柳树单宁含量与光肩星天牛危害的关系

根据光肩星天牛的发生规律,通过对不同柳树品系木质部和韧皮部在生长期与休眠期单宁含量的变化规律的分析,研究了柳树中次生代谢物质单宁含量与青杨天牛危害的关系。利用香草醛比色法测定单宁,在柳树休眠期,光肩星天牛危害率与各部分单宁含量相关性不强,在柳树生长期,被害率与被害韧皮部、被害木质部显示较强的负相关性;无论是树木休眠期还是生长期,各柳树品系韧皮部单宁含量均明显大于木质部含量,危害后,除黄柳之外单宁含量有所增加;树木休眠期与生长期的韧皮部、木质部单宁含量差异显著;不同树种间韧皮部与木质部单宁含量差异均显著;健康木与被害木无论是韧皮部还是木质部差异均显著。说明单宁含量增高,抑制虫害能力增强,可视单宁为树种抗虫的一个因素。     

不同地理种源红松抗虫性及其与次生代谢产物相关性

调查不同地理种源红松Pinus koraiensis的球果被害率,以及主要害虫球果尺蛾Eupithecia abietaria和果梢斑螟Dioryctria pryeri的虫口比例。按虫期与被害部位,选取南亚、中亚和北亚3个地理种源的红松,分别测定健康与被害红松韧皮部和球果的单宁、总酚和黄酮含量,分析次生代谢产物与其抗虫性的相关性。结果表明,中亚的红松球果被害率显著高于南亚和北亚种源,其球果中球果尺蛾和果梢斑螟危害率与后2个种源的差异显著;3个种源健康样本韧皮部与球果的单宁和黄酮含量差异显著;受害后3种次生代谢物质含量均呈上升趋势;健康红松不同部位3种次生代谢产物均与其被害率呈负相关,其中韧皮部的单宁含量、球果的单宁和黄酮含量在0.05水平与其被害率显著相关。     

柳树化学成分与光肩星天牛危害相关分析

通过对不同柳树化学成分的分析,柳树韧皮部可溶性糖含量与光肩星天牛Anoplophora gla-bripennis Motsch产卵刻槽数、卵孵化数、越冬幼虫存活数显著正相关,木质部可溶性糖含量与光肩星天牛越冬幼虫存活率显著正相关.柳树韧皮部可溶性蛋白质含量与光肩星天牛越冬幼虫存活率显著正相关,木质部可溶性蛋白质含量与产卵刻槽数、卵孵化数、越冬幼虫存活数显著负相关.柳树韧皮部单宁含量与光肩星天牛卵孵化率呈极显著负相关,木质部单宁含量与光肩星天牛越冬幼虫存活率呈显著负相关关系.取食不同柳树的光肩星天牛羧酸酯酶与光肩星天牛越冬幼虫存活数之间相关关系较为密切,但达不到显著水平.     

不同品系杨树次生代谢物质的对比研究

采用高效液相色谱法提取6个杨树品系的酚酸类次生代谢产物及水杨甙,并分离提纯木质部和韧皮部的单宁,结果表明,不同杨树品系间次生代谢产物含量有一定的差异,韧皮部和木质部的丹宁含量在不同品系间差异不显著,而二者的单宁含量有明显的季节性变化。共提取6种酚酸类次生物质,分析结果显示,绿原酸新疆杨含量最高,银中杨最低;对羟基苯甲酸3930最低,其他几个品系含量比较接近;丁香酸、香豆酸和阿魏酸含量6个品系间无明显差异;木质部水杨甙含量测定结果显示,3930含量最高,而其他5个品系间差异较小。     

天然次生白桦木质部及韧皮部营养元素含量的分布及动态特性

对东北东部山区天然次生白桦林内白桦树干木质部、韧皮部中营养元素含量空间分布及动态特性的研究结果表明：（１）随树高增加，木质部、韧皮部中Ｎ、Ｐ、Ｋ、Ｍｇ含量呈增加趋势，而Ｃａ则相反；（２）木质部、韧皮部中Ｍｎ、Ｆｅ变幅较大，Ｚｎ、Ｎ变幅较小，而Ｃａ在木质部中变幅较大，在韧皮部中变幅较小；（３）木质部中各营养元素含量动态变化与叶、１年生枝中相应营养元素含量变化有相近的规律性。     

