维管束病害的产量损失估计

对于维管束病害的概念,目前还缺乏统一的规范。通常多认为是镰刀菌之类的病原物所引起的各种枯萎病,如棉花枯萎病(Fusarium vasinfectum Ark.),芝麻枯萎病(F.vasinfectum Atk.var.sesami Zap.),番茄枯萎病(F.oxysporum(SchL.)),西瓜萎蔫病(F.oxysporum(SchL.),蚕豆枯萎病(F.avenaceum(FR)Sacc.)等,有人认为应该包括菌核类的各种病害,如烟草和油菜的菌核病(Sclerotinia sclerotiorum(Lib.)     

五味子茎基腐病发生初报

通过对辽宁省多个地区的调查,发现此病害发生普遍,尤其是二年生的五味子茎基腐病发生严重。五味子茎基腐病在5月上旬开始出现,6月初为发生盛期。本文对五味子茎基腐病进行了症状描述,并对不同地点采集的病样分别进行木质部和韧皮部病原物的分离、纯化。对分离得到的菌株按照柯赫氏法则进行致病性测定并对病原菌进行鉴定,结果表明,此病害可由木贼镰刀菌(Fusarium equiseti)、茄腐镰刀菌(F.solani)、尖孢镰刀菌(F.oxysporum)和半裸镰刀菌(F.semitectum)4种镰刀菌属真菌引起。针对此病害的发生特点,提出了相应的防治措施。     

百会枯萎病发生规律研究

百会枯萎病是江西省百合严重发生的一种病害．研究表明．病菌以菌丝在种球内,或以菌丝体、厚垣孢子及菌核随病残体在土壤中越冬,成为翌年的主要初侵染源．病害的发生与品种、连作、种球带菌、栽培技术及气候因素等密切相关．     

百合根腐病病原分离与鉴定

【目的】百合根腐病是严重为害百合鳞茎的一种土传病害,其病原种类多样,已成为遏制百合产业发展的重要因素之一。研究从百合根腐病的病样中分离得到多种分离物,选取其中2种做进一步鉴定。【方法】采用组织分离法对江西省鹰潭市余江区杨溪乡发生的百合根腐病样品进行病原分离,进一步通过形态观察、ITS和tef1序列比对以及致病性测定对病原进行鉴定。【结果】明确引起百合根腐病的病原为藤仓镰刀菌（Fusarium fujikuroi）和茄病镰刀菌百合专化型（Fusarium solani f. sp. lilii Wang）。【结论】研究从江西余江区采集的龙牙百合病鳞茎组织上分离得到两种代表性镰刀菌,分别为藤仓镰刀菌和茄病镰刀菌百合专化型。研究结果为百合根腐病的预防和防治提供了参考依据。     

百合枯萎病研究

 对镰刀菌(Fusarium sp.)引致的百合枯萎病,迄今国内外文献尚无详尽的报道。1989-1991年,对该病进行了初步研究。     

山东省大豆根腐病病原菌及其生物学研究

 1988-1989年采集山东大豆根腐病标样553个,经分离接种证明,致病菌有茄病镰刀菌[Fusarium solani(Mart.)Sacc.]、尖孢镰刀菌(F.oxysporum Schl.)和木贼镰刀菌[F.equiseti(Corda)Sacc.]三种,以茄病镰刀菌的分离频率最高,致病力最强,为主要致病菌。并对其培养特性、形态特征、寄主范围和光照、温度及pH对生长的影响进行了研究,根据这些研究结果,将大豆根腐病主要致病菌定名为茄病镰刀菌大豆专化型[Fusarium solani(Mart.)Sacc.f.sp.glycines Li et Luo],本专化型过去没有报告。     

