东北三省玉米气候适宜度变化分析

利用东北三省25个农业气象观测站平均资料及176个气象站1961～2007年的逐日气象资料,对玉米全生育期及各主要玉米生育阶段的气候因子及综合气候适宜度进行计算分析。结果表明,自1961年以来,玉米各发育期对气候因子适宜程度不同,播种期-出苗期、出苗期-开花期、开花期-成熟期温度适宜度呈上升趋势,日照适宜度呈下降趋势;播种期-出苗期降水呈上升趋势,其余各生育期降水均为下降趋势。玉米全生育期降水、日照适宜度呈下降趋势,温度适宜度呈上升趋势,综合气候适宜度东北三省均呈下降趋势。各气候因子组合效果较好,玉米产量与各生育阶段的不同气候因子的适宜度相关性差异较大。     

Chemical management of Fusarium wilt of watermelon

Watermelon yield loss due to Fusarium wilt is increasing in the U.S., due in part to the emergence of the virulent race 2 of Fusarium oxysporum f. sp. niveum, and to the shift in production to triploid cultivars, which generally have less host resistance than previously grown diploid cultivars. One potential management strategy is the use of soil-applied fungicides to reduce Fusarium wilt. The U.S. national program, interregional project 4 (IR-4) supported multistate trials of soil-applied chemicals to manage Fusarium wilt of watermelon. Greenhouse trials were conducted in Maryland, Indiana and Georgia to test the efficacy of 14 chemicals on Fusarium wilt. Based on the performance of these chemicals in the greenhouse, six in Maryland and Delaware and eight in Indiana were selected for subsequent field evaluations. These chemicals were applied once, as a drench at planting, in field trials in Maryland, Indiana, and Delaware in 2008. The fungicides prothioconazole, acibenzolar-S-methyl, and thiophanate-methyl resulted in the greatest reduction in Fusarium wilt, and caused no phytotoxicity. In Maryland and Indiana in 2009, these chemicals were applied through the drip irrigation line alone and in combination, at 0, 2 and 4 weeks after planting. The experiment was repeated in 2010 in Maryland. Prothioconazole alone and in combination with acibenzolar-S-methyl or/and thiophanate-methyl resulted in the greatest decrease in the area under the disease progress curve (AUDPC) of Fusarium wilt of watermelon in Maryland in 2009. The same trend was observed in 2010 in Maryland where three of the prothioconazole treatments ranked the lowest of all treatments and prothioconazole in combination with thiophanate-methyl had significantly lower Fusarium wilt AUDPC compared to the non-treated control. All chemical applications except for acibenzolar-S-methyl in combination with prothioconazole reduced Fusarium wilt AUDPC in Indiana in 2009. Prothioconazole alone and prothioconazole in combination with thiophanate-methyl ranked lowest in Fusarium wilt AUDPC, although not significantly lower than most other treatments. These studies are the first to demonstrate that the soil-applied fungicides prothioconazole and thiophanate-methyl may provide an additional field management option for Fusarium wilt of watermelon.     

Mechanism of action of insecticidal secondary metabolites of plant origin

Insect pest management is facing the economic and ecological challenge worldwide due to the human and environmental hazards caused by majority of the synthetic pesticide chemicals. Identification of novel effective insecticidal compounds is essential to combat increasing resistance rates. Botanicals containing active insecticidal phytochemicals appear to be promising to address some of these problems. Therefore, there is a continuous need to explore new active molecules with different mechanisms of action. Secondary metabolites present in plants apparently function as defense (toxic), which inhibits reproduction and other processes. The phytochemical biomolecules could be used for maximizing the effectiveness and specificity in future insecticide design with specific or multiple target sites, while ensuring the economic and ecological sustainability. In this article, the current state of knowledge on phytochemical sources and insecticidal activity, their mechanism of action in insects, resistance, and promising advances made in phytochemical research are reviewed.     

