冠毒素和茉莉酸甲酯对诱导小麦、黑麦和高羊茅草颖花开放的效应

 茉莉酸类化合物（ＪＡｓ）是一类新型植物激素，在植物中广泛存在。ＪＡｓ是重要的信号传递物质，在对环境各种胁迫的反应中可调节植物防卫基因的表达。最近曾晓春和周燮发现ＪＡｓ中的重要一员茉莉酸甲酯（ＭｅＪＡ）可诱导水稻颖花的开放。冠毒素是植物病原菌假单胞菌产生的一种致病毒素，国外的许多研究证实它是ＪＡｓ的环戊烷结构类似物，在一些方面可以模拟ＪＡｓ的功能。通过对ＭｅＪＡ和冠毒素是否具有诱导小麦和其它植物颖花开放的作用，诱导效果如何等的探讨结果表明，４ｍｍｏｌ／Ｌ的ＭｅＪＡ和１．１～４．４μｍｏｌ／Ｌ的冠毒素对小麦的颖花开放有明显的诱导效果，ＭｅＪＡ和冠毒素对颖花开放的诱导作用在植物品种之间有明显的差异。     

甲基对硫磷降解菌P-29的筛选及降解特性研究

采用富集培养法,从长期受农药污染的土壤中分离得到1株能高效降解甲基对硫磷的菌株P-29,经鉴定为铜绿假单胞菌(Pseudomonas aeruginosa)。该菌株以甲基对硫磷为唯一碳源时,30℃培养30h降解率达84.69%,其酶活性随培养时间的增加呈上升趋势。     

茉莉酸甲酯(MeJA)对小麦开颖的诱导效应

为了探讨MeJA对小麦开颖特性的诱导效应,以T冀5418 A和冀5418 B为试材,采用0.3、3.0、6.0 mmol/L MeJA和蒸馏水(CK)对其活体穗和离体穗进行浸穗处理3 min.结果表明,MeJA具有诱导开颖数增加的效应,3.0 mmol/L诱导活体穗开颖数指数比CK高1.5和5.2,比6.0 mmol/L诱导的高1.0和3.5;6.0 mmol/L诱导离体穗开颖数指数比CK高5.8和4.8,比3.0 mmol/L高1.5和5.5;0.3 mmol/L处理结果不及CK.MeJA处理穗的开颖度大,开颖时间长.6.0 mmol/L诱导开颖度比CK高1.0～1.5 mm,开颖时间比CK长42～70 min,差异均达显著或极显著水平;其它浓度处理与CK相比无显著差异.MeJA诱导保持系开颖特性优于其不育系,并且3.0 mmol/L MeJA诱导保持系花药外露,处理后4 h花药外露率比CK高7.7%,差异显著.因此,MeJA具有诱导小麦颖壳开张和调节小麦花期的效应,是杂交小麦制种的有效调节剂.     

Efficacy of 1,3-dichloropropene plus chloropicrin application methods in combination with pebulate and napropamide in tomato

Small-plot research and large-field validations were conducted to determine the effect of 1,3-dichloropropene (1,3-D)+chloropicrin (Pic) application methods in combination with the herbicides pebulate and napropamide on pest control in fresh market tomato (Lycopersicon esculentum Mill.). In both the small-plot trials and the large-validation fields, various treatments compared the efficacy of soil fumigants and herbicides based on methyl bromide, in-bed and broadcast applications of 1,3-D+Pic, pebulate, and napropamide. The results consistently indicated that either in-bed or broadcast applications of 1,3-D+Pic in combination with pebulate and napropamide are equally effective against the weed Cyperus spp., the nematodes Tylenchorhynchus spp., Belonolaimus longicaudatus, and Meloidogyne spp., and the soilborne disease Fusarium oxysporum f.sp. lycopersici in fresh market tomato. Therefore, broadcast 1,3-D+Pic application can reduce personnel exposure and poisoning risks, without losing pest control efficacy.     

Methyl bromide alternatives for strawberry and tomato pre-plant uses: A meta-analysis

This paper reports the results of a meta-analytic synthesis of information from a large number of horticultural experiments that evaluated the technical feasibility of methyl bromide alternatives as soil fumigants in strawberry (Fragaria ananassa) cultivation in California, Florida, and Spain, and in tomato (Solanum lycopersicum) cultivation in Florida. A technically feasible alternative is defined as a treatment that provides pest control and crop yields similar to methyl bromide standard fumigation. We selected papers using five criteria, which jointly ensured inclusion of field experiments that contained usable information on at least three treatments—(1) an untreated control, (2) a methyl bromide treatment, and (3) a treatment that is an alternative to methyl bromide treatment. Because of the differences in regional cropping environments, we performed separate meta-analyses for four crop/region combinations. To explore the potential effects of missing information on past fumigation history and pest pressure on the results, we performed two sensitivity analyses, in which the set of usable field experiments included only those experiments in which the improvement of the methyl bromide treatment yield over the control yield was either 15% or 50%. Finally, the definition of several potential alternative chemical treatments took into account differences in formulations and application rates. The results we obtained do not support the technical superiority of methyl bromide over its alternatives. We found several potential alternatives for which we could not reject the hypothesis of technical feasibility, based on the experimental data for strawberries in California and Spain. In particular, the results on strawberry field experiments in California indicate that the estimated effect size of the treatment using 1,3-dichloropropene/chloropicrin 65:35 formulation (applied at the standard rate) was close to the estimated effect size for methyl bromide. The results from strawberry and tomato field experiments in Florida were inconclusive. However, this does not establish that methyl bromide is technically superior to its alternatives. Given the data-related limitations of the analysis, standard protocols are necessary for conducting and reporting the experiments to allow for more meaningful synthesis of the experimental data.     

