水稻根系活力测定方法及超级稻两优培九生育后期根系活力研究

以孕穗期的两优培九为材料,用伤流法测定根系活力,调查了影响根系伤流收集量的因素。结论如下：在两优培九孕穗期用脱脂棉收集伤流液,以2.0 g的脱脂棉填充量为宜;两优培九主茎和分蘖的伤流量差异显著（P＜0.05）;白天和夜晚的伤流量差异极显著（P＜0.01）;稻桩高低对伤流量影响不显著（P＞0.05）;连续两次测定的差异不显著（P＞0.05）。用上述最佳方法,对两优培九及其对照品种汕优63抽穗后的根系活力（根系伤流强度）进行了调查,结果如下：两优培九抽穗前的根系活力比汕优63相对较高,二者均在抽穗后1周左右出现峰值,随后呈下降趋势,但与汕优63相比,两优培九伤流强度下降幅度相对较大,且一直维持在较低水平。同时,对两个品种抽穗后剑叶叶绿素含量的测定结果表明,两优培九和汕优63的剑叶叶绿素含量抽穗后都迅速下降,但是相对于汕优63,两优培九剑叶叶绿素含量下降速度要慢,能维持相对较高的水平。因此,根系活力的下降可能是两优培九生育后期易早衰的原因。     

温度与再生稻农艺性状的相关性研究

1987-1988年用杂交稻汕优63和冈矮63，在重庆市渝北区同一坡面海拔250-450m作中稻种植，使其再生稻在不同的自然温度下生长发育，结果表明：再生季日均温随海拔高度递增而逐渐下降，它与再生稻全生育日数和千粒重均呈显著负相关，与再生苗数、有效穗数、株高、穗长、穗着粒数、穗实粒数、结实率等农艺性状以及单位面积产量均呈显著正相关；再生稻长苗期和抽穗开花期的日均温与再生稻单产亦呈显著正相关。据此提出重庆地区中迟熟杂交稻品种再生稻稳定较高产量的适宜种植区海拔高度上限约为340m，其对应的年均温为17.8C，稳定通过10C初至连续5d≥22C终日间的日均温为22.8C。     

头季稻齐穗期剑叶光合产物分配与再生稻产量的相关性

以两系、三系杂交组合及其父本为材料,用14C同位素示踪法研究了头季稻齐穗期剑叶光合产物的分配及其与再生稻产量的相关性,结果表明:(1)头季稻齐穗期剑叶光合产物80%~90%分配到穗部,10%~20%残留于叶、茎,且主要残留在剑叶中,仅5%左右残留在茎鞘中,茎鞘各节间残留量一般表现为倒1>倒2>倒3>倒4的趋势,倒2以下节间贮藏的光合产物占茎秆总量的1/3~2/3,品种(组合)间差异较大;(2)稻桩贮藏光合产物的52%~70%转运至再生稻体内,且分配至穗部的最多;(3)头季稻成熟期残留在茎鞘中,特别是倒2以下节间中的光合产物越多越有利于再生稻产量的提高;(4)本试验条件下,再生稻产量构成因素中,影响产量的首要因素是穗粒数。可见,选用穗粒数多、成熟期残留在茎鞘,特别是倒2以下节间中的光合产物较多的品种进行再生培植,有利于获得再生稻高产。     

提高再生稻产量的气象条件探讨

本文采用通径分析的方法,分析了几个主要气象条件对再生稻产量的效应和气象条件与产量构成因素间的关系。根据四川东南部秋季气候规律,提出了再生稻稳产高产的抽穗开花临界期,并评判了其安全保证率和稳产高产的出现频率。     

分根灌水对玉米根系活力及叶片含水量的影响

采用交替分根和固定分根处理方法 ,比较分根灌水预处理对玉米根系活力和叶片含水量的影响结果表明 ,交替分根灌水处理对玉米叶片含水量及质膜透性和根系活力及质膜透性的影响较小 ,其保水效果优于固定分根灌水处理。根系活力和质膜透性与叶片含水量分别呈显著正相关和负相关 ,维持根系活力与保持较高的叶片含水量有密切关系。     

