干旱胁迫下复叶槭挥发物在7月和8月的变化(英文)

1999年 7月和 8月对干旱胁迫下 3年生复叶槭幼苗挥发物进行了检测 .7月检测出 10种挥发物 (丁醇、戊醇、Z 3 己烯 1 醇、E 2 己烯 1 醛、戊醛、戊酸、己醛、己酸、苯乙酮和长叶烯 )明显受干旱的影响 .除长叶烯外 ,其他化合物释放量随干旱程度的增加而增加 .复水后 ,除长叶烯外其他化合物释放量都下降 .在 8月份 ,没有发现上述挥发物与干旱之间的相关性 .但是 ,另外 7种物质受干旱影响较大(包括环己基异硫氰酸酯、肉桂腈、苯酚、萘、庚醛、长叶烯、苯丙噻唑 ) .这些物质在干旱条件下释放量下降而复水后大部分物质升高     

西双版纳辣木主要病虫害研究初报

经2003～2006年调查,初步描述了云南西双版纳生产性实验栽培辣木的5种病害和5种虫害,其中以半裸镰刀菌和黑星菌所致的落叶病、嫩梢萎蔫病、枝条溃疡病、豆荚褐腐病、幼荚干缩病,以及白蚁、蚜虫等为害严重,经济地位重要;对辣木病害的综合管理进行了讨论。     

Effect of ectomycorrhizal fungi on bacterial wilt of Eucalyptus

Bacterial wilt caused by Pseudomonas solanacearum, is a very serious disease of Eucalyptus in southern China, mainly in Guangdong, Hainan and Guangxi provinces. It causes the death of seedlings and young trees and the mortality may exceed 90 percent in some sites. Susceptible species include E. grandis, E. urophylla, hybrids between the two and E. citriodora. In nursery and field trials with E. urophylla and field trial with E. grandis x E. urophylla inoculation of ectomycorrhizal fungi was found to reduce the incidence of the disease. Some fungal isolates were more effective than others.     

Different development of pine wilt disease in artificially infectedPinus thunbergii seedlings potted together with different tree species

To evaluate the effect of adjacent tree species on the susceptibility of Japanese black pine (Pinus thunbergii) to pine wilt disease, an inoculation experiment was conducted usingP. thunbergii seedlings potted with seedlings of six tree species,i. e. Alnus sieboldiana, Eurya japonica, Lespedeza bicolor formacutifolia, Pinus thumbergii, Robinia pseudo-acacia andSarothamus scoparius. About ten months after planting, they were inoculated with the pinewood nematode (Bursaphelenchus xylophilus) in early July 1992. After that, the proportion of pine seedlings with completely discolored foliage increased more quickly when the seedlings were potted withR. pseudo-acacia, S. scoparius orA. sieboldiana than when potted withP. thunbergii, L. bicolor orE. japonica. At the end of the study period, 17 weeks after inoculation, it reached 90.6%, 90.0%, 87.5%, 72.7%, 63.3%, and 59.4% when the pine seedlings were potted withR. pseudo-acacia, S. scoparius, A. sieboldiana, P. thunbergii, L. bicolor andE. japonica, respectively. This indicated that the susceptibility ofP. thunbergii seedlings to pine wilt disease was influence by the species of adjacent trees.     

光肩星天牛对干旱胁迫下复叶槭挥发物的嗅觉反应

对干旱胁迫下3a生复叶槭的挥发物进行了鉴定。当复叶槭受到干旱胁迫时，9种化合物释放量升高(包括：丁醇、戊醇、反—2—己烯—1—醛、顺—3—己烯—1—醇、戊醛、戊酸、己醛、己酸、苯乙酮)，而长叶烯释放量降低：复叶槭复水后苯乙酮升高，但其他挥发物释放量降低。通过GC—EAD检测了光肩星天牛对其中某些化合物的触角电位反应，并使用诱捕器和人工合成单体进行了田间生测实验。丁醇、戊醇和顺—3—己烯—1—醇能引起光肩星天牛的触角反应，这一结果在田间实验中得到了证实。这表明干旱胁迫在光肩星天牛选择寄主植物方面起着重要作用。     

Seasonal variations in the incidence of pine wilt and infestation by its vector, Monochamus alternatus, near the northern limit of the disease in Japan

