Foliage‐applied sodium nitroprusside and hydrogen peroxide improves resistance against terminal drought in bread wheat

Terminal drought is threatening the wheat productivity worldwide, which is consumed as a staple food by millions across the globe. This study was conducted to examine the influence of foliage‐applied stress signalling molecules hydrogen peroxide (H₂O₂; 50, 100, 150 μm ) and nitric oxide donor sodium nitroprusside (SNP; 50, 100, 150 μm ) on resistance against terminal drought in two bread wheat cultivars Mairaj‐2008 and BARS‐2009. These stress signalling molecules were applied at anthesis stage (BBCH 61); drought was then imposed by maintaining pots at 35% water holding capacity. Terminal drought caused significant reduction in grain yield of both tested bread wheat cultivars; however, foliage application of both stress signalling molecules at either concentration improved the performance of both bread wheat cultivars. Maximum improvement in 100‐grain weight (12.2%), grains per spike (19.7%), water‐use efficiency (WUE; 19.8%), chlorophyll content index (10.7%), total soluble phenolics (21.6%) and free leaf proline (34.3%), and highest reduction in leaf malondialdehyde contents (20.4%) was recorded when H₂O₂ was foliage‐applied at 100 μm . Foliage application of SNP enhanced the grains per spike, 100‐grain weight and grain yield by 14.9%, 11.3% and 20.1%, respectively, than control. The foliage‐applied stress signalling molecules improved the accumulation of soluble phenolics, proline and glycine betaine with simultaneous reduction in malondialdehyde contents, which enabled wheat plants to sustain the biological membranes under stress resulting in better stay green (high chlorophyll contents) under drought. This helped improving the grain number, grain weight, grain yield, WUE and transpiration efficiency. In crux, foliage‐applied H₂O₂ and SNP, at pre‐optimized rate, may be opted to lessen the drought‐induced yield losses in bread wheat in climate change conditions.     

秸秆深还机具特点和作业效率分析

秸秆深埋还田(秸秆深还)作为一种新兴的秸秆还田模式,其机具有别于地表覆盖还田和铧式犁翻压还田。为了科学管理、合理运用秸秆深还机械,提高机组的作业效率,在调查测试秸秆深还作业的基础上,对机具的特点进行了分析,同时对测试机组分别进行了时间利用率和作业效率分析。结果表明:对于各个机具的作业时间利用率和总作业效率影响因素有所不同。作业速度、幅宽、故障维修和地头转向是影响机械作业效率的主要因素。根据调查和分析的结果,针对秸秆深还作业中存在的问题提出了机组的合理运行模式。     

基于DEA方法的旅游经济效率分析——以海南为例

采用DEA(Data Envelopment Analysis)方法对海南旅游经济效率进行评价，并提出海南旅游投入的调整策略，以期让海南旅游发展更加合理，为旅游投资规划和产业结构调整提供可参考的依据。     

复杂疾病的遗传咨询技术

复杂疾病大面积爆发使人们的生活健康面临着重大挑战。在这一环境下,遗传咨询在人们的生活中占据了越来越重要的地位。依据基因与环境互作共同影响个体健康的原理,咨询者在遗传咨询师的指导帮助下合理解决各种遗传学问题可以有效降低复杂疾病的发病率。目前国内的遗传咨询发展尚处于萌芽期,随着遗传咨询在健康领域的地位上升,该技术在未来将会进一步推广应用。     

水稻卷叶突变体rlm1的基因克隆

叶片是植物光合作用的主要场所,优良的叶片形态有利于塑造理想的株型,提高光合效率。为了研究叶片形态建成的分子机制,自水稻T-DNA插入突变体库中筛选获得1个叶片半卷曲的卷叶突变体(roll leaf mutant,命名为rlm1),突变体rlm1主要特征为成熟叶片沿中脉向内卷,叶片最终卷成直立半圆筒状,叶片卷曲度达0.64,叶片直立参数达95,且光合效率显著优于野生型。通过图位克隆技术,确定突变体rlm1突变位点位于LOC_Os03g06654基因的第1个内含子,LOC_Os03g06654基因编码黄素单氧化酶(flavin-containing monooxygenase),RT-PCR表达分析表明LOC_Os03g06654基因因T-DNA插入而导致完全失活。该基因与已报道的水稻卷叶基因Os COW1(Constitutively Wilted 1)为等位基因,而且突变体rlm1所表现的农艺性状均佳,可期待利用该突变体进行高光合的育种实践。     

设施农业高效用水信息化发展及其技术体系探讨

发展设施农业用水信息化是提高水资源利用效率与效益,实现水资源优化配置的重要途径。在分析国内外设施农业用水信息化发展现状的基础上,结合信息化发展的需求,研究了设施农业高效用水信息化的技术体系,重点分析了基础数据的监测网络及共享平台、作物需水信息评价与检测、输配水系统的构成、功能及工作过程,旨在为提高设施农业用水信息化水平提供决策依据。     

