Effect of SO2 and NH3 on growth behavior of some phylloplane fungi of wheat in in vitro

The colony growth of some phylloplane fungi of wheat viz. Alternaria alternata, Aspergillus favus, Amiger, Cladosportium cladosporioides, Curvularia lunata, Drechslera australiensis, Epicoccum purpurascens, Fusarium oxysporum, Penicillium chrysogenum and P. citrinum were studied in chamber fumigation experiments exposed to 2669 ± 105 μg SO₂ m^?3 and 708.33 ± 55 μg NH3 m^?3 air, separately, for 10, 30 and 60 min. The colony growth of all the test fungi was significantly (P=0.01/0.005) inhibited on prolonged period of SO₂/NH₃ exposure. However, some of the test fungi namely A. favus, A. niger, E. purpurascens and F. oxysporum showed growth stimulation after 10 min exposure of SO₂. Similarly, the growth of C. lunata and F. oxysporum increased only after 10 min exposure of NH3. The inhibitory effect of SO₂/NH₃ was directly correlated with the exposure times.     

Growth of wheat plants exposed to cement dust pollution

Cement dust in the environment poses a threat to the proper functioning of plants in the vicinity of cement factories,as apparent from a field study conducted at different locations in the environs of Churk Cement Factory in Mirzapur District, U.P. Plant samples were collected at 100, 500, 1000, 1500, 2000, and 4000 m northeast of the factory, at three successive stages of plant growth The plant samples collected at 4000 m distance were treated as control, as there was no apparent deposition of cement dust on their surface. The samples were analyzed with respect to foliar injury symptoms, chlorophyll concentration and phytomass accumulation. Only plants closest to the factory displayed symptoms of foliar injury. The results reveal that wheat plants at polluted sites contained decreased concentration of chlorophyll in their leaves and had reduced accumulation of phytomass, as compared to control. The grains obtained from affected sites showed quantitative and qualitative deterioration. Physico-chemical properties of the soils at polluted sites also underwent some undesirable changes. These effects had negative correlation with the distance from the factory.     

非灭菌条件下VA菌根真菌对小麦生长发育的影响

本文在盆栽条件下研究了非灭菌条件接种ＶＡ菌根真菌Ｇｌｏｍｕｓｍｏｓｅａｅ对小麦生长发育的影响。结果表明,接种ＶＡ菌根真菌能显著提高对小麦的侵染率,接种株的营养生长、磷吸收、叶绿素含量、可溶性糖含量及光合作用参数都明显优于对照株。不同施磷水平对小麦植株的生理指标都有不同程度的影响。说明接种ＶＡ菌根真菌能够促进小麦生长,提高磷肥的利用率。     

Effect of fungicides on three vesicular-arbuscular mycorrhizal fungi associated with winter wheat (Triticum aestivum L.)

Summary We studied the effects of field application rates of three fungicides on spore germination and root infection in three species of Glomus. Bavistin (carbendazim) prevented germination of spores of G. monosporum and G. mosseae whereas Calixin (tridemorph) had no effect. Tilt Turbo (propiconazole) inhibited spore germination less than Bavistin. Spores of G. geosporum germinated in the presence of all three fungicides. Foliar applications of Bavistin alone and in a triple-spray programme significantly reduced infection of all three Glomus species in wheat roots grown in conditions of low P availability (2 mg P 1^–1). Two fungicides with triazole derivatives, Sportak and Tilt Turbo, also decreased infection and the former significantly reduced spore production of all three Glomus species. Calixin-treated plants, however, showed increased infection levels, resulting in greater yields and greater foliar-P concentrations than control plants. Milgo (ethirimol) was not detrimental to the vesicular-arbuscular mycorrhizal (VAM) symbiosis when applied as a foliar spray.     

Effect of salinity and arbuscular mycorrhizal fungi on growth and some physiological parameters of Citrus jambheri

