Susceptibility of Eucalyptus grandis provenances to a root rot associated with Ganoderma sculptrutum in Zimbabwe

Widespread cankering, gummosis, wilting and death of Eucalyptus grandis were first observed in Zimbabwe in 1956. Recent investigations have revealed the symptoms and deaths to be associated with infection by Ganoderma sculptrutum. Indigenous tree species, in particular Brachystegia spiciformis and Julbernardia globiflora, provide inoculum source for the fungus. A total of 170 half-sib families in 23 provenances were assessed for symptoms and death associated with G. sculptrutum infection. There were statistically significant differences (p ≤ 0.001) in observed symptoms among families in a provenance. Provenance differences were not significant (p > 0.05). There were significant differences among provenances (p ≤ 0.05) and families (p ≤ 0.001) for death associated with G. sculptrutum. Differences among the four blocks were significant for both symptoms (p ≤ 0.01) and death (P ≤ 0.001). Family heritability estimates ranged from 0.00 (±0.82) to 0.79 (±0.13) for symptoms and from 0.00 bb (±0.82) to 0.75 (±0.14) for death.     

Fertilization in a Fourth Rotation Eucalyptus grandis Plantation with Minimal Management

ABSTRACT

Successive rotation and wood harvest of fast growing trees, like Eucalyptus grandis, can deplete soil nutrient pools. In these intensively used soils, productivity can decrease, and fertilization can be necessary to recover soil fertility. The aim of this work is to evaluate if fertilization with N and P increases tree growth and foliar nutrients in an Eucalyptus grandis plantation growing over a soil used for three rotations of this species. In the same experiment, both fertilization on seedlings and coppiced trees were evaluated. One and two years after planting, any fertilization treatment increased tree growth, even though coppiced trees had higher total height and DBH than replanted trees. Coppiced trees had lower specific leaf area, as well as lower N and P leaf concentration. The lack of promotion in growth due to fertilization can be explained by the inputs of nutrients from the harvest residues of the previous rotation. As residues were never burned in this site, its decomposition released a high part of nutrients necessary to sustain growth during the first two years. We conclude that in sites where residues were left on site and were not burned, nutrient availability is enough and so fertilization at establishment is not necessary. It remains to be determined if fertilization is necessary at mid or end rotation, in order to balance nutrients export with harvest wood.     

Susceptibility of Eucalyptus grandis and Acacia mearnsii seedlings to five Phytophthora species common in South African plantations

Eucalyptus grandis and its hybrids, as well as Acacia mearnsii, are important non‐native trees commonly propagated for forestry purposes in South Africa. In this study, we conducted pathogenicity trials to assess the relative importance of five commonly isolated Phytophthora spp. (Phytophthora alticola, P. cinnamomi, P. frigida, P. multivora and P. nicotianae) from the plantation environment on E. grandis and A. mearnsii seedlings. Overall E. grandis was more susceptible to the tested Phytophthora spp. than A. mearnsii. Phytophthora cinnamomi was the only pathogen that had a significant negative effect on both the host tree species, leading to a reduction in root and shoot weight as well as to death in the case of E. grandis. Phytophthora alticola and P. nicotianae exclusively affected E. grandis and A. mearnsii, respectively. This study updated the current knowledge on the pathogenicity of Phytophthora spp. on two important non‐native commercially propagated tree species from South Africa.     

尾巨桉试管苗移栽基质配方的研究

以五色土、堆沤木糠渣、锯木屑、泥炭为供试基质材料，进行尾巨桉3229试管苗移栽基质配方筛选研究。结果表明，五色土和锯木屑(1：2、1：1、2：1)三个配比的混合基质均可作为尾巨桉3229试管苗的移栽基质，其成活率高(达98．21％以上)和生长快，与对照(五色土)的成活率96．43％相近；纯五色土和泥炭(1：2和1：1)二个配比的混合基质也可作为尾巨桉试管苗的移栽基质。     

遂宁市巨桉引种试验研究

就巨桉在遂宁市的气候、土壤条件下，通过不同立地条件的引种对比试验，探索出巨桉的适生范围以及影响生长的主导因子，从而为大面积推广提供科学依据。     

巨桉遗传改良研究进展

进行巨桉种源试验和地理变异研究时, 应重视从树种的生物学特性出发, 考虑试材的取样标准、群体的生殖和生态特性, 采用现代生物气候方法综合分析。巨桉有些群体存在着复杂的多型性, 采用复合轮回选择能明显提高自由授粉家系后代的遗传增益, 并提高种子园改良的质量。应用入选家系或个体的无性繁殖材料进行改良, 可获得更大的遗传增益。巨桉遗传改良应把有性和无性两条途径结合起来, 遵循简便、实用和高效的原则;基于这个原则, 本文提出了巨桉目前可能的最佳改良程序。     

湖南省巨桉育种策略

从湖南气候、森林资源及树种结构特征等方面,阐述了制定湖南引进树种-巨桉育种策略的目的意义.根据10多年的引种、种类种源及家系试验,更加明确了巨桉的育种目标,提出了巨桉的育种策略,并对湖南开展巨桉育种提出了建议.     