Rheology of Mixtures of Glutenin Subfractions

The dynamic rheological behaviours of mixtures of glutenin fractions extracted from wheat cultivar Hereward were investigated as a function of the relative concentration of high to low molecular weight glutenin concatenations. Time-temperature superposition could be applied to both the mixtures and to the total gluten, as long as heat-treated samples were distinguished from unheated samples. The ratio of high to low molecular weight concatenations was found to be very important for the rheological behaviour of the network. High molecular weight fractions promoted the network properties of the mixture, as could be seen from the presence of a plateau in the rheological spectrum. Low molecular weight fractions gave rise to a plasticizing effect as indicated by their narrowing effect on the width of the plateau region in the rheological spectrum. Upon heating, the modulus increased over the full range of frequencies, as for single fractions. This increase indicated that a thermal association occurred in the concatenations at temperatures around 40 °C. As a result of heating, the transition zone became apparent in the spectrum at high frequencies. The slopes of the loss modulus G” in the transition zone were found to be higher for mixtures rich in low molecular weight concatenations. The effect of the relative abundance of each fraction on the rheological characteristics of the mixtures was summarized in a number of simple rheological blending rules for the small-deformation rheological properties of glutenin.     

不同基因型冬小麦冠层温度与产量性状的关系

为分析小麦冠层温度与产量性状的关系,选用55个不同基因型冬小麦品种(系),在灌溉条件下研究了不同冬小麦基因型产量性状,冠层温度差异及二者的相关性.结果表明,基因型间冬小麦的冠层温度在开花期、花后7 d、花后21 d和花后28 d均存在极显著差异.除花后21 d外,不同测量时期在重复间也均有极显著差异.开花期和花后21 d的冠层温度分别与穗数和穗粒数呈显著相关,灌浆期间冠层温度与千粒重呈显著或极显著相关.冠层温度与产量的相关性依次为花后7 d>花后21 d>开花期>花后28 d>花后14 d>抽穗期,其中花后7 d和21 d的冠层温度与产量呈极显著相关(P<0.01).冠层温度在灌浆中后期持续偏低与冬小麦绿叶功能和衰老机制的延缓有密切关系,可用于鉴定冬小麦产量潜力.     

芦笋枯萎病病原鉴定

对造成福建省漳州市东山县的芦笋枯萎病病原菌进行分子鉴定,以期确定病原菌的属、种名,为防治该病害寻求理论依据。试验对分离纯化的病原菌核糖体DNA的ITS区进行测序,在Genbank中搜索其同源性并构建它们的系统发育树,结果表明：引起芦笋枯萎病的病原菌是镰刀属中的尖孢镰刀菌(Fusarium oxysporum),且病原菌之间的同源性高达89%,遗传差异不显著。     

Some biochemical aspects of the efficiency of plants

The chemical composition of seeds can vary enormously with respect to the major constituents, oil, carbohydrate and protein. Thus oil can vary from about 2% to 70%, carbohydrate from 5% to 80% and protein from 3% to 50% in different seeds. During evolution the pathways of seed metabolism in different crops have taken diverse routes all of which are compatible with seed function. Nevertheless, these differences have important inferences for the dietary value of a particular crop. The breeder in striving to increase yields has furthermore selected for biochemical and physiological characteristics which can lead to constraints to further improvements as expressed for example in the negative correlations between yield and protein content and between yield and protein quality. This paper examines the biochemical pathways involved in seed metabolism and calculates the efficiency of utilisation of input materials both with respect to the total and the ‘useful’ components of the grain using stoichiometric considerations. Constraints due to controlling reactions in biochemical pathways, those due to inefficient biochemical synthetic routes and limitations due to inputs into the seed, will be analysed. Kinetic as well as thermodynamic constraints will be considered such as those due to varying ammounts, activities or locations of enzymes. Particular emphasis will be placed on protein metabolism.     