Arbuscular mycorrhizal (AM) fungi alleviate the unfavorable effects of salinity stress on plant growth. A pot study was conducted to determine the effects of AM fungi and salt on growth and some physiological parameters of Citrus jambheri rootstock. Four levels of salinity (2, 4, 6, and 8 dS m^?1 as NaCl) and three mycorrhizal treatments (Glomus etunicatum, Glomus intraradices and non-mycorrhizal (NM) control) were used. As salinity increased, all measured characteristics of plants after 4.5-month growth except Na uptake, proline content, and electrolyte leakage decreased. Shoot dry weight and K uptake were significantly higher in G. intraradices-colonized seedlings than NM controls at all salinity levels. Root dry weight and shoot P uptake were significantly higher in G. etunicatum-colonized seedlings than NM controls at all salinity levels. G. intraradices-colonized seedlings had significantly higher proline content than NM controls and G. etunicatum-colonized seedlings at salinity levels of 4, 6 and 8 dS m^?1. The electrolyte leakage percentage was significantly lower in G. intraradices-colonized seedlings than NM controls at all salinity levels. The data demonstrated that mycorrhizal citrus seedlings exhibited greater tolerance to salt stress than NM seedlings and the enhanced proline content seems to be one of the mechanisms involved.     

接种丛枝菌根真菌对小麦根内氮转运蛋白基因表达的影响

通过盆栽试验,研究了在低氮(不施氮)和高氮(施氮0.2 g·kg~(-1))水平下接种不同种类丛枝菌根(AM)真菌[Funneliformis mosseae(BGC-NM03D)、Claroideoglomus etunicatum(BGC-NM01B)和Rhizophagus intraradices(BJ09)]对小麦生长、氮吸收及根内4个硝态氮转运蛋白(NRT)基因、1个辅助蛋白(NAR)基因和2个铵态氮转运蛋白(AMT)基因表达的影响。结果表明,3种AM真菌均能够侵染小麦根系,以R.intraradices菌根的侵染率最高;接种R.intraradices或C.etunicatum能够显著提高小麦的生物量或地上部氮吸收量;无论是高氮还是低氮处理,接种AM真菌后均显著下调了小麦根内NRT、NAR和AMT基因的表达水平,且不同AM真菌调控小麦根内氮转运蛋白基因表达的能力具有明显差异。     

Effects of some benzoxazinoids on in vitro growth of Cephalosporium gramineum and other fungi pathogenic to cereals and on Cephalosporium stripe of winter wheat

The benzoxazolinones benzoxazolin-2(3H)-one (BOA) and 6-methoxybenzoxazolin-2(3H)-one (MBOA) and selected degradation products of these compounds were examined for their in vitro antifungal activity against Cephalosporium gramineum, Gaeumannomyces graminis var. graminis, and Fusarium culmorum. BOA was also applied to the soil-incorporated inoculum of C. gramineum to test its capability of reducing Cephalosporium stripe disease in winter wheat. MBOA reduced the mycelial growth of G. graminis var. tritici, C. gramineum, and F. culmorum by 50% (EC50) at the concentrations of 77, 134, and 271 microg/mL of corn meal agar, respectively, and the corresponding BOA EC50 values for the fungi were 11, 189, and 456 microg/mL. BOA degradation products 2-amino-3H-phenoxazin-3-one (APO), 2-acetylamino-3H-phenoxazin-3-one (AAPO), and o-aminophenol (o-AP) were much more inhibitory to the growth of C. gramineum and G. graminis var. tritici than the parent compounds. APO, AAPO, and o-AP EC50 values were found to be as low as 0.58, 4.57, and 1.4 microg/mL, respectively, for C. gramineum and 0.78, 2.18, and 0.80 microg/mL for G. graminis var. tritici. These compounds applied at the corresponding concentrations did not significantly affect the mycelial growth of F. culmorum. The treatment of C. gramineum inoculum with a 1% water solution of BOA resulted in a significant reduction infection of winter wheat with C. gramineum as compared to the control with the untreated inoculum,but this treatment was not as effective as the application of a commercial fungicide.     

Effect of fungicide treatment on the quality of wheat flour and breadmaking

Fungicides are applied to crop plants to ensure disease protection and improve growth. To assess the effects of five commercial foliar and spike fungicides in four different combinations on wheat (Triticum aestivum L.), various quality parameters and flour processing properties, including baking quality, were determined. Three commonly used wheat cultivars with different quality classes (E, B, and C) were tested. Falling number, crude protein content, water absorption ability, protease activity, viscosity, and the free amino acid content were mainly lower in the fungicide-treated grains than in the untreated grains. None of the fungicides caused any significant changes in the wet gluten content, dough properties, the mono- and oligosaccharide content, or the breadmaking quality. In general, the commercial fungicide treatments did not cause any statistically significant differences between the treated and the untreated samples with respect to the quality parameters analyzed, although there were indeed significant differences between the three cultivars themselves.     

