油菜素内酯调控植物响应非生物逆境胁迫的生理机制

油菜素内酯属于甾体类激素中的油菜素甾醇类物质，是其生物合成中产生的活性副产物，对植物生长发育具有重要的调节作用。在非生物胁迫条件下，外源施用油菜素内酯可以增强植物的抗氧化系统，增加渗透物质水平，维持内源激素平衡，稳定离子和水分平衡，改善气体交换属性和光合作用，最终减轻逆境危害并促进植物生长。该文综述油菜素内酯对非生物胁迫下植物生长、生理调节的影响及调控途径，对油菜素内酯提高植物抗逆境能力的未来研究方向进行展望。     

新型植物生长调节剂——天丰素

天丰素的有效成份是油菜素内酯（简称表－ＢＲ），具有良好抑制植物某些酶的活性，除能抑制植物氧化酶与水解酶的活性外，还能增强植物呼吸和调节内源激素的平衡，提高植物的免疫功能和起到抗逆性作用；促进植物对营养物质的吸收、运转、提高光合作用的速率，使植物组织保...     

干旱胁迫下油菜素内酯对文冠果苗木抗氧化酶活性和抗氧化剂含量的影响

用蘸根和叶面喷施不同浓度油菜素内酯(BRs)的方法,在人工控制土壤水分条件下,对黄土高原重要造林树种文冠果苗木重要的抗氧化酶活性和抗氧化剂含量变化进行研究。结果表明,用0.05~0.4 mg/L BRs处理文冠果苗木,超氧化物歧化酶(SOD)活性在中度干旱胁迫下较清水对照增加,但差异不显著,重度胁迫下增加显著;在中度和重度胁迫下,各处理文冠果苗木过氧化氢酶(CAT)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)活性均较清水对照升高,且差异显著;在中度和重度胁迫下,5个浓度BRs处理对抗坏血酸(ASA)和还原型谷光甘肽(GSH)含量均具显著的增加效应。轻度和重度胁迫下,0.2 mg/L BRs处理对文冠果苗木抗氧化酶活性和抗氧化剂含量的增加效应均最为显著。     

新型植物激素—油菜素内酯类在农林上的应用研究进展

油菜素内酯类是一种新型的植物激素,近几年来,随着油菜内酯的工业化生产,试验研究不断深化,在农林上的应用也逐渐增加,取得了一些新的研究成果,本文主要介绍了油菜素内酯提高种子活力和发芽率,促进作物和树木的生长发育,增产效果以及在环境胁迫条件下的应用研究进展。     

天然油菜素内酯对黄土丘陵区富士苹果几种生理指标的影响

采用叶面施肥的方法,初步研究了叶面喷施4种不同浓度的天然油菜素内酯后,苹果叶片内叶绿素色素(Chl)、类胡萝卜素色素(Car)、游离脯氨酸(Pro)、丙二醛(MDA)、超氧化物歧化酶(SOD)和过氧化物酶(POD)等有关生理指标以及单株产量的变化。结果表明,喷施4种浓度的天然油菜素内酯后,MDA含量明显降低,SOD和POD活性显著增强,叶绿素色素含量、类胡萝卜素色素含量和游离脯氨酸含量都有显著提高,且0.2mg/L的处理增产效果最为明显。     

芸苔素内酯在小麦上的应用效果

芸苔素内酯属激素类植物生长调节剂,可广泛应用于多种阔叶作物,如棉花、烟草及各种果蔬,均可有效地促进作物生长、提高产量,增强作物抗逆性。为了解芸苔素内酯在禾谷类作物上的应用效果,我们于2007年4—6月在武汉市江夏区五里界镇民主村进行了0．01％芸苔素内酯在小麦上的田间试验,并取得了较好的应用效果,增产4．93％～7．69％。现将试验结果整理如下。     

植物生长调节剂对烟草生长发育及钾素吸收与分配影响研究

通过盆栽试验,采用不同钾素水平,在烟草植株打顶后夹吸不同的植物生长调节剂对烟草生长发育进行研究。研究表明,不同钾水平对烟草植株的株高、最大叶面积、根体积、倒二叶叶面积均没有显著的促进作用,但是能够显著增加根鲜重,而烟株打顶后夹吸生长调节剂能显著地促进烟草植株的株高、最大叶面积、根体积、根鲜重、倒二叶叶面积的增长。同时,植物生长调节剂能明显提高不同部位烟叶中的钾含量和各部位钾素的积累量,促进钾素从根、茎部向叶部的转移,显著提高烟草的品质,其中表油菜素内酯(BR)与赤霉素(GA3)处理效果最为明显。     