虫害诱导的杨树不同品种次生代谢产物季节变化规律

根据青杨天牛的发生规律,在3月、6月、9月及12月对不同品种杨树木质部和韧皮部主要次生代谢产物含量的变化规律进行分析,研究次生代谢产物含量与青杨天牛危害的关系,结果表明:不同品种杨树对青杨天牛的抗性差异显著,其抗性从强到弱的顺序为白林3号杨、小青黑杨、群众杨、晚花杨、黄快杨;在幼虫危害期(6月),各品种杨树木质部和韧皮部中的单宁、总酚及黄酮含量均高于幼虫越冬末期(3月),表明杨树在与害虫长期协同进化的过程中,能够通过不断调节次生代谢产物的含量以抵御昆虫的侵害。     

柳树还原糖含量与光肩星天牛危害的关系

利用3,5-二硝基水杨酸比色法检测还原糖,检测结果为无论是树木休眠期还是生长期,韧皮部还原糖含量均明显大于木质部含量。休眠期,不同柳树品系韧皮部的还原糖含量除黄柳被害后增加外,其余品种均有所减少,木质部还原糖含量被害前后变化无规律。不同品种间的还原糖含量差异显著,各品系韧皮部与木质部间差异显著,健康与被害树种之间差异不显著。生长期,除糖槭之外,各品系无论是韧皮部还是木质部,还原糖含量均有所增加。不同品种间的还原糖含量差异显著,各品系韧皮部与木质部间差异显著,健康与被害树种之间差异显著。无论是休眠期还是生长期,韧皮部以及木质部的还原糖含量与柳树被害率均无紧密相关性。     

核桃砧、穗直径与内含物质含量关系研究

测定了不同直径核桃接穗、砧木的主要内含物质含量,并分析了砧、穗直径与内含物质间的关系,以便为核桃砧、穗质量与嫁接成活之间的关系研究提供理论依据。结果表明:接穗中大部分内含物质含量与直径呈负相关关系,随着接穗直径的增长,木质部和韧皮部中可溶性糖、淀粉、可溶性蛋白质、氨基酸含量都表现出下降趋势,其中韧皮部淀粉、可溶性蛋白质和氨基酸含量最为明显,与接穗直径的相关系数分别为-0.784、-0.822和-0.813,达极显著水平;接穗木质部和韧皮部中含水率总体表现为随直径增大而增加的趋势,但钾、钙、镁含量在木质部与韧皮部中表现不同,在木质部中总体呈现下降趋势,在韧皮部中总体呈现上升趋势。砧木主要内含物质含量与直径呈正相关关系,随着砧木直径的增加,木质部和韧皮部中可溶性糖、淀粉、可溶性蛋白质、氨基酸含量也随之增加,其中砧木直径与韧皮部和木质部可溶性糖、氨基酸,以及木质部可溶性蛋白质含量的相关系数分别为0.818、0.858、0.868、0.972和0.767,达极显著水平;而氮、磷、钾、镁含量则呈现下降趋势。     

‘72杨’韧皮部的构造与理化性能

将‘72杨’、杉木和毛竹的木质部进行对比试验,观察并测试‘72杨’韧皮部的解剖构造以及理化特性,为其高值化利用提供基础数据。使用场发射环境扫描电镜、X射线衍射仪、傅里叶变换红外光谱仪等设备和NREL标准对‘72杨’韧皮部的微观结构、结晶度、化学成分等物化性质进行测定与分析。研究结果表明,‘72杨’韧皮部中韧皮薄壁细胞和筛管分子占细胞总面积的(81.9±1.8)%,结构相对简单。‘72杨’韧皮部气干密度为0.358 g/cm3,绝干密度为0.321 g/cm3;而木质部的相应密度较高,分别为0.497和0.482 g/cm3;‘72杨’韧皮部结晶度仅为19.4%,比木质部低8.7%。‘72杨’韧皮部纤维素、半纤维素、木质素的含量分别为28.7%,11.1%,24.1%,均低于木质部中相应成分的含量,且木质化程度低,半纤维素以木糖为主。此外,由红外谱图发现‘72杨’韧皮部含有单宁、酚类、胼胝质等物质。‘72杨’韧皮部具有低密多孔、结构疏松、结晶度低、木质素含量低、抽提物含量高等特点。因此,‘72杨’韧皮部特别有利于机械(能耗低)或化学(抗降解屏障低)降解以及物化改性(多孔、可及性强),可提取酚类、单宁、胼胝质等物质用于工业应用,研究结果可为‘72杨’韧皮部的高值化利用提供重要的理论依据。     