长期施用堆肥对小麦根际及非根际土壤化学性质的影响

Compost of different rates was applied to artificial field plots of a low humic andosol at National Agriculture Research Center (NARC)of Japan for 15 or 28 years,and their effects on the chemical properties of wheat rhizosphere soil and nonrhizosphere soil were measured.Contiuous application of compost for 28 years resulted in raise of soil C,N,P,pH and exchangeable based.The building up of compost for 28 years resulted in raise of soil C,N,P,pH and exchangeale bases,The building up of organic matter in the soil occureed slowly.A residual effect of the compost on soil chemical properties was still present after 13 years of no application,but this effect was weaker in comparison with that of the continuous application treatments.In the rhizosphere soil,NaHCO3-extracted P and exchangeable Ca were higher than those in the bulk soil.The removal of free organic acid slightly affected the soil pH,especially,the rhizosphere soil pH.The raise of soil pH may result from the increase of exchangeable base by the application of compost.     

Grazing preferences of some collembola for endomycorrhizal fungi

The ability of five collembolan species to distinguish and graze selectively on vesicular-arbuscular mycorrhiza (VAM) has been verified. Four species preferred the food infected by VAM fungi. All collembolan species showed more of less significant preferences for one species/isolate of the VAM fungi.     

Evaluation of cement kiln flue dust as a potassium and sulfate fertilizer

Abstract

The main objective of this study was to determine the efficacy of cement kiln flue dust as a substitute for potassium sulfate fertilizer. Chemical and X‐ray diffraction analyses revealed that the flue dust contained about 20.7% K of which 9.1% was present as aphthitalite (K₃Na(SO₄)₂) , 4.4% as sylvite (KCl) and the remaining 7.2% as arcanite (K₂SO₄) . Accordingly, about 80% of the potassium in the dust was present as sulfates, though it contained 30% total sulfate and 15% Ca.

The effects of flue dust were compared to some or all of the following fertilizers: KCl, K₂SO₄ and a synthetic fertilizer, on 11 soils ranging in texture from sand to clay in three greenhouse experiments. The synthetic fertilizer was made from K₂SO₄ and CaSO₄.2H₂O which were applied at the same rate of K and Ca as contained in the flue dust. The experimental results show that flue dust is as effective a K source as any of the fertilizers tested as it increased potato, barley and alfalfa yields and tissue and soil K concentrations to the same level. Furthermore, the flue dust increased the tissue sulfur concentration and the quantities of available sulfate in soils to the same level as potassium sulfate. Finally, the Ca contained in flue dust increased the concentration of this element in potato tops and soils when grown on eight coarse textured soils. The flue dust had, however, no effect on soil pH on any of the soils tested.     

Effect of lignite humic acid treatment on the rate of decomposition of wheat straw

Comparisons were made between the rates of microbial respiration during the incubation of milled wheat straw in the presence or absence of a dispersal of lignite humic acids. Lignite treatment significantly reduced both the rate of O₂ consumption and CO₂ evolution from the straw substrate over a 4-week period. In view of this observed inhibitory effect, additions of exogenous humic acids from lignite during composting might have a practical application as a means of increasing the microbial stability of horticultural composts derived from plant waste materials.     

缓释肥处理下麦田土壤细菌和真菌群落对气候变化的响应

采用控制系统来模拟未来大气CO₂浓度和气温升高的气候变化情景,借助基于半导体芯片技术的IonS5TMXL测序平台并结合相关生物信息学方法对气候变化背景下缓释肥处理的麦田土壤进行16S rRNA细菌V4区和18S rRNA真菌ITS区测序分析,探究了缓释肥处理下麦田土壤细菌和真菌对气候变化的响应。结果显示,所有样品测序后获得细菌和真菌平均有效序列数分别是80543和64303个,平均OTUs分别是3149和1161个。Alpha多样性分析显示,大气CO₂浓度升高小麦土壤细菌的Shannon和Chao1指数均降低,而土壤真菌在各气候环境下均无显著差异。主成分分析显示,各处理下土壤细菌群落结构差异不明显,真菌群落结构在气温升高时差异明显。缓释肥处理与普通肥相比,土壤细菌和真菌的Alpha多样性及群落结构在不同气候条件下均没有差异。菌群分类学表明,小麦土壤的优势细菌门为变形菌门、放线菌门、拟杆菌门和酸杆菌门,主要的优势细菌属有9种;优势真菌门为子囊菌门、被孢菌门和担子菌门,主要的优势真菌属有7种。大气CO₂浓度升高条件下,施用普通尿素使变形菌门和鞘氨醇单胞菌属的相对丰度分别增加10.34%和46.27%。在对照温度对照CO₂浓度条件下,缓释肥处理比普通肥处理使子囊菌门和毛壳菌属相对丰度分别显著增加39.85%和295.33%;在升高温度对照CO₂浓度条件下,缓释肥处理比普通肥处理使子囊菌门和毛壳菌属分别增加33.16%和154.49%。CO₂对变形菌门、鞘氨醇单胞菌属和毛壳菌属的影响达显著水平。在各气候变化环境下,各土壤理化性质均有所改善;与普通氮肥相比,缓释氮肥处理在各气候环境下土壤有机质、碱解氮和全氮含量降低,土壤有效磷和总磷含量升高。冗余分析表明,土壤细菌群落结构主要受土壤全氮和盐分含量的影响,而真菌群落结构主要受土壤pH和有效磷含量的影响。研究结果表明,未来气候环境变化对土壤微生物群落的影响大于缓释肥处理。该结果加深了缓释肥对土壤微生物群落结构和多样性影响的认识,为未来气候环境变化下缓释肥推广使用提供理论依据。     

