Soil microorganisms alleviate the allelopathic effect of Eucalyptus grandis × E. urophylla leachates on Brassica chinensis

Soil microbes may be critical players in determining the allelopathic potential of some plants. Low levels of plant community biodiversity in Eucalyptus plantations have been attributed to the allelopathic potential of these tree species. The role of soil microbes in the allelopathic effect of leaf leachates of the hybrid tree Eucalyptus grandis x E. urophylla, was tested in Petri dish assays with Brassica chinensis as a receiver plant. Soils were collected from either a local garden (soil A) or a Eucalyptus plantation (soil B) and half of each soil was sterilized to remove microbes. These soils were then treated with E. grandis x E. urophylla leachates for 0-72 h. Seed germination of B. chinensis was significantly inhibited in soils treated with leaf leachates relative to untreated soils. The inhibitory effect of the leaf leachates was more pronounced in sterilized soils. Total phenolic content was obvious lower in nonsterile leachate-treated soils than in sterile soils. Biomass of B. chinensis was negatively correlated with the total phenolic content in soils. Our findings suggest that soil microbes can alleviate the allelopathic potential of Eucalyptus and thereby its negative impact on plant growth.

Comparative microsporogenesis and flower development in Eucalyptus urophylla×E.grandis

Microsporogenesis and flower development in Eucalyptus urophylla × E. grandis were examined using chromosome tableting to provide a method to predict the meiotic stages in this species. Although microsporogenesis was normal, cytokinesis during meiosis of pollen mother cells occurred simultaneously, with strong asynchronism observed in the two different lengths of stamens in a flower bud. In a single flower, the developmental period of microsporogenesis in anthers on the longer stamens was always ahead of those on the shorter stamens. Flower development was also asynchronous at different locations on a branch. Flower buds on the upper side of the branch were larger in diameter than those on the lower side. In addition, a correlation was observed between microsporogenesis development and flower bud diameter growth. The pachy- tene stage was first observed when the diameter of the flower buds increased to 3.0 mm, and the majority of the meiotic stages were observed when bud diameters ranged from 3.5 to 5.0 mm. This study showed that the developmental stages of microsporogenesis in Eucalyptus urophylla × E. grandis could be distinguished readily, which may be applicable to future breeding studies.

Note on Glycaspis brimblecombei Moore (Hemiptera Psyllidae): A new pest of Eucalyptus in Greece

Leaves of eucalyptus infested by Glycaspis brim-blecombei Moore were found on river red gum (E. camaldulensis) and blue gum (E. globulus) trees in Attiki and Chania region, Greece. The psyllid is recorded for the first time in Greece. Brief information about this psyllid is provided.

Monoterpene hydrocarbons,major components of the dried leaves essential oils of five species of the genus Eucalyptus from Cote d’Ivoire

The chemical composition of the essential oils obtained from the dried leaves of five species of the genus Eucalyptus (E. camaldulensis, E. de-glupta, E. grandis, E. torelliana, E. urophylla) growing in C?te d’Ivoire, was analyzed by means of GC and GC/MS. The density and the refractive index were measured. The major components of all these oils are: α-pinene, β-pinene, α-phellandrene, limonene, γ-terpinene, p-cymene and β-caryo-phyllene. The particularity of these oils is their monoterpene hydrocarbons major components.

尾巨桉愈伤组织蛋白质含量和氧化酶活性比较

以尾巨桉(Eucalyptus urophylla×E.grandis)无性系DH32-29无菌苗的茎段为外植体,优化的激素组合的愈伤组织诱导率高,随后培养中愈伤组织分化出绿色、黄绿色、白色和褐色4种类型,绿色和部分黄绿色的为胚性愈伤组织,后两种为非胚性愈伤组织。分别测定不同类型愈伤组织的蛋白质含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性,结果表明,愈伤组织蛋白质含量从高到低为绿色、黄绿色、白色、褐色;胚性愈伤组织的SOD、POD和CAT活性显著高于非胚性愈伤组织,并且绿色愈伤组织3种酶活性均高于其他愈伤组织。

