华山松大小蠹和共生真菌分泌酶组成分析

对华山松大小蠹消化道和共生真菌胞外蛋白和酶类组成分析的结果表明 ,华山松大小蠹消化道和共生真菌胞外均可分泌多种酶类 ,其中华山松大小蠹消化道具自身分泌纤维素酶、酯酶、蛋白酶和淀粉酶的能力 ,但不具分泌漆酶等木质素分解酶的能力 ,因此 ,其虽然可以直接利用寄主华山松韧皮部和木质部边材组织内的纤维素、淀粉、多糖、酯类和蛋白等营养物质 ,但不能分解利用木质素类营养。而共生真菌除具有胞外分泌纤维素酶、酯酶、蛋白酶和淀粉酶的能力外 ,还能够在寄主华山松组织内木质素的诱导下分泌漆酶 ,以充分利用华山松韧皮部和木质部内纤维素、木质素、淀粉和脂类物质。此外 ,华山松大小蠹消化道和共生真菌胞外分泌的纤维素酶、酯酶、淀粉酶和蛋白酶还存在结构和营养利用方面的差异。     

华山松大小蠹对华山松韧皮部营养和矿物元素的利用

对健康和蓝变真菌侵染的华山松韧皮部以及华山松大小蠹排泄物中粗蛋白、粗脂肪、粗纤维、淀粉、还原性糖、可溶性总糖、游离态氨基酸和Na,K,Ca,Mg,Fe,Cu,Mn,Zn等8种元素进行分析,结果表明:华山松大小蠹对寄主华山松营养物质的利用率依次为:还原性糖＞粗脂肪＞可溶性总糖＞粗纤维＞淀粉＞粗蛋白.华山松韧皮部的17种游离态氨基酸中含有华山松大小蠹必需的9种氨基酸;华山松大小蠹对寄主华山松韧皮部组织内的Na,K,Ca,Mg,Fe,Cu,Mn,Zn等8种矿物元素需求量存在明显差异,其中对K元素的需求量最大,而对Cu,Mn,Zn 3种元素的需求量较小.同时,华山松大小蠹共生真菌能够加速华山松木质部和韧皮部中营养的分解转化,为华山松大小蠹在被害华山松韧皮部和木质部间的生存和发育创造条件,并加速被害华山松树势的衰弱和死亡.     

华山松大小蠹带菌部位及贮菌器结构研究

研究了秦岭林区华山松大小蠹带菌部位及贮菌器结构,结果表明：华山松大小蠹成虫具有前胸背板体壁凹陷和刺毛构成的贮菌器,用于携带和传播真菌,其所携带真菌种类以穿孔细帚霉和小线嘴壳为主,以真菌孢子为唯一携带方式,并在在虫入侵健康寄主华山检针携带真菌孢子接种于华山松木质部。华山松大小蠹消化道内不具有含菌细胞和特化的带菌结构,消化道内存在的真菌也没有菌丝发育形成的附着孢或吸盘结构,使真菌不能被有效地贮存或携带     

秦岭华山松小蠹生态位研究

通过对秦岭林区海拔１６００～２２００ｍ的中山地带华山松小蠹虫种类和生态位的研究,结果表明：在秦岭林区入侵危害寄主华山松的小蠹虫有１９种,其中能构成竞争和共存的小蠹虫主要有１１种。虽然,这１１种小蠹虫具有各自不同的生态位宽度,且存在不同程度的生态位重叠,但各小蠹虫可依据其对寄主树木营养和空间需求的不同、种群密度的相互制约,以及入侵寄主树木时序的差异达到竞争的平衡和共存。秦岭华山松小蠹生态系统的建立,首先是由华山松大小蠹入侵健康华山松,并通过携带蓝变真菌入侵寄主树木,迅速克服寄主树木抗性系统,使寄主树木树势衰弱;其次松六齿小蠹、暗额星坑小蠹和松十二齿小蠹,作为秦岭华山松的主要次期性小蠹,迅速入侵衰弱的寄主华山松;最后其它次期性小蠹虫入侵寄主树木,利用寄主华山松剩余营养和空间。从而实现秦岭华山松立木小蠹生态系统的动态稳定。     

神农架林区华山松大小蠹危害风险分析

利用景观生态学的研究方法,以神农架林区华山松大小蠹Dendroctonus armandi为研究对象,从华山松Pinus armandii景观空间格局分析林区华山松大小蠹发生情况,并对林区各林场乡镇的风险程度进行分析.结果表明:华山松大小蠹发生与寄主华山松的面积分布占比、斑块密度呈正相关,相关系数R值分别为0.504和...     