Effect of winter wheat cover cropping with no-till cultivation on the community structure of arbuscular mycorrhizal fungi colonizing the subsequent soybean

Winter cover crops increase the amount of indigenous arbuscular mycorrhizal fungi (AMF) in the soil, providing beneficial effects such as enhancement of phosphorus uptake by the subsequent crop. However, its impact on the AMF community structure is not well understood. In the present study, we aimed to reveal the effect of winter wheat cover cropping with no-till cultivation on the AMF community structures in soil and roots of the subsequent soybean. For this purpose, we conducted a field experiment consisting of two treatments, no-till soybean cultivation after winter wheat cover cropping (NTWC) and conventional soybean cultivation after winter fallow management as a control (CONT). At the flowering stage of soybean, higher AMF colonization of soybean roots was observed in the NTWC plots compared with the CONT plots. Additionally, aboveground biomass and phosphorus uptake of soybean in the NTWC plots were significantly higher than those in the CONT plots. Molecular community analyses based on PCR-denaturing gradient gel electrophoresis (DGGE) of AMF 18S rRNA genes indicated that the AMF community structures in the soil and soybean root of the NTWC plots were clearly different from those of the CONT plots. The DGGE profiles showed that the wheat cover cropping preferentially increased some phylotypes belonging to Glomeraceae and Claroideoglomeraceae. In addition, most of the phylotypes were characteristically observed in the subsequent soybean root of the NTWC plots, strongly suggesting that these phylotypes colonizing the cover crop wheat were taken over by the subsequent soybean. Our study revealed the significant effect of winter cover cropping with no-till cultivation on the structure of AMF community colonizing the subsequent soybean.     

Effect of soil matric potential on sharp eyespot in germinating wheat following seed treatment

The influence of soil matric potential on sharp eyespot was examined in wheat seedlings following seed treatment with the fungicide cyproconazole. Emergence of wheat was tested at matric potentials between 0 and –850 hPa in non-infested soil and in soil infested with Rhizoctonia cerealis. Optimal shoot emergence was at –50 and –20 hPa in non-infested and infested soil, respectively. Disease severity was strongly affected by soil matric potential. It continuously increased as matric potential decreased from –5 to –200 hPa. In contrast, optimum growth conditions for the pathogen was at matric potentials between –50 and –200 hPa. With decreasing matric potential the drought stress for the plant seems to increase its predisposition to the pathogen. Seed treatment with cyproconazole reduced sharp eyespot although disease severity increased with decreasing soil matric potential.     

不同品种混种对小麦产量及条锈病的影响

用"繁19"、"引11-12"、"川麦107"、"靖麦10号","青春55"、"46548-3"和"安96-8"7个不同小麦品种,组合成6个品种混种的群体,于2003～2004年、2004～2005年、2005～2006年在云南省曲靖市对其产量效应进行了多年多点试验,并在自然发病条件下,调查了6个品种混种群体对小麦条锈病发生程度的影响.结果表明,小麦品种混种的产量效应平均为+3.9%;小麦品种混种在产量上的正效应、0效应,负效应所出现的频率分别为69.4%、8.3%、22.3%;年份、地点等具体环境条件会影响小麦品种混种的产量效应.在小麦条锈病发病强度相对较高的年份,品种混种可降低条锈病病情指数.因此,品种混种在我国一些小麦产区有利用价值.     