韦赤桉与杉木、马尾松混交造林成效研究

为克服单一树种经营的弊端,提高林分生产力,开展韦赤桉纯林、杉木纯林、马尾松纯林、韦赤桉×杉木混交林、韦赤桉×马尾松混交林和杉木×马尾松混交林6种模式造林试验,对其7年生林分生长情况进行调查分析,结果表明:6种造林模式的保存率均超过87%;与3种纯林造林模式相比,林分密度为2505株/hm-2,韦赤桉与杉木1∶3比例混交和杉木×马尾松1∶1比例混交的两种造林模式取得了双赢的效果,在这两种混交造林模式下,韦赤桉、马尾松、杉木的生长状况均较纯林造林模式好,其中韦赤桉与杉木混交林的韦赤桉平均胸径、平均树高和平均单株材积分别较韦赤桉纯林高出9.96%、19.82%和40.05%,杉木的平均胸径、平均树高和平均单株材积分别较杉木纯林提高了24.89%、10.73%和69.23%。

尾巨桉DH_(32-26)组培快繁技术

[目的]探索尾巨桉DH_(32-26)组培快繁技术,为其规模化生产提供参考。[方法]采用组织培养手段,以尾巨桉DH_(32-26)半木质化萌发茎段为材料,对外植体诱导及无菌组织培养体系进行研究。[结果]最佳外植体诱导培养基为改良MS+6-BA 1.0 mg/L+NAA 0.5mg/L,发芽率为92.3%;最佳增殖培养基为改良MS+6-BA 0.4 mg/L+NAA 0.2 mg/L,增殖个数为3.7;最佳生根培养基为改良1/2MS+IBA 0.2 mg/L+ABT 0.3 mg/L,生根率可达98.3%。[结论]该研究获得了尾巨桉初代诱导、增殖和生根适宜培养基和培养条件,初步达到工厂化生产要求。

冷处理对尾巨桉几种生理指标和POD基因转录的影响

6℃冷处理尾巨桉(Eucalyptus urophylla×E.grandis)半年龄树苗24 h后,检测叶片电导率、叶绿素含量、丙二醛含量、可溶性蛋白质含量、SOD活性、POD活性等生理指标的变化,进行POD同工酶电泳,并用实时定量PCR(Real-time quantitative PCR,q PCR)检测了4个POD基因的转录变化。结果表明,与常温相比,冷处理后尾巨桉的叶绿素含量、可溶性蛋白质含量和SOD活性无明显变化;但相对电导率、丙二醛含量和POD活性都有升高,且与常温下有显著差异。POD同工酶电泳结果显示,冷处理后,L1、L2、L8、L9和L10共5个酶带表达增强;L3、L4、L5、L6、L7共5个酶带的表达明显受到抑制。实时定量PCR检测POD1、POD2、POD3、POD4基因的转录变化发现,低温处理后4个基因的转录明显被抑制,其转录水平分别是常温下的0.21、0.41、0.40和0.21倍。上述结果表明,低温胁迫对尾巨桉的相对电导率、丙二醛含量、POD活性、POD同工酶表达变化和POD基因的转录水平等指标有显著影响,低温下这几个指标的变化幅度可作为筛选耐寒性较强尾巨桉株系的参考。

Influence of Planting Spacing on Mechanical Properties of Eucalyptus grandis × E. urophylla Planted in China

The objective of this study was to understand influence of planting spacing on mechanical properties of Eucalyptus grandis × E. urophylla planted as a potential species for solid wood products in China. Four trees at age of 13 were selected from each of 6 groups of planting spacing and a total of 24 sampling trees were selected from the Dongmen Forestry Center of Guangxi Province in China. Furthermore, a one-meter-long log from each tree was cut into small blocks for wood properties testing. MOE, MOR and compression strength parallel to wood grain were determined in accordance with Chinese standards. In addition, wood density and shrinkage properties were measured. Statistical analysis by SAS software indicated significant differences among the 6 groups of planting spacings on the air-dried density, radial shrinkage and bending MOR properties at the 0.05 level, and also on the compression strength at the 0.10 level. However, it was observed that there is no significant differences among shrinkages in tangential and volume, and MOE.