水稻抗旱性的研究进展

随着全球水资源的日益匮乏和旱灾的日趋严重,水资源短缺正成为制约我国农业发展的重要因素。培育抗旱栽培稻品种并实现水稻旱种,不但可较大程度地节约水资源,且有利于稳产增产、节约能源和减少环境污染,故栽培稻的抗旱性研究作为稻作科学研究的重要课题显得愈来愈重要。本文从水稻抗旱性鉴定形态指标、生理指标和分子标记研究三方面分别概述,并对今后水稻抗旱性方向进行了探讨。     

中国水稻生产形势分析

对1991-2007年中国各省(区、市)水稻生产统计数据进行分析,结果表明:1991-2007年中国水稻种植面积总体呈现下降趋势,从1991年的3 259.01万hm~2下降到2007年的2 891.90万hm~2,下降幅度达到11.26%;水稻单产从1991年的5 745 kg/hm~2上升到2007年的6 433 kg/hm~2,上升幅度11.98%,单产的提高在一定程度上确保了水稻总产变化相对平稳;东部经济发达地区水稻种植面积明显下降,中部和西部变化相对平稳;南方水稻种植面积明显下降,东北地区明显上升,华北、西北地区小幅下降;南方地区单季稻比例快速上升,双改单现象明显,这是导致中国水稻种植面积下降的重要原因.要保证全国水稻生产平稳发展,重点在于稳定南方水稻种植面积,一要加大耕地保护力度,二要合理处理粮食作物与非粮食作物之间的结构调整,三是稳定双季稻种植面积.目前的工作重点是要稳定湖南、江西等水稻种植大省的双季稻种植面积.     

《生物安全法》实施背景下基因编辑技术的安全评价与监管

2020年10月17日,《中华人民共和国生物安全法》(以下简称《生物安全法》)通过全国人大常委会的审议,自2021年4月15日起施行.生物技术的研究与应用安全是《生物安全法》涉及的主要内容之一,基因编辑作为近几年生物技术领域的研究热点,其安全性评价和监管备受关注.本文概述了基因编辑技术的应用现状,比较了不同国家对基因编...     

Evaluation of an avirulent strain ofPseudomonas solanacearum for biological control of bacterial wilt of potato

An avirulent strain ofPseudomonas solanacearum, B82, was tested for its ability to protect the potato cultivar, Ontario, from bacterial wilt caused by virulent strains of this bacterium. Strain B82 was not antagonistic to 124 virulent strains ofP. solanacearum and was not bacteriocinogenic. When potato seedpieces were soaked for 5 hr in suspensions of B82 (10⁸ to 10⁹ cfu/ml), reduction in disease severity (up to 50%) was noted in some experiments. The treated plants, grown in the greenhouse or growth room for 4–5 wk, were challenged by stem inoculation, soil drenching, or root-to-root infection with virulent strains (276 or Br5) of the bacterium. Protection was not obtained consistently, however, and much of the variability could be attributed to differences in ambient temperature and light conditions in the greenhouse between experiments. In general, high ambient temperatures and/or reduced sunlight resulted in no protection. Protection appeared to depend on the ability of strain B82 to multiply in the vascular system in the crown region and to colonize the rhizosphere of treated plants. Soil temperatures above 24 C affected the ability of strain B82 to survive in the rhizosphere. The close dependence of protection on environmental conditions suggests that this method of control may not be practical under field conditions.     