尾巨桉幼苗对低温胁迫的生理生化反应

以尾巨桉无性系幼苗为材料,研究了低温胁迫对其生理生化的影响。试验结果表明,3℃低温胁迫对尾巨桉幼苗的电解质渗出率,随着胁迫持续时间的延长呈逐渐上升的趋势;叶绿素a的含量、叶绿素b的含量及叶绿素总量均随胁迫时间的延长而呈下降的趋势;SOD酶活性随胁迫时间呈先上升(1~3 d)而后下降(3~9 d);可溶性糖的含量随低温胁迫时间的延长而随之上升。     

Temperature effects on wood anatomy, wood density, photosynthesis and biomass partitioning of Eucalyptus grandis seedlings

Wood density, a gross measure of wood mass relative to wood volume, is important in our understanding of stem volume growth, carbon sequestration and leaf water supply. Disproportionate changes in the ratio of wood mass to volume may occur at the level of the whole stem or the individual cell. In general, there is a positive relationship between temperature and wood density of eucalypts, although this relationship has broken down in recent years with wood density decreasing as global temperatures have risen. To determine the anatomical causes of the effects of temperature on wood density, Eucalyptus grandis W. Hill ex Maiden seedlings were grown in controlled-environment cabinets at constant temperatures from 10 to 35 degrees C. The 20% increase in wood density of E. grandis seedlings grown at the higher temperatures was variously related to a 40% reduction in lumen area of xylem vessels, a 10% reduction in the lumen area of fiber cells and a 10% increase in fiber cell wall thickness. The changes in cell wall characteristics could be considered analogous to changes in carbon supply. Lumen area of fiber cells declined because of reduced fiber cell expansion and increased fiber cell wall thickening. Fiber cell wall thickness was positively related to canopy CO2 assimilation rate (Ac), which increased 26-fold because of a 24-fold increase in leaf area and a doubling in leaf CO2 assimilation rate from minima at 10 and 35 degrees C to maxima at 25 and 30 degrees C. Increased Ac increased seedling volume, biomass and wood density; but increased wood density was also related to a shift in partitioning of seedling biomass from roots to stems as temperature increased.     

巨桉、尾叶桉及其无性系在思茅地区引种栽培适应性论证

通过对巨桉、尾叶桉生物学特性、省外栽培情况、思茅地区小面积引种情况、省外栽植地点和引种地的立地条件进行分析比较，选择气候因子进行相似优先比论证，得出思茅地区在一定范围内大面积引种巨桉、尾叶桉是可行的结论。     

巨桉在平岗林场的引种生长效果分析

1999年从澳大利亚引种巨桉,种植于西江林业局平岗林场,5年生时进行生长调查,结果表明:5 年生的巨桉平均树高达18．4 m,平均胸径15．2 cm,平均单株材积0．161 1 m3,最大胸径达24．1 cm,最高树高28．0 m,最大单株材积0．497 7 m3,平均蓄积量145．0 m3/hm2,与同时引种的立地基本相同的尾巨桉比较,优势较明显。平岗林场巨桉的引种取得良好的效果,适宜在广东西江两岸大面积推广种植。     

Nighttime water use in an irrigated Eucalyptus grandis plantation

Sap flow measurements showed that a well-watered four-year-old plantation of Eucalyptus grandis (Hill ex Maiden) at Wagga Wagga, New South Wales, Australia, used 0.8 mm of water between 2100 and 0500 h on the midwinter night of July 30. Sap flow ceased for 2 to 3 h after sunset before recommencing at high rates that reached a maximum of 0.3 mm per h between 0200 and 0300 h. This pattern is inconsistent with the replenishment of tissue water reserves depleted during the day. Moreover, maximum leaf conductance at night was about 20 times maximum cuticular conductance values reported in the literature, which strongly suggests that stomata were partly open and that there was substantial water loss by way of the foliage. In an 8-month period from late winter to mid-autumn, comparable rates of nighttime water use were observed on only one other occasion. However, water use at rates of 0.1 mm per h or more occurred on 24 other nights. Almost 70% of the variation in nighttime sap velocity was explained by nighttime mean vapor pressure deficit and nighttime mean wind speed. Total recorded nighttime water use of the plantation was 48 mm, or 5% of total transpiration during the 8-month study. In view of the insensitivity of heat pulse measurements at low sap flows, this value may be an underestimate of actual nighttime transpiration.     

人工林尾巨桉株内、株间纤维形态变异的研究

对5株13年生的尾巨桉纤维形态的径向变异进行研究,在显微镜下观察木材解剖构造,同时对纤维长、纤维宽、胞壁厚和纤维长宽比进行了测量.结果表明:尾巨桉属阔叶散孔材,纤维形态指标径向上具有增大的趋势,株内径向上各纤维形态指标差异显著,株间略有差异.尾巨桉木材平均纤维长0.73~1.01 mm,胞壁厚4.36~5.09μm,纤维长宽比42~51,能满足纤维工业原料的要求,属较好的纸浆工业用材.     