Growth Process of Eucalyptus urophylla × E.grandis Stand Based on Logistic Equation

Eucalyptus is the most valuable cultivated forest genus in the tropical and subtropical areas nowadays. It has been a challenge for foresters to model growth due to the genetic variations, management regimes, and multiple products generated from the plantations. In this paper, Logistic equation was used to study the stock growth process of E. urophylla × E. grandis plantation at age of 14 with 6 spacing treatments. And the biological interpretation of the parameters of Logistic equation was analyzed. The results show that it is flexible, precise and accurate to fit the growth process.

韦塔桉种子园营建技术

韦塔桉因其品质优良纯正、树干通直高大而成为珍贵的桉树基因资源。为保存该资源,在雷州林业局纪家林场建立201个家系、13个种源试验林,对其进行种源/家系试验。经过8a对家系生长量、保存率、生长特性的调查分析并进行家系选择,通过技术将试验林转化为实生种子园。这将为雷州林业局营造桉树纸浆用材林基地提供优质良种树种、保持桉树人工林生产力长期稳定起到深远意义和重要作用。

Effect of Initial Moisture Content on Solar Drying Ratefor Eucalyptus grandis × E. urophylla

Wood drying is one of the most important process links in wood products processing.However, the existing drying methods mainly depend on heat to desiccate wood, which makes wooddrying consume roughly 40% - 70% of the total energy in the entire wood process. Using solar energyfor drying is greatly significant in two aspects of energy conservation and environment protection. Themoisture content (MC) of lumber affects not only the target value of wood drying, but also the heattransfer properties, moisture rate of expansion, etc., affecting dried lumber quality and drying rate.Eucalyptus grandis × E.urophylla lumbers were collected from Guangdong as test materials and dried inthe solar dryer with low temperature schedule and the effect of initial moisture content were primarystudied on drying rate. Experiments showed that solar drying was suitable for timber with high MC. Interms of drying rate and dried lumber quality, solar drying was as good as traditional steam drying withthe same schedule. And the solar dryer had distinct energy-saving effect.

不同坡向对尾巨桉人工林林下草本植物多样性的影响

为了解不同坡向对尾巨桉(Eucalyptus urophylla×E.grandis)人工林林下草本植物多样性(Margalef指数dMa、Simpson指数D、Shannon-wiener指数H、Pielou指数J)的影响,以云南省临沧市双江县忙安林场8年生人工林为研究对象,设置不同坡向(阳坡、半阳坡、阴坡、半阴坡)的12个样地进行调查。研究结果显示:1)尾巨桉人工林共调查统计到林下草本植物30种,隶属16科28属,草本层植物物种数在阴坡、半阴坡相同且均高于阳坡、半阳坡。2)不同坡向尾巨桉人工林林下草本物种主要以禾本科的芭茅、菊科的紫茎泽兰为优势物种,占据主导地位。3)不同坡向尾巨桉人工林林下草本层植物在半阴坡的dMa、D、H、J值最大,阳坡最小。综合不同坡向尾巨桉人工林林下植物多样性指数分析比较,阴坡更有利于林下草本植物的生存。

尾巨桉等桉树无性系生长特性分析及选择

对尾巨桉(Eucalyptus urophylla×E.grandis)、巨尾桉(E.grandis×E.urophylla)、尾叶桉(E.urophylla)无性系试验林生长性状和干形进行了分析,为选择优良无性系提供科学依据。结果表明,不同无性系及同一无性系在不同林龄时的胸径、树高、单株材积生长率均有所不同,总体上QL4、QL7无性系生长率较大,而QL1、QL2无性系的生长率则较小;林龄1.5年及6.5年时无性系间胸径、单株材积均有显著差异,而无性系间树高仅在林龄1.5龄时差异显著;其余林龄无性系间的差异均不显著。用6.5年生参试无性系胸径、树高、单株材积、干形观测值对各无性系进行综合评定,结果QL7无性系的综合评定结果最佳,被评为优良无性系,其6.5年生时平均胸径、树高、单株材积分别是16.83 cm、21.42 m、0.233 1 m^3;而QL1无性系综合评定排最后一位;因此,不同无性系及同一无性系在不同阶段的生长表现均有所不同,无性系间胸径、单株材积在其生长的早期及后期均存在显著差异,而树高则在早期差异显著,所选择的QL7优良无性系可在试验地所在区域推广种植。