根际通气对盆栽玉米生长与根系活力的影响

针对盆栽作物生长空间有限且通气不良的生长环境问题,为改善根际气体环境,试验设每隔2d通气1次(T1)、每隔4d通气1次(T2)两个通气处理,以不通气(CK)为对照,研究根际通气对盆栽玉米生长及根系活力的影响。结果表明,T1和T2处理均能提高玉米株高、叶面积、叶绿素含量,促进地上部分和地下部分干物质的积累。T1、T2处理有利于提高玉米根冠比和根系活力,拔节期T1和T2处理的根冠比分别是CK的1.27倍、1.18倍,根系活力分别为CK的1.26倍和1.54倍;抽穗期根冠比分别为CK的1.18倍、1.09倍,根系活力分别为CK的1.22倍和1.40倍。同时,通气处理能够促进作物吸收土壤内的养分。研究结果表明,根际通气能够增强盆栽玉米的根系活力,促进植株的生长发育。     

头季稻氮肥运筹对再生稻干物质积累、产量及氮素利用率的影响

为探讨头季稻不同肥料运筹方式对再生稻产量和氮素利用率的影响,以杂交稻组合"Ⅱ优航2号"为材料,在头季施氮量225.00kg·hm-2的基础上,研究了不同基蘖穗肥氮素配比[3种基蘖肥与穗肥配比分别为8:2(N1)、7:3(N2)、6:4(N3)]头季稻-再生季稻氮素累积量、干物质生产、产量及氮素利用率的特性。结果表明:与N1、N2相比,头季成熟期N3处理氮素累积量分别增加9.26%、3.54%,头季齐穗期～头季成熟期N3处理氮素转移量分别增加21.47%、6.76%,整个生育期N3处理干物质净积累总量分别增加5.10%、4.78%。N3处理头季产量最高,达12431kg·hm-2,极显著高于N1、N2处理;氮肥利用率达46.44%,比N1、N2处理提高14.81%、5.43%;氮肥农学利用率达20.66kg·kg-1,比N1、N2处理提高14.97%、12.34%。研究结果还表明,头季不同基蘖穗肥氮素配比对再生稻再生季的影响不显著。     

不同水氮条件下水稻根系超微结构及根系活力差异

【目的】探讨不同水氮耦合对水稻根系超微结构及根系代谢特性的影响,从根尖细胞超微结构及根系活力方面阐明不同水氮组合处理在根际环境间的差异。 【方法】以新稻 20 号为材料,进行盆栽试验,设置浅水层灌溉、轻度水分胁迫 (灌 1～2 cm 水层,至土壤水势降到 –20 kPa 再灌浅水层,如此反复) 和重度水分胁迫 (灌 1～2 cm 水层,至土壤水势降到 –40 kPa 再灌浅水层,如此反复) 3 种灌溉方式及不施氮肥,适量氮 (N 240 kg/hm2) 和高量氮 (N 360 kg/hm2) 3 种氮肥水平,测定了不同处理水稻根系氧化力、根系伤流量及根系分泌有机酸总量,并观测了根系细胞超微结构。 【结果】随着生育进程,根系氧化力表现为先增加后降低的趋势,在幼穗分化期达到峰值,根系伤流液及根系分泌物中有机酸总量先增加后降低,在抽穗期达到峰值。在同一氮肥水平下,轻度水分胁迫后根系细胞完整,核膜界限清晰,结构特征典型;与保持水层相比,根系氧化力及根系伤流量在分蘖盛期分别增加 25.6%～32.0% 及 9.1%～18.8%,根系分泌有机酸总量在抽穗期前平均增加 16.4%。重度水分胁迫后嗜锇体和淀粉体较多,后期细胞完全扭曲变形,细胞间隙明显增多增大、细胞器出现断裂降解,细胞基质中仅存细胞器碎片,细胞壁较完整,未出现断裂情况;与保持水层相比较,根系氧化力及根系伤流量在幼穗分化始期平均降低 8.8% 及 25.6%,根系分泌有机酸总量平均降低 22.8%。在同一灌溉方式下,适量氮处理根系细胞结构较完整,核膜较清楚,有利于根系活力的提高及根系有机酸的分泌;重施氮处理根系细胞壁和核膜降解加速。与适量氮相比,高氮处理下根系氧化力及根系伤流量在分蘖盛期至幼穗分化始期分别降低了 6.6%～9.8% 及 7.7%～15.4%,根系分泌物中有机酸总量在抽穗前平均降低 11.6%,整体上根系活力降低、有机酸的分泌量显著减少。 【结论】轻度水分胁迫耦合适量氮处理的水稻根系超微结构最优,细胞结构特征典型,核膜最为清晰,细胞完整,根系代谢能力最强。表明通过适宜的水氮耦合调控,能够提高根尖细胞的生理功能,增强根系活力、促进根系有机酸的分泌,能为水稻的生长创造良好的根际环境。     

