巨桉EXP基因家族的生物信息学分析

[目的]本研究有助于了解EXP基因家族的基本特征,为深入研究其功能搭建平台。[方法]本研究对从巨桉(Eucalyptus grandis Hill)中筛选出35个EXP基因家族成员(Egr EXP1 Egr EXP35),利用生物信息学方法对其基因特征与表达模式进行综合分析。[结果]巨桉EXP基因分布在8条染色体之上,EXP蛋白均定位在细胞质膜上发挥作用,大多数的家族成员具有信号肽。巨桉EXP编码的蛋白质由α-螺旋、延伸链、无规卷曲、β-转角组成。进化分析结果表明,巨桉EXP蛋白与毛果杨(Populus trichocarpa) EXP蛋白的进化关系接近。35个巨桉EXP基因在巨桉未成熟木质部、成熟叶片、韧皮部、茎尖、木质部以及幼叶组织中表达模式存在显著差异。[结论]EXP基因家族各成员的表达模式不同,Egr EXP17、Egr EXP18可能在巨桉木材形成过程中起重要作用。     

新型液态肥与常规颗粒肥对尾巨桉林分生长及效益的影响

为探索新型液态肥与常规颗粒肥对尾巨桉林分生长的影响,在同等经营管护条件下,分别设置施用常规颗粒肥与新型液态肥两种施肥处理,通过对施肥后尾巨桉林木进行生长量调查及施肥效益分析。结果表明,在等养分施肥条件下,施用颗粒肥的成本低于施用液态肥,且尾巨桉平均树高生长量、平均胸径生长量分别较施用液态肥林木约提高4%～14.9%、6.6%～10.8%。但液态肥施肥方便快捷,其施肥速度是常规颗粒肥的4～6倍,在任务量大、人工短缺及亟需施肥的前提下,施用液态肥具有较大的优势。     

Photosynthetic response to green crown pruning in young plantation-grown Eucalyptus pilularis and E. cloeziana

The loss of foliage through pruning of live branches may reduce tree growth or it may be compensated by photosynthetic up-regulation of the remaining crown. Here, the changes in light-saturated photosynthesis following pruning to remove 50% of green crown length were examined in 4-year-old Eucalyptus pilularis Sm. and Eucalyptus cloeziana F. Muell. trees. The objectives of the study were to: (1) compare leaf-level physiological (light-saturated photosynthesis (A_max), stomatal conductance (g), transpiration (T), dark respiration (R_d), quantum yield (Φ), light compensation point (Γ), water-use efficiency (WUE), nitrogen-use efficiency (NUE)) traits in species with contrasting crown dynamics and structure, (2) examine the effect of crown position on these traits, and (3) examine the effect of pruning on A_max, g, T, WUE, NUE, leaf N and P concentrations and specific leaf area (SLA). Prior to pruning there were no differences in R_d, Γ and Φ between E. pilularis and E. cloeziana but differences in A_max, T, g, leaf N, leaf P, WUE, NUE and SLA. Whereas the rate of physiological processes (A_max, T, and g) and leaf N and P concentrations increased with crown height, R_d, Γ, Φ and SLA declined along this vertical gradient, except in the upper crown of E. cloeziana where A_max, T and g were not different to the lower crown. No up-regulation of photosynthesis or changes in leaf physiology occurred between 6 and 13 months after pruning in either species. The results provide an important basis for modelling pruning effects in process-based tree growth models.     

Effect of Tectona grandis on phenylhydrazine-induced anaemia in rats

Traditional oral report indicates that Tectona grandis is used in the treatment of anaemia in Togo. For this purpose, the extract of T. grandis leaves is evaluated on anaemia model of rat induced by intraperitoneal injection of phenylhydrazine at 40 mg/kg for 2 days. Oral administration of T. grandis extract at 1 g/kg/day and 2 g/kg/day, to the rats previously treated with phenylhydrazine, increased the concentration of haemoglobin, red blood cells number, haematocrit and reticulocytes rate. Moreover, the extract of T. grandis enhanced the osmotic resistance of the red blood cells that confirm the important presence of young red blood cells. These results support partially the traditional use of T. grandis in the treatment of anaemia.     

热带四种按树人工林的土壤指标对氮肥反应的评价

较低氮利用性经常会导致桉树人工林的减产.为检验氮矿化的土壤指标的利用并预测桉树对添加氮肥的响应,研究四种桉树人工林(印度海岸低洼地2种细叶桉人工林和和喀拉拉邦高地的2种巨桉人工林)对添加氮肥和相关季节性氮矿化以及其他氮利用率指标的响应,测定几种生化指标对氮肥的响应,包括全氮,土壤C:N比和在厌氧、有氧孵化过程中释放的氮.结果表明,在4块实验地里,增加氮肥可以相应的提高生产率7%至70%;在有氧孵化过程中,释放的氮与氮肥间有最显著相关性(R2=0.92,p<0.01).与有氧孵化过程中释放的氮相比,季节性土壤氮矿化作用是一个较差的肥料响应的指标.虽然有的指标有很好的应用价值,但在广泛应用之前还需验证测试.     