滇南尾巨桉人工林对不同间伐抚育措施的生长响应及其效益分析

本实验旨在揭示不同抚育措施对尾巨桉(Eucalyptus urophylla×E.grandis)人工林生长的影响,为滇南地区尾巨桉人工林的培育提供理论依据。以云南省宁洱市小黑江林区4年生尾巨桉林为研究对象,依立地特征将其划分为Ⅰ、Ⅱ、Ⅲ等3个类型,连续4年对样地进行观测,分别进行每木检尺、树高测量以及林下灌木和草本的统计,通过显著性差异分析、连年增长量分析以及生物多样性指数的比较,评价不同间伐措施的抚育效果。结果表明:在Ⅰ类样地中,间伐处理样地伐后第1年树高和胸径的连年增长量均高于对照YP(树高连年增长量约0.5 m/a,胸径连年增长量约1.28 cm/a),间伐强度为30%样地(BTQ1-30%-1/1、CCD1-30%-1/1和MMH1-30%-1/1等)伐后第1年树高和胸径的连年增长量均高于间伐强度为50%的样地(CCD2-50%-1/1和XSHK-50%-1/1等);同时,经过抚育间伐样地的林下植被多样性指数均高于对照样地,间伐强度为50%样地(MZP2-50%-1/1和BTQ2-50%-3/3)的林下灌木种类在各样地中最多(均达到10种),间伐方式为砍三留三样地比砍一留一样地的植被多样性指数高。在Ⅱ类样地中,间伐强度为50%的情况下,砍三留三样地的树高、胸径连年增长量均高于对照样地和砍一留一样地。在Ⅲ类样地中,仅开展间伐抚育样地的林分伐后第1年胸径连年增长量(0.90 cm/a)同对照样地(0.85 cm/a)并没有较大差别,而间伐抚育+施肥措施结合样地的伐后第1年胸径连年增长量(1.35 cm/a)却明显高于对照。在各立地条件样地中,间伐抚育林地的667 m^2蓄积量和经济总产值均大于对照样地,不同间伐措施样地之间也存在一定的差异;其中,Ⅰ类立地中间伐强度为30%,砍一留一样地的667 m^2产量最高,经济产值也最大;在Ⅱ类立地中,间伐强度为50%,砍三留三样地的产量最高,经济产值也明显高于对照和其他样地。可得出结论,间伐抚育能够提高滇南地区尾巨桉人工林胸径的增长量、667 m^2蓄积量以及经济产值,丰富林下植被多样性。其中,间伐强度为30%更适于Ⅰ类立地,间伐方式为砍三留三更适于Ⅱ类立地(间伐强度为50%的情况下),Ⅲ类立地在间伐的同时应该结合施肥等措施才能有效改善林分的生长。同时,砍三留三的间伐方式比砍一留一的间伐方式更有利于丰富林分的林下植被多样性。此外,样地的立地条件越好,进行间伐抚育所取得的效益一般越高。

巨尾桉人工林林木二元形高模型的研建

为研究巨尾桉(Eucalyptus grandis×E.urophylla)人工林林木二元形高模型,利用编制双江县巨尾桉二元立木材积表的138株造材样木实测数据(随机划分编表样本103株,检验样本35株),使用SPSS 21.0软件非线性回归分析工具对8个常用的二元形高备选模型进行拟合,根据分析计算的相关指数(R2)、均方差(RMSE)、平均绝对偏差(MAD)、总相对误差(RS)、模型预估精度(P)等指标对模型进行统计分析和综合评价,结果表明:模型FH=aHb Dc和FH=aHb/Dc的各项评价指标综合得分并列最高,基于国内外林学界在二元形高模型方面的应用传统,本研究选定FH=aHb/Dc作为巨尾桉人工林林木二元形高的编表模型,代入参数值的模型表达式为FH=0.633358 H^(1.356645)/D^(0.493597)。使用35株检验样本实测数据进行适用性检验的结果表明:模型的相关指数(R2)为0.90480,估计值的均方差(RMSE)为0.61151,平均绝对偏差(MAD)为0.50557,总相对误差(RS)为1.561%,预估精度(P)为98.52%;经残差检验,检验样本残差图以横轴为中轴线分布均匀;经进行F检验,计算得F值为0.96,小于F_(0.05)(1,33)的查表值4.14。生产性检验的结果表明:模型的相关指数(R2)为0.99035,估计值的均方差(RMSE)为3.37780,平均绝对偏差(MAD)为2.85151,总相对误差(RS)为1.836%,预估精度(P)为99.48%。编表样本和检验样本的各项评价指标结果表明,模型FH=0.633358 H^(1.356645)/D^(0.493597)的拟合精度高、误差小,适合作为巨尾桉人工林林木的二元形高模型,以此为基础编制的二元形高表可以在生产实践中应用。

