM） and non-flooded plastic mulching cultivation （PM）, were conducted during the whole season. Grain yield showed that there was no significant difference between SM and TF rice, but the grain yield of SM cultivation was significantly higher than that of PM. The tiller numbers were inhibited in the early stage under non-flooded mulching cultivation, but the situation was reversed at the later period. Both SM and PM rice reduced dry matter accumulation of shoot, but increased root dry weight, enhanced the remobilization of assimilates from stems to grains and increased the harvest index. During the middle and later grain filling period, mulched plants showed a faster decrease in chlorophyll concentrations, photosynthetic rates of flag leaves and root activity than TF rice, indicating that non-flooded mulching cultivation enhanced plant senescence. In comparison, SM treatment produced higher grain yield and, more dry matter accumulation and panicle numbers than the PM treatment. The overall results suggest that high yield of non-flooded mulching cultivation of rice can be achieved with much improved irrigaUonal water use efficiency.     

不同育秧方式和插植密度下早籼稻群体动态结构的研究

于1996年早季研究了湿润与旱育秧方式在稀植(2苗/科)和多植(4苗/科)情况下超高产早籼品种特三矮2号在本田生长期的群体动态结构与产量表现。与多植比较,稀植的比叶重较大,中期叶面积系数较小,每穗颖花数较多;但有效分蘖数较少。与湿润育秧比较,旱育秧每科穗数较多,抽穗后群体保持较高的叶面积系数和干物质生产力;但生育期较长。旱育稀植的谷草比较高。     

Seedling vigour and the early growth of transplanted rice (Oryza sativa)

Previous studies suggest that the positive response of transplanted rice (Oryza sativa L.) to nursery fertiliser application was due to increased seedling vigour or possibly to increased nutrient content. This paper presents results of two glasshouse experiments designed to test the hypothesis that seedling vigour was responsible for the response of transplanted seedlings to nursery treatments. The aim of the present study was to explore the concept of seedling vigour of transplanted rice and to determine what plant attributes conferred vigour on the seedlings. Seedling vigour treatments were established by subjecting seedlings to short-term submergence (0, 1 and 2 days/week) in one experiment and to leaf clipping or root pruning and water stress in another to determine their effect on plant growth after transplanting. Submerging seedlings increased plant height but depressed shoot and root dry matter and root:shoot ratio of the seedling at 28 days after sowing. After transplanting these seedlings, prior submergence depressed shoot dry matter at 40 days. Nursery nutrient application increased plant height, increased root and shoot dry matter, but generally decreased root:shoot ratio. Pruning up to 60% of the roots at transplanting decreased shoot and root dry matter, P concentration in leaves at panicle initiation (PI) and straw dry matter and grain yield at maturity. By contrast, pruning 30% of leaves depressed shoot and root dry matter by 30% at PI, and root dry matter and straw and grain yield by 20% at maturity. The combined effects of leaf clipping and root pruning on shoot, root and straw dry matter were largely additive. It is concluded that the response of rice yield to nursery treatments is largely due to increased seedling vigour and can be effected by a range of nutritional as well as non-nutritional treatments of seedlings that increase seedling dry matter, nutrient content, and nutrient concentration. Impairment of leaf growth and to a lesser extent root growth in the nursery depressed seedling vigour after transplanting. However, rather than increasing stress tolerance, seedling vigour was more beneficial when post transplant growth was not limited by nutrient or water stresses.     

Critical Yield Factors for Achieving High Grain Yield in Early-Season Rice Grown under Mechanical Transplanting Conditions

Double-season rice cropping systems occupy a large portion of the rice production area in southern China. Because the problem of insufficient labor, mechanical transplanting (in contrast to the manual transplanting) was become more attractive in double-season rice system. However, the decisive yield factors which resulting in high grain yield of early-season rice are unclear under mechanical-transplanted conditions. In present study, the field experiments were conducted in the early season in 2017 and repeated in 2018 in Santang Town, Hunan Province, China. Ten early season rice cultivars (Zhuliangyou 819, Lingliangyou 268, Lingliangyou 104, Luliangyou 996, Xiangzaoxian 24, Xiangzaoxian 32, Xiangzaoxian 45, Xiangzaoxian 42, Zhongjiazao 17, and Zhongzao 39) were used as materials in this study. The difference in grain yield and closelyrelated agronomic and physiological traits of ten tested cultivars were compared. The range of yields (t ha^–1 at 86% dry matter) in 2017 was 6.2 to 8.7 (mean 7.8) and in 2018 was 6.5 to 8.4 (mean 7.8). Grain weight and pre-heading biomass accumulation had potent significant positive correlations with the grain yield. The greater pre-heading biomass accumulation was major attributed to higher apparent radiation use efficiency. Our results suggested that early-season rice cultivars to achieve the high grain yield in mechanical-transplanted conditions depends on apparent radiation use efficiency in the pre-heading period and higher grain weight.     