西瓜枯萎病的防治研究进展

西瓜枯萎病又称萎蔫病,是由镰孢菌属尖镰孢菌西瓜专化型(Fusarium oxysporum schl.f.sp.niveum(E.F.Smith)Syn.et Hans.)侵染引起的维管束病害。枯萎病是西瓜上为害最严重的病害,在世界各西瓜产区均造成较大损失。由于该病属于土传病害,病菌一般分布在15~30cm深的耕作层内,主要以菌丝体、厚垣孢子在土壤中越冬,并可存活5~6a,防治十分困难,重茬地一般发病率在30%以上,严重地块达80%以上,甚至造成绝产。国内外对西瓜枯萎病的防治工作均十分重视,并取得了一些研究进展,现介绍如下。1农业防治1·1土壤处理土壤酸度过高,钙含量下降,有利于病菌…     

大白菜枯萎病病原镰刀菌种类的初步研究

 2014~2016年,由于栽培管理及重茬等原因,大白菜枯萎病在我国大面积发生,造成了巨大的经济损失。为了明确引起大白菜枯萎病的病原菌,本课题组从山东、内蒙古、河北、甘肃等大白菜主产区采集了具有典型枯萎病症状的病样,并对样品中的病原菌进行了分离和鉴定。形态学鉴定结果表明:分离物分别具有尖孢镰刀菌 (Fusarium oxysporum)、茄病镰刀菌 (F. solani) 和木贼镰刀菌 (F. equiseti)的形态学特征。柯赫氏法则验证结果表明:3种病原菌均能使大白菜发病,且发病症状与田间症状一致。此外,基于病原菌的rDNA-ITS和mt SSU序列的测序比对,3种病原菌与尖孢镰刀菌、茄病镰刀菌和木贼镰刀菌的同源性分别达99%~100%,这与形态学鉴定结果相一致。尖孢镰刀菌引起白菜枯萎病为国内首次报道,而茄病镰刀菌和木贼镰刀菌引起白菜枯萎病为国内外首次报道。     

浙江省荸荠上镰刀菌种类及其致病性

作者从浙江省11个县市采集病、健株及球茎标样共669个,经分离、纯化、鉴定,获以下7个镰刀菌种;尖孢镰刀菌(Fusarium oxysporum)、锐顶镰刀菌(F.acuminatum)、半裸镰刀菌(F.semitectum)、层出镰刀菌(F.proliferatum)、茄病镰刀菌(F.solani)、禾谷镰刀菌(F.graminearum)和木贼镰刀菌(F.equiseti)。田间观察和接种试验证明:F.oxysporum是引起荸荠茎秆枯萎的主要病原,这是一种新的危险性病害。病株矮小、黄化、基腐、后期倒伏。1986～1990年少数县市发病率达40％～50％。人工接种证明:F.acuminatum也属强致病性的种类。而F.proliferatum和F.solani则是引起贮藏期球茎腐烂的主要病原。其余种类仅具微弱或无致病性。     

百合枯萎病的防治技术

百合枯萎病又称茎腐病 ,半知菌类真菌是百合生产上的重要病害。染病株初期表现生长缓慢 ,下部叶片发黄失去光泽 ,后症状渐向上扩展 ,最后全株叶片萎蔫下垂 ,变褐后枯死。此外 ,尖镰孢菌百合专化型还可侵染鳞茎外皮基部 ,基盘上出现褐色坏死或腐烂 ,造成鳞片散落。从病鳞茎长出的植株叶片发黄或变紫 ,花茎少且小 ,鳞茎没有全部烂掉时就裂开 ,引起鳞茎腐烂后枯死。发病特点 :病菌以菌丝体在鳞茎内或以菌丝体及菌核随病残体在土壤中越冬 ,成为翌年初侵染源。该病常与百合其他地下根腐、鳞片腐等同时发生 ,带病鳞茎和污染的土壤是该病主要侵染源…     

The effects of soil solarization and soil fumigation on Fusarium wilt of watermelon grown in plastic house in south-eastern Spain

