3种桉属植物乙醇抽提物对爪哇根结线虫的毒杀活性

采用直接浸泡法,测定了桉属(Eucalyptus)植物柠檬桉(E.citriodora)、杂交桉(E.urophyla×E.grand)和尾叶桉(E.urophyla)小枝条乙醇抽提物对爪哇根结线虫(Meloidogyne javanica)卵孵化的抑制活性以及对2龄幼虫的毒杀活性。结果表明:柠檬桉、杂交桉和尾叶桉乙醇抽提物对爪哇根结线虫卵的孵化均有较强抑制活性,以20 mg/mL乙醇抽提物液处理24、48、72 h后,抑制孵化率均达94%以上;对爪哇根结线虫2龄幼虫也有较强的毒杀活性,3种桉属植物以20 mg/mL乙醇抽提物液处理2龄幼虫72 h后,线虫校正死亡率均达90%以上。将柠檬桉和杂交桉的茎、叶干粉分别拌土盆栽防治空心菜(Ipomoea aquatica)和黄瓜(Cucumis sati-vus)爪哇根结线虫病。结果表明:柠檬桉和杂交桉茎、叶干粉对爪哇根结线虫病均有较好的防治效果,植株根系的根结数、根结内雌虫数和雌虫产卵粒数均下降,植株地上部鲜质量增加,且均与对照差异显著。     

Antibacterial sideroxylonals and loxophlebal A from Eucalyptus loxophleba foliage

Loxophlebal A, a new antibacterial formylated phloroglucinol was isolated from the mother liquor obtained after separation of sideroxylonals from the chloroform–methanol extract of leaves of Eucalyptus loxophleba ssp lissophloia. The structure of loxophlebal A was determined to be 3-desformyl sideroxylonal A by spectroscopic methods including 1D- and 2D-NMR. The stereochemistry of loxophlebal A was determined by chemical correlation with sideroxylonal A. This article also reports an efficient, simple and economic method for large scale isolation of sideroxylonals in a purity of > 90% from the leaves of Eucalyptus loxophleba ssp lissophloia.     

Effects of irrigation on water use and water use efficiency in two fast growing Eucalyptus plantations

Eucalyptus plantations occupy almost 20 million ha worldwide and exceed 3.7 million ha in Brazil alone. Improved genetics and silviculture have led to as much as a three-fold increase in productivity in Eucalyptus plantations in Brazil and the large land area occupied by these highly productive ecosystems raises concern over their effect on local water supplies. As part of the Brazil Potential Productivity Project, we measured water use of Eucalyptus grandis × urophylla clones in rainfed and irrigated stands in two plantations differing in productivity. The Aracruz (lower productivity) site is located in the state of Espirito Santo and the Veracel (higher productivity) site in Bahia state. At each plantation, we measured stand water use using homemade sap flow sensors and a calibration curve using the clones and probes we utilized in the study. We also quantified changes in growth, leaf area and water use efficiency (the amount of wood produced per unit of water transpired). Measurements were conducted for 1 year during 2005 at Aracruz and from August through December 2005 at Veracel. Transpiration at both sites was high compared to other studies but annual estimates at Aracruz for the rainfed treatment compared well with a process model calibrated for the Aracruz site (within 10%). Annual water use at Aracruz was 1394 mm in rainfed treatments versus 1779 mm in irrigated treatments and accounted for approximately 67% and 58% of annual precipitation and irrigation inputs respectively. Increased water use in the irrigated stands at Aracruz was associated with higher sapwood area, leaf area index and transpiration per unit leaf area but there was no difference in the response of canopy conductance with air saturation deficit between treatments. Water use efficiency at the Aracruz site was also not influenced by irrigation and was similar to the rainfed treatment. During the period of overlapping measurements, the response to irrigation treatments at the more productive Veracel site was similar to Aracruz. Stand water use at the Veracel site totaled 975 mm and 1102 mm in rainfed and irrigated treatments during the 5-month measurement period respectively. Irrigated stands at Veracel also had higher leaf area with no difference in the response of canopy conductance with air saturation deficit between treatments. Water use efficiency was also unaffected by irrigation at Veracel. Results from this and other studies suggest that improved resource availability does not negatively impact water use efficiency but increased productivity of these plantations is associated with higher water use and should be given consideration during plantation management decision making processes aimed at increasing productivity.     