不同生育期遮光对水稻生长发育和产量形成的影响

研究了不同生育期遮光45%(水稻生长的前期、中1期、中2期、后期)对水稻形态发育、光合产物积累、稻株养分含量、产量构成等的影响,并重点研究了植株对N、P、K养分的吸收规律。结果表明,各期遮光后均使干物质积累速率降低,植株N、P、K养分吸收量减少,对产量有不同程度的影响,但植株体内N、P、K养分含量上升。前期遮光主要使分蘖数急剧下降,有效穗数减少,叶面积系数下降,产量下降11.56%,但株高增加;中1期遮光后对水稻生长影响不大,产量仅降低5.46%;中2期遮光主要使每穗粒数和千粒重下降,对产量影响较大,降低幅度达30.80%;后期遮光主要影响结实粒和千粒重,其产量最低,降低55.40%.文中还对弱光照条件下的生育期安排和施肥决策提出了建议.     

不同灌溉方式对水稻生物学特性与水分利用效率的影响

以杂交水稻两优培九为试验材料,利用测坑栽培条件,比较了4种灌溉方式下的水稻生物学特性与水分利用效率.结果表明,与淹水灌溉相比,间歇灌溉叶面积指数大,叶片光合速率高,蒸腾速率较低,叶片水分利用效率高;半干旱栽培叶片水分利用效率相对较高;干旱栽培叶面积指数小,叶片净光合速率和水分利用效率降低,且后期叶片早衰.间歇灌溉、半干旱栽培和干旱栽培比淹水灌溉分别节水8.75%、17.96%和29.69%;产量分别增产24.02%、减产5.07%和减产38.93%;水分利用效率以间歇灌溉最高,半干旱栽培次之,淹水灌溉和干旱栽培较低.间歇灌溉下稻粒的整精米率、精米率、粒长均高于其它处理,但垩白粒率和垩白度低于其它处理;随着稻田耗水量的减少,水稻的直链淀粉含量降低,而胶稠度和蛋白质含量提高.试验结果表明间歇灌溉为南方稻区较适宜的灌溉方式.     

猪粪配施化肥对稻-麦轮作系统籽粒产量和氮素利用率的影响

通过大田试验,以水稻(品种‘F优498’)-小麦(品种‘内麦863’)轮作体系为研究对象,根据成都平原稻麦种植体系常规施氮水平,设7个不同猪粪施用处理:对照(CK,无化学氮肥,无猪粪)、常规化肥(T₁,无猪粪)、化肥减量25%+猪粪2500 kg·hm^-2(T₂)、化肥减量50%+猪粪5000 kg·hm^-2(T₃)、猪粪10000 kg·hm^-2(T₄)、猪粪15000 kg·hm^-2(T₅)和猪粪20000 kg·hm^-2(T₆),研究添加猪粪对稻麦干物质、氮素积累及分配特征、籽粒产量和氮素利用率等的影响.结果表明: 猪粪配施化肥对稻麦各生育期干物质积累均有促进作用,稻麦成熟期作物地上部干物质积累量均以高量猪粪施用处理(T₆)最高,但其干物质积累及氮素分配向茎叶富集,且籽粒干物质积累及氮积累分配率显著低于T₂处理;随着配施猪粪用量的增加,稻麦氮肥偏生产力、氮肥农学利用率、籽粒产量均呈现先增加后减少趋势,其中水稻季以T₃处理最优,较常规化肥处理提高11.4%、55.4%、11.4%,小麦季则以T₂处理最优,较常规化肥处理提高14.0%、29.1%、14.0%.本试验条件下,2500～5000 kg·hm^-2猪粪+化肥减量25%～50%处理,有利于促进稻麦干物质积累、氮素向籽粒运移,达到增产及提高氮素利用率的效果,超量施用猪粪(15000～20000 kg·hm^-2)后,土壤氮素供应过量,干物质向经济器官运移受阻,氮素向茎秆富集,贪青晚熟现象严重,稻麦籽粒产量显著下降.     