Effect of some nursery practices on incidence and severity of diseases,and growth of Eucalyptus grandis seedlings*

Nursery practices influenced incidence and severity of diseases of Eucalyptus grandis viz. damping-off caused by Pythium sp., Rhizoctonia solani and Cylindrocladium quinqueseptatum, web might by R. solani, seedling blight by C. quinqueseptatum and shoot wilt by Sclerotium rolfsii. Growth of seedlings of E. grandis and microclimatic conditions were also affected by nursery practices. Shading with coconut leaf thatch led to low light intensity (av. 1463 lux) with high soil water potential, low soil and ambient temperatures, and high severity of damping-off and web blight diseases and poor shoot:root ratio of seedlings. Seed beds under coirmat had dispersed light (av. 22 299 lux), apparently high severity of seedling blight and shoot wilt, and good growth (snoot:root ratio) of seedlings. In both the types of shading high soil moisture regime and high seed rate contributed to high disease severity as well as low shoot:root ratio of seedlings.     

四川巨桉人工林微量元素养分诊断

采用相关分析和矢量诊断法对四川60块巨桉人工林标准地进行微量元素养分诊断。结果表明:1)5种微量元素中,Cu,Zn吸收量与林分蓄积显著相关;2)N,P,K等大中量养分吸收受多种微量元素供应量和吸收量的影响,微量元素与大量元素之间以及微量元素之间存在显著的交互作用关系,如Cu-K,Cu-Fe,Mn-N的促进作用,N-Zn,P-Zn,Ca-Zn,P-Fe,K-Fe,Mn-K以及Cu,Zn,Fe,Mn之间的相互拮抗作用;3)Cu在低海拔地区以过量毒害为主,高海拔地区以缺乏为主;Zn以稀释效应为主,极少数标准地缺乏受限;Fe含量地区变异较大,在土壤高pH值地区容易缺乏受限,土壤低pH值地区则容易过量毒害或发生拮抗作用;Mn含量普遍较高,多表现为拮抗和过量毒害作用,局部地区出现缺乏;B供应充分,主要为拮抗作用,表现稳定。     

巨桉种源遗传多样性的RAPD分析

用随机扩增多态DNA(RAPD)分子标记方法对巨桉11个种源80个个体进行了遗传变异的比较分析.通过20个10bp随机引物的扩增,共检测到149个位点,其中89个为多态性标记位点,总的多态位点百分率为59.73%.各个种源多态位点百分率较高,为42.86%～55.89%,多态位点最多的是8号种源,最低的是6号种源.Shannon表型多样度估测值的统计表明,遗传多样性主要存在种源内部.遗传变异在种源间占28.74%,在种源个体间占71.26%.Shannon表型多样度估测值在种源间为0.1720～0.2650,平均为0.2373.8号种源的遗传多样性最高,6号种源的遗传多样性最低;种源间的遗传距离为0.0391～0.1344,平均为0.0817.这些遗传变异为巨桉优良种源的早期选择提供了科学依据.     

巨桉纤维素合酶Ces家族的生物信息学分析

纤维素合酶(Cellulose synthase,Ces)基因家族成员负责催化纤维素的合成。利用Phytozome网站对巨桉(Eucalyptus grandis)全基因组序列进行检索,共发现31条蛋白质序列属于Ces家族,其中包括18个CesA亚族成员与13个CslD亚族成员。使用ClustalW、Protparam、TMHMM等生物学在线服务器,对巨桉31个Ces家族成员进行全面生物信息学分析预测,结果显示:31条蛋白质序列均具有Cellulose synthase特征性保守结构域,具有Ces家族成员特征;巨桉Ces家族与拟南芥Ces家族、杨树Ces家族在亚族种类、成员组成、蛋白理化性质方面存在变异性;蛋白结构域、二级结构、跨膜区预测、无序性、亚细胞定位分析结果存在保守性。     

Growth and yield models for Eucalyptus grandis grown in Swaziland

The aim of this study was to develop a stand-level growth and yield model for short-rotation Eucalyptus grandis grown for pulp wood production at Piggs Peak in Swaziland. The data were derived from a Nelder 1a spacing trial established with E. grandis clonal cuttings in 1998 and terminated in 2005. Planting density ranged from almost free-growing trees established at 161 trees ha^?1 to extremely dense stands at 6 809 trees ha^?1. Functions were fitted to describe stand density, dominant height and basal area development over time. The functions performed well when scrutinised for their goodness of fit. They were also found to be consistent with forest growth theory when their logical behaviour was tested over the range of planting densities.     

Inbreeding Effects in Eucalyptus grandis in Relation to Degree of Relatedness

This publication describes a series of tests designed and inspected by the South African Forestry Research Institute to determine the performance of laminated pine railway sleepers, crossing and bridging timbers installed in South African Railways lines over a period of 13 years. The results showed that laminated pine sleepers, properly impregnated with creosote, will have an average service life in excess of 15 years.