干旱胁迫下茉莉酸甲酯对水稻叶片质膜透性及无机离子含量的影响

茉莉酸甲酯(MeJA)是植物体内一种具有应答外界刺激,传导逆境信号及启动抗逆基因的天然生理活性物质,提高作物的抗旱性是MeJA的重要生理功能之一。研究了干旱胁迫下施用不同浓度(250,2.5,0.25μmol/L)MeJA对水稻幼苗的生理调控作用。结果表明,干旱处理后水稻叶片水势和叶绿素含量显著下降,叶片MDA含量、电导率及无机离子(K+,Ca2+,Mg2+)含量均显著上升,而喷施不同浓度的MeJA则显著提高叶片水势和叶绿素含量,降低质膜透性和叶片无机离子含量,从而增强水稻幼苗的抗旱性。以0.25μmol/L MeJA处理抗旱效果最好,2.5μmol/L次之,然后是250μmol/L。     

春大豆EMS诱变M1、M2代主要农艺性状的遗传变异及相关性

利用0.5％甲基磺酸乙酯(EMS)溶液处理7个春大豆品种种子,并对M1和M2代主要农艺性状的遗传变异及相关性进行分析.结果表明:M1代主要是化学物质扰乱了植株生理而产生生理损伤发生了形态变异.M2代分枝数、单株荚数、单株粒数和单株粒重的变异系数较大.M2代各性状的广义遗传力以株高、主茎节数较高,而分枝数、单株粒数、单株...     

Evaluation of non-fumigant alternatives to methyl bromide for weed control and crop yield in California strawberries (Fragaria ananassa L.)

In California, USA, agricultural fumigant use regulations hinder the complete transition from methyl bromide (MB) to alternative fumigants. Alternative fumigants such as 1,3-dichloropropene (1,3-D) and chloropicrin (Pic) are being used on approximately half of California conventional strawberry production fields. Geographic use limits and buffer zones set by the California Department of Pesticide Regulation for 1,3-D + Pic restrict a more complete replacement of MB. Due to the regulatory constraints and public resistance to fumigant use, it is necessary to develop fumigant-free strawberry production systems. Trials were conducted during the 2007/2008 and 2008/2009 strawberry growing seasons at Salinas and Watsonville, California. Non-fumigant treatments including steam, mustard seed meal (MSM), Muscodor albus, and furfural, fertilizers including Mustard Products & Technologies fertilizer and stabilised urea, and fungicide treatments including AG3(NP), fludioxonil + mefenoxam (mfx), and mfx + thiophanate-methyl were evaluated for weed control and strawberry fruit yield, and compared to MB + Pic (MBPic) standard soil fumigation and an untreated control. Steam treatment applied pre-plant to achieve soil temperature of ≥70 °C for 20 min up to 25 cm soil depth consistently provided weed control similar to the MBPic standard soil fumigation. Use of oxyfluorfen herbicide prior to fungicide applications in 2008/2009 also controlled weeds similar to the MBPic standard soil fumigation. Strawberry yields in steam-treated plots with the exception of steam alone in 2007/2008 at Salinas, were comparable to MBPic. At Watsonville in 2008/2009, treatment effect on strawberry yields was insignificant. Yields in furfural and MSM treatments were comparable to MBPic only in some years or sites. With the exception of steam, none of the treatments can be considered viable replacement to MB.     

Effects of soil amendment with poultry manure on carnation Fusarium wilt in greenhouses in southwest Spain

In a search for alternatives to methyl bromide for controlling carnation vascular wilt caused by Fusarium oxysporum f. sp. dianthi (Fod), poultry manure plus soil solarization was studied in soil under greenhouse conditions in four 2-year experiments. These were conducted in naturally infested soil to compare the effects of this treatment with soil solarization alone and methyl bromide. Soil treatments were performed during June 2000 for Experiment 1, from July to mid-August 2002 for Experiment 2, from late July to late August 2006 for Experiment 3 and from late May to late June 2008 for Experiment 4. Additionally, a treatment with commercial poultry manure pellet plus soil solarization was included in the two latter experiments. Poultry manure caused reductions of Fod viability in soil samples at depths of 15 and 30 cm, ranging respectively from 93 to 100% and 89 to 100% for Experiments 1, 2 and 3. Carnations planted in plots treated either with poultry manure, methyl bromide or soil solarization had lower final disease incidences, smaller areas under their disease progress curves and higher yields in comparison with untreated plots in Experiments 2, 3 and 4. In Experiment 1, soil solarization was performed under suboptimal conditions, and it provided disease levels and yields similar to those of the untreated control plots. Nevertheless, under the same conditions, previous amendment of Fod-infested soil with poultry manure increased disease control over soil solarization alone, improved carnation yield and quality and also increased plant vigor, thus providing a satisfactory alternative to methyl bromide. The application of organic amendment to the same plot before every crop cycle is recommended to ensure continuous disease control, but the rates of application could be reduced to half for the third and fourth crop cycles, thereby reducing undesirable environmental effects.