Increasing wood production through old age in tall trees

How long forest trees can sustain wood production with increasing age remains an open question, primarily because whole-crown structure and growth cannot be readily measured from the ground or on felled trees. We climbed and directly measured crown structures and growth rates of 43 un-suppressed individuals (site trees) of the two tallest species – Eucalyptus regnans and Sequoia sempervirens – representing a wide range of tree sizes and ages. In both species, ground-level measurements of annual growth, including height, ring width, and basal area increment, exhibited the oft-reported trend of decreasing growth (or no change in growth) with age, yet wood production of the entire main trunk and whole crown both increased with size and age up to and including the largest and oldest trees we measured. The balance between structural metrics of whole-crown respiratory demands (cambium area, inner bark volume, sapwood volume, and heartwood deposition area) and photosynthetic capacity (leaf area and green bark area) was statistically independent of size but not age. After accounting for the effect of size, trees with lower potential respiratory demands grew more than trees with higher potential respiratory demands per unit photosynthetic area. The strongest determinant of tree energy balance was the ratio of aboveground cambium area to leaf area. Among the site trees we examined, over 85% of the variation in annual wood production was explained by variation in size, and the proportion of total aboveground wood production in appendages (branches, limbs, and reiterated trunks) increased linearly with size. With increasing age in both species, the proportion of annual wood production converted to heartwood increased in main trunks and appendages. The oldest tree we measured produced more heartwood in its main trunk over 651 years (351 m³) than contained in any tree we measured <1500 years old. The two tallest tree species achieve similar stature despite divergent growth dynamics and ecologies. At one extreme, E. regnans attains great size quickly but dies relatively young because trees are susceptible to fire and fungi. At the other extreme, S. sempervirens attains great size more slowly but has a long lifespan because trees resist fire and prioritize investment in decay-resistant heartwood. Increasing wood production as trees age is a mechanism underlying the maintenance of biomass accumulation during forest development and the carbon-sink capacity of old-growth forests.     

Antioxidant compounds from <Emphasis Type="Italic">Eucalyptus grandis</Emphasis> biomass by subcritical liquid water extraction

The effectiveness of subcritical liquid water processing for extraction of antioxidants from the leaves of Eucalyptus grandis biomass was evaluated by determining the capability of the processed samples to scavenge peroxynitrite radicals in vitro, as compared with the extracts obtained by conventional extraction. Pyrogallol (1), 5-hydroxymethyl-2-furaldehyde (2), and 4,4,6,6-tetramethyl-3,5-dioxo-cyclohex-1-enecarboxylic acid (3) were identified as the major products obtained from the subcritical liquid water extracts. Among these, pyrogallol (1) exhibited stronger antioxidant activity than butylated hydroxytoluene, which was used as a standard for the antioxidant activity measurement. This research was presented at the conference of the Japan Society for Bioscience, Biotechnology, and Agrochemistry (JSBBA) in Tokyo, March 2007.     

Tree mortality and habitat shifts in the regeneration trajectory underneath canopy of an old-growth subalpine forest

To better understand tree regeneration trajectories and the resultant coexistence of Abies with co-dominants, Picea jezoensis var. hondoensis, Tsuga diversifolia and Betula ermanii, in an old-growth subalpine forest, we investigated spatial mortality patterns during the regeneration of Abies mariesii and A. veitchii, which are abundant in the understory reflecting their shade tolerance. Regeneration of these Abies spp. from shaded understory to canopy status is affected by other canopy co-dominants. Snags of understory Abies spp. were common, suggesting that the primary mortality agent is suppression by the overstory. Although live, small Abies trees in the understory were positively associated with a Picea canopy, the long-term survival was reduced among Abies trees close to the canopy, suggesting that shading by large Picea in the overstory negatively affects understory Abies plants. The existence of shade-intolerant canopy co-dominants such as Picea and also Tsuga, which are larger and longer lived than the shade-tolerant Abies, may play an important role in preventing the Abies spp. from competitively displacing these other tree species, which are much rarer in the understory, though common in the canopy. Moreover, in spite of the fact that Betula canopies fostered recruitment and growth of Abies saplings, Abies showed no association with Betula canopy and their survival at later-stage was rather reduced near or beneath Betula canopies at the subsequent understory small tree stage. Based on spatially significant events related to tree death, this study detected such “habitat shifts” in the trajectory of tree regeneration. Accordingly, it can be concluded that careful consideration of the regeneration habitat is required for a fuller understanding of ecological processes in spatially complex old-growth forest systems.     