树干注药后吡虫啉在枣树不同部位的传导分布动态

为了阐明吡虫啉在金丝小枣树体内的传导机理,在树干滴注林果注干杀虫剂后,测定其不同方位叶片、枝条木质部及韧皮部中的吡虫啉含量。结果表明,经树干滴注杀虫剂后,吡虫啉在枣树叶片、枝条木质部及韧皮部组织中均具有良好的传导、分布性能,随着时间的延长,枣树叶片、枝条木质部及韧皮部中的吡虫啉含量均表现出先上升后下降的变化趋势;注药后21 d、15 d、15 d枣树叶片、枝条木质部及韧皮部中的吡虫啉含量分别达到最高值0.90 mg/kg、1.03 mg/kg、0.83 mg/kg。然后逐渐降低,均于用药70 d后变化趋于平缓,而注药后85 d时,枣树叶片、枝条木质部及韧皮部中的吡虫啉含量分别为0.79 mg/kg、0.54 mg/kg、0.64 mg/kg,仍处于较高水平;枣树不同部位吡虫啉平均含量由大到小依次为叶片、枝条木质部、枝条韧皮部,叶片中的吡虫啉平均含量为0.70 mg/kg,比枝条木质部和韧皮部分别增加25.00%和45.83%,木质部平均含量为0.56 mg/kg,比韧皮部含量增加16.67%;树冠上层叶片、上层枝条木质部及上层枝条韧皮部中的吡虫啉平均含量分别达到0.78 mg/kg、0.58 mg/kg、0.49 mg/kg,均高于下层的含量,说明吡虫啉在树体内传输时纵向传导能力较强。枣树经树干滴注吡虫啉后,药效持续时间长,可有效防治枣树生长期内的主要害虫。     

北五味子各器官中木脂素含量分析

对北五味子果实,不同年龄藤条和根的木质部和韧皮部,以及北五味子不同部位叶片中的木脂素进行测定,首次系统地对北五味子不同部位木脂素含量做出定量分析及比较。结果表明,北五味子4种木脂素以种子的含量最高,其中五味子醇甲含量最高,五味子乙素次之,五味子甲素含量最低;在藤条韧皮部,木脂素含量随年龄增长而逐渐升高,在藤条木质部,木脂素含量随年龄增加而逐年降低。     

不同产脂量云南松树脂道解剖学比较研究

为确定高产脂云南松的早期选择指标,采用石蜡切片法对不同海拔、不同产脂量云南松的针叶、树干韧皮部和木质部的组成性树脂道特征进行解剖观察,结果表明:高产脂与低产脂云南松的针叶树脂道个数、树干木质部树脂道密度、韧皮部树脂道大小及单位长度树脂道数量存在极显著差异(P＜0.01),但不同海拔之间无显著差异;高、低海拔高产脂云南松针叶树脂道数量分别比低产脂的高38.89％、30.34％,树干木质部树脂道密度分别高58.06％、48.48％,韧皮部树脂道大小分别高32.20％、29.73％,韧皮部单位长度树脂道数量分别高21.95％、38.51％.说明针叶树脂道数量、树干木质部树脂道密度及韧皮部树脂道大小3项指标,也可作为云南松产脂力评价的部分指标.     

Cambial Anatomy and Annual Rhythm of Secondary Xylem Development in the Twigs of Azadirachta indica A. Juss. (Meliaceae) Growing in Different Forests of Gujarat State

Abstract

Seasonal behavior of vascular cambium and development of secondary xylem were studied in the 2-3-years-old branches of Azadirachta indica A. Juss. (Meliaceae) growing in moist deciduous (MDF), dry deciduous (DDF) and scrub land (SF) forests of Gujarat State. Development of xylem began with the sprouting of new leaves in January in both MDF and DDF. Xylem production culminated in July in MDF whereas it reached peak in April and July in DDF. Cambial cells ceased to divide with the maturation of leaves in November and October in MDF and DDF, respectively. Mature xylem and phloem derivatives surrounded the cambium in December in MDF and November in DDF. Radial growth in the branches of trees growing in SF was found continuous throughout the year with peak cambial activity in April, July and November. In all the three forests, maximal radial growth was encountered in July when the rains were heavy. Cambial activity and xylem development showed significant correlation with the phenology of the trees in MDF and DDF whereas cambium was found active throughout the year and no correlation was found between the cambial activity and phenology in SF.     