巨尾桉根径一元材积表的编制

使用编制县级巨尾桉(Eucalyptus grandis×E.urophylla)胸径一元材积表的138株解析木,分编表样本103株,检验样本35株。以根径立木材积表编制技术规程推荐的13个根径-胸径回归方程作为备选模型,根据103株编表样本的根径和胸径数据,应用Levenberg-Marquardt迭代法进行拟合评价,以离差平方和、相关系数、总相对误差、相对误差平均值、相对误差绝对值作为评价指标,选择拟合效果最好的回归方程作为编表模型。编表样本各备选回归方程评价指标的结果表明:根径-胸径回归方程以D=a_(0)+a_(1)×DR+a_(2)×DR^(2)+a_(2)×DR^(3)为最优,主要的两项评价指标相关系数(R)为0.98148,总相对误差(RS)为0.03358%,显示回归模型具有很高的拟合精度。经使用35株检验样本对优选的根径-胸径回归模型进行适用性检验,结果显示:总相对误差(RS)为1.43519%,在±5%的误差范围内;相对误差绝对值平均值(REAA)为5.93209%,在10%的误差范围内;F检验统计量为1.08,小于F_(0.05)(1,33)的临界值4.14,检验的结果表明模型适用。本文通过根径和胸径回归备选模型拟合、评价选优和适用性检验,利用最优根径-胸径回归方程中两个变量之间的回归关系,以编表样本中最小根径和最大根径值作为编表的根径幅度,以1 cm作为根径一元材积表的径阶距,导入县级巨尾桉胸径一元材积表公式V=0.000256 D^(2.281034)1.013750^(D),编制形成巨尾桉根径一元材积表。

巨尾桉林分直径结构与材种出材率模型

为研究巨尾桉(Eucalyptus grandis×E.urophylla)林分直径结构与林分材种结构的相关关系,构建高精度的林分材种出材率模型,以云南省临沧市双江县123个巨尾桉伐区小班的标准地每木检尺及造材数据作为研究对象,分82个建模样本和41个检验样本。在建模样本中,分别使用林分平均胸径、径阶林木株数比率模型和径阶断面积比率模型计算标准地林分材种出材率,分析评价基于这3种方法计算的林分材种出材率预测值与实测值的编表精度。建模样本的拟合评价结果显示,使用林分平均胸径测算的造纸原木、胶合板原木和经济材林分材种出材率平均系统误差分别为21.03%、-30.37%和1.7%,总体误差较大;基于径阶林木株数比率模型构建的造纸原木、胶合板原木和经济材林分材种出材率模型的相关指数R^(2)分别为0.80057、0.79612、0.76195,基于径阶断面积比率模型构建的造纸原木、胶合板原木和经济材林分材种出材率模型的相关指数R2分别为0.99992、0.99918、0.99914,径阶断面积比率模型构建的林分材种出材率模型精度最高。使用41个检验样本的林分材种出材率预测值与实测值数据,对径阶断面积比率模型构建的林分材种出材率模型进行检验,结果显示:造纸原木、胶合板原木和经济材林分材种出材率的平均系统误差分别为0.27%、-0.22%和-0.02%,具有很高的编表精度;置信椭圆F-检验的结果造纸原木、胶合板原木的F-统计量分别为1.48和1.54,均小于F_(0.01)(2,38)的临界值5.21;对经济材预测值与实测值进行独立样本t检验的结果显示,经济材林分材种出材率预测值与实测值两总体样本没有显著差异。研究表明,径阶断面积比率模型能更准确地反映林分的直径分布状态,以此为基础可以构建高精度的林分材种出材率模型。