寄生性天敌对华山松大小蠹种群控制作用评价

对秦岭林区优势先锋虫种华山松大小蠹 Dendroctonus armandi 寄生蜂种群的林问分布规律进行了研究.在标准地调查基础上,选择华山松大小蠹虫害木作为解析木,分期分批采集华山松大小蠹幼虫和蛹进行室内饲养.结果表明:秦岭林区华山松大小蠹有寄生蜂7种.在河谷地带华山松林中寄生蜂种类最多,7种寄生蜂都有分布,总寄生率最高(37.5%～42.5%),其它依次为竹子华山松林、鹿蹄草华山松林、苔草华山松林、山坡下部华山松林;华山松虫害木树干不同部位寄生蜂种群组成和总寄生率不同,华山松大小蠹寄生蜂种群在华山松虫害木树干上的垂直分布与华山松大小蠹种群相吻合,说明华山松大小蠹种群和寄生蜂种群长期以来建立了相互制约而又相互依存的密切关系.     

华山松大小蠹的一种高效引诱剂

华山松大小蠹Dendroctonus armandi Tsai et Li是危害我国华山松Pinus armandii的主要蛀干害虫。收集和测定华山松树皮和华山松大小蠹的挥发物,根据挥发物组分设计配制8种诱芯,采用漏斗诱捕器进行林间诱捕筛选试验;应用诱芯Ⅱ进行多点诱捕验证和有效诱捕距离试验。结果表明:诱捕期内,诱芯Ⅱ平均诱捕华山松大小蠹1 070头/诱捕器,显著高于其它7种诱芯;单个诱捕器一天最多诱捕1 652头。诱芯Ⅱ在3个地点的平均诱捕量差异不显著,分别为83,114,101头/诱捕器,诱捕效果不存在地理差异;距离林缘50 m处诱捕量为43.5头/诱捕器,为最佳有效诱捕距离。该华山松大小蠹高效引诱剂可为我国华山松大小蠹的治理提供新技术。     

神农架林区华山松大小蠹扩散规律研究

为摸清神农架林区华山松大小蠹扩散规律。查阅了华山松大小蠹侵害的本底资料,分析了华山松大小蠹的发生趋势,研究了华山松大小蠹危害和海拔、年均高、低温的关系。结果表明:神农架林林区中西部,特别是高海拔地区危险性高,海拔1 822 m以上区域华山松大小蠹发生严重,海拔高度和疫情受害面积呈现正相关,拟合方程为Y=657.571 43+374.119 05 X-30.238 1 X~2,相关系数R~2为0.927 04,但不显著;年均高、低温和华山松大小蠹危害面积表现出相同的线性关系,年均低温在7~9℃,年均高温在16~20℃呈现正相关,多项式拟合方程Y=4.656 18E9-4.626 45E6 X+1 149.22685 X~2,相关系数为0.871 89。     

太白山华山松大小蠹防治初探

华山松大小蠹是为害华山松主要的蛀干害虫,被称为＂华山松的癌症＂,多年来人们一直在探索尚未见一成效显著的办法。本文根据太白山西河营林区地处秦岭北麓的地理位置及气候环境,结合连续几年对深山区华山松林发生的华山松大小蠹虫的监测与防治实践工作,归纳整理的一些采取营林与化学药剂相结合的防治措施,对于周边林区防治华山松大小蠹虫害具有参考价值。     

华山松大小蠹对华山松韧皮部不同溶剂粗提物的行为反应

采用3种溶剂(正己烷、乙醚和正戊烷)提取华山松韧皮部有效成分,通过Y型嗅觉仪测定华山松大小蠹对韧皮部粗提物的行为反应。结果表明:3种粗提物对华山松大小蠹雌成虫的引诱率从大到小依次为正己烷>正戊烷>乙醚;对雄成虫的引诱率从大到小依次为正己烷>乙醚>正戊烷。试验结果说明,正己烷作为有机溶剂,在采取浸提法提取华山松韧皮部时效果好于正戊烷和乙醚。     

