油茶幼林根腐病防治试验

油茶幼林根腐病是近年来在我市油茶更新工程幼林中发生的一种新病害。病菌主要从植株伤口侵入，自发病到死亡要2～3年。保护幼树根茎部和主根是防治该病的关键措施。加强栽培管理，增强树势，用热石灰和适时用多菌灵、退菌特进行保护和防治是行之有效的防治措施。     

油茶根腐病根际土壤和根系内细菌群落结构及多样性

【目的】为鉴定根腐病潜在病原菌，改善土壤施肥制度，筛选油茶病害生防菌及研发防控药剂提供参考依据。【方法】采用16S rRNA基因Illumina Miseq高通量测序技术与PICRUSt功能预测相结合的方法，对5个病情等级下油茶根际土壤和根系内细菌群落结构和功能进行分析，并借助冗余分析等方法探讨土壤化学性质与细菌群落结构的关系。【结果】从油茶根际土壤和根系内共获得1 707个OTU，分属于18门257属。患根腐病后，细菌的丰富度指数（Chao1）及均匀度指数（Ace）升高。相较于健康油茶，患病油茶土壤内酸杆菌门的丰度有不同程度的下降，变形菌门的丰度升高；根系内变形菌门的丰度随病情等级的上升，逐级升高。相较于健康油茶，患病油茶土壤内慢生根瘤菌属的丰度有不同程度的增加；根系内苯基杆菌属的丰度随着根腐病病情等级的上升逐级升高。油茶林土壤细菌群落结构的主要影响因子为土壤的pH值、有机质含量、速效磷含量、速效钾含量。发病情况较轻与发病情况较重的油茶根际土壤和根系内细菌群落结构差异较大。油茶根际土壤和根系内细菌以代谢功能为核心，患病导致油茶根系内碳水化合物代谢和氨基酸代谢功能丰度提高，根际土壤内碳...     

油茶根际硅酸盐细菌拮抗菌筛选及稳定性分析

油茶Camellia oleifera是我国重要的木本油料树种,其种子提取的茶油富含不饱和脂肪酸,素有"东方橄榄油"之称。由层生镰刀菌Fusarium proliferatum引起的油茶根腐病,导致植株不能正常吸收养分和水分导致干枯死亡,给油茶产业发展带来了严重的威胁。硅酸盐细菌是一类重要的微生物肥料菌种,同时具有一定的生防功效。从油茶根际土壤中分离、纯化获得硅酸盐细菌,采用平板对峙培养法,筛选对油茶根腐病原菌层生镰刀菌有拮抗作用的菌株。结果表明:分离纯化得到的73株硅酸盐细菌,有7株具有具有拮抗作用,其中菌株K56抑制效果最好,平板对峙抑制率达到85.9%;对其稳定性进行分析发现,该菌抑菌活性物质经过热处理以后,基本失去生物活性;在pH值5.0~8.0时都有一定的抑菌活性,其中pH值6.0抑菌效果最好,抑菌圈直径达到8.8 mm;紫外线照射60 min后,抑菌圈直径为8.6 mm。抗菌谱测定结果表明,该菌的生防效果较专性。     

氮磷钾不同比例对油茶幼林根际土壤细菌群落结构的影响

本研究以3年生油茶幼林为研究对象,采用高通量测序技术对有机肥、氮磷钾不同比例的有机无机复合肥以及不施肥处理下的油茶根际土壤细菌多样性及群落结构进行分析.研究结果表明:5个处理中Y1处理的OTU和特有微生物数量为最高;各个处理优势细菌有所不同,CK、Y1、Y2的优势菌种为绿弯菌门,而Y3、Y4的优势菌种为放线菌门;群落物种丰富度指数(Chao1指数和ACE指数)表明,施肥能提高土壤细菌的丰富度,其中Y1处理的Chao1指数、Y4的ace指数分别比对照提高了19.2％、20.3％;AN、AK、TK是油茶幼林根际土壤优势细菌的主要影响因子,Y1处理下土壤细菌的丰度为所有处理中最高.研究结果揭示了氮磷钾不同比例对油茶幼林根际土壤细菌的群落结构的和影响,为油茶幼林施肥提供了理论依据.     