Improvement of rice (Oryza sativa L.) growth in upland conditions with deep tillage and mulch

The productivity of upland rice in Japan as well as in the world is low and unstable owing to scarce and unpredictable rainfall. The objective of this study was to examine whether agronomic methods could enhance grain yield of upland rice. Four field experiments were conducted from 2001 to 2003 in Nishitokyo, Japan, under upland conditions with different water supplies, in order to quantify the effects of deep tillage combined with deep placement of manure (50-cm depth), straw mulch (6 t ha⁻¹), or their combinations on the growth and grain yield of rice. Mulch kept surface soil moisture higher than without mulch even at reproductive stage, and it increased yield to the greatest extent under the most favourable conditions with much rainfall before heading (i.e., 2003). Deep tillage with deep placement of manure induced deep root proliferation and higher nitrogen uptake, increasing biomass production, and panicle number, and consequently grain yield was enhanced under the two lowest yielding environments with less rainfall before heading. Rice plants with deep tillage with deep manure application without mulch tended to have lower leaf water potential and higher diffusion resistance during drought, and negative effects on grain filling and harvest index in some experiments compared with the control. When deep tillage with deep placement of manure was combined with mulching in two experiments in 2002 and 2003, grain yield always enhanced compared with the control (P < 0.10, 6.0 t ha⁻¹ versus 5.4 t ha⁻¹ on average), suggesting their synergetic mechanisms for yield increase and stabilization. The results showed that deep tillage or mulching can improve grain yield of rice under drought-prone rainfed upland conditions in a temperate climate on an Andosol, and their combination had more consistent and greater positive effects.     

水稻籽粒灌浆的发育遗传与分子生态特性研究

本文从发育遗传生理和分子生态学角度, 综述了近年来国内外研究水稻籽粒灌浆的现状与存在的问题。提出了水稻籽粒发育与物质充实涉及信号传递与多基因调控及其与环境互作的分子生态学过程。强、弱势粒由于基因时空表达模式和功能蛋白作用方式的不同, 导致不同粒位胚乳细胞发育程序、籽粒灌浆速率和干物质重的明显差异。已有研究结果表明, 强势粒发育灌浆早、充实快, 具有明显的遗传稳定性; 而弱势粒发育灌浆起步晚, 充实度较差, 易受环境调控。通过分子遗传改良和分子生态调节是改善弱势粒胚乳细胞健康顺利发育, 实时启动灌浆充实, 提高结实率和千粒重, 最终实现高产的两条有效途径, 已成为世界各国优先研究的领域。本文认为籽粒灌浆为何存在一个滞育期(stagnant phase), 强弱势粒在这一发育阶段基因表达和功能作用为何存在差异是值得深入研究和回答的科学问题。     

微量元素叶面喷施对水稻(Oryza sativa L.)产量及其构成因素的影响

[目的]基于微量元素在水稻营养和代谢中的重要作用,研究叶面喷施(Fe EDTA 0.1％,Zn EDTA 0.05％,B 0.02％,Cu EDTA 0.05％,and Mn EDTA 0.05％)对水稻品种Shiroodi产量的影响,明确叶面喷施微量元素的最佳次数和时期.[方法]为了准确评估液体肥料(Fe-EDTA ...     