高、低产脂思茅松树脂道的解剖学比较

通过对比观察高、低产脂思茅松枝干、针叶树脂道直径、外鞘细胞和分泌细胞个数及树脂道的数目,结果显示高产脂枝干中的树脂道个数和分泌细胞个数明显高于低产脂;并且产脂力系数越大,其树脂道数目和分泌细胞个数也最多,反之亦然。这说明树脂道的数目和分泌细胞数目,尤其是树脂道的数量决定了产脂力的大小,而树脂道的大小和外鞘细胞数目对其产脂力影响并不大。因此,以树脂道数量作为一个重要的指标衡量产脂力,对于高产脂类型思茅松的早期选育具有重要价值。     

混交林中黄斑星天牛选择寄主的行为与寄主抗虫性关系的研究

通过观察混交林中黄斑星天牛选择寄主的行为,认为对不同抗生寄主,它选择寄主的行为不同。它能通过复杂的感觉行为和一定的时间找到混交林中的感性树种并造成严重危害和它们种群密度在感性树种上的上升。这种天牛选择寄主在远距离一般以植物气味定向,近距离则以性信息素 增加种群密度。除视觉外,它的主要感觉行为是触角摆和胫节磨擦,选择到达合适寄主是通过逐步的感觉阶段完成的。树皮粗糙程度,叶片特征,枝条特征及混交林密度     

Effects of mass inoculation on induced oleoresin response in intensively managed loblolly pine

Oleoresin flow is an important factor in the resistance of pines to attack by southern pine beetle, Dendroctonus frontalis Zimm., and its associated fungi. Abiotic factors, such as nutrient supply and water relations, have the potential to modify this plant-insect-fungus interaction; however, little is known of the effects of inoculation with beetle-associated fungi on oleoresin flow. We observed that constitutive and induced resin yield in loblolly pine, Pinus taeda L., were affected by either fungal inoculation (with the southern pine beetle-associated fungus Ophiostoma minus (Hedgcock) H. & P. Sydow) or silvicultural treatment. The effects of mass wounding (400 wounds m(-2)) and mass wounding and inoculation with O. minus were assessed by comparison with untreated (control) trees. The treatments were applied to trees in a 2 x 2 factorial combination of fertilizer and irrigation treatments. Fertilization did not significantly affect constitutive resin yield. Even as long as 105 days post-treatment, however, mass-inoculated trees produced higher induced resin yields than control or wounded-only trees, indicating a localized induced response to fungal inoculation. We noted no systemic induction of host defenses against fungal colonization. Although beetles attacking previously attacked trees face a greater resinous response from their host than beetles attacking trees that had not been previously attacked, the effect of an earlier attack may not last more than one flight season. Despite mass inoculations, O. minus did not kill the host trees, suggesting that this fungus is not a virulent plant pathogen.     

纵坑切梢小蠹蓝污真菌侵害云南松树组织解剖观察

通过对云南松树进行纵坑切梢小蠹（Tomicus piniperda）蓝污真菌（Leptogramphium yunnanense）接种试验，对云南松受害组织进行了形态解剖观察，验证了蓝污真菌对云南松的致病作用。蓝污真菌发现于受害木质部和韧皮组织中的各类细胞中，在木质部，蓝污区域呈现出以心材为中心的扇形分布。在韧皮组织内，蓝污真菌主要沿着细胞轴向在垂直方向上生长，并可通过孔纹进入到水平方向上的相邻细胞内。本项研究揭示了该蓝污真菌在云南松树干韧皮和木质部组织，细胞内的生长和蔓延规律，进一步表明纵坑切梢小蠹蓝污真菌L.yunnanense是云南松的一种病原真菌。     

华山松大小蠹危害流脂特征及变化规律研究

通过研究可以看出,华山松流脂流脂点分布的时段特征明显,以6月份流脂时段最长,9月中下旬时段次之,10月下旬时段最短;新流脂株全部出现在9月中下旬和10月下旬二个时段;6月上中下三旬流脂时段的后二年度复侵率连续为100%,新侵株为0;9月中下旬和10月下旬时段的流脂特征全部为堆形,而6各旬的流脂特征为堆状、泪腊状和白浆状.10月下旬和9月中下旬时段出现的流脂点均分布在单株的下区和中下区现象.     