Volume of individual internodes of sugarcane stalks

Sugarcane (Saccharum spp.) is rather unusual among field crops in that it is not the seed that is of economic value, but rather the stalk. Sucrose is extracted from the large stalks that are produced by sugarcane plants. Considering their economic value, it is rather surprisingly that there is very little information concerning the development and size of the individual internodes over the length of sugarcane stalks. The objective of this study was to document internode volume over the sugarcane stalk of four cultivars and to observe changes in individual internode volume later in the growing season and in response to lodging. When harvested in August, the size of the internodes varied in a continuous manner along the stalk with the largest internode occurring at the bottom of the plant at approximately internode #15. One cultivar (CP80-1743) had much less of a decrease in internode volume below internode #15 than the other cultivars, indicating that growth was more concentrated in the lower internodes of this cultivar. Since the internode volume diminished as the apex was approached, much of the harvested material was concentrated in the bottom nodes. Comparison of a mid-season harvest (August) and a final harvest (January) indicated both that additional internodes were added to the stalk and that the size of all internodes increased. That is, plant growth was distributed all along the stalk and not focused on one particular zone. Similarly, the negative impact of plant lodging was uniformly distributed over the entire stalk, although there appeared to be differences in cultivars in the extent to which the growth of the stalk was decreased.     

Simulation of production potential of self-defoliating sugarcane cultivars

Cane burning before harvest is increasingly questioned due to environmental concerns. Harvesting of un-burned or green cane, whether by mechanical or manual means, increases trash delivery to the sugar mills with consequent losses in sugar recovery and increased transport costs. The self-defoliating trait, in which the leaves fall naturally as the cane matures, offers the potential to facilitate green cane harvesting. The effects of the self-defoliating character on cane production and sugar concentration had not been determined. Trials were superimposed on commercial cane of two cultivars (CC 85-63 and V 71-51), in which leaves were artificially removed to simulate the self-defoliating character. The two cultivars responded differently to the leaf removal treatments. CC 85-63 with only four leaves per stem produced similar levels of cane with similar sugar concentration to the controls with 10 leaves per stem. In V 71-51, cane production decreased as leaf number per stem decreased from eight leaves per stem found in the controls. Nevertheless, in both cases, high levels of productivity of more than 16 t recoverable sugar/ha in 13 months were obtained with only four leaves per stem in both cultivars. In CC 85-63, net photosynthetic rate of individual leaves increased as leaf number per stem was reduced, whilst in V 71-51 no compensation was observed. Lodging in both cultivars tended to be less as leaf number per stem decreased. The results indicate that breeders can develop self-defoliating cultivars with a minimum of 4 to 6 leaves per stem, which are highly productive in terms of total sugar production and which also maintain acceptable levels of recoverable sugar.     

The effect of nitrogenous fertilizer on the photosynthesis of leaves of a ryegrass sward

The addition of nitrogenous fertilizer to a newly cut, N-deficient ryegrass sward resulted in an increased photosynthetic capacity in the next leaf to expand, showing that greater photosynthesis per unit leaf area as well as greater leaf area contributes to the increased growth of fertilized swards. Later in the 4-week growth period there was little difference in photosynthetic capacity between fertilized and unfertilized swards.     

黑龙江省不同生态区玉米杂交种主要农艺性状的遗传相关与通径分析

运用SPSS18.0对不同生态区玉米杂交种产量与主要农艺性状中的生育期、株高、穗位高、穗长,穗粗、秃尖长、穗行数、行粒数、百粒重和出籽率关系进行逐步回归分析和通径分析。结果表明,根据积温、地理和气候条件,黑龙江省试验二区在品种选育上应着重选择粗穗、长穗、行多和出籽率高的品种;黑龙江省试验四区在品种选育上应着重选择生育期适当、低穗位高和适当提高株高的品种;黑龙江省试验五区在品种选育上应着重选择粗穗、长穗、出籽率高和封顶性好的品种;黑龙江省试验六区在品种选育上应着重选择中长穗和封顶性好的品种。     

Influence of ethylene on black spot of potato tubers

Sound, hand harvested, whole potatoes were exposed to continuous flowing atmosphere containing air, air with 3 or 5% CO₂, and air with concentrations of 0.5, 1.0, and 10ppm C₂H₄ for periods of 1 to 11 days at 20°C. At 1-day intervals, potatoes were bruised and black spot development assessed. Development of black spot in potatoes exposed to C₂H₄ was equal to or less than in potatoes at harvest. The severity remained low during 3-day exposure to 1 ppm C₂H₄ and after transfer to 4 days in air, then increased. Severity of black spot increased in potatoes exposed to air, with intermediate response from exposure to air with CO₂. With an increase in sprouting, differences in black spot among treatments diminished. Less black spot developed in immature than in mature potatoes.     

