Comparison of chlorophyll fluorescence and whole-plant bioassays of isoproturon

Summary The response to aqueous solutions of isoproturon was examined on intact plants of Matricaria perforata , Apera spica-venti and Sinapis alba in greenhouse tests, comparing visual estimates of shoot phytotoxicity at 30 d after application (DAA) with measurements of fast chlorophyll fluorescence induction at 10 DAA on leaves of the same treated plants. The sensitivity was greatest from pre-emergence application to intact plants of M. perforata and A. spica-venti , whereas post-emergence sprays were relatively more active on S. alba . The use of fluorescence induction was investigated further in Petri-dish experiments on excised M. perforata leaf segments. The Petri-dish bioassay enabled detection of isoproturon at concentrations above 9 × 10⁻⁷ M within 96 h after herbicide exposure. The potential for using chlorophyll fluorescence assays for the determination of isoproturon content in soil extracts is discussed.     

荠菜等4种野生蔬菜栽培试验

[目的]研究荠菜、苣荬菜、桔梗、防风这4种野生蔬菜的栽培技术。[方法]对荠菜等4种野生蔬菜进行种子发芽试验及温室栽培驯化试验,调查统计发芽情况、出苗情况及产量等。[结果]4种野生蔬菜都可以通过播种方法进行繁殖,但是荠菜在播种时需要选择低于25℃播种才可以获得较高的出苗率。荠菜在温室中1 a能采收2次,苣荬菜、桔梗与防风1 a均可以采收4次,其产量均达18 000kg/hm~2以上。[结论]荠菜、苣荬菜、桔梗、防风这4种野生蔬菜能够在日光温室内栽培,且产量能够达到一般叶菜类蔬菜的平均产量,适合在北京地区推广种植。     

田旋花 EPSPS 基因启动子的克隆、序列分析及转化

根据已克隆的田旋花（ Convolvulus arvensis L．） EPSPS基因mRNA序列设计引物,通过染色体步移技术获得了1142 bp的EPSPS-P启动子片段（ GenBank 登录号：KC107822）。对启动子序列分析显示,该片段富含A/T碱基、TATA-box、CAAT-box及其他作用元件如GATA-motif、TC-rich repeats、sp1等。将该启动子与GUS报告基因连接以构建植物表达载体,利用农杆菌介导法获得转基因拟南芥;PCR和GUS组织化学染色分析证明, EPSPS-P已转化到拟南芥中。     

野芥芥酸合成酶基因fae1的克隆与序列分析

根据GenBank中脂肪酸延长酶基因fae1序列(AY 888037)设计了PCR扩增引物,以野芥总DNA为模板进行扩增得到了特异扩增条带.测序结果表明,该片段长1 651 bp,序列分析表明其氨基酸编码区为55～1 575 bp,不含内含子序列,共编码506个氨基酸.该基因序列已提交GenBank,登录号为FJ870905.BLASTn分析结果表明,野芥中fae1基因与其他芸薹属品系的fae1基因核苷酸同源性为76%～98%;BLASTp分析结果表明,野芥中的FAE1与油菜中FAE1存在32个位点差异,其中部分差异可能导致了芥酸含量的不同.     

田旋花EPSPS基因表达特征及草甘膦对其表达的影响

采用实时荧光定量RT-PCR测定了田旋花不同组织、不同叶龄的EPSPS基因mRNA的相对表达量以及草甘膦对EPSPS基因相对表达量的影响。结果表明:田旋花EPSPS基因在不同组织表达量差异显著,在叶的表达量高于茎和根;该基因在9叶期的表达量最高,是3叶期的1.5倍;在草甘膦处理后,田旋花EPSPS基因的表达量先升高后降低,在处理后24h达最大值。随草甘膦剂量增加,该基因的表达量升高。研究结果可为深入解析田旋花对草甘膦耐药性机理提供参考。     

Yield and Resource Use Optimization in Late Transplanted Mint (Mentha arvensis) under Subtropical Conditions

A field experiment was conducted during 1994 and 1995 at Lucknow (26.5°N, 80.5°E, 120 m above mean sea level) to optimize planting density and fertilizer-N application for high essential oil yield of late transplanted mint ( Mentha arvensis ). The treatments studied were 2.5, 2.0 and 1.66 × 10⁵ mint seedlings ha⁻¹ and 0, 80, 160 and 240 kg N ha⁻¹. Under 3 months delayed planting conditions using 2-month-old seedlings, the high planting density of 2.5 × 10⁵ plants ha⁻¹combined with 160 kg N ha⁻¹ gave significantly higher herb and essential oil yields compared with those of lower planting densities (2 and 1.66 × 10⁵ plants ha⁻¹) and all other rates of N application. It is demonstrated that a transplanted mini crop, yielding essential oil at a level of 164 kg ha⁻¹, is feasible after the harvest of rabi cereal, oil seed or legume crops in the north Indian plains.     