During the last few decades, pine wilt disease has spread to cool-climate regions in Japan and, more recently, the potential risk of it spreading into the European midwest has also become a concern. In a coastal pine stand (84.7?ha) in Akita, near the northern limit of pine wilt disease in Japan, we investigated seasonal variations in the incidence of damage caused by the disease to trees and oviposition by the disease’s insect vector, Monochamus alternatus, during a two-year period. Foliage discoloration occurred throughout each year, and its seasonal variation showed a bimodal pattern in Pinus thunbergii (a higher peak in May–June and a smaller peak in October) and a clear peak in June in P. densiflora, which differed from the patterns in seasonal variation seen for warm-climate regions. Oviposition scars by M. alternatus were found in 40–45% of the trees damaged each year. The percentage of trees that had oviposition scars was higher in P. thunbergii than in P. densiflora. This appeared to reflect the difference in seasonal discoloration pattern between the two species. Analysis of the oviposition risk showed that trees that exhibited discoloration starting between July and October had a significantly higher risk or significantly higher oviposition scar densities, particularly for those that became discolored between August and September (2.5–14.6-fold higher risk than during other months). Oviposition scar densities per damaged tree were similar within the period of higher oviposition risk. Considering both oviposition risks and scar densities, we concluded that trees with discoloration that become apparent between July and October are important targets for preventing the spread of pine wilt disease in Akita.     

Nutrient concentrations in roots, leaves and wood of seedling and mature sugar maple and American beech at two contrasting sites

Differences in sensitivity to soil conditions across tree species and developmental stage are important to predicting forest response to environmental change. This study was conducted to compare elemental concentrations in leaves, stems, and roots of (1) sugar maple (Acer saccharum Marsh.) seedlings vs. mature trees and (2) mature sugar maple vs. mature American beech (Fagus grandifolia Ehrh.) in two sites that differ in soil base saturation and pH. Both sites are located in Huntington Forest, NY, USA; one site (hereafter ‘H’) has higher soil pH and Ca, Mg, and Mn concentrations than the other site (hereafter ‘L’). Sugar maple growth at H (14.8 cm² year⁻¹ per tree) was much greater than at L (8.6 cm² year⁻¹ per tree), but the growth of beech was not different between the two sites. Leaves, roots, and stem wood of mature beech trees and sugar maple seedlings and mature trees were sampled for nutrient analysis. Foliar Ca, K, and Al concentrations were positively correlated with soil elements, but Mn concentrations were negatively correlated. Sugar maple differed more than beech between sites in foliar K and Mn concentrations. Root Mg and P concentrations reflected soil chemistry differences, in contrast to foliar concentrations of Mg and P, which were indistinguishable between the sites. In sugar maple, seedlings differed more than in mature trees in nutrient concentrations in roots, especially for Mg and Mn. Although beech was not as responsive to nutrient availability as sugar maple in foliar and root nutrient concentrations, Ca and Mg concentrations in beech wood were higher in H (52% higher for Ca and 68% higher for Mg), while sugar maple did not differ between sites. Sugar maple regeneration failure on acidic soils in the same region is consistent with our finding that sugar maple seedlings were very sensitive to nutrient availability. This sensitivity could ultimately contribute to the replacement of sugar maple by American beech in regions of low pH and base cations if base cation leaching by anthropogenic deposition and tree harvesting continues.     

Fusarium equiseti is associated with the wilt and dieback of Aquilaria malaccensis in Northeast India

Aquilaria malaccensis, categorized by IUCN as globally vulnerable, is in high demand in the Middle East and Asian markets for its unique resinous agarwood. In August 2015, symptoms of dieback were observed on A. malaccensis trees planted in the Medicinal and Aromatic Plant Garden, Panbari, Golaghat of the Assam Forest Department. The entire crowns of 70 trees showed complete leaf loss and severe dieback. Rotting at the collar region and of roots was also observed. Isolation from the infected roots consistently yielded Fusarium equiseti identified following standard laboratory procedures and analysis of the internal transcribed spacer (ITS) sequence of the ribosomal DNA. Symptoms of wilt, dieback and root rot were observed on 5‐month‐old Aquilaria seedlings 25 days after inoculation with the isolated fungus. This paper is the first report of F. equiseti causing wilt and dieback of A. malaccensis.     

