A New Species of Tsuga(Pinaceae) based on Lignified Wood from the Late Miocene of Central Yunnan, China, and Its Paleoenvironmental Implications

A new species, Tsuga nanfengensis sp.nov.（Pinaceae）, is described on the basis of lignified fossil wood from the late Miocene of the Xianfeng Basin, central Yunnan, southwestern China.Detailed observation of the fossil wood specimens show the following characteristics： distinct growth rings, absence of resin canals, uniseriate bordered pits in the radial wall of tracheids, ray tracheids and piceoid and cupressoid cross-field pits.These features indicate similarities to the wood of extant Tsuga canadensis, T.chinensis, and T.dumosa.According to the fossil record, Tsuga was present in Xundian County during the Miocene.Today Tsuga is drought intolerant, preferring wet conditions with no extant species growing naturally in Xundian County.The presence of Tsuga in the Miocene of Xundian County indicates a humid climate consistent with previous palaeoclimatic reconstructions showing a wetter and probably shorter dry season in the Miocene, relative to the present day.Therefore, the change in the local climate such as increasing aridity through the Miocene might explain the local extinction of Tsuga from central Yunnan.

CHARACTERIZATION OF MOLECULAR MASS OF SIX WATER-SOLUBLE POLYSACCHARIDE -PROTEIN COMPLEXES FROM GANODERMA TSUGAE MYCELIUM

Six water-soluble polysaccharide-protein complexes coded as GM1, GM2, GM3, GM4, GM5 and GM6 wereisolated from the mycelium of Ganoderma tsugae by extracting with 0.2 mol/L phosphate buffer solution at 25, 40 and80℃, water at 120℃, 0.5 mol/L aqueous NaOH solution at 25 and 65℃, consecutively. Their chemical components wereanalyzed by using IR, GC, HPLC and ^(13)C-NMR, and some new results were obtained. The four samples GM1, GM2, GM3and GM4 are heteropolysaccharide-prote in complexes, in which, α- (1→3) linked D-glucose is the major monosaccharidewhile galactose, mannose and ribose are the secondary ones. GM5 and GM6 are β-(1→3)-D-glucan-protein complexes. Theprotein content increased from 32% to 69% with the progress of isolation. Weight-average molecu1ar mass M_w and theintrinsic viscosity [η] of the GM samples in 0.5 mol/L aqueous NaCl solution at 25℃ were measured systematically by laserlight scartering (LLS), size exclusion chromatography (SEC) combined with LLS, and viscometry. The M_w of GM1 to GM6are 35.5, 46.8, 58.9, 41.6, 3.3 and 22.0×10~4, respectively. The conformation and molecular mass of the two fractions of sample GM5 were characterized satisfactorily by SEC-LLS without further fractionation.

Antitumor Active Protein-containing Glycans from the Body of Ganoderma tsugae

To explore the effects of traditional herbal medicine Ganoderrna tsugae（G, tsugae） on immunomodulatory and antitumor activities, the crude polysaccharides of G. tsugae were purified by filtration, diethylaminoethyl（DEAE） sepharose-fast flow chromatography and sephadex G-100 size-exclusion chromatography. Two main fractions, pro- tein-containing glyeans CSSLP-1 and CSSLP-2, were obtained via the gradient elution. The protein content, molecu- lar weight, and monosaccharide composition of the two fractions were analyzed. Furthermore, the influence of the protein-containing glycans from G. tsugae on the activation of human acute monocytic leukemia cell line（THP-l） and their antitumor activities to the human hepatocellular liver carcinoma cell（HepG-2） in vitro were evaluated. The re- sults indicate that CSSLP-1 and CSSLP-2 could increase the pinocytie activity of THP-1 cells and induce THP-1 cells to produce the eytokines of TNFa and IL-2, significantly. CSSLP-1 and CSSLP-2 also played an inhibiting effect on the cancer cell（HepG-2）. Moreover, the anti-proliferation activity of CSSLP-1 and CSSLP-2 increased with the par- ticipation of TNFa and IL-2 or other antitumor factors induced from THP-1 cells by G. tsugae protein-containing glycan fractions.