开放式空气CO2增高对水稻物质生产与分配的影响

在大田栽培条件下,研究开放式空气CO2增加(FACE)200μmol·mol^-1的处理对水稻物质生产与分配的影响．结果表明,FACE处理使移栽至抽穗后20d的干物质积累量显著增加,使抽穗后20d至成熟期的干物质生产量显著减少,生物产量显著提高．移栽至抽穗期的干物质积累量增加是由于叶面积系数和净同化率共同提高所致;抽穗期至抽穗后20d的干物质积累量增加主要是由于叶面积系数的增加所致;抽穗后20d至成熟期的干物质生产量减少主要是由于净同化率的下降所造成．提高茎鞘占全株干物重的比例,降低叶片占全株干物重的比例,对穗占全株干物重的比例无显著影响,能显著提高水稻抽穗期茎鞘中可溶性糖、淀粉的含有率和含量,提高FACE处理的生物产量能极显著提高水稻产量(r＝0．7825)．     

生活污水尾水灌溉对麦秸还田水稻幼苗及土壤环境的影响

通过盆栽试验研究了麦秸还田下生活污水尾水灌溉对水稻幼苗和土壤环境的影响.测定了不同处理水稻幼苗根系形态、根系活力、分蘖、株高、干物质累积量、土壤亚铁、有机酸、酶活性.结果表明: 与自来水灌溉相比,不施化肥氮时,生活污水尾水灌溉显著提高了水稻移栽后41 d的分蘖数和根系活力;正常施氮肥时,生活污水尾水灌溉显著促进了水稻根系和植株生长,根长、根表面积、根体积、根系活力、水稻分蘖数和干物质累积量均显著高于自来水灌溉处理.生活污水尾水灌溉处理显著降低了土壤Fe²⁺和有机酸含量,土壤脲酶、过氧化氢酶活性等显著提高.生活污水尾水灌溉和施氮耦合能有效缓解秸秆还田初期对水稻幼苗生长的不利影响,改善水稻生长状况,提升土壤肥力和质量.     

Physiological mechanisms contributing to the increased water-use efficiency in winter wheat under deficit irrigation

Deficit irrigation in winter wheat has been practiced in the areas with limited irrigation water resources. The objectives of this study were to (i) understand the physiological basis for determinations of grain yield and water-use efficiency in grain yield (WUE) under deficit irrigation; and (ii) investigate the effect of deficit irrigation on dry matter accumulation and remobilization of pre-anthesis carbon reserves during grain filling. A field experiment was conducted in the Southern High Plains of the USA and winter wheat (cv. TAM 202) was grown on Pullman clay loam soil (fine mixed thermic Torretic Paleustoll). Treatments consisted of rain-fed, deficit irrigation from jointing to the middle of grain filling, and full irrigation. The physiological measurements included leaf water potential, net photosynthetic rate (Pn), stomatal conductance (Gs), and leaf area index. The rain-fed treatment had the lowest seasonal evapotranspiration (ET), biomass, grain yield, harvest index (HI) and WUE as a result of moderate to severe water stress from jointing to grain filling. Irrigation application increased seasonal ET, and ET increased as irrigation frequency increased. The seasonal ET increased 20% in one-irrigation treatments between jointing and anthesis, 32-46% in two-irrigation treatments, and 67% in three- and full irrigation treatments. Plant biomass, grain yield, HI and WUE increased as the result of increased ET. The increased yield under irrigation was mainly contributed by the increased number of spikes, and seeds per square meter and per spike. Among the irrigation treatments, grain yield increased significantly but the WUE increased slightly as irrigation frequency increased. The increased WUE under deficit irrigation was contributed by increased HI. Water stress during grain filling reduced Pn and Gs, and accelerated leaf senescence. However, the water stress during grain filling induced remobilization of pre-anthesis carbon reserves to grains, and the remobilization of pre-anthesis carbon reserves significantly contributed to the increased grain yield and HI. The results of this study showed that deficit irrigation between jointing and anthesis significantly increased wheat yield and WUE through increasing both current photosynthesis and the remobilization of pre-anthesis carbon reserves.     