Performance evaluation of venturi aeration system

The venturi aeration is an effective practice to increase the dissolved oxygen accessibility in the water bodies. This study aims to optimize the various geometrical parameters of the venturi aeration system. A non-dimensional technique was applied to find the optimum performance of various geometric parameters i.e. throat lengths (t_l), number of air holes (N), and converging and diverging angles (α and β). These experiments have been carried out using 1124 L capacity of tank having dimensions of 105 cm long, 105 cm wide and 102 cm deep. The experiments were conducted at a constant flow velocity of water (1.096 m/s) with varying throat length (t_l = 20–100 mm keeping 20 mm as interval between two consecutive length), number of air holes (N = 1–17 at an equal hole to hole distance of 5 mm between them), and converging and diverging angles (α and β = 10°, 15°, 20° and 25°). Multiple non-linear regression equations were also developed from the linear relation with the dependent variable (Non-dimensional form of standard aeration efficiency, NDSAE) and independent variables (t_l and N). With the geometrically optimized venturi aerator the optimum performance was found for t_l =100 mm, N = 17, and α and β = 15°. The maximum value of standard oxygen transfer rate (SOTR) and standard aeration efficiency (SAE) obtained was 0.0216 kgO₂/h and 0.611 kgO₂/kWh respectively. From the non-dimensional study, it was found that the NDSAE is the function Reynolds number (Re) and Froude number (Fr). The simulation equations were developed on the basis of Re and Fr for NDSAE, and subjected to 7.378 × 10⁻⁶ < Re < 3.689 × 10^-5 and 0.163 < Fr < 0.817, respectively.     

水稻高产、优质和氮高效协同的氮素调控研究

以超级粳稻‘新稻18号’为试验材料,大田条件下,研究不同施氮量(0、232.5、255.0、277.5、300.0、322.5和345.0kg/hm2纯氮水平)对水稻产量、品质及氮肥吸收利用效率的影响,以明确高产、优质和氮高效协同的适宜氮素水平。结果表明,随氮素水平提高,水稻产量、稻米品质和氮肥吸收利用效率均呈先增后降趋势。施氮量为255.0kg/hm2纯氮处理下,产量最高为9 878.11kg/hm2,稻米的糙米率、精米率和整精米率较高,分别为84.81%、72.85%和66.94%,垩白粒率和垩白度较低,分别10.00%和2.86%,氮肥吸收利用效率较高,为41.34%。低氮肥和高氮肥处理,产量、品质和氮肥利用效率相对较低。说明,在适宜的氮肥水平下,水稻高产、优质和氮高效可达到协同一致。     

Nitrogen use efficiency of cotton (Gossypium hirsutum L.) as influenced by wheat–cotton cropping systems

Wheat–cotton rotations largely increase crop yield and improve resources use efficiency, such as the radiation use efficiency. However, little information is available on the nitrogen (N) utilization and requirement of cotton under wheat–cotton rotations. This study was to determine the N uptake and use efficiency by evaluating the cotton (Gossypium hirsutum L.) N use and the soil N balances, which will help to improve N resource management in wheat–cotton rotations. Field experiments were conducted during 2011/2012 and 2012/2013 growing seasons in the Yangtze River region in China. Two cotton cultivars (Siza 3, mid-late maturity with 130 days growth duration; CCRI 50, early maturity with 110 days growth duration) were planted under four cropping systems including monoculture cotton (MC), wheat/intercropped cotton (W/IC), wheat/transplanted cotton (W/TC) and wheat/direct-seeded cotton (W/DC). The N uptake and use efficiency of cotton were quantified under different cropping systems. The results showed that wheat–cotton rotations decreased the cotton N uptake through reducing the N accumulation rate and shortening the duration of fast N accumulation phase as compared to the monoculture cotton. Compared with MC, the N uptake of IC, TC and DC were decreased by 12.0%, 20.5% and 23.4% for Siza 3, respectively, and 7.3%, 10.7% and 17.6% for CCRI 50, respectively. Wheat–cotton rotations had a lower N harvest index as a consequence of the weaker sink capacity in the cotton plant caused by the delayed fruiting and boll formation. Wheat–cotton rotations used N inefficiently relative to the monoculture cotton, showing consistently lower level of the N agronomic use efficiency (NAE), N apparent recovery efficiency (NRE), N physiological efficiency (NPE) and N partial factor productivity (NPFP), particularly for DC. Relative to the mid–late maturity cultivar of Siza 3, the early maturity cultivar of CCRI 50 had higher N use efficiency in wheat–cotton rotations. An analysis of the crop N balance suggested that the high N excess in preceding wheat (Triticum aestivum L.) in wheat–cotton rotations led to significantly higher N surpluses than the monoculture cotton. The N management for the cotton in wheat–cotton rotations should be improved by means of reducing the base fertilizer input and increasing the bloom application.     

Achieving legislation requirements with different nitrogen fertilization strategies: Results from a long term experiment

The Nitrates Directive (91/676/EEC, Anonymous, 1991) was developed in Europe to limit environmental threats from intensive livestock farming and N fertilizer applications to crops. It imposed several rules on farmers and public bodies, one of which was nutrient fertilization plan adoption. Here we use results from the Tetto Frati (Northern Italy) Long-Term Experiment to verify the terms and coefficients in the official Italian guidelines and evaluate the limitations imposed to organic fertilization amounts. For this purpose, we mined long-term experimental data of crop yield, N uptake, N use efficiency, and soil organic matter content from miscellanea cropping systems fertilized with farmyard manure (FYM) and bovine slurry (SLU), typical of a dairy farm in Northern Italy. N fertilization efficiency indicators (Removal to Fertilizer ratio, Apparent Recovery and Nitrogen Fertilizer Replacement Value) indicated that in the long run, FYM behaved similarly to urea, and better than SLU. Even N supply rates as high as 250 kg N ha⁻¹ were justified by high rates of crop removal. In fact, among the terms of the mass-balance equation, SOM mineralization was found to be most relevant, followed by meadow rotation residual effects. We conclude that a revised Nitrates Directives application scheme could be more relaxed in its application limit of manure-N, but should be more ambitious in setting efficiency coefficients for manure fertilization.