Synthetic pyrazole derivatives as growth inhibitors of some phytopathogenic fungi

The present study was carried out to investigate the antifungal activity of pyrazole/isoxazole-3-carboxamido-4-carboxylic acids, 4-oxo-5-substituted pyrazolo[3,4-d]pyrimidine-6-thiones, and N-alkyl/aryl-N'-(4-carbethoxy-3-pyrazolyl)thioureas against Pythium ultimum, Botrytis cinerea, and Magnaporthe grisea. The results on growth inhibition showed differences in the sensitivity of the three fungi to the tested substances, and in general P. ultimum was shown to be the most sensitive. On all phytopathogens the best results within the pyrazole/isoxazolecarboxamide series are given by the compounds with the carboxamide and carboxylic groups in positions 3 and 4; the presence of these groups seems to be critical for biological activity in this series of compounds. Among the pyrazolopyrimidines the derivative supplied with the benzylic group was the most active on the three fungi and in particular against P. ultimum. Several compounds belonging to the thiourea series are able to inhibit selectively M. grisea at 50 and 10 microg mL(-1), doses at which the reference commercial compound tricyclazole had low or no effect.     

蒸汽爆破处理对麦麸的酚酸组成及其抗氧化活性的影响

该试验旨在研究蒸汽爆破处理对小麦麸皮的酚酸组成及抗氧化活性的影响.将麦麸在不同处理压力(0.5,1.5,2.5 MPa)和不同处理时间(30,90 s)条件下进行蒸汽爆破预处理.通过水解和碱提的方法,将得到的麦麸进行提取,得到游离酚酸和结合酚酸2部分,对其中的几种主要酚酸,如香草酸、丁香酸,4-香豆酸,阿魏酸进行研究.结果表明,4种主要酚酸的含量在蒸汽爆破处理后均有所提高,其中阿魏酸的含量最高,结合酚酸中由未处理时的57.232μg/g提高到了1454.092 μg/g.该试验还进行了总酚测定,抗氧化活性的测定.通过总酚的测定可以看出,蒸汽爆破处理后,总酚的含量高于未处理麦麸,且随着处理强度的增加,呈现先增加后减少的趋势,在处理条件为2.5 MPa,30 s,总酚含量最高,约为未处理时的9倍.抗氧化试验得到的变化趋势与总酚呈现相似的规律,与未进行蒸汽爆破预处理的麦麸相比,处理后的麦麸表现出了更高的1,1-二苯基-2-三硝基苯肼(DPPH)和2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS)自由基清除率,以及在亚油酸体系中的抗氧化活性和还原能力.当处理条件为2.5 MPa,30 s时,抗氧化活性表现最高.由此可得到,2.5 MPa 30s是蒸汽爆破处理麦麸的最佳条件,此时麦麸中酚酸含量和抗氧化活性均较优,为以后麦麸中酚类物质的深度开发利用提供理论支持.     

Effects of herbicides on three vesicular-arbuscular fungi associated with winter wheat (Riticum aestivum L.)

Summary We studied the effects of field application rates of four herbicides (Avenge, Ceridor, Dicurane, and Harrier) on spore germination and infection of wheat roots by three species of Glomus grown under conditions of low P availability. Low concentrations of Ceridor (bifenox, mecoprop) and Harrier (mecoprop, ioxynil, clopyralid) inhibited spore germination while higher concentrations were stimulatory. Avenge (difenzoquat methyl sulphate) prevented spore germination completely, while Dicurane (chlortoluron) had no effect. The herbicide applications had no significant effect on the infection rates of any of the three fungi except Harrier on G. geosporum. The herbicide treatments did, however, affect plant growth and ear yields. Ceridor and Harrier increased ear yields, while Dicurane showed marked phytotoxic effects.     

丛枝菌根真菌对棉花耐盐性的影响研究

盆栽灭菌试验研究丛枝(AM)真菌对棉花耐盐性的影响结果表明,自然盐渍化土壤和人工模拟盐渍条件下接种AM真菌处理的生物产量显著高于不接种处理,相同土壤下菌根真菌对棉花植株生长的促进作用随盐水平的提高而增大,表明AM真菌与植株建立的共生关系有利于棉花在盐渍土壤中生长。盐胁迫下棉花植株对P的需要量增加,接种AM真菌可提高植株含P量,促进植株生长,提高棉花的耐盐性。