水氮互作下直播稻群体质量与氮素利用特征的关系

探讨水氮耦合下直播稻群体质量和氮素利用特征可为直播水稻丰产高效生产提供理论基础和实践依据。以杂交稻‘F优498’为试验材料,设置淹水灌溉(W₁)、干湿交替灌溉(W₂)、旱种(W₃)3种灌水方式和基肥∶蘖肥∶穗肥分别为5∶3∶2(N₁)、3∶3∶4(N₂)、3∶1∶6(N₃)3种氮肥运筹模式,以不施氮处理(N₀)为对照,研究水氮互作对直播稻群体质量和氮素利用特征的影响,并探讨水氮互作下直播稻群体质量构建与氮素利用特征和产量的关系。结果表明:灌溉方式和氮肥运筹对直播稻各生育时期干物质积累、稻谷收获指数、抽穗及抽穗20 d高效叶(上3叶)干重、结实期群体透光率、氮素积累总量、氮肥表观利用率、氮肥偏生产力、氮肥生理利用率和产量均存在显著的互作效应。综合直播稻群体质量、产量和氮肥利用特征,各灌溉方式下,氮肥后移比例均以占总量的20%～40%(N₁～N₂)为宜,氮肥后移比例达到总量的60%(N₃)和W₃处理均会显著降低直播稻群体质量、产量、氮肥农学利用率和氮肥偏生产力。相关分析表明,水氮互作下直播稻产量和氮素利用特征与最终有效分蘖数、结实期干物质积累、其余叶(除上三叶以外叶片)干重减少量、总叶片干重减少量,以及群体中部和基部受光率均呈显著或极显著正相关。干湿交替灌溉(W₂)可以提高直播稻茎蘖成穗率、各时期干物质积累、稻谷收获指数、氮肥吸收总量、氮肥农学利用率和最终产量,配合N₂的氮肥运筹模式可优化调控直播稻群体质量,实现高产与氮肥高效利用的协调统一,为本试验最优组合。     

Regulation of Nitrogen Metabolism,Photosynthetic Activity,and Yield Attributes of Spring Wheat by Nitrogen Fertilizer in the Semi-arid Loess Plateau Region

It is critical for spring wheat (Triticum aestivum L.) production in the semi-arid Loess Plateau to understand the impact of nitrogen (N) fertilizer on changes in N metabolism, photosynthetic parameters, and their relationship with grain yield and quality. The photosynthetic capacity of flag leaves, dry matter accumulation, and N metabolite enzyme activities from anthesis to maturity were studied on a long-term fertilization trial under different N rates [0 kg ha^?1(N1), 52.5 kg ha^?1 (N2), 105 kg ha^?1 (N3), 157.5 kg ha^?1 (N4), and 210 kg ha^?1 (N5)]. It was observed that N3 produced optimum total dry matter (5407 kg ha^?1), 1000 grain weight (39.7 g), grain yield (2.64 t ha^?1), and protein content (13.97%). Our results showed that N fertilization significantly increased photosynthetic parameters and N metabolite enzymes at all growth stages. Nitrogen harvest index, partial productivity factor, agronomic recovery efficiency, and nitrogen agronomic efficiency were decreased with increased N. Higher N rates (N3–N5) maintained higher photosynthetic capacity and dry matter accumulation and lower intercellular CO₂ content. The N supply influenced NUE by improving photosynthetic properties. The N3 produced highest chlorophyll content, photosynthetic rate, stomatal conductance and transpiration rate, grain yield, grain protein, dry matter, grains weight, and N metabolite enzyme activities compared to the other rates (N1, N2, N4, and N5). Therefore, increasing N rates beyond the optimum quantity only promotes vegetative development and results in lower yields.

