蔬菜作物根际促生菌分离筛选、鉴定及促生特性测定

为从4种蔬菜作物根际分离和筛选植物根际促生菌(plant growth promoting rhizobacteria,PGPR)并研究其促生特性,采用固氮、无机和有机磷培养基筛选根际促生菌株,对其促生特性进行定性和定量分析,并通过形态特征及16SrDNA序列分析对优良促生菌株进行鉴定。结果表明:从4种蔬菜根际中共获得57株PGPR菌株,其中固氮菌24株,溶磷菌33株。筛选出的19株优良PGPR菌株的固氮酶活性在0.14~3 664.97 nmol C2H4·h~(-1)·mL~(-1)之间,以NCRS1菌株固氮酶活性最高;溶解无机磷菌株的溶磷量在36.99~362.60μg/mL之间,培养液p H为4.57~5.75,以NCRP2菌株溶磷量最大;溶解有机磷菌株的溶磷量在9.24~55.21μg/mL之间,培养液p H为6.24~7.75,以PPRS3菌株溶磷量最大;菌株分泌IAA量均小于3.36μg/mL;NCRP2菌株对小麦长蠕孢病菌Helminthosporium tritici-vulgaris、番茄早疫病菌Alternaria solani、黄瓜枯萎病菌Fusarium oxysporum、马铃薯立枯丝核病菌Rhizoctonia solani、油菜菌核病菌Sclerotinias clerotiorum和玉米小斑病菌Bipolaria maydis均有抑制作用。对19株优良PGPR菌株进行初步鉴定,分属于假单胞菌属Pseudomonas、不动细菌属Acinetobacter、Advenella、叶杆菌属Phyllobacterium、细杆菌属Microbacterium、芽胞杆菌属Bacillus。本研究筛选出的优良PGPR菌株,可为今后生物菌肥推广应用提供菌种资源。     

植物根际优良促生菌（PGPR）筛选及其接种剂部分替代化肥对玉米生长影响研究

通过测定植物根际促生菌株固氮酶活性、溶磷量、分泌植物生长素、对病原菌的拮抗作用及菌株生长速度,筛选出了5株具有较好促生特性的优良菌株.利用筛选的优良菌株研制复合接种剂,并于2009年和2010年进行田试,测定其部分替代化肥对玉米生长的影响.结果表明:利用筛选的优良促生菌研制的复合微生物接种剂符合《微生物肥料》NY227-94标准.施用接种剂替代20％ ～ 30％的化肥,玉米株高、地上植物量、穗长、穗粗、单位面积穗数、穗粒数和经济产量等均有提高.研制的微生物接种剂(菌肥+80％化肥),2010年大田推广使用,玉米增产9.86％,减少化肥投入、增产收入及直接经济效益分别为620.1元,hm-2、2 291.4元,hm-2和2 851.5元.hm-2.     

模拟降雨量下微集水种植对玉米光合速率及水分利用效率的影响

利用人工模拟降雨装置,设置平作和垄作两种种植方式,以平作为对照组,研究了玉米在垄沟集雨下光合特性和水分利用效率的变化。结果表明,在230 mm3、40 mm的降雨量下,沟垄集雨种植玉米的光合速率显著高于对照组,分别提高了41.1%和10.5%,在440 mm的降雨量下,两者的差异不显著;在3个雨量下,沟垄集雨种植玉米的叶片瞬时水分利用效率比对照组均有提高,分别提高了20.5%、18.9%和10.7%;沟垄集雨种植玉米和对照组的光合速率日变化均呈"单峰型"曲线,对照组水分利用效率在230 mm、340 mm降雨量下呈"单峰型"曲线,在440 mm降雨量下呈现逐渐下降的趋势,沟垄集雨种植的玉米水分利用效率均呈"单峰型"曲线。     

太阳能消毒与植物根际促生菌(PGPR)联合对黄瓜根腐病的防治效果

为明确太阳能土壤消毒与植物根际促生菌(PGPR)联合对黄瓜根腐病防治效果, 在对温室进行太阳能土壤消毒之后, 采用蘸根和灌根的方式测定了解磷?抑菌效果较好的3个菌株JPG-5?LWG-5和YB-4对黄瓜根腐病的田间防治效果及其对黄瓜根围养分的影响?结果表明:1)YB-4 300倍蘸根对黄瓜根腐病防治效果最高, 病指防效为89.49%, 显著高于LWG-5 300倍和JPG-5 500倍的防治效果?2)LWG-5 500倍灌根对黄瓜根腐病防治效果最高, 为89.47%, 显著高于LWG-5 800倍和JPG-5 500倍防治效果?3)不管是灌根还是蘸根, JPG-5 500倍和YB-4 300倍均能显著提高黄瓜根围有效磷含量, 分别为99.68?86.81 mg/kg和84.30?86.56 mg/kg?因此, PGPR菌株在田间促进养分转化效果和对根腐病的防治效果综合评判, 用YB-4 300倍蘸根?JPG-5 500倍灌根和LWG-5 500倍灌根效果较好?     