Methyl jasmonate induces changes mimicking anatomical defenses in diverse members of the Pinaceae

Conifers have defenses such as the production of phenolic compounds and resins that can be induced by bark beetles and other invading organisms, but the signaling agents involved are unknown. The anatomical effects of methyl jasmonate (MJ), a potent inducer of certain plant defenses, were compared with wounding of the bark of 12-15-year-old trees of five conifer species. Wounding in all species resulted in tissue necrosis and wound periderm development immediately around the wound site. One cm from the wound, swelling of phloem polyphenolic parenchyma cells and phenolic accumulation were observed in Pseudotsuga menziesii (Mirb.) Franco, Picea pungens Engelman, Larix occidentalis Nutt. and Pinus monticola Douglas ex D. Don, but not in Taxus brevifolia Nutt. Traumatic resin ducts were formed in response to wounding in three species of Pinaceae, but not in P. monticola, which formed irregular clusters of cells rather than ducts. Taxus brevifolia did not form resin ducts in response to either wounding or MJ treatment. In the Pinaceae species studied, surface application of 100 mM MJ caused similar anatomical changes to those observed in response to wounding, including phenolic accumulation, cell swelling and traumatic resin duct formation, but it did not induce a wound periderm. Traumatic resin ducts differed in size among the study species, ranging from small in L. occidentalis to very large in P. menziesii. In P. menziesii, P. pungens and L. occidentalis, traumatic resin ducts were more abundant after MJ treatment than after wounding. We conclude that the octadecanoid pathway is likely involved in defense responses in stems of the Pinaceae, but not necessarily in other taxa.     

Rockfall and snow avalanche impacts leave different anatomical signatures in tree rings of juvenile Larix decidua

Rockfall and snow avalanche events often cause injury to European larch (Larix decidua Mill.) trees, giving rise to the formation of callus tissue and tangential rows of traumatic resin ducts (TRDs). We analyzed and quantified anatomical reactions of juvenile trees injured before the start of the growing season by snow avalanches (15 trees, 324 cross sections) or rockfalls (18 trees, 270 cross sections). Traumatic resin ducts were observed in the growth ring formed following injury in 94.3% of the rockfall samples and 87.3% of the snow avalanche samples. Traumatic resin ducts were formed at the beginning of the new annual ring around wounds caused by rockfalls. In contrast, in trees injured by snow avalanches, TRDs were not formed until after the formation of several rows of early earlywood (EE) tracheids (mean +/- SD = 4.19 +/- 2.56 rows). The dimensions of the EE tracheids observed in the snow avalanche samples were greatly reduced in the tissues bordering the wound, with radial width reaching an average of only 50% and lumen cross-sectional area an average of only 46% of pre-event values. It is therefore possible to differentiate injuries due to past snow avalanches from injuries due to rockfall based on anatomical growth reactions in the tissues bordering scars.     

Methyl jasmonate and oxalic acid treatment of Norway spruce: anatomically based defense responses and increased resistance against fungal infection

To study the effect of chemical pretreatment on conifer resistance, 13-year-old Norway spruce (Picea abies (L.) Karst.) trees were treated with methyl jasmonate (MJ) or oxalic acid (OxA) on the outer bark and inoculated with the pathogenic blue-stain fungus Ceratocystis polonica (Siem.) C. Moreau 4 weeks later. Both chemicals significantly reduced symptoms of fungal infection, but MJ was more effective than OxA (51 versus 18% reduction in length of necrotic lesions in the phloem relative to untreated control trees). Anatomical examination of treated stem tissues showed that MJ induced extensive formation of traumatic resin ducts in the xylem and extra polyphenolic parenchyma (PP) cells in the secondary phloem between the cambium and the regular annual PP cell layer. No traumatic resin ducts were formed after treatment with OxA, and the coverage of extra PP cells in OxA-treated tissues was not significantly higher than in the controls. The anatomically based defense reactions induced by MJ were similar to the reactions observed after pathogen infection, mechanical wounding and bark beetle attack. Neither MJ nor OxA had apparent phytotoxic effects on Norway spruce at the concentrations used, with needle and stem tissues of all trees appearing normal without visible symptoms of toxicity. However, trees treated with MJ had 30% less radial sapwood growth than control trees. In conclusion, MJ treatment of Norway spruce appears to have practical potential as a tool for increasing plant resistance to fungal infection, but with a modest reduction in sapwood growth.