西南桦和尾巨桉凋落叶分解及其与土壤性质的相关性

[目的]探讨南亚热带西南桦和尾巨桉人工纯林的凋落叶分解动态及其与土壤化学性质之间的相关关系.[方法]采用原位分解袋法研究凋落叶的分解过程.[结果]表明:西南桦、尾巨桉人工林凋落叶分解系数分别为0.96 a^-1和0.88 a^-1.在为期12个月的分解试验中,2种凋落叶有机C含量在整个分解过程中呈逐渐下降趋势;全K含量和C/N比在分解前期迅速下降,之后趋于平缓;全N含量和全P含量在整个分解过程中呈逐渐上升趋势;2种凋落叶N/P比则呈先升高后下降的趋势.无论是分解前期还是分解后期,凋落叶质量损失与N含量均呈显著正相关(前期R=0.877;后期R=0.855),与C/N均呈显著负相关(前期R=-0.735;后期R=-0.697).与尾巨桉林地土壤性质相比,西南桦凋落叶分解提高了林地0~10、10~20 cm土壤的有机C、全N、全P、全K、N/P,对2030 cm土壤有机C、全K、pH值、C/N、N/P则未产生显著影响.相关分析表明:凋落叶初始有机C含量与土壤有机C、全N、全P、全K、N/P显著相关;凋落叶初始全N含量与土壤全N、pH值、C/N显著相关.[结论]凋落叶的养分含量与土壤养分的关系紧密;与尾巨桉相比,西南桦凋落叶的养分含量明显较高,分解速率更快,释放到土壤中的养分也更多.     

巨桉耐寒无性系井冈1号的选育

采集抗寒巨桉单株的萌芽条,通过组培方式繁殖试验苗,以邓恩桉、赤桉、巨桉无性系Eg5、广林九、巨赤桉无性系DH201-2、尾巨桉无性系DH3229等品系作对照,经过多点对比试验的生长观测、抗寒性调查、抗雪压调查以及主要病虫害抗性的测定与调查,综合评价了井冈1号的生长与适应性,并讨论了井冈1号的适宜栽培区域和发展前景。结果表明:井冈1号的抗寒性与邓恩桉、赤桉接近,但抗雪压能力较邓恩桉、DH3229好,井冈1号的保存率、高生长和胸径生长均比邓恩桉、赤桉、Eg5等抗寒品系好。     

巨桉无性系EG5叶片高效再生体系的建立

以巨桉栽培无性系EG5无菌苗的叶片为外植体进行愈伤组织诱导与植株再生研究。结果表明:愈伤组织高效诱导和不定芽分化的最适培养基为改良MS+0.12 mg·L-1TDZ+0.25 mg·L-1NAA;硝酸铵对EG5叶片愈伤组织生长及植株分化的影响较大,最适宜质量浓度为0.412 5 g·L-1;最佳伸长培养基配方为改良MS+0.3 mg·L-16BA+0.05 mg·L-1IBA+0.3 mg·L-1IAA;暗培养10 d能促进不定芽分化,延缓愈伤组织老化和褐变速度。生根培养基为改良MS+0.4 mg·L-1NAA时生根率最高,为65.47%,移植成活率为90%以上。     

雷州半岛尾巨桉人工林树干液流对台风天气的响应

[目的]为正确认识台风对桉树人工林蒸腾耗水的影响。[方法]采用热扩散茎流计对尾巨桉树干液流在台风前后进行连续监测,分析其对台风天气的响应,并同步测定林分气象条件,分析台风过程中树干液流与气象因子之间的相关性。[结果]表明:台风当天,树干液流密度与台风登陆前后(单峰)不同,呈不规律多峰型曲线,树干日均液流密度(2.89 mL·h~(-1)·cm~(-2))较台风前减少53%,夜间液流波动较大;日间最大峰值(7.76 mL·h~(-1)·cm~(-2))出现在下午,峰值较台风前降低55%,树干液流日通量极显著小于台风登陆前后;台风登陆前树干液流密度峰值(17.4 mL·h~(-1)·cm~(-2))及平均液流密度(6.15 mL·h~(-1)·cm~(-2))分别是台风登陆过后的1.24倍和1.14倍,台风后树干液流日通量较台风前均有所下降;台风当天,影响液流的主要气象因子为风速、大气温度、空气湿度、水汽压亏缺和降雨量,液流与风速的相关系数较台风前增大52%,与降雨量的相关系数是台风前的2.6倍,与其他因子的相关系数较台风前均下降了50%左右,而台风登陆前后之间的主要影响因子差异不大。[结论]台风当天的日均液流密度、白天的平均液流密度和日通量均极显著小于台风前后,而夜间液流显著大于台风前后;台风前后的日均液流密度差异不显著,夜间液流台风前显著大于台风后;台风过程中风速成为影响液流的关键因子,与太阳辐射相关性不显著,其他影响因子与台风前后相同,但相关系数除风速和降雨量外均显著下降。     