孑遗植物长苞铁杉(Tsuga longibracteata)分布格局对未来气候变化的响应

长苞铁杉(Tsuga longibracteata)是中国特有的珍贵树种,不仅对研究裸子植物的系统发育、古生态和古气候具有重要作用,而且该树种具有造林、用材和药用等方面的较高价值。研究长苞铁杉在气候变化下的分布格局变化是制定其保护和可持续利用的重要基础。采用最大熵模型(MaxEnt),结合不同时期(当前、2050年和2070年)和不同二氧化碳排放情境下(RCP2.6和RCP8.5)的气候因子变量,探讨气候变化与物种地理分布格局的关系,预测长苞铁杉的潜在分布区变迁。本研究考虑了空间约束对物种分布的限制作用,构建了气候因子预测模型(C)和气候+空间约束因子预测模型(C+S)分别进行潜在分布区预测,比较其结果差异。结果显示,最干月降水量和温度年较差是影响长苞铁杉地理分布的主导气候因子,空间约束因子对长苞铁杉未来的地理分布有重要影响。随时间年限增加,长苞铁杉总潜在适生区面积降低,特别是中高等级的适生区面积有不同程度地减少,分布范围总体向北移动,这些变化趋势在RCP8.5情境下更加突出。这一结果表明未来气候变化会导致长苞铁杉种群分布范围收缩和生境适宜度下降,加剧其受胁程度。加入空间约束因子后,C+S模型的预测精度更高,结果更符合长苞铁杉的迁移、扩散特性。长苞铁杉未来的核心分布区仍位于现存的湘、桂、黔结合部,表明其具有"原地避难"的特性,应进一步加强对现有野生资源的保护。渝、川、鄂结合部的大巴山等地区是未来气候变化下长苞铁杉的理论分布区域,可作为长苞铁杉应对未来气候变化的引种地区,应提早进行人工引种、栽培等前期研究。研究结果可为气候变化背景下长苞铁杉的保护、物种迁地保存和可持续管理提供科学依据,也可为准确预测濒危、珍稀植物的地理分布范围提供方法参考。

Volatile Constituents of Juniperus communis L., Taxus canadensis Marshall. and Tsuga canadensis （L.） Carr. from Canada

The essential oil composition leaves of Juniperus communis L., Taxus canadensis Marshall. and Tsuga canadensis （L.） Carr. from Canada were investigated by head space solid phase microextraction （HS-SPME） and gas chromatography/mass spectrometry （GC-MS）. Thirty-three, thirty and thirty-one components were identified representing 95.78%, 93.89%, 96.14% of the oil, respectively. Limonene （26.12%）, benzene （15.62%）, 13-mrycene （9.08%） and β-pinene （7.30%） were found to be the main constituents of J. communis; 1-propanone （36.38%）, morpholine （10.95%）, methylamine （9.10%） and methanone （8.14%） were detected main components of Taxus canadensis; bornylacetate （26.84%）, α-pinene （23.74%）, camphene （11.93%） and limonene （6.02%） were determined as major constituents of Tsuga canadensis. The chemical distributions of the essential oil compounds in the genus pattern were discussed in means of chemotaxonomy and natural products.

Identification of Tsuga Germplasm by Morphological Characters and RAPD Markers

Germplasm collection is important to preserve and maximize genetic diversity for germplasm conservation.Tsuga dumosa(D.Don)Eichler in Engler & Prantl.and T.chinensis var.forrestii(Downie)Silba germplasm was collected from three localities in China:Mt.Yulong,Wenfeng Temple and Mt.Dishiergu,Yunnan Province.Accessions were identified based on morphological characters and RAPD markers.The shapes of the apices and margins of needles were examined,and the length and width of needles,cones and seeds from accessions of mature plants were used to compare the morphological differences and to identify the germplasm.Molecular markers generated by randomly amplified polymorphic DNA(RAPD)were also used to characterize the taxa.Although the clustering based on RAPD markers was inconsistent with the morphological characters of the needles,based on the overall morphological characters and on RAPD markers,the accessions from Mt.Yulong and Wenfeng Temple were identified as T.chinensis var.forrestii,and those from Mt.Dishiergu identified as T.dumosa.Taxonomic identification of the accessions was made based on morphology and by RAPD markers concurred.The results indicate that the shapes of the apices and margins of needles particularly from young plants could not be used as a possible key to identify T.dumosa and T.chinensis var.forrestii.Fig 6,Tab 3,Ref

Fitness and physiology of Adelges tsugae （Hemiptera： Adelgidae） in relation to the health of the eastern hemlock

The hemlock woolly adelgid, Adelges tsugae Annand is an invasive insect that frequently causes hemlock （Tsuga spp.） mortality in the eastern United States. Studies have shown that once healthy hemlocks become infested by the adelgid, nutrients are depleted from the tree, leading to both tree decline and a reduction of the adelgid population. Since A. tsugae is dependent on hemlock for nutrients, feeding on trees in poor health may affect the ability of the insect to obtain necessary nutrients and may consequently affect their physiological and population health. Trees were categorized as lightly or moderately impacted by A. tsugae based on quantitative and qualitative tree health measurements. Population health ofA. tsugae on each tree was determined by measuring insect density and peak mean fecundity; A. tsugae physiological health was determined by measuring insect biomass, total carbon, carbohydrate, total nitrogen, and amino nitrogen levels. Adelges tsugae from moderately impacted trees exhibited significantly greater fecundity than from lightly impacted trees. However, A. tsugae from lightly impacted hemlocks contained significantly greater levels of carbohydrates, total nitrogen, and amino nitrogen. While the results of the physiological analysis generally support our hypothesis that A. tsugae on lightly impacted trees are healthier than those on moderately impacted trees, this was not reflected in the population health measurements. Adelges tsugae egg health in response to tree health should be verified. This study provides the first examination of A. tsugae physiological health in relation to standard A. tsugae population health measures on hemlocks of different health levels.