Hormonal physiology of wood growth in willow (Salix viminalis L.): effects of spermine and abscisic acid

Summary Willow cuttings from two-year-old twigs were grown in nutrient solution alone, nutrient solution with 0.1 mM abscisic acid or with the spermine. Roots and leaves emerged within three weeks and the cambium was activated in the shoot. In most cases earlywood was generated, even when the seedlings were made in late summer. In contrast to plantlets grown in regular nutrient solution, those treated with hormones either inhibited (ABA) or advanced (spermine) the formation of roots, leaves and wood. In addition, SEM observations of wood were combined with autoradiographic studies and metabolite analysis.¹⁴C-labeled photoassimilates from the leaves were unloaded from the phloem of the shoots and transported via the rays into the cambial zone and the xylem. In spermine treated plants labeled assimilates were highly concentrated in all cells of the newly built xylem. However, cells from plants treated with abscisic acid appeared only weakly labeled. Quantitative analysis of the assimilates after two-dimensional thin-layer chromatography showed that wood from spermine-treated plants accumulated 19% more assimilates than the control, while xylem from ABA-treated plants imported 81% less labeled compounds from the phloem. Thus, the results strongly support the view that hormones play a key role in wood formation.     

Environmental and physiological controls over oxygen and carbon isotope composition of Tasmanian blue gum, Eucalyptus globulus

We measured oxygen isotope ratios (delta18O) of xylem sap, phloem sap, leaves, wood and bark of Eucalyptus globulus Labill. growing in southwestern Australia. Carbon isotope ratios (delta13C) were measured in the dry matter of phloem sap, leaves and wood. Results were used to test several aspects of a mechanistic model of 18O enrichment and provided insights into post-photosynthetic variations in dry matter delta13C. Xylem water delta18O varied little within the tree crown, whereas variation at the landscape-level was more pronounced, with plantations near the coast being enriched by up to 3 per thousand compared with plantations less than 100 km inland. Phloem water was significantly enriched in 18O compared with xylem water in two of three sampling campaigns; mean enrichments were 0.5 and 0.8 per thousand. Phloem sap sugars exported from E. globulus leaves closely reflected observed leaf water enrichment when diurnal variation in photosynthesis was taken into account. Photosynthetic rates were higher in the morning than in the afternoon, whereas leaf water 18O enrichment increased to maximum values in the afternoon. A non-steady-state model of leaf water 18O enrichment accurately predicted observed values through a full diel cycle. Mean estimates of the proportion of organic oxygen effectively exchanging with xylem water during cellulose synthesis were close to 0.40 for both leaves and wood. Carbon isotope ratios of nascent xylem tissues did not differ from those of phloem sap sugars collected concurrently, whereas nascent leaf tissues were depleted in 13C by 2 per thousand compared with phloem sap sugars, suggesting that, in E. globulus, 13C enrichment of sink tissues compared with source leaves does not result from an enriching process within the sink tissue.     

Soluble N compound profiles and concentrations in European beech (Fagus sylvatica L.) are influenced by local climate and thinning

We assessed seasonal changes of total soluble nonprotein nitrogen compounds (TSNN) in adult European beech trees (Fagus sylvatica, L.) growing under different local climate during the growing season immediately following a thinning treatment and 3 years later. In both years, samples of leaves, xylem sap and phloem exudates from beech trees growing in thinned and unthinned (control) stands on a dry, warm SW exposed and a cooler, moist NE exposed site were collected in May, July and September. In May of both years, asparagine (Asn) and glutamine (Gln) were most abundant in leaves and xylem, respectively, whereas arginine (Arg) dominated in the phloem. In July, TSNN concentrations decreased in all tissues and sites, but differences in water availability between aspects were reflected in TSNN concentrations. In September, differences in the increase of Arg concentration in the phloem were related to differences in the onset of senescence between treatments. Thinning treatment increased amino compound concentrations of beech tissues in July on both aspects, particularly at the NE thinned site. It is supposed that, the N balance of adult beech is favoured by both, the thinning treatments as well as the cool-moist climate prevailing at the NE aspect.     

Locating the initial in the vascular cambium of Pinus strobus L. by electron microscopy

Summary The results of this investigation by electron microscopy on the vascular cambium in Pinus strobus L. confirm the results of earlier investigations by light microscopy. First, they showed that differences in the thickness of tangential walls of cambial cells exist and that these differences permit grouping of cells according to the sequence of the previous divisions of the initial. This, in turn, permits the site of the initial cell in the cambial zone to be deducted. The thicker distal tangential wall of the initial in the successive series of tissue production allows for precluding the direction in which the initial function proceeds, toward the xylem or toward the phloem. Second, it was demonstrated that immature xylem cells exist in groups of four, that immature phloem cells exist in pairs, and that at all times more cells are produced toward the xylem than toward the phloem. Third, it was shown that the extra-thick tangential wall in immature xylem serves as a landmark to signal the changeover in the initial function from phloem to xylem production.     