植物生长调节剂的使用技术和使用误区

植物生长调节剂是用于调节植物生长发育的一类农药,是从植物体内直接提取的天然植物激素或者模拟植物内源激素人工合成的化合物。具有调控植物生长发育功能物质的调节剂有生长素、赤霉素、乙烯、细胞分裂素、脱落酸、油菜素内酯、水杨酸、茉莉酸和多胺等,在农业生产中主要应用的是     

油菜素内酯对三个树种苗木抗旱性影响的综合评价

采用盆栽控水模拟土壤干旱环境,根系浸蘸和叶面喷施不同浓度的油菜素内酯(BR)溶液,对黄土丘陵区3个主要造林树种沙棘(Hippophae rhamnoides L.)、山杏(Prunus armeniaca L. var.ansu)、紫穗槐(Amorpha fruticosa L.)苗木20项抗旱性指标进行了测定,应用主成分分析法对3种苗木受油菜素内酯影响的抗旱性变化做了多指标的综合评价.实验结果显示当BR施用浓度在0.1-0.3 mg/L时,对3种苗木抗旱性影响的有效值均高于对照,其中能够有效提高3种苗木抗旱性的BR最佳施用浓度为0.2 mg/L.     

油菜素内酯提高水稻抗病性的分子机制

<正>油菜素内酯(brassinosteroid,BR)是植物生长发育所必需的一类甾醇类激素,在抗病毒、病菌等方面起着重要作用。Nakashita et al.(2003)发现BR能诱导水稻对烟草花叶病毒(Tobacco mosaic virus,TMV)、稻瘟病菌Pyricularia grisea和水稻白叶枯病菌Xanthomonas oryzae产生广谱抗性。为探明BR提高水稻抗病性的分子机制,本试验利用双向电泳技术筛选受BR调控的在抗病过程中起重要作用的蛋白质,通过     

Studies on regulation of plant physiology by pesticides

Some agrochemicals have unique activities on plant, which modes of actions differ from those of herbicides and plant growth regulators. Because these induce useful and important phenotypic characteristics by activating physiological mechanisms in plant cell, understanding the underlying mechanism of their activities should be crucial for plant physiology and agriculture. As examples of such agrochemicals, studies on agrochemicals that activate the plant immune systems or root elongation, are described. Plant activators, inducers of systemic acquired resistance, were divided into two types, acting on upstream and downstream of salicylic acid (SA) biosynthesis, respectively. They have been useful research tools to clarify the regulation mechanism of SA-mediated disease resistance and to investigate another type of disease resistance mechanism mediated by brassinosteroids. By analyzing the roles of phytohormones in the isoprothiolane-induced root elongation indicated a positive effect of jasmonic acid and ethylene on primary root elongation. These types of research, categorized to one of chemical biology, would provide novel insight into plant physiology, which also contribute to control of crops.     

Ameliorative Effects of Brassinosteroids on Growth and Productivity of Snap Beans Grown Under High Temperature

The effect of brassinosteroids (BRs) was tested, in order to assess the possibility of alleviation of the adverse effects of high temperature stress on snap bean plants during delayed summer cultivation. Therefore, two field experiments were carried out in successive seasons, 2010 and 2011, with two bean cultivars ‘Paulesta’ and ‘Oxzira’, spraying with BRs of the following concentrations 0 (control), 25, 50 and 100 ppm. Plant growth, yield and pods quality of beans were studied. Spraying bean plants with BRs at a concentration of 25 and 50 ppm increased vegetative growth, total yield and quality of pods with no significant difference between both treatments. Using BRs at 25 ppm increased the total free amino acids (FAA) in leaves and total phenolic acids in the pod in comparison to control-treatment. ‘Oxzira’ cultivar resulted in the highest number of leaves, number of branches, dry weight of whole plant, total yield, total FAA in leaves and total phenolic acids in pod. Whereas, ‘Paulesta’ cultivar had the highest of plant length and total FAA in pods.     

Significant plant virus diseases in India and a glimpse of modern disease management technology