The effects of pre-planting solarization or fumigation with metham-sodium of sand-mulched soil on fusarium wilt of watermelon in plastic house culture were investigated at Almeria, south-eastern Spain. In two trials, 2 months' solarization increased the average maximum soil temperature by c. 5°C to 44-48° C at 10 cm depth and by 4-5° C to 40-42° C at 20-30 cm. The amount of Fusarium oxysporum in the upper 15 cm of a naturally infested soil was reduced by solarization and by fumigation. During the 9 months following treatment, the F. oxysporum population stabilized at a low level in soil solarized for 2 months, but fluctuated in soil solarized for 1 month and increased in fumigated soil. The amount of wilt in watermelon sown into this soil after treatment was generally low; plants growing in solarized or fumigated soil suffered less wilt than plants in untreated soil but the differences were not significant. In a soil artificially infested with the highly pathogenic race 2 of F. oxysporum f. sp. niveum, F. oxysporum populations were greatly reduced following solarization or fumigation, and fluctuated erratically thereafter. Solarization for 2 months completely controlled wilt in watermelon and gave a fruit yield almost five times that of plants in untreated soil. Solarization for 1 month only slowed disease development slightly but gave a yield more than twice that in untreated soil. Fumigation with metham-sodium retarded disease development considerably and tripled fruit yield. Plant performance was significantly better in soil solarized for 2 months than in uninfested control soil, suggesting beneficial effects of this treatment additional to wilt control.     

农田土壤中水盐运移理论与模型的研究进展

农田土壤水盐模型是了解农田土壤水盐动态变化规律 ,进行农田水盐模拟和预报的最有效的方法之一。围绕国内外土壤学者在农田土壤水盐运移方面的研究成果 ,综述了农田土壤中水盐运移的基本理论及其发展过程 ,就农田土壤中常用的几种数学模型的研究现状进行了概述。对水盐运移模型的数值解法进行了探讨 ,以期消除数值波动现象 ,减小计算中的数值弥散。最后就农田土壤水盐运移模型研究方面存在的问题进行了分析 ,对其发展趋势和今后研究重点进行了展望 ,希望为进一步的研究工作提供帮助。     

Black spot disease of alstroemeria caused by <Emphasis Type="Italic">Alternaria alstroemeriae</Emphasis> in Japan

A black spot disease on cultivated alstroemeria was found in Nagano Prefecture, Japan, in January 2008. The causal fungus isolated from the diseased plants was morphologically identified as Alternaria alstroemeriae E.G. Simmons & C.F. Hill. An inoculation test with the isolated fungus demonstrated that the disease is caused by this species. This is the first report of black spot on alstroemeria (kokuhan-byo, in Japanese) caused by A. alstroemeriae in Japan.     

Effects of artificially cultivated biological soil crusts on soil nutrients and biological activities in the Loess Plateau

Biological soil crusts （BSCs） play an important role in the early succession of vegetation restoration in the Loess Plateau, China. To evaluate the effects of artificially cultivated BSCs on the soil surface micro-envir- onment, we obtained natural moss crusts and moss-lichen crusts from the Loess Plateau of Shaanxi province, and subsequently inoculated and cultivated on horizontal and sloping surfaces of loess soil in a greenhouse. The chemical and biological properties of the subsoil under cultivated BSCs were determined after 10 weeks of cul- tivation. The results indicated that BSCs coverage was more than 65% after 10 weeks of cultivation. Moss crust coverage reached 40% after 5 weeks of cultivation. Compared with the control, soil organic matter and available nitrogen contents in moss crust with the horizontal treatments increased by 100.87% and 48.23%, respectively; increased by 67.56% and 52.17% with the sloping treatments, respectively; they also increased in moss-lichen crust with horizontal and sloping treatments, but there was no significant difference. Available phosphorus in cultivated BSCs was reduced, soil pH was lower and cationic exchange capacity was higher in cultivated BSCs than in the control. Alkaline phosphatase, urease and invertase activities were increased in artificially cultivated BSCs, and alkaline phosphatase activity in all cultivated BSCs was obviously higher than that in the control. Numbers of soil bacteria, fungi and actinomycetes were increased in the formation process of cultivated BSCs. These results indicate that BSCs could be formed rapidly in short-term cultivation and improve the mi- cro-environment of soil surface, which provides a scientific reference for vegetation restoration and ecological reconstruction in the Loess Plateau. China.     