Sap flow measurements reveal influence of temperature and stand structure on water use of Eucalyptus regnans forests

We examined water use by maturing Eucalyptus regnans, growing with or without an mid-storey stratum of Acacia spp. (Acacia dealbata or A. melanoxylon), for >180 consecutive days. Study sites were located in the Upper Yarra catchment area in south-eastern Australia. Depending on their contribution to stand basal area, mid-storey Acacia spp. increased total stand water use by up to 30%. Monthly water use in such stands reached more than 640,000 L ha⁻¹ (compared to 545,000 L ha⁻¹ in stands where acacias were absent) in early spring. Water use was curvilinearly related to sapwood area of Acacia spp. and logistically related to sapwood area of E. regnans. Water use of all three species showed a strong relation to daily maximum air temperatures. Distinct and simple relationships provide clear guides to the likely impacts of climate change and forest management on water yield. We compared a traditional up-scaling approach, from individual tree water use to stand water use, to a new approach that incorporates variation in temperature. Development of this approach can lead to greater precision of stand water use estimates – and in turn catchment water yield – under current climate change scenarios, which predict a rise in air temperatures of 0.6–2.5 °C by 2050 for the study area. Our temperature-dependent approach suggests that under conditions of non-limiting water availability, stand water use will rise by 2% for every 0.25 °C increase in maximum air temperatures during winter, and possibly more than that during summer.     

预处理对尾巨桉单板染色性能的影响

采用乙醇处理、碱处理和热水处理三种方式对尾巨桉单板进行预处理,由正交试验确定最佳染色工艺并在最佳染色工艺条件下对预处理单板进行染色,然后对染色单板的着色性能、耐光色牢度及耐水色牢度进行测定。结果表明：正交试验确立的最佳染色工艺为染液温度70℃、染色处理时间45 m in和酸性蓝浓度0.2%,其中染液温度是影响染色效果的最主要因素;三种预处理方法能够提高尾巨桉单板的渗透性并对着色性能影响不大,同时会使染色处理材的耐光性小幅下降;三种预处理方式对染色材的耐水色牢度有较好的促进作用,其中热水处理最好,乙醇处理次之,而碱处理最差。     

ITS序列在桉树种质资源鉴定中的应用研究

利用ITS序列分析技术对3个桉树优良无性系广林巨尾桉5号(GLGU-5)、广林巨尾桉9号(GLGU-9)、广林尾叶桉4号(GLU-4)以及巨尾桉和尾叶桉实生苗材料进行位点差异性分析。并根据ITS序列变异特点对3个优良无性系与巨尾桉和尾叶桉实生苗进行分子鉴定。结果表明:(1)优良无性系的ITS扩增片段比巨尾桉、尾叶桉实生苗长38~45 bp,因此,无性系与尾叶桉、巨尾桉实生苗之间ITS序列的长度差异,可以作为区分无性系与巨尾桉和尾叶桉实生苗之间的依据;(2)无性系之间存在ITS碱基位点差异,这些位点差异可以作为无性系之间的鉴定依据。     