India has a diverse agroclimate representing tropical, subtropical and temperate climates with zones ranging from average to high in temperature, humidity and rainfall; from low to scarce rainfall in deserts to cold to very cold plains and upland areas. Thus it is the home of one of the richest flora and fauna in the world. For pests and pathogens, too, tropical and subtropical climates are ideal for growth and development. A majority of the world’s fruits, vegetables, cereals, pulses, oil seed crops, fiber crops, sugarcane, spices, and ornamentals are cultivated in India. Virus diseases and their vectors are also in abundance. Since ancient times, virus-like diseases and management practices have been known in India. This knowledge has now been revived and adopted in organic farming, especially for medicinal and aromatic plants. Current trends for extensive and intensive agriculture, open international agricultural trade, and thus food security and sustained economy have brought new challenges in the fight against virus diseases. In this changing scenario, current diseases of significance are caused by begomoviruses, badnaviruses, cucomoviruses, potyviruses, ilarviruses in crops such as vegetables, fruits, ornamentals, fiber crops, and sugarcane. Variability in the viruses is also common. Briefly reviewed here is the positive effect of an isolate of Rice necrosis mosaic virus; when artificially inoculated on jute and mesta fiber crops enhanced their fiber contents. Diseases of significance, e.g., leaf fleck disease of sugarcane, citrus yellow mosaic disease, banana bunchy top, banana bract mosaic, mungbean yellow mosaic, mosaic in chrysanthemum, gladiolus and orchids are also discussed. Efficient, reliable diagnostic tools have been developed and used extensively. Some of the advanced laboratories have been accredited for virus indexing under the National Certification System for tissue-cultured plants. International standards for phytosanitary measures have been promulgated, and a mandatory nodal agency is in place for the conservation and exchange of germplasm; a Containment Level-4 facility to examine incoming transgenics and a fully equipped laboratory to intercept virus-infected plant material are functional. A National Agricultural Biosecurity System will soon be in place. All these measures are essential to protect agricultural systems and to compete in the international agriculture market. Continued vigilance, disease mapping and adopting the latest technology are required to practice sustainable agriculture.     

Weed Problems in Food Crops in Indonesia

Abstract

Losses due to weeds in food crop production are discussed. Types of weeds differ from one crop to another; environmental conditions, crop management and other factors affect weed growth.

Hand weeding is practised on small farms, even in upland crops where weed problems are more complicated. Some experiments with herbicides on food crops have been introduced by various institutions. Due to the rising cost of labour, especially on large-scale mechanised farms, chemical weed control will become more important.

It is suggested that applied research in new methods of weed control as well as basic research in weed biology related to agriculture should be encouraged.     

Replacing methyl bromide in annual strawberry production with glucosinolate-containing green manure crops

The use of biocidal green manure crops is an agronomic technique for amending soil with fresh organic matter containing volatile compounds active in controlling some soil-borne pests and diseases. Two new selections of the Brassicaceae family were cultivated, incorporated before planting strawberries and tested as an alternative to fumigation with methyl bromide. Two biocidal green manure crops (Brassica juncea L sel ISCI20, Eruca sativa Mill cv Nemat) containing glucosinolate-myrosinase systems, a conventional green manure (barley), untreated soil and a fumigated control were evaluated during two seasons. The effect of these soil management systems on subsequent strawberry performance was evaluated by monitoring yield and plant growth parameters. In both years, biocidal plant green manure treatments led to a fruit yield lower than with methyl bromide, but higher than with conventional green manure or untreated soil. These results confirm the good prospects for biocidal green manures, not only as an environmentally friendly alternative to methyl bromide in conventional agriculture, but also in organic agriculture as an alternative to conventional green manure crops.     

Herbicide-resistant crops and weed resistance to herbicides

The adoption of genetically modified (GM) crops has increased dramatically during the last 3 years, and currently over 52 million hectares of GM crops are planted world-wide. Approximately 41 million hectares of GM crops planted are herbicide-resistant crops, which includes an estimated 33.3 million hectares of herbicide-resistant soybean. Herbicide-resistant maize, canola, cotton and soybean accounted for 77% of the GM crop hectares in 2001. However, sugarbeet, wheat, and as many as 14 other crops have transgenic herbicide-resistant cultivars that may be commercially available in the near future. There are many risks associated with the production of GM and herbicide-resistant crops, including problems with grain contamination, segregation and introgression of herbicide-resistant traits, marketplace acceptance and an increased reliance on herbicides for weed control. The latter issue is represented in the occurrence of weed population shifts, the evolution of herbicide-resistant weed populations and herbicide-resistant crops becoming volunteer weeds. Another issue is the ecological impact that simple weed management programs based on herbicide-resistant crops have on weed communities. Asiatic dayflower (Commelina cumminus L) common lambsquarters (Chenopodium album L) and wild buckwheat (Polygonum convolvulus L) are reported to be increasing in prominence in some agroecosystems due to the simple and significant selection pressure brought to bear by herbicide-resistant crops and the concomitant use of the herbicide. Finally, evolution of herbicide-resistant weed populations attributable to the herbicide-resistant crop/herbicide program has been observed. Examples of herbicide-resistant weeds include populations of horseweed (Conyza canadensis (L) Cronq) resistant to N-(phosphonomethyl)glycine (glyphosate). An important question is whether or not these problems represent significant economic issues for future agriculture.     