三种槭树三年生幼苗抗寒性研究

温度影响着植物的自然地理分布,其中极端低温会给辽东的城市园林绿化建设以及绿化树幼苗培育带来诸多不利,致使许多观赏性绿化树种栽植和培育过程中,因遭受低温胁迫超过其低温耐受极限造成树木整株死亡。近年对于彩叶树抗寒性研究比较多,但对于苗圃播种苗、移床苗抗寒性的讨论和研究不是很多。以秋季红叶观赏性为主要特点的元宝枫、色木槭、拧筋槭3年生幼苗作为研究对象,通过低温处理,然后测定其相对电导率,并用logistic方程回归求其半致死温度,研究3种槭树幼苗的抗寒性,为辽东山区苗圃地培育绿化用彩叶树幼苗提供依据。     

Bacterial Wilt and Boron Deficiency Stress： A New Disorder in Eucalypt Plantations in South China

INTRODUCTIONEucalypts are particularly sensitive to Boron (B)deficiency resulting in loss of crown vigour, shootdeath, poor stem form, and reduced wood quality.B deficiency is a major constraint to theproductivity of eucalypt plantations in many partsof Asia (Dell et al. 2001, 1994). The symptoms ofB deficiency are more severe during the dry seasonand thus mildly affected trees may partially recoverduring the following wet season. The sites withsandy soils derived from granite and sands…     

松材线虫病生物防治研究进展

松材线虫Bursaphelenchus xylophilus是外来入侵生物,主要依靠媒介昆虫的携带在自然界中扩散传播。目前松材线虫病的生物防治研究主要集中在对松材线虫本身及其传播媒介——松墨天牛的控制两方面。本文对国内外松材线虫病的生物防治方法研究做了总结。     

Relationship between the incidence of pine wilt disease and the drainage area

We examined the relationship between the incidence of pine wilt disease and moisture conditions in the stand level ofPinus densiflora Sieb. et Zucc. forests in the warm-temperate zone of the western part of Japan. For this analysis, pine trees killed by pine wilt disease were distinguished from the suppressed trees by their position in the layer of the pine forest stand. The drainage area, which is small in the upper part and large in the lower part of the slope, was adopted for representing the moisture conditions in the soil of the slope. The percentage of the pine trees killed by pine wilt disease increased as the size of the drainage area increased. This result suggested that the incidence of pine wilt disease tended to be high in areas with moist conditions. Pine trees attacked by the pinewood nematode die from extensive water deficit due to tracheid cavitations. Pine wilt disease mainly emerges in the summer when the soil water conditions become especially severe, and the radical water stress is thought to accelerate the disease. It was assumed that pine trees in the plots with the small drainage area resisted the influence of the attack of the pinewood nematode because pine trees in the plots with the small drainage area encountered long-term water stress and acquired drought tolerance. Pine trees in the plots with the large drainage area were presumed to be well established in the moist conditions and not to have acquired drought tolerance. The drought tolerance of pine trees was thought to be an important factor in resistance to pine wilt disease.     

Natural regeneration in oak wilt centers

Openings, 0.2 ha and less, and 3–12 years old, caused by the oak wilt fungus Ceratocystis fagacearum had abundant oak reproduction, averaging 4700 stems per ha. Species of other woody reproduction made up over 27 000 stems per ha. Seedling sprouts comprised 54%, seedlings 30%, and stumps sprouts the remainder of the reproduction. No infections were found except a few on stump sprouts of diseased oak stumps. Oakhickory reproduction was abundant on all site qualities, but especially so on the poorer sites with over 8000 stems per ha. Sugar maple reproduction was much more abundant on high quality sites, also with over 8000 stems per ha. The reproduction in the oak wilt openings was judged to be similar to that of selection cuttings in disease-free but otherwise similar stands, and should respond in like manner.     

我国桉树青枯病研究进展

桉树青枯病害是危害桉树生产的主要病害,近年来桉树青枯病的流行和发生对我国南方桉树产业造成很大经济损失.本文对当今主要桉树青枯病病害特点,青枯病的发生和流行因素,青枯假单胞杆菌对寄主桉树的致病机制及对抗病的差异和抗病机理等研究成果和现状作一概述,并就存在的问题提出相应的建议.     