     

Crop traits and the tolerance of wheat and barley to foliar disease

The relationship between yield loss and disease severity can differ widely between crops. This has given rise to the concept of disease tolerance, with some crops exhibiting a smaller yield loss under a given severity of disease than others. Genetic improvement to minimise yield loss under disease is an attractive goal, as it exerts little or no selection pressure on pathogen populations, and could form a useful component of durable disease management programmes. However, progress towards this end requires a thorough understanding of the phenotypic traits that influence the response of yield to disease, their genetic control and the possible trade-offs involved with other desirable agronomic characteristics. This paper examines the candidate crop traits that may confer tolerance of foliar disease in wheat and barley and reviews evidence of genetic variation in their expression. In wheat grown under the relatively low light conditions of North-West Europe, post-anthesis source (assimilate supply) and grain sink capacity (capacity for dry matter accumulation) appear to be closely balanced. Traits associated with maintaining post-anthesis radiation interception and radiation use efficiency in spite of disease may confer tolerance. The most promising traits include a larger flag leaf and compensatory increases in photosynthetic rate in non-infected parts of leaves. In barley, yield is often more strongly sink limited, and early-season disease management is required to protect the formation of potential grain sites. A wider range of potential traits may influence tolerance including compensatory adjustments in leaf growth and morphology, and differences in the sensitivity of tiller and spikelet mortality to photoassimilate supply. Different methods for quantifying tolerance are suggested depending on the trait of interest.     

稗属杂草对水稻生长发育和产量的影响

以新两优6号(籼稻)和南粳46(粳稻)为材料,自水稻移栽至成熟分别与无芒稗(T₁)、稗(T₂)、西来稗(T₃)和光头稗(T₄)共生,稗草密度为6株·m^-2,以无稗草水稻处理为对照,研究不同稗草对水稻生长发育和产量的影响.结果表明：与对照相比,不同稗草对水稻的干扰表现不同,T₁、T₂、T₃处理使籼稻产量分别下降19.2%、10.8%、21.9%,使粳稻产量分别下降39.7%、25.3%、47.3%,但T₄处理对2个水稻品种的产量均无显著影响.水稻和稗草共生过程中,T₁、T₂和T₃处理显著降低了水稻成熟期的干物质积累量及灌浆期的剑叶光合速率、根系氧化力和籽粒ATP酶活性,降低幅度为T₃>T₁>T₂,T₄处理与对照差异不显著;各处理对水稻最终分蘖数和株高均无显著影响.表明4种稗草对水稻生长的影响由强到弱表现为：T₃>T₁>T₂>T₄,稻 稗共生时水稻剑叶光合速率、根系氧化力和籽粒ATP酶活性降低是导致水稻生产力下降的重要原因.     

限水灌溉冬小麦冠层氮分布与转运特征及其对供氮的响应

以高产冬小麦品种周麦18为材料,在大田春灌1水条件下,设置不同供氮水平和氮肥运筹处理试验,研究并探讨了在华北地区限水灌溉条件下氮肥施用对冬小麦冠层叶片氮素时空分布与转运及氮肥利用的影响。结果表明,冬小麦适量施氮可显著增产,2008-2009年以施氮量180 kg/hm²时(N21)产量最高,为8749 kg/hm²;2009-2010年以施氮量270 kg/hm²时(N32)产量最高,但施氮量210 kg/hm²(N22)处理与N32处理产量无显著差异,分别为8340 kg/hm²和8558 kg/hm²。氮肥利用效率和氮肥偏生产力均随施氮量增加而降低;氮肥利用率与氮肥农学效率均随施氮量的增加呈先升后降的趋势,分别在N21和N22处理时最高。冠层叶片氮素含量和积累量随叶层层次自上而下降低而下降,垂直梯度分明,各时期冠层叶片氮素垂直梯度随施氮量的增加总体呈先增大后减小的趋势。冠层叶片氮素转运量、转运率和对籽粒的贡献率均呈现为:第1层>第2层>第3层>第4层。相关分析表明,冠层叶片氮素梯度与叶片氮素转运率呈显著正相关关系(R²=0.722^*),与贡献率呈极显著正相关关系(R²=0.975^**)。适量施氮(120-210 kg/hm²)增大了叶层间氮素垂直分布梯度,促进了氮素在植株内的运移分配,有利于叶片氮素向外转运,提高了叶片氮素转运量和对籽粒贡献率,保持了较高的氮素利用率。施氮过多(330 kg/hm²)减小了叶层间氮素垂直分布梯度,减弱了氮素在植株内的再利用,叶片氮素转运不畅,导致叶片氮素转运量和对籽粒贡献率下降,氮素利用率显著降低。连续两年试验结果显示,通过适量氮肥调控可以增大冠层叶片氮素垂直梯度,有利于叶片中的氮素输出,促进氮素的再分配、再利用,从而提高氮素利用率,并可获得较高的籽粒产量和蛋白质含量。     