作物获得最佳产量的亏缺灌溉及其实施策略

要想减少对灌溉水量的相对需求，必须尽可能降低或防止不必要的水分损失，同时可通过亏缺灌溉使有限供水得到强化利用。作者在总结前人工作的基础上，提出实施亏缺灌溉的七条原则来优化管理有限水分资源，使作物产量降低较小的同时获得最大水分利用效率。它们是：（１）使用抗旱能力较强的作物；（２）考虑水分亏缺发生时的作物生长发育阶段；（３）增加降雨对作物水分需求的贡献；（４）播前灌溉的需要性；（５）应用于深层土壤具有中等程度以上持水性能的土地；（６）管理地面灌溉系统以降低水分渗漏和径流；（７）改进作物栽培措施。     

Plant protection means used in organic farming throughout the European Union

Following the obligatory implementation of integrated pest management in the European Union (EU), the plant protection means suitable for application in organic agriculture attracted the attention of quite a wide group of potential users. In spite of the common rules of organic production, as well as the uniform principles of placing plant protection products on the market, the availability of products that can be legally used in organic crop protection differs significantly among the Member States. There is a uniform list of 10 basic substances that can be used in the protection of organic crops throughout the entire EU. Twelve Member States have official registers of plant protection products for use in organic agriculture, and the total number of qualified products per country varies from 11 in Lithuania to 576 in Italy. Some products that improve plant vigour or resistance and may be of use in protection of organic crops are placed on the market as biostimulants. They fall under the law that governs fertilisers and the systems of their registration vary widely among the Member States. In addition, there exist a number of products that have been legally introduced onto the markets of some Member States without registration as a consequence of a loophole in the law. The use of unregistered products in organic agriculture raises some doubts, but currently it seems that there is no legal basis on which to explicitly prohibit the practice. © 2017 Society of Chemical Industry     

United States Department of Agriculture-Agricultural Research Service research on pre-harvest prevention of mycotoxins and mycotoxigenic fungi in US crops

Mycotoxins (ie toxins produced by molds) are fungal metabolites that can contaminate foods and feeds and cause toxic effects in higher organisms that consume the contaminated commodities. Therefore, mycotoxin contamination of foods and feeds results is a serious food safety issue and affects the competitiveness of US agriculture in both domestic and export markets. This article highlights research accomplished by Agricultural Research Service (ARS) laboratories on control of pre-harvest toxin contamination by using biocontrol, host-plant resistance enhancement and integrated management systems. Emphasis is placed on the most economically relevant mycotoxins, namely aflatoxins produced by Aspergillus flavus, Link, trichothecenes produced by various Fusarium spp and fumonisins produced by F verticillioides. Significant inroads have been made in establishing various control strategies such as development of atoxigenic biocontrol fungi that can outcompete their closely related, toxigenic cousins in field environments, thus reducing levels of mycotoxins in the crops. Potential biochemical and genetic resistance markers have been identified in crops, particularly in corn, which are being utilized as selectable markers in breeding for resistance to aflatoxin contamination. Prototypes of genetically engineered crops have been developed which: (1) contain genes for resistance to the phytotoxic effects of certain trichothecenes, thereby helping reduce fungal virulence, or (2) contain genes encoding fungal growth inhibitors for reducing fungal infection. Gene clusters housing the genes governing formation of trichothecenes, fumonisins and aflatoxins have been elucidated and are being targeted in strategies to interrupt the biosynthesis of these mycotoxins. Ultimately, a combination of strategies using biocompetitive fungi and enhancement of host-plant resistance may be needed to adequately prevent mycotoxin contamination in the field. To achieve this, plants may be developed that resist fungal infection and/or reduce the toxic effects of the mycotoxins themselves, or interrupt mycotoxin biosynthesis. This research effort could potentially save affected agricultural industries hundreds of millions of dollars during years of serious mycotoxin outbreaks.     

The benefits of herbicide-resistant crops

Since 1996, genetically modified herbicide-resistant crops, primarily glyphosate-resistant soybean, corn, cotton and canola, have helped to revolutionize weed management and have become an important tool in crop production practices. Glyphosate-resistant crops have enabled the implementation of weed management practices that have improved yield and profitability while better protecting the environment. Growers have recognized their benefits and have made glyphosate-resistant crops the most rapidly adopted technology in the history of agriculture. Weed management systems with glyphosate-resistant crops have often relied on glyphosate alone, have been easy to use and have been effective, economical and more environmentally friendly than the systems they have replaced. Glyphosate has worked extremely well in controlling weeds in glyphosate-resistant crops for more than a decade, but some key weeds have evolved resistance, and using glyphosate alone has proved unsustainable. Now, growers need to renew their weed management practices and use glyphosate with other cultural, mechanical and herbicide options in integrated systems. New multiple-herbicide-resistant crops with resistance to glyphosate and other herbicides will expand the utility of existing herbicide technologies and will be an important component of future weed management systems that help to sustain the current benefits of high-efficiency and high-production agriculture. Copyright © 2012 Society of Chemical Industry