Biocontrol potential of Pseudomonas azotoformans,Serratia marcescens and Trichoderma virens against Fusarium wilt of Dalbergia sissoo

Wilt disease caused by Fusarium solani is a serious constraint to Dalbergia sissoo (shisham) plantations in northern India. In this study, the antagonistic potential of 40 bacterial isolates recovered from rhizophere soil of healthy shisham trees, and a well‐characterized Trichoderma species (Trichoderma virens) were tested for their possibility as biocontrol agents for F. solani. Two promising isolates (S1 and S15) were identified which inhibited pathogen growth, caused chitin degradation, produced siderophores and solubilized phosphate in vitro. Isolate S15 scored highest for hydrogen cyanide (HCN) production while isolate S1 was a non‐HCN producer. These two isolates were identified as Serratia marcescens (S1) and Pseudomonas azotoformans (S15) following sequence analysis of 16S rDNA. In dual culture assays, T. virens caused 80% inhibition of mycelial growth of the test fungus. The three selected antagonists when tested in planta in the glasshouse completely suppressed production of wilt symptoms on 12‐month‐old shisham plants. Further work is needed to ascertain the potential of these isolates to be used as biocontrol agents to manage shisham wilt under field conditions.     

First report of Fusarium solani causing wilt of Melia dubia

Melia dubia, a multipurpose tree species, is gaining importance to meet the demand supply gap of timber, plywood and pulpwood . In June 2016, a serious outbreak of wilt disease was observed in M. dubia seedlings planted in the Central Nursery of Forest Research Institute (FRI), Dehradun, India. The disease led to the destruction of one hundred thousand (100,000) seedlings. Earlier in June 2012, serious wilting of M. dubia seedlings was observed in Haryana, India. The pathogen was identified as Fusarium solani following standard laboratory procedures and sequence analysis of the internal transcribed spacer (ITS) region of the ribosomal DNA (rDNA). The pathogenicity of three isolates has been proved under greenhouse conditions. This is the first report of F. solani causing wilt of M. dubia.     

Antioxidant activity of Pinus pinaster infected with Fusarium circinatum is influenced by maternal effects

The antioxidant activity of Pinus pinaster seedlings originating from two contrasting maternal environments and inoculated with the fungal pathogen Fusarium circinatum was examined. The antioxidant activity related positively to the stem necrosis caused by the pathogen (p = 0.005), but this relationship differed significantly between maternal environments (p ≤ 0.002). Seedlings from mother trees grown under a favourable environment expressed a more variable antioxidant activity to F. circinatum than seedlings from mother trees grown in a less favourable environment. Antioxidant activity ranging from 80 to 100% resulted in shorter necrosis in seedlings from the favourable maternal environment than in seedlings from the unfavourable environment. Maternal effects caused shifts in the relationship between antioxidant activity and necrosis in offspring, and significantly modified the individual plant capacity for antioxidant response on pathogen penetration.     

重灾区松材线虫病的治理试验

松材线虫病近距离传播是由松褐天牛自然扩散完成的。通过人工清理病死木结合化学防治,在中心疫区保住了1块松林。实践证明,人工清理后通过有效保护措施,能够控制松材线虫病。     

Molecular phylogeny and pathotyping of Fusarium solani: a causal agent of Dalbergia sissoo decline

Sissoo (Dalbergia sissoo), commonly known as shisham, is amongst the finest woods of South Asia, but ‘wilt’ disease has caused a rapid decline in this species. The cause of the disease remains uncertain. The aim of this study is to identify the causal agent of the disease and characterize isolates made from diseased trees, based on genomic data and variations in virulence. Samples of infected roots, stems and the ooze exuded from infected trees were obtained from plants showing symptoms in different geographical regions of India for the isolation of microorganisms. Isolates were used to inoculate healthy plants. Based on the morphological characteristics, genus‐ and species‐specific PCR, and in silico analysis of 5.8S rDNA‐ITS regions, of the 38 fungal isolates, 24 and 14 were identified as Fusarium solani and Fusarium sp., respectively. In a pathotyping study, eighteen F. solani isolates, isolated from roots and stem parts of symptomatic plants, induced typical wilt symptoms when inoculated through soil and roots on D. sissoo seedlings of 1–15 months in age. The population of F. solani was the highest in infected roots and the lowest in parts of stems, gradually decreasing with height, and was isolated constantly up to approximately 40% height of the seedling. F. solani isolates used in inoculations were successfully re‐isolated from the rhizosphere, infected roots and wilted stems, as confirmed using isolate‐specific DNA fingerprints. Molecular phylogenies based on rDNA‐ITS sequences showed that the 38 isolates fell into 2 groups. Group I comprised of F. solani isolates from D. sissoo and F. solani sequences in the NCBI GenBank database, whereas group II included Fusarium isolates other than F. solani. These results are helpful in developing integrated control measures for this highly variable pathogen and to establish a base for future population studies.