桉树4个种遗传多样性的ISSR分析

以桉树的赤桉、巨桉、细叶桉和粗皮桉4个种18个种源为研究材料,根据优化的ISSR-PCR反应体系和扩增条件,从100条引物中筛选出12条扩增条带特异、条带数适中、背景清晰、重复性好的引物,总计扩增出120条清晰可重复的DNA条带,其中93条是多态性条带。每个引物可扩增的多态条带长度范围为300~2 500 bp,数目在4~11条,平均为7.75条,多态带百分率为77.5%。通过软件POPGENE 1.31、MVSP 32软件和NTSYS-pc软件对所得数据进行分析,从而得出4个种18个种源的遗传相似系数,并绘制分子聚类图和主坐标分析图,结果表明,遗传一致度的变化范围在0.387 1~0.914 0之间,遗传距离的变化范围在0.089 9~0.949 1之间,种间遗传相似性差异较大,种内遗传相似性极高。     

桉树葡萄糖-6-磷酸脱氢酶（G6PDH）的全基因组分析与进化研究

[目的]对桉树基因组中葡萄糖-6-磷酸脱氢酶（G6PDH）进行全基因组分析与进化研究。[方法]利用巨桉（Eucalyptus grandsis）全基因组数据,采用BLAST等生物信息学软件分析桉树G6PDH的基因特性、蛋白序列、系统进化树以及启动子特征。[结果]桉树基因组内存在6个G6PDH基因,其编码蛋白中,1个为胞质型G6PDH,5个为质体型G6PDH,而且桉树G6PDH均含有保守基序motif1、motif2、motif3、motif7、motif9和motif11。此外,桉树G6PDH启动子序列中均存在TATA框、增强子与涉及光应答、激素应答、胁迫应答等调控元件。[结论]可为下一步研究桉树G6PDH家族基因的分子功能提供参考。     

桉树枝瘿姬小蜂在尾巨桉幼林扩散为害研究

在崇左市江州区以零星分布在林中的已受桉树枝瘿姬小蜂(Leptocybe invasa Fisher&La Salle)严重为害的巨园桉(Eucalyptus grandis×E.tereticornis)DH201-2植株作为虫源株,研究其产生的桉树枝瘿姬小蜂对由尾巨桉(Eucalyptus urophylla×E.grandis)DH32-29组成的幼林自然扩散为害情况。结果表明:以虫源株为中心约100 m2范围内尾巨桉DH32-29平均受害株率69.6%,平均有虫瘿株率51.9%,受害植株中平均枝条受害率20.4%,平均有虫瘿枝率1.9%。根据受害植株中有虫瘿枝率,巨园桉DH201-2虫源株所产生的桉树枝瘿姬小蜂对尾巨桉DH32-29扩散为害程度为轻度。     

Mining new resources for grape resistance against Botryosphaeriaceae: a focus on Vitis vinifera subsp. sylvestris

Botryosphaeria dieback is an important grapevine trunk disease with global impact. Susceptibility differences between grape varieties manifest as different expression of canopy symptoms in the field. However, the cause of these dieback symptoms and their relation with wood necrosis remain only partially understood. As a first step towards future strategies for resistance breeding, wood necrosis was investigated over a large selection of the Vitaceae family members following artificial inoculation of the Botryosphaeriaceae fungi Neofusicoccum parvum and Diplodia seriata into woody internodes. Large variation of resistance levels was found, with good performance in several accessions from V. vinifera subsp. sylvestris, the ancestor of cultivated grapevine. To get insight into the mechanisms of this apparent resistance, expression of defence genes was studied in V. vinifera cv. Chardonnay, Gewürztraminer and different V. vinifera subsp. sylvestris genotypes, in both green and necrotic areas of inoculated woods. Resistance to Botryosphaeriaceae in V. vinifera subsp. sylvestris correlated with earlier and higher induction of some defence genes, both in green and necrotic wood. Moreover, leaves of several V. vinifera subsp. sylvestris accessions were also less susceptible to necrosis induced by treatment with a culture filtrate of Botryosphaeriaceae, compared to commercial cultivars of V. vinifera. The results show that V. vinifera subsp. sylvestris provides interesting genetic resources for breeding new varieties with enhanced resistance to botryosphaeria dieback.