青海云杉林昆虫群落垂直结构研究

采取以线路调查为主,踏查与详查、人工采集与灯诱相结合的方法,对祁连山自然保护区青海云杉林中不同林层的昆虫分别进行了采集调查分析.结果表明祁连山区青海云杉林中植食性昆虫具有明显的垂直分层结构,根据林分的垂直结构和昆虫寄生、取食树木组织部位可划分为6个群落,其种类由多到少依次为灌木和草本层昆虫群落(928种),土壤与根部昆虫群落(约780种),嫩梢与针叶昆虫群落(117种),树干韧皮部与木质部昆虫群落(66种)、枝梢与嫩皮昆虫群落(38种)、花与种实昆虫群落(14种).危害程度由重到轻依次为嫩梢与针叶昆虫群落、树干韧皮部与木质部昆虫群落、花与种实昆虫群落、枝梢与嫩皮昆虫群落、灌木和草本层昆虫群落、土壤与根部昆虫群落.在青海云杉寄生或取食的昆虫多数种类为单食性或寡食性,少数种类为多食性,取食或寄生于林下灌木层和草本层的昆虫大多数为多食性,少数种类为寡食性,较少为单食性.多数种类的取食部位较为固定,但也有许多种类可以在几个部位取食.     

Effect of sweetpotato whitefly, <Emphasis Type="Italic">Bemisia tabaci</Emphasis> (Homoptera: Aleyrodidae) infestation on eggplant (<Emphasis Type="Italic">Solanum melongena</Emphasis> L.) leaf

The nature of damage of sweetpotato whitefly, Bemisia tabaci (Gennadius) B biotype was investigated at the vegetative stage on eggplant (Solanum melongena L., family Solanasae, variety Baiyu) under laboratory conditions (temperature 25 ± 1°C, RH 70 ± 10% and photoperiod 12 h L:12 h D). The investigations were carried out after completing one generation of whitefly on the basis of morphology, physiology and anatomy of eggplant leaf. Significant differences were observed on three morphological parameters—leaf area, leaf fresh weight, and leaf dry weight. The reduction percentages of these three parameters were 26.6, 21.8 and 19.27%, respectively. Significant differences were also observed on two physiological parameters—chlorophyll content and rate of photosynthesis. The reduction percentages of these two parameters were 9.7 and 65.9%, respectively. There were no damaged tissue observed in the epidermis and mesophyll, but there were some damage tissue observed in the vascular bundle of infested leaf. There were no damaged vascular bundles observed in the control leaves. The non-damaged vascular bundles contained both xylem and phloem; while some damaged vascular bundles contained either xylem or phloem. Associated with the non-damaged vascular bundles on whitefly infested leaves were two settled whitefly nymphs apparently deriving nutrition from phloem sap. After one generation of whitefly infestation, the number of damaged and non-damaged vascular bundles of eggplant leaf was significantly different.     

Spatial and seasonal variation in amino compounds in the xylem sap of a mistletoe (Viscum album) and its hosts (Populus spp. and Abies alba)

In a field study, the composition and concentrations of amino compounds in the xylem sap of the mistletoe, Viscum album L., and in the xylem sap of two host species, an evergreen conifer (Abies alba Mill.) and a deciduous broad-leaved tree (Populus x euramericana), were analyzed. The xylem sap of both hosts and mistletoe contained large, but similar amounts of total organic nitrogen in low molecular weight amino compounds (TONLW). Nevertheless, individual amino compounds accumulated in the xylem sap of mistletoe relative to the host xylem sap, indicating selective uptake. In the xylem sap of Populus, major amino compounds (asparagine (Asn) and glutamine (Gln)) and the bulk parameters, TONLW and proteinogenic amino acids, showed significant seasonal variation. In Abies and in mistletoe on either host, variation of amino compounds in xylem sap was largely explained by inter-annual differences, not by seasonal variation. In both hosts, TONLW in the xylem sap was dominated by Gln. There was a steady decrease in relative abundance of Gln from the host xylem sap to the mistletoe xylem sap and to the stems and leaves of mistletoe. Simultaneously, the abundance of arginine (Arg) increased. Arginine was the predominant amino compound in the stems and leaves of mistletoe, occurring at concentrations previously observed only in leaves of trees exposed to excess nitrogen. We conclude that Gln (2 mol N mol(-1)) delivered by the host xylem sap is converted, in mistletoe, to Arg (4 mol N mol(-1)) and that the organic carbon liberated from Gln contributes significantly to the parasite's heterotrophic carbon gain. Statistical analyses of the data support this conclusion. Accumulation of Arg in mistletoe is an indication of excess N supply as a result of the uptake of amino compounds from the host xylem sap and a lack of phloem uploading.