氮磷钾不同比例对油茶幼林根际土壤细菌群落结构的影响

本研究以3年生油茶幼林为研究对象,采用高通量测序技术对有机肥、氮磷钾不同比例的有机无机复合肥以及不施肥处理下的油茶根际土壤细菌多样性及群落结构进行分析.研究结果表明:5个处理中Y1处理的OTU和特有微生物数量为最高;各个处理优势细菌有所不同,CK、Y1、Y2的优势菌种为绿弯菌门,而Y3、Y4的优势菌种为放线菌门;群落物种丰富度指数(Chao1指数和ACE指数)表明,施肥能提高土壤细菌的丰富度,其中Y1处理的Chao1指数、Y4的ace指数分别比对照提高了19.2％、20.3％;AN、AK、TK是油茶幼林根际土壤优势细菌的主要影响因子,Y1处理下土壤细菌的丰度为所有处理中最高.研究结果揭示了氮磷钾不同比例对油茶幼林根际土壤细菌的群落结构的和影响,为油茶幼林施肥提供了理论依据.     

褐根病菌分子检测与生物防治研究进展

褐根病是由有害木层孔菌Phellinus noxius引起的林木和多年生果树的重要根部病害。通过综述了近年来有关褐根病菌的单克隆抗体检测法等4种分子检测技术和生防放线菌等4种生物防治的研究,指出由于分子检测方法的敏感度和特异度高,可用于早期诊断褐根病菌;同时也表明用生物防治替代传统的化学防治进行褐根病菌防治,并使生物制剂有效推广运用,将是今后研究的热点和控制该病害的主要手段。     

绿巨人褐腐病化学防治试验

用29种杀菌剂对绿巨人褐腐病病原菌进行室内毒力测定，结果显示：25％健绿宝、70％代高乐、40％百可宁、50％消菌灵、72％克露、70％百德富、25％绿乳铜和70％土菌消8种药剂对绿巨人病株叶柄病斑和根部感染具强烈抑制作用。用这些杀菌剂进一步进行室外防治试验，对绿巨人叶柄、根部接种防治试验和对自然感染防治试验结果都表明，最理想的防治药剂为健绿宝。代高乐、百德富、新万生和土菌消也有明显的抑制效果，但百德富药效不太稳定。无伤口接种病菌不能侵入，而植株一旦受到创伤，喷淋杀菌剂在24h内都不能阻止病菌的接触侵入，接种前或后喷药都不能有效根除病菌的侵染；所以防止人为创伤、虫伤、自然风雨伤是防病的重要措施。     

油茶软腐病的鉴别和防治试验

本文从症状特点、病菌形态和发生发展时期将油茶软腐与油茶炭疽病、油茶赤枯病进行了比较,为生产上准确鉴别油茶软腐病提供依据,有利于针对性地进行防治。文中介绍了防治试验结果,提出了切实有效的防治措施。     

笋用竹正常植株和病害植株根际微生物的分析

以竹园采集土样分离出的根际微生物为主要研究对象,采用16s rDNA分子生物学手段和常规生理生化分析方法,对笋用竹正常生长植株及病害植株进行分析研究。有病竹植株的根际微生物可培养菌落数目比正常竹植株的多。特征分析表明:在分离纯化出的45株细菌中,其中的8株细菌初步鉴定为:菌株5-1-4为地衣芽孢杆菌Bacillus licheniformis,菌株5-1-10为苏云金芽孢杆菌Bacillus thuringiensis,4-1-17为枯草芽孢杆菌Bacillus subti-lis,菌株3-1-8为洋葱博克霍尔德菌Burkholderia cepacia,菌株2-1-9为粘金黄菌Chryseobacterium gleum,菌株4-1-14为短小芽孢杆菌Bacillus pumilus,菌株4-1-16为普通变形菌Proteus vulgaris,菌株4-1-6为产气肠杆菌Enterobacter aerogenes。     

毛竹及浙江淡竹根际联合固氮的研究*

对毛竹和浙江淡竹利用Ｎ２回充法测定根系固氮活性，分别可达９．９和２．１ｎｍｏｌＣ２Ｈ４／（ｇ干根．ｈ）；用半固体培养基富集后的极系固氮活性范围在２０－１００ｎｍｏｌＣ２Ｈ４／（ｇ鲜根．ｈ）的占４０％以上。对浙江淡竹根据各部位固氮菌数采用乙炔还原－ＭＰＮ法计测结果是根际土壤３．４×１０＾５菌数／ｇ干土；根表、根内分别为２．２×１０＾５，３．０×１０＾４菌数／ｇ干根。采用划线法在浙江淡竹根际分离到３株     