4种长苞铁杉群落木质残体生物量及碳储量特征

[目的]揭示天宝岩国家级自然保护区内长苞铁杉群落木质残体在碳循环中的基础作用,为长苞铁杉群落保护与森林可持续经营提供依据。[方法]以天宝岩国家级自然保护区4种长苞铁杉群落(长苞铁杉纯林、长苞铁杉+阔叶树混交林、长苞铁杉+猴头杜鹃混交林和长苞铁杉+毛竹混交林)为研究对象,对林内不同树种、不同存在形式(细木质残体、倒木、枯立木和树桩)开展动态调查(2012年、2014年、2016年),估算木质残体生物量和碳储量并分析其动态变化。[结果]表明:(1)4种群落内不同树种木质残体均是长苞铁杉的生物量占比最大(31.57%~77.77%);(2)4种长苞铁杉群落同一林型不同年份相同存在形式的木质残体类型生物量差异均不显著(p>0.05),同一林型不同年份的木质残体类型均是倒木生物量最高(长苞铁杉纯林:5.82~9.48 t·hm^(-2);长苞铁杉+阔叶树混交林:10.90~17.83 t·hm^(-2);长苞铁杉+猴头杜鹃混交林:7.20~10.37 t·hm^(-2);长苞铁杉+毛竹混交林:6.11~9.77 t·hm^(-2));3次调查结果中长苞铁杉纯林枯立木生物量与其他3种群落枯立木生物量均差异显著(p<0.05);(3)4种长苞铁杉群落均是长苞铁杉的碳储量最多,且随着年份的增长,其碳储量总体呈现增长趋势(长苞铁杉纯林:3.64~4.62 t·hm^(-2);长苞铁杉+阔叶树混交林:4.67~4.71 t·hm^(-2);长苞铁杉+猴头杜鹃混交林:2.29~2.53 t·hm^(-2);长苞铁杉+毛竹混交林:3.10~4.79 t·hm^(-2));(4)4种长苞铁杉群落木质残体中均是倒木的碳储量最高,除长苞铁杉+毛竹混交林倒木碳储量是先减少后增加外,其他3种长苞铁杉群落倒木的碳储量均呈现上升趋势,且4种群落中,长苞铁杉+阔叶树混交林的倒木碳储量最高,为4.91~7.68 t·hm^(-2);3次调查结果中,长苞铁杉纯林枯立木碳储量与其他3种混交林枯立木碳储量均具有显著差异(p<0.05)。[结论]p4种长苞铁杉群落中,不同形式木质残体中均是倒木的生物量和碳储量最高;不同树种木质残体均是长苞铁杉的生物量和碳储量最高。长苞铁杉纯林内枯立木生物量、碳储量与其他群落内枯立木差异显著(p<0.05)。

长苞铁杉林倒木不同结构组分难降解物含量的分解程度差异

[目的]探究倒木不同结构组分难降解物含量的分解程度差异,为长苞铁杉林科学经营提供理论依据。[方法]以福建省天宝岩国家级自然保护区中的长苞铁杉林倒木为对象,采用空间代替时间法,在4种林分类型(长苞铁杉纯林、长苞铁杉+阔叶树混交林、长苞铁杉+猴头杜鹃混交林、长苞铁杉+毛竹混交林)中,探究倒木不同结构组分(树皮、边材、心材)的难降解物含量在分解过程中的变化趋势。[结果]显示:(1)在倒木分解过程中,纤维素、总酚和缩合单宁含量降低,木质素含量升高;倒木缩合单宁含量除了在长苞铁杉+阔叶树混交林中随腐烂等级增加呈先升后降趋势外,在其它3种林分类型中均呈现逐渐下降趋势;(2)从第Ⅰ腐烂等级到第Ⅴ腐烂等级,长苞铁杉倒木的难降解物质含量变化均为显著,其中树皮、边材和心材的纤维素含量分别下降100.08 g·kg^(-1)(20.6%)、73.79 g·kg^(-1)(15.0%)和89.87 g·kg^(-1)(17.5%);木质素含量分别升高42.53 g·kg^(-1)(37.7%)、36.71 g·kg^(-1)(37.9%)和22.25 g·kg^(-1)(22.0%);缩合单宁含量分别下降34.45 g·kg^(-1)(47.4%)、11.02 g·kg^(-1)(23.5%)和16.83 g·kg^(-1)(44.0%);总酚含量分别下降4.87 g·kg^(-1)(57.6%)、1.78 g·kg^(-1)(32.0%)和2.06 g·kg^(-1)(41.7%)。[结论]长苞铁杉林倒木分解中难降解物含量除了与其自身C、N、P含量有关外,还受到林分类型及其结构组分与林分类型交互作用的综合影响。研究结果为指导长苞铁杉林分经营提供了理论依据。