土壤风蚀量随风速的变化规律研究

使用野外风洞作为风蚀研究的试验手段,通过农田土壤、沙及生土的风洞试验研究发现,农田土壤的风蚀量随风速呈指数函数变化,沙及生土的风蚀量随风速呈幂函数变化。试验研究还表明,农田土壤的风蚀量与表土层(3cm)的含水量呈显著负相关,沙的风蚀量与含水量的相关性不显著。风蚀导致土壤中的细颗粒成分大量损失,这是土壤颗粒粗化的原因所在。     

Conversion of communal grazing land into arable land and its impacts on soil properties and vegetation cover

With rapid population growth and absence of agricultural intensification, smallholders need more land to grow crops. This resulted in communal grazing land conversion to cultivated land. This study, therefore, aimed at exploring the magnitude of communal grazing land conversion and its influence on soil properties and vegetation cover change. Ecological time line approach was used to measure the magnitude of change. Plants and soil samples were taken from open grazing land, seasonal grazing land, 6 years old cultivated land, 16 years old cultivated land and 20 years old cultivated land. Moreover, 95 respondents were selected to assess their perception on the subject. Data were analyzed using statistical analysis system software. Results showed that grazing land declined by 41.88%, while cultivated land increased by 56.80% in the years between 1992 and 2012. Plant attributes showed significant (P?P?相似文献   

新疆不同植被类型土壤有机碳特征

准确评估不同植被类型的土壤有机碳库,对揭示土壤有机碳在陆地生态系统碳循环中的作用具有重要意义。通过分析新疆地区10种植被类型的土壤有机碳密度(SOCD)的分布特征,估算了该地区的土壤有机碳储量。结果表明:在10个植被类型的0~100 cm土壤剖面中,SOCD垂直分布特征明显,呈逐渐降低趋势。新疆SOCD以针叶林最大,其值为63.86 kg·m~(-2),其他植被类型依次为:草甸、阔叶林、沼泽、草原、灌丛、高山植被、栽培植被、荒漠和无植被类型。土壤有机碳储量最大值分布在草甸中,为4.89 Pg,其他植被类型依次为:荒漠、草原、高山植被、无植被(裸地)、针叶林、栽培植被、阔叶林、灌丛、沼泽。在0~100 cm的土壤层,新疆地区土壤有机碳储量为16.4Pg。     

荒漠草原区不同类型草地土壤水分特征研究

农牧交错带发展人工草地的关键是土壤水分的适应性,针对年平均降水量250mm的地区,以人工甘草草地、人工苜蓿地、人工苜蓿混播甘草地和天然草地为对象,通过2010年观测,计算各种草地0-100cm土层质量含水量的均值、变异系数,分析土壤水分的空间分布特征;利用土壤水分平衡和土壤分层储水量公式计算不同草地0-100cm土层总储水量,结合试验地生长季降水量变化,分析不同草地储水量与消耗量以及0-20、20-60、60-100cm土层水分均值随植被生长季的变化规律。     

Mineralisation of atrazine, metolachlor and their respective metabolites in vegetated filter strip and cultivated soil

In vegetated filter strips (VFS) the presence of perennial vegetation, rhizodeposition of labile organic substrates and the accumulation of an organic residue thatch layer may enhance microbial numbers and activity, thereby increasing the potential for mineralisation of herbicides and herbicide metabolites retained during run-off events. The objective of this laboratory experiment was to compare the mineralisation of atrazine and metolachlor with that of their respective metabolites in VFS and cultivated soil. With the exception of total bacteria, propagule density of the microbial groups, endogenous soil enzymes and microbial diversity were higher in the VFS soil. This correlated with increased mineralisation of metolachlor and its metabolites in the VFS soil and indicates potential for VFS to curtail the subsequent transport of these compounds. In contrast, the mineralisation of atrazine and the majority of its metabolites was substantially reduced in VFS soil relative to cultivated soil. Consequently, the potential for subsequent transport of atrazine and many of its metabolites may be greater in VFS soil than in cultivated soil if reduced mineralisation is not offset by increased sorption in the VFS.