枣疯病的研究现状

枣疯病是枣树的毁灭性病害,在我省陕北、关中等枣区有日趋严重之势。该病症状为萎黄丛生及花、叶畸形,其病原为类茵原体(MLO)。除可通过嫁接传病外,中华拟菱纹叶蝉、凹缘菱纹叶蝉和红闪小叶蝉是三种重要的传病媒介昆虫。枣疯病的发生还与枣树的品种、枣园的土壤、海拔、坡向等有关。枣疯病的防治途径有药物治疗、砍疯枝、铲病株、热处理脱毒等,但以培育抗病品种、选育无病苗木和加强栽培管理、增强树势为其根本的防治措施。     

花椒根腐病防治的研究

苗圃预防试验结果表明，粉锈宁可有效地防治花椒苗期根腐病，经处理后的苗圃发病率为对照的１／１７。不同立地类型移栽试验显示，新垦山地及农耕地中的砂土，砂壤土较适宜花椒生长，不易感染根腐病，成年椒园根腐病的防治效果，以粉锈宁灌根方式较好，并与施药剂的次数有关，在此基础上，本文结合病害流行条件与花椒栽培布局结构关系，初步探索出预防和治疗根腐病害的综合措施。     

枣缩果病研究进展

对枣缩果病病原的种类、症状类型、侵染途径、影响发病因素、防治方法等方面的研究进展进行了综述。迄今已报道过的病原菌有6种真菌和2种细菌,病原菌在枣树皮、枣枝、枣头、枣叶、枣吊等部位皆可越冬;病原主要借助风雨作用传播,通过伤口或自然孔口传病;从花期开始整个生长期地上部各器官都可侵染,其中在叶和枣花上不表现症状,果实上到近成熟期才开始表现症状;果实症状主要有铁皮和缩果两种类型,果实症状发展可分为晕环、水渍、提前着色、萎缩、脱落5个阶段;发病程度受气候、地势、土壤类型、栽培条件和间作物种类、品种、树龄、枝龄、树势、枣果成熟度等多种因素的影响;防治措施包括加强枣园综合管理,提高树体抗病能力及化学农药防治等。针对枣缩果病研究中的问题,提出了今后的研究方向。     

球毛壳菌对樟子松的侵染规律研究

榆林风沙区樟子松枯死主要发生在10—15年生幼龄林上，7月上旬至8月下旬为感病高峰期，翌年4月中旬至5月中旬为死亡高峰期。病菌孢子在整个生长季均能放散与传播，降雨节律及降雨量直接影响孢子的扩散与数量。人工接种发现：病菌的侵入期主要在6月中旬至8月中旬，潜育期半个月，侵入途径是伤口，病株感病部位及枯死枝是病原菌的越冬场所，密度高，植被盖度大的林分感病重。     

Effect of slash removal on Gremmeniella abietina incidence on Pinus sylvestris after clear-cutting in northern Sweden

The Gremmeniella abietina outbreak in Sweden in 2001-2003 forced forest owners to sanitary clear-cut large areas of middle-aged Pinus sylvestris stands. There is, however, little knowledge of effective reforestation of P. sylvestris on G. abietina-infected sites. Gremmeniella abietina disease incidence on P. sylvestris seedlings planted in 2003 was studied with and without (control) removal of infected P. sylvestris slash. Removed slash was piled in stacks around the regeneration plots. The seedlings were planted within 1 year after sanitation felling on three sites in northern Sweden. One year after planting, G. abietina pycnidia were found on 32% of the control seedlings and total infection, including stem cankers, reached 44%. Total and G. abietina-induced mortality was 15 and 10%, respectively. The method of removing and piling the infected slash reduced the number of infected seedlings by 50% and seedling mortality by 27% 1 year after planting, compared with control. Consequently, even if there is a clear sanitation effect of removing infected slash to the sides of the regeneration area, it does not eradicate the infection source from the stands. Postponed planting, slash burning or complete removal of the infected slash is needed to minimize the infection risk. The positive correlation found between slash coverage and infection rate indicates that clear-cuts with large amounts of infected slash should be given priority for slash treatment.     