四川盆地东南部再生稻开花期受低温冷害的风险预测

为准确预测不同区域再生稻开花期受自然低温冷害的风险程度，并为开花期耐低温冷害品种的合理布局与制定相应的避（缓）高产稳产技术提供科学依据，于2018年和2019年，以近几年四川省推广的22个杂交中稻品种为材料，分别在四川盆地东南部不同生态点开展试验，研究了基于经度、纬度和海拔高度的再生稻开花期受自然低温冷害风险的预测方法。结果表明，再生稻齐穗后第5日日序与经度呈显著负相关，与海拔呈极显著正相关；建立了基于经度和海拔高度预测再生稻齐穗后第5日日序的回归模型，F检验值为22.88**～65.11**,决定系数高达0.9196～0.9702。该模型经多个品种连续两年在6个生态点验证，实测值与预测值1∶1回归模型的决定系数高达0.8391～0.8638，实测值与预测值之间的均方根差（RMSE）值为0.93%～1.21%，预测值与实测值之间具有较好的一致性。将本研究建立的再生稻齐穗期与地理位置关系模型与作者等先期建立的基于地理位置（纬度、海拔）预测≤22℃最早发生期预测模型相结合，探明了不同地理位置再生稻开花期受低温冷害的机率。利用地理位置信息可准确预测再生稻开花期受低温冷害的风险程度，具有较强的...     

芸薹属种子贮藏蛋白质亚基构成及亲缘关系分析

采用线性梯度SDS－PAGE分析芸薹属4个种17个品种（系）的种子贮藏蛋白亚基组成，表明种子贮藏蛋白比较复杂，共有58条带，分子量范围是8000～300000D，不同种不同品系带型不同，种间差异主要表现在8000～70000D之间，品种（系）的差异主要在70000～300000D之间，相似度指数也表现出同种内不同的品种之间相似度高，种内品种间相似度大于种间。     

施氮次数对无刺卡因菠萝产量和品质的影响研究

选用无刺卡因菠萝,采用大田试验,固定N肥施用水平(400 kg/hm2),从0至4依序增加施肥次数,分析施氮次数对菠萝产量和品质的影响.结果表明:2次平均分施对增加无刺卡因的产量最适宜,在此基础上,增加或减少施氮次数都会造成单果重和产量的下降;就品质而言,增加N的施肥次数将导致可滴定酸、含糖量和Vc含量下降,不利于保持卡因的品质.本研究为果农从事无刺卡因菠萝的优质栽培提供施肥参考.     

Comparative analysis of temporal changes of multifunctionality benefit of two major rice paddy plains in Taiwan

Recently, free trade of farm land, changes of agricultural policy and global climate changes have resulted a significant reduction of rice planting area and the multifunctionality values of paddy field in Taiwan. This study aims to evaluate the temporal changes of multifunctionality benefit of two major rice paddy plains in Taiwan. The main agricultural production regions of the Chou-Shui river alluvial fan and Ping-Tung plain are selected for the comparative study. The replacement method is adopted to quantify the multifunctionality of the paddy field. The results show that percentage of cultivated paddy to the total paddy gradually decreases from 92 to 80% and the external value remains from 572,000 to 668,000 NT$/ha in the Chou-Shui river alluvial fan. Whereas, the percentage of area of cultivated paddy to the total paddy markedly decreases from 37 to 23% from 1999 to 2006 and resulting the external values of paddy only ranges from 156,000 to 258,000 NT$/ha in the Ping-Tung plain. To maintain the sustainable agriculture in the paddy field, government needs to formulate incentive policy to conserve the paddy farming, promote, and transmit the general understanding of the environmental and living-hood multifunctionality values to the people.