Comparative study on the chemical composition of lipophilic fractions from three wood tissues of <Emphasis Type="Italic">Eucalyptus</Emphasis> species by gas chromatography-mass spectrometry analysis

Abstract The chemical compositions of lipophilic fractions from Eucalyptus urograndis and Eucalyptus urophylla cultivated in Brazil and Eucalyptus camaldulensis from Mexico were determined by gas chromatography-mass spectrometry (GC-MS) before and after alkaline hydrolysis followed by derivatization. In all fractions, fatty acids (including small amounts of α-and ω-hydroxy fatty acids) and sterols were the most abundant components followed by smaller amounts of long-chain aliphatic alcohols, phenolic acids, and hydrocarbons. The presence of steroid esters and triacylglycerols in all three species was indirectly confirmed by the increased amount of fatty acids and sterols (manly β-sitosterol) in the hydrolyzed fractions compared with the corresponding nonhydrolyzed fractions. The amount of liphophilic compounds (mainly fatty acids and sterols) identified in hydrolyzed fractions of E. urograndis, E. camaldulensis, and E. urophylla corresponded to 1921, 1915, and 634 mg kg⁻¹ of dry matter, respectively. The lower abundance of fatty acids and sterols in the fractions from E. urophylla indicates that problems related to pitch formation will be less severe for this species than for the other two.     

Growth and survival of termite-piped Eucalyptus tetrodonta and E. miniata in northern Australia: Implications for harvest of trees for didgeridoos

The most common canopy trees in the savannas of northern Australia, Eucalyptus tetrodonta and E. miniata are also two of the most common species harvested to make didgeridoos, the traditional musical instrument of northern Australian Aboriginal peoples now experiencing high demand from international markets. Most of the trees of the area naturally have hollow cores, or pipes, due to termite activity, but little is known of the relationships of the cores to size of tree, tree growth or survival. In a wooded savanna of northern Australia, 267 individual trees with known growth and survival rates were cored to determine degree of termite-piping. Generalized linear modelling and multi-model inference showed that frequency of piping increased with diameter (dbh) tree for E. tetrodonta, but >85% of E. miniata trees were piped regardless of dbh. Growth (dbh increment) and survival (4-year) were size-dependent. Survival of both species decreased strongly with degree of piping (pipe ratio). For any given diameter, the growth rate of E. miniata trees was independent of pipe ratio, but for E. tetrodonta trees decreased strongly with pipe ratio. From modelled data, a 10-cm tree with pipe ratio of 0.60 was very vulnerable, growing at 0.0 cm year⁻¹ with 46% survival rate, whereas a 40-cm tree, even with large pipe ratios (0.80), grew 0.05 cm year⁻¹ with 98% survival rate. Traditional methods of tree harvesting remove only those smaller hollow trees that are already suffering low growth rates and are likely to die before reaching maturity, whereas current large-scale commercial methods also remove trees with higher growth and survival rates—those trees most likely to contribute to sustainable tree populations. Incorporating traditional selection and harvest methods into current commercial operations would help ensure longevity of this source of livelihood for indigenous peoples of the region.     

Species and site selection for timber production on farm boundaries in the humid Atlantic Lowlands of Costa Rica and Panama

In 1987–89 the CATIE-GTZ Agroforestry Project set up experiments with five timber tree species planted in single lines on twelve farm boundaries in cooperation with local farmers. When the trees were five years old, their height, diameter and total stem volume were: Acacia mangium 17 m, 19 cm and 67 m³ km^–1, Cordia alliodora 14 m, 20 cm and 46 m³ km^–1, Eucalyptus deglupta 22 m, 24 cm and 85 m³ km^–1, Tectona grandis 17 m, 20 m and 64 m³ km^–1, Terminalia ivorensis 18 m, 23 cm and 104 m³ km^–1. Considering these excellent growth rates, planting of Cordia alliodora, Eucalyptus deglupta and Tectona grandis in lines on farm boundaries should be promoted. T. ivorensis and A. mangium are not recommendable for sites with impeded drainage because of mortality caused by root rot, mostly due to Rosellinia sp.