Influence of Long‐Term Application of Organic and Inorganic Fertilizer to Build Up Soil Fertility and Nutrient Uptake in Mint‐Mustard Cropping Sequence

Abstract

Field experiment was conducted for 7 years continuously to evaluate the influence of combined application of organic and inorganic fertilizer on soil fertility buildup and nutrient uptake in mint (Mentha arvensis) and mustard (Brassica juncea) cropping sequence. Maximum organic carbon was observed under full supply of organic manure (T₂; FYM at 20 t ha^?1) averaged across all the Stages of cropping sequence. It was increased by 38, 50, and 51% in T₂ in Stages I (after mint harvest/presowing of dhaincha), II (after incorporation of dhaincha (Sesbania aculeata)/presowing of mustard), and III (after harvest of mustard/preplanting of mint), respectively, over their respective controls. In general, magnitude of organic carbon was recorded higher in Stage II after green manuring of Sesbania compared with Stages I and III. Nitrogen availability in treated plots was increased by 26.0–89.9, 15.2–64.5, and 4.9–52.0% in Stages I (after mint harvest/presowing of Sesbania), II (after incorporation of dhaincha/presowing of mustard), and III (after harvest of mustard/preplanting of mint), respectively, over their respective control. Average across all the three Stages showed a positive balance of nitrogen (N), phosphorus (P), and potassium (K) in soil under different treatments. Mean of the three Stages indicated that maximum available N, P, and K were increased by 36.1, 129.0, and 65.20% in T₄ (N:P:K: 133:40:40 and FYM at 6.7 t ha^?1), T₄ (N:P:K::133:40:40 and FYM at 6.7 t ha^?1), and T₃ (N:P:K::100:30:30 and FYM at 10 t ha^?1), respectively, over their initial status. Supply of organic and inorganic fertilizer (T₄; N:P:K::133:40:40 and FYM at 6.7 t ha^?1) was found most suitable combination with respect to N, P availability in soil, and productivity of mint and mustard crop.     

Effects of non-chemical soil fumigant treatments on root colonisation with arbuscular mycorrhizal fungi and strawberry fruit production

The effects of biofumigation and soil heating on arbuscular mycorrhizal fungi (AMF) colonisation, strawberry growth and strawberry yield in pot experiments compared with untreated soil and chemical fumigation with dazomet were tested. Three different Brassicaceae species (Brassica juncea, Eruca sativa, Sinapis alba) were used as biofumigant plant green manure and soil heating was applied to simulate soil solarisation. Half of the plants were inoculated with indigenous arbuscular mycorrhizal fungi inoculum. With one exception (E. sativa) among the uninoculated plants, the treatments significantly decreased the mycorrhizal colonisation parameters compared with the untreated control. Dazomet displayed the greatest inhibitory effects on AMF establishment. In addition, the intensity and number of bands corresponding to Glomus spp. obtained with temporal temperature-gradient gel electrophoresis were lower for strawberry plants from biofumigant treatments than from the control. For the inoculated plants, there were almost no significant differences among the mycorrhizal colonisation parameters. The mass of leaves for the uninoculated and inoculated plants was higher for almost all non-chemical soil fumigant treatments compared with the control, except for heating of the uninoculated treatments. The number of strawberry fruits for the uninoculated biofumigant treatments was the highest, being higher than the values observed for the heating treatments, the chemical disinfection treatments and the control. There were no significant differences among the inoculated treatments. Biofumigation with Brassicaceae species resulted in higher soil organic matter and mineral nutrients and had a relatively small effect on AMF colonisation (F% = 59.0, 80.3, 47.3 for Bj, Es and Sa, respectively) compared with uninoculated controls (F% = 84.3). Despite the reduced AMF colonisation, biofumigation resulted in a higher fruit number and mass of leaves. Therefore, it represents a non-chemical soil fumigation method that should be applied in sustainable strawberry production.     

A molecular genetic assessment of herbicide-resistant Sinapis arvensis

The acquisition of resistance to both the auxinic herbicide dicamba and the sulfonylurea herbicide chlorsulfuron has been recorded in Canadian populations of the weed species Sinapis arvensis L. (charlock, wild mustard) To study the effect of this selection for herbicide resistance on levels of genetic variation, polymerase chain reaction-based DNA fingerprinting techniques were used to characterize two herbicide-resistant and one susceptible population of S. arvensis . Analysis of the resultant DNA marker profiles revealed extensive polymorphism between individuals. However, segregation of the three biotypes was detectable despite high levels of intrabiotype polymorphism. No reduction in the levels of heterozygosity within the resistant populations were found compared with the susceptible population.