水稻籽粒碳氮代谢与品质性状间遗传相关性的研究

研究分析水稻籽粒C、N代谢与稻米主要品质性状间遗传相关性结果表明,水稻籽粒C、N代谢与稻米主要品质性状间有一定遗传相关性,提高可溶性糖含量,则糖氮比显著提高,糙米长、千粒重和直链淀粉含量显著降低;提高全N含量可能显著提高糙米厚和直链淀粉含量,而糖氮比、糙米长和千粒重随之显著降低;随糖氮比的提高,糙米厚、千粒重和直链淀粉含量将显著降低。种子、细胞质和母体植株3套遗传体系同时对成对性状的遗传相关性起作用,且各遗传体系在不同成对性状间的作用效果各异,可溶性糖含量与糙米宽、可溶性糖含量与糙米厚、全N含量与糙米长、全N含量与糙米厚等成对性状间遗传相关性主要受种子直接效应的控制;而可溶性糖含量与糙米长宽比、可溶性糖含量与千粒重、可溶性糖含量与直链淀粉含量、全N含量与糙米宽、全N含量与糙米长宽比、糖氮比与糙米宽、糖氮比与糙米厚等成对性状则以母体植株效应为主。     

耐阴水稻种质资源的快速筛选技术研究

阴害直接限制了水稻高产潜力发挥。建立快速筛选耐阴水稻种质资源的技术对利用耐阴种质、选育耐阴品种具有重要意义。以中粳02428、南粳35、中籼苏农3037为材料对各种筛选指标进行了比较研究，结果表明水稻苗期黑暗下保绿能力与弱光驯化下同期的叶片干重、叶绿素含量变化，同分蘖-拨节期的叶绿素含量、净光合速率变化以及与瞬时弱光照下的净光合速率下降相一致。此指标鉴定水稻苗期黑暗下保绿能力简单方便，故可用于建立耐阴种质快速筛选技术。     

Effect of puddling intensity on temporal variation in soil physical conditions and yield of rice (Oryza sativa L.) in a Vertisol of central India

Puddling as well as no-puddling for growing transplanted and direct seeded rice, respectively, have their disadvantages as well as advantages on the physical condition of the soil and yield of rice. The soil that is more susceptible to changes in structure is easy to puddle. However, what should be the extent of puddling is not well established. Generally, farmers have a tendency to create a very fine puddle that actually may not be required. Keeping in view the current global emphasis on conservation of resources as well as reduction of the production cost to improve the economic gain of farmers, this study attempted to find out the influence of varying intensities of puddling on the soil physical condition and rice yield (cv. IR 36) in a Vertisol of central India. The study was conducted over two cropping seasons during year 2000 and 2001. Three puddling intensities i.e. no-puddling (P₀), and puddling by four (P₁) and eight (P₂) passes of a 5 hp power tiller were evaluated.