A proteomics view on the role of drought-induced senescence and oxidative stress defense in enhanced stem reserves remobilization in wheat

Drought is one of the major factors limiting the yield of wheat (Triticum aestivum L.) particularly during grain filling. Under terminal drought condition, remobilization of pre-stored carbohydrates in wheat stem to grain has a major contribution in yield. To determine the molecular mechanism of stem reserve utilization under drought condition, we compared stem proteome patterns of two contrasting wheat landraces (N49 and N14) under a progressive post-anthesis drought stress, during which period N49 peduncle showed remarkably higher stem reserves remobilization efficiency compared to N14. Out of 830 protein spots reproducibly detected and analyzed on two-dimensional electrophoresis gels, 135 spots showed significant changes in at least one landrace. The highest number of differentially expressed proteins was observed in landrace N49 at 20days after anthesis when active remobilization of dry matter was observed, suggesting a possible involvement of these proteins in effective stem reserve remobilization of N49. The identification of 82 of differentially expressed proteins using mass spectrometry revealed a coordinated expression of proteins involved in leaf senescence, oxidative stress defense, signal transduction, metabolisms and photosynthesis which might enable N49 to efficiently remobilized its stem reserves compared to N14. The up-regulation of several senescence-associated proteins and breakdown of photosynthetic proteins in N49 might reflect the fact that N49 increased carbon remobilization from the stem to the grains by enhancing senescence. Furthermore, the up-regulation of several oxidative stress defense proteins in N49 might suggest a more effective protection against oxidative stress during senescence in order to protect stem cells from premature cell death. Our results suggest that wheat plant might response to soil drying by efficiently remobilize assimilates from stem to grain through coordinated gene expression.     

不同生态环境下水稻基因型产量形成与源库特性的比较研究

以日本和IRRI的9个水稻品种为材料,分别以武香粳9号和两优培九为对照,在江苏南京和云南丽江研究了不同水稻基因型干物质积累与源库形成特征及其在不同生态环境下的差异.结果表明,生态环境对水稻产量和干物质积累量影响显著.高产水稻品种积累了高额干物质量,且干物质生产优势在中后期.高产品种的总颖花量、LAI及群体生长速率(CGR)都较高.稻谷产量随干物质积累总量的增加而提高,与齐穗后干物质积累量、总颖花量和LAI呈极显著正相关,与粒叶比呈显著正相关.与云南丽江点相比,群体LAI、单位面积颖花量和抽穗后干物质积累量少及生长速率(CGR)低是南京点稻谷产量低的关键因素.     

Differential responses of system of rice intensification (SRI) and conventional flooded-rice management methods to applications of nitrogen fertilizer

Background

Rising food demand, slowing productivity growth, poor N-use efficiency in rice, and environmental degradation necessitate the development of more productive, environmentally-sound crop and soil management practices. The system of rice intensification (SRI) has been proposed as a methodology to address these trends. However, it is not known how its modified crop-soil-water management practices affect efficiency of inorganic nitrogen applications.

Methods

Field experiments investigated the impacts of SRI management practices with different N-application rates on grain yield, root growth and activity, uptake of N and its use-efficiency, leaf chlorophyll content, leaf N-concentration, and photosynthetic rate in comparison with standard management practices for transplanted flooded rice (TFR).

Results

Overall, grain yield with SRI was 49 % higher than with TFR, with yield enhanced at every N application dose. N-uptake, use-efficiency, and partial factor productivity from applied N were significantly higher in SRI than TFR. Higher leaf nitrogen and chlorophyll contents during the ripening-stage in SRI plants reflected delayed leaf-senescence, extension of photosynthetic processes, and improved root-shoot activities contributing to increased grain yield.

Conclusions

Rice grown under SRI management used N fertilizer more efficiently due to profuse root development and improved physiological performance resulting in enhanced grain yield compared to traditional flooded rice.     

不同育秧方式和插植密度下晚籼稻群体动态结构的研究

不同育秧方式和插植密度下晚籼稻群体动态结构存在差异。旱育秧群体分蘖速度快,分蘖能力强。稀植可促进个体分蘖多发、有效穗数增多,但旱育稀植并无分蘖早发的优势。旱育稀植使主茎基部叶片变短而上部叶片变长,生育后期叶面积消长平稳,地上部干物质积累较多。旱育秧、稀植都使主茎叶总数增多,全生育期延长。