不同干旱方式和干旱程度对玉米苗期根系生长的影响

以玉米杂交种高油115为材料,研究了直接干旱和渐进干旱两种方式(各设水分充足、轻度干旱和严重干旱3种处理)对管栽玉米苗期根系发育的影响.结果表明,采用渐进干旱方式,根系在轻度干旱时生长最好,严重干旱时最差;而采用直接干旱方武,根系在水分充足时生长最好,轻度干旱次之,严重干旱时最差.在水分充足条件下,细根(直径0.05～0.25 mm)的根长和根表面积及其占总根系的比例高于中等根(直径0.25～0.45 mm)和粗根(直径＞0.45 mm),直接干旱表现出降低细根比例、增加中等根和租根比例的趋势,说明细根受干旱的影响较中等根和粗根更大.这可能是玉米幼苗根系生长对干旱的一种适应性反映.     

Rhizobacteria‐mediated resistance against the blackeye cowpea mosaic strain of bean common mosaic virus in cowpea (Vigna unguiculata)

BACKGROUND: The present study investigated the effect of seven Bacillus‐species plant‐growth‐promoting rhizobacteria (PGPR) seed treatments on the induction of disease resistance in cowpea against mosaic disease caused by the blackeye cowpea mosaic strain of bean common mosaic virus (BCMV). RESULTS: Initially, although all PGPR strains recorded significant enhancement of seed germination and seedling vigour, GBO3 and T4 strains were very promising. In general, all strains gave reduced BCMV incidence compared with the non‐bacterised control, both under screen‐house and under field conditions. Cowpea seeds treated with Bacillus pumilus (T4) and Bacillus subtilis (GBO3) strains offered protection of 42 and 41% against BCMV under screen‐house conditions. Under field conditions, strain GBO3 offered 34% protection against BCMV. The protection offered by PGPR strains against BCMV was evaluated by indirect enzyme‐linked immunosorbent assay (ELISA), with lowest immunoreactive values recorded in cowpea seeds treated with strains GBO3 and T4 in comparison with the non‐bacterised control. In addition, it was observed that strain combination worked better in inducing resistance than individual strains. Cowpea seeds treated with a combination of strains GBO3 + T4 registered the highest protection against BCMV. CONCLUSION: PGPR strains were effective in protecting cowpea plants against BCMV under both screen‐house and field conditions by inducing resistance against the virus. Thus, it is proposed that PGPR strains, particularly GBO3, could be potential inducers against BCMV and growth enhancers in cowpea. Copyright © 2009 Society of Chemical Industry     

利用播期研究气候条件对黑龙江春玉米产量性状的影响

不同播期致使作物所处的气候条件不同,进而影响作物的生长发育和产量。本文以哲单37(特早熟,生育期113 d)、先玉335(中早熟,118 d)、郑单958(中熟,120 d)等3个玉米品种为试验材料,于2012年到2014年在黑龙江林甸县进行了为期三年分期播种试验,分析了玉米产量相关性状与各个生育阶段气象因子的关系。结果显示:分期播种对3个玉米品种均有影响,其中对早熟品种影响最大。播期主要通过影响玉米百粒重、穗长和秃尖引起产量的变化,贡献最大的因素是百粒重,总效应为0.847,其次是穗长,总效应为0.840,秃尖为负效应,总效应为-0.213。产量性状与气候条件相关性分析发现,玉米产量与抽雄~成熟期的日均温度、降雨呈显著正相关。因此在黑龙江第二积温带播种中早熟和中熟玉米品种(先玉335和郑单958)适当早播可增加抽雄~成熟期的日均温度,增加积温以达到增产的效果;晚播有利于避开早春易发生的干旱、冷害等自然灾害。采用偏最小二乘路径模型PLS-PM处理分析结果显示,播期对产量性状有较大的直接作用(0.763),同时通过影响各生育期的气候和土壤条件间接影响产量。综上所述,在黑龙江西部地区影响玉米产量最关键的气象因子是抽雄~成熟期的温度和降雨,此时适量的灌溉更有利于增加产量。     

The effect of soil type and farm size on the variability of weed infestation in maize (Zea mays L.) fields in the south-west region of Poland

Weeds are a primary factor limiting maize yield. Their occurrence and abundance are affected considerably by environmental factors and farming practices. The variability of weed number in maize depending on the soil type and farm size was investigated. Farms of different sizes vary in farming practices, which affects weediness. Based on this assumption, farm size was considered as indirect factor affecting weed abundance. An investigation of 45 farms that differed in size (5–15 ha, 15–50 ha, >50 ha) and soil type (chernozem, distric cambisol, haplic luvisol) was conducted. Thirteen dominant weed species persistently occurring in maize fields in south-western Poland were examined. Regardless of the soil type and farm size, the most abundant weed species were Echinochloa crus-galli and Chenopodium album. In addition to these species, the most numerous weeds on chernozems were Setaria viridis and Solanum nigrum, while on haplic luvisols and distric cambisols, the most numerous were Viola arvensis and Elymus repens. Additionally, on haplic luvisols, Anthemis arvensis was abundant. Small farms were stronger infested by weeds than large farms due to the implementation of extensive weed-supressing practices, especially low herbicide use. Soil type affected the number of weeds to a greater extent than did farm size.     

不同程度干旱胁迫对油菜种子萌发及幼苗生长特性的影响

采用不同渗透势聚乙二醇(PEG 6000)模拟干旱胁迫处理,观察油菜种子的萌发及生长状况.结果表明,干旱胁迫不同程度降低了油菜种子的萌发速率和出苗速率,-0.5～-1.0 MPa处理的最终发芽率随着渗透势的降低而显著降低,较对照降低了3.9%～86.9%,在-0.6～-1.0 MPa渗透势范围内不能成苗.试验7 d后将...