The aggregate mean weight diameter (AMWD) of soil (0–15 cm depth) for P₀ remained almost unchanged till harvest. At 15 days after puddling, AMWD in P₁ and P₂ compared to P₀ was less by 45 and 59% in the first year and by 60 and 69% in the second year, respectively. These values at harvest changed to 22 and 46% in the year 2000 and 28 and 43% in the year 2001, respectively. Soil bulk density (BD) and penetration resistance (PR) increased significantly from transplanting to harvest in puddled soil, but in unpuddled soil significant increase in PR only at the surface 0–7 cm layer was observed. Higher intensity of puddling favoured more soil wetness at harvest, as the puddled soil maintained 25% more water than P₀. Compared to P₁, P₂ showed an increase of 4.3, 10.3 and 7.7% in length, width and depth of cracks, respectively, while the increase in P₁ over P₀ in the same order was 35, 23.5 and 13.3%, respectively. Thus, crack dimensions (length, width and depth) were larger under high intensity of puddling. Water loss through seepage plus percolation was significantly higher in P₀ as compared to P₁ and P₂ and the higher intensity of puddling reduced the losses more. The grain yield of P₂ was slightly higher than P₁ but both were significantly above P₀. Higher grain yield resulted in 46 and 49% more water use efficiency under P₁ and P₂ than P₀, respectively. This 2-year study has shown that puddling beyond P₁ i.e., four passes of a 5 hp power tiller may not be required to obtain higher yield or other benefits in Vertisols having similar hydrology to that reported here. Puddling only to the required level will also deteriorate less the soil physical condition as compared to more intense puddling. The unpuddled direct seeded rice maintained the soil in a better physical condition but the yield was significantly lower in relation to the puddled ones.     

Using diffusive gradients in thin films technique for in-situ measurement of labile phosphorus around Oryza sativa L. roots in flooded paddy soils

Behavior of phosphorus(P) in flooded rice soil is controlled by iron(Fe) redox cycling in root-zone. In this study, we applied a novel approach—the diffusive gradients in thin films(DGT) technique—for investigating the in-situ distribution of labile phosphorus(P) and Fe in close proximity to Asian rice(Oryza sativa L.) roots at submillimeter to millimeter spatial resolutions during the seedling and booting stages. We conducted a seven-year field experiment under rice-wheat rotation with different P fertilizer treatments. The results showed a significant and strong positive relationship of the average DGT-labile P concentration with soil Olsen P(R2= 0.77, P < 0.01) and with rice total P concentration(R²= 0.62, P < 0.05). Furthermore, results on one-and two-dimensional changes of DGT-labile P indicated that fertilization only in the wheat season produced sufficient amounts of labile P in the flooded paddy soils, similar to when fertilizer was applied only in the rice season;dissolved P concentrations, however, were lower. A co-occurrence and significant positive correlation(P < 0.01) between DGT-labile P and Fe indicated Fe-coupled mobilization of P in flooded paddy soils. These results collectively indicated that the DGT technique provided information on in-situ distribution of labile P and its variability in close proximity to rice roots. This suggests that the DGT technique can improve our understanding of in-situ and high-resolution labile P processes in paddy soils and can provide useful information for optimizing P fertilization.     

水稻生育后期根系响应氮肥调控的蛋白作用机制分析

以大穗型水稻‘金恢809’为试验材料,设置前氮后移(施氮量的30%作基肥,30%作蘖肥,30%作穗肥,10%作粒肥)及传统氮肥(施氮量的40%作基肥,30%作蘖肥,30%作穗肥)施用两种处理,并采用双向电泳技术分析了水稻生育后期根系对前氮后移调控的蛋白响应机制。通过构建的不同氮肥处理下水稻开花后15 d根系蛋白2-DE电泳图谱,并结合MALDI-TOF/MS分析,共成功鉴定到57个出现差异表达的蛋白,其中40个在前氮后移处理下上调表达,17个下调表达。依据其蛋白功能可以归为12类,主要涉及信号转导,氨同化,胁迫与防御,糖酵解,三羧酸循环,氨基酸代谢、蛋白合成及折叠等代谢途径。研究发现水稻生育后期根系GTP结合的核蛋白、GDP解离抑制因子、液泡型H+-ATP酶亚基C会响应氮肥的调控而出现表达变化,并将信号传递到电压依赖性离子通道蛋白、液泡型ATP酶亚基C以及膜联蛋白p35,进而调节根系细胞间物质运输与信息的传递。本研究结果还表明,前氮后移的施肥方式,通过适当增加水稻生育后期氮肥的施用,调节根系糖类转换、糖酵解及三羧酸循环相关蛋白的表达,增加了根系ATP的供应;通过增强根系中清除过氧化氢系统及防御相关蛋白的表达,延缓了根系的衰老;通过上调谷氨酸脱氢酶、天冬氨酸转氨酶和谷氨酞胺合成酶的表达丰度,促进了根系对土壤中氮元素的吸收与转运。研究结果对于进一步明确水稻根系响应氮素调控的分子生态特性具有重要的理论与实际意义。     