杂交竹枯萎病侵染情况研究

杂交竹枯萎病是近年来在广西首次发现的新病害,该病害传染迅速,可造成竹林成片枯死。我们对自然感病的植株组织分离培养并纯化菌落,获得镰刀菌的纯培养,以该菌株进行病害的田间人工诱发试验,无论是菌株营养体菌丝或繁殖体孢子,在无伤或有伤的情况下,笋期均可从幼嫩组织侵入,并能引起与自然相一致的症状;经过对先年生的越冬病竹进行病变组织的分离培养试验和病竹周围表土内越冬病菌的分离培养试验,在上一年生的病竹内和病竹周围的表土内,越冬后的病原菌均能存活,可成为来年病害发生的初次侵染源。     

Armillaria root rot: Influence of soil nutrients and pH on the susceptibility of conifer species to the disease1

Seedlings growing on soil with nutrient deficiency and a lower pH were smaller and less vigorous than the seedlings growing on non-deficient soil with a comparatively higher pH. A higher percentage of roots and seedlings were infected and more seedlings died on soil with nutrient deficiency and a lower pH than on non-deficient soil with a higher pH. Non-vigorous seedlings also contacted infection earlier and showed more mycelial growth than the vigorous seedlings. Roots of vigorous seedlings showed more resinosis and callus formation, indicating resistance during the establishment of the fungus on the host. Alterations in the level of nutrients in vigorous and non-vigorous infected seedlings were generally similar.     

Impacts of burial and insect infection on germination and seedling growth of acorns of Quercus variabilis

Rodents usually exert important role, through their scatter seed hoarding behavior, on plant regeneration in the field. To investigate the effects of burial and insects infection on germination and seedling growth of acorns of Quercus variabilis, perfect and infected acorns were buried in the soil among four depths, 0 cm, 4 cm, 8 cm and 12 cm, to simulate the seed hoarding behavior by rodents in the field. The results showed that (1) the germination rate were both high, under 4 cm burial depth, for perfect and infected acorns (92% and 53% separately), and decreased significantly with increased burial depth; (2) perfect acorns germinated better in 4 cm burial depth group by autumn of first year; (3) there 32% (perfect) and 26% (infected) acorns with 0 cm burial depth, on the soil surface, germinated successfully; for infected acorns, the 4 cm depth group had the best germination or seedling recruitment in both the first year and the second year; (4) acorns of Q. variabilis exhibited dormancy period ca 7 months; (5) burial, infection, and the interaction between these two factors influenced several aspects including stem height, leaf weight, Tannic acid, and biomass within seedling growth; (6) the results from this study suggest that proper burial would be helpful for the germination and seedling growth, and seedlings of shallow buried acorns had an advantage in their early development; and (7) infection by insects will not inevitably influence seedling early development.     

Localized within‐ and between‐tree variation in nematode distribution during latent state of pine wilt disease makes the disease status cryptic

The pinewood nematode (PWN), Bursaphelenchus xylophilus, is the causal agent of pine wilt disease, an epidemic disease that has severely damaged pine forests in East Asia. The disease has spread to northern areas in Asia and parts of Europe. To prevent disease spread as the forefront of damage prevention, a better understanding of infection status is highly important. Not all infected trees show disease symptoms, and such asymptomatic PWN‐carrying trees are likely to be overlooked and can become a pathogen reservoir. To elucidate PWN infection status in asymptomatic trees, we performed PWN inspection of branches and trunks in 21 test trees in two different conditions: trees that had experienced PWN inoculation and those with suspected PWN infection that had experienced transient foliage discoloration. We detected PWNs in eight test trees (38%) and in 13 (1.5%) of a total of 843 samples. The difference in these percentages suggests that nematode inhabitation was highly localized within the trees, possibly owing to the restricted migration of PWNs. Our data demonstrated that trees that were once weakened but recovered their vigour can persist, as the asymptomatic carriers, in the forest. The implications for disease control are also discussed.     

Controlling and predicting the spread of heterobasidion annosum from infected stumps and trees of picea abies

Two Norway spruce stands with heavy infections of Heterobasidion annosum were clear‐cut in 1957 and 1959 in Sweden. The stumps were extracted, the soil sifted to remove most of the roots, and young Norway spruce were planted. After 25 and 28 years, H. annosum had infected 1 % and 2% of trees on plots where stumps had been removed and 17 % and 12% of the trees on control plots, respectively. Several of the H. annosum clones fruiting on old‐growth stumps were also detected in decayed, standing trees. The same fungal clone was found to be infecting adjacent trees from several old‐growth stumps. In addition to old stumps, stumps from recent thinnings and diseased living trees were traced as infection sources. Their relative importance in spreading disease was estimated. Disease risk predictions based on the distance of a tree from various infection sources correlated well with observed frequencies of rot.