松杉灵芝孢子油超声波辅助提取响应面优化

以松杉灵芝孢子粉为原料,提取灵芝孢子油。通过单因素试验研究超声功率、超声时间、超声温度对灵芝孢子油得率的影响,并利用响应面法对松杉灵芝孢子油超声波辅助提取工艺进行优化。结果表明,超声功率300 W,超声时间30 min,超声温度25℃,在此工艺条件下灵芝孢子油的得率为28.5%。

液态深层发酵松杉灵芝提取麦角硫因的技术研究

本文通过单因素以及正交试验确定液态深层发酵松杉灵芝提取麦角硫因的提取条件。结果表明,最佳提取条件为最大允许装液量的60%,转速200 r·min^(-1),发酵液pH=6,发酵温度30℃,发酵通气量0.6 L·min^(-1)。

铁杉属的起源、扩散与传播——基于化石证据

铁杉属是松科的重要组成部分,具有典型的北美—东亚间断分布特征。关于该属的起源、扩散与传播,目前存在较多的争议。本次研究收集了亚洲铁杉属大化石记录,整合了铁杉属花粉记录,获取地质历史时期该属在中国的分布,推测该属的起源和传播路径。该属大约起源于晚白垩世的西欧地区,于马特斯里赫特期—达宁期通过欧亚大陆传播到中国,而在古新世—始新世时期通过北大西洋陆桥传播到北美。早始新世以后北美与东亚的铁杉属植物可以通过白令陆桥进行物种交流,当图尔盖海峡在渐新世干涸后,铁杉属能够通过西西伯利亚和中亚哈萨克斯坦地区在欧亚大陆上交流。在晚中新世铁杉属可以通过北大西洋陆桥进行交流。依据化石记录推断的铁杉属起源和传播的结果与分子学研究存在一定差异,需要更多的铁杉属化石记录及分子学研究提供更可靠的证据。

Effect of Gap Size on Seedling Establishment of Tsuga longibracteata

Effects of three gaps which are large (118 m2), medium (86 m2) and small (20 m2), respectively, and under canopy of Tsuga longibracteata forest on the seedling establishment of T. longibracteata were studied through seed burial experiments from December 2003 to January 2005 in Tianbaoyan National Nature Reserve of Fujian, China. The results showed that the area of gap had an evident effect on the seedling establishment of T. longibracteata. The seedling emergence rates of T. longibracteata in plots of large gap, medium gap, small gap and under canopy were 10%, 10%, 4% and 6%, representing an increasing trend along with the gap size increasing without a significant difference. Rain eroding and insects feeding were two main factors leading to seedling death. The larger the gap size was, the more seedlings were killed by rain erosion and the fewer seedlings were killed by insects feeding. The emergence time of seedlings was almost same in all plots while their death time was different respectively. The gap size had a significant impact on seedling survival rate. The seedling survival rate was highest in the medium gap plot (27.0%) and next to the highest in large gap plot (7.3%), and seedling in small gap plot and under canopy plot died out after one growing season. Increased light supply in gaps was favorable for the seedlings growth and survival. Increased light supply in the large gap could enhance the growth of seedling leaf and root of T. longibracteata, and the seedling in turn allocated more dry mass to root and leaf, but it has little impact on the growth of stem. This research indicates that T. longibracteata is a pioneer species and its seedling establishment need a medium or large gap (>50 m2).

松杉灵芝多糖结构分析及对小鼠运动性疲劳的缓解作用

目的:研究松杉灵芝多糖的结构和单糖组成及对小鼠运动性疲劳的缓解作用。方法:采用沸水煎煮、热水浸提和乙醇醇沉提取松杉灵芝多糖,进一步分离纯化得到多糖纯品,采用电镜、傅里叶红外光谱仪和HPLC对多糖的结构和单糖组成进行分析;通过小鼠爬杆试验和负重游泳试验,分别测定爬杆时间和负重游泳时间,同时测定血清中肝糖原(HG)、肌糖原(MG)、血乳酸(BLA)、血尿素氮(BUN)、丙二醛(MDA)的含量和乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)的活性。结果:灵芝多糖表面凹凸不平呈瘤状物形态,其异头碳为β构象,进一步分析发现灵芝多糖是由甘露糖、木糖、葡萄糖、半乳糖组成的