Improvement of phosphorus uptake, phosphorus use efficiency, and grain yield of upland rice (Oryza sativa L.) in response to phosphate-solubilizing bacteria blended with phosphorus fertilizer

Phosphorus (P) limitation in soil is a major concern for crop productivity. However, the use of chemical fertilizer is hazardous to the environment and costly. Therefore, the use of phosphate-solubilizing bacteria (PSB) is an eco-friendly approach for a sustainable agricultural system. In the present study, a field trial was conducted for two consecutive years to study the effects of three PSB strains isolated, Bacillus licheniformis, Pantoea dispersa, and Staphylococcus sp., with different P fertilizer rates on P uptake, P use efficiency (PUE), and grain yield of rice. The activities of soil enzymes were also studied in relation to PSB treatments. Comparative analysis of the yield and biochemical parameters revealed that inoculation of PSB consortium could reduce almost 50% of the recommended P dose in rice cultivation. Three PSB strains in combination with 50% P dose was most effective and showed the highest increases in P uptake and PUE as compared to the uninoculated control. Moreover, the PSB consortium combined with 50% P dose contributed to 50.58% and 35.64% yield increases compared to the uninoculated control for 2018 and 2019, respectively. Significant increases in the activities of soil dehydrogenase, alkaline phosphatase, and acid phosphatase were also recorded under PSB treatment.     

Si/As调控苗期水稻吸收、外排和转运砷的研究

通过生物模拟法,将水稻幼苗分别暴露于含有10μmol/L无机三价砷As(Ⅲ)或五价砷As(V)的营养液中12,24,48h,探究硅砷摩尔比(Si/As为0∶1,100∶1和200∶1)对苗期水稻吸收、外排、转运和累积砷的影响。结果表明,水稻暴露于含As(Ⅲ)营养液中12h,与Si/As为0∶1相比,Si/As为200∶1的处理使水稻的As(Ⅲ)吸收速率降低30.7%(P0.05),且随着暴露时间的延长,水稻对As(Ⅲ)的吸收速率逐渐降低,不同Si/As对其吸收速率的影响也减弱。处理48h,100∶1和200∶1的Si/As均降低水稻根部As(Ⅲ)向茎叶的转移系数,较Si/As为0∶1分别降低51.2%和56.9%,同时水稻地上部As(Ⅲ)含量比Si/As为0∶1的处理分别降低50.7%和67.2%;暴露在As(V)营养液中12h,Si/As为100∶1促进水稻对As(V)的吸收,增幅高达82.3%,但暴露24h,Si/As为200∶1则抑制水稻根系对As(V)的吸收,以及As(Ⅲ)的外排和As(Ⅲ)由水稻根系向茎叶的转运,降幅分别为28.0%,41.9%和39.9%。暴露48h时,Si/As为200∶1的水稻As(Ⅲ)转移系数较Si/As为100∶1的处理降低57.9%,并且处理24,48h时,Si/As为100∶1和200∶1水稻地上部As(Ⅲ)含量显著降低53.6%和75.0%,25.0%和52.8%。此外,水稻根系对As(V)的吸收与As(Ⅲ)的外排之间呈极显著正相关关系(r=0.921,P0.01),该关系不受Si/As和暴露时间的影响。无论是As(Ⅲ)或As(V)处理,在12～48h的暴露时间内,Si/As为200∶1显著抑制砷的吸收、As(Ⅲ)的外排和As(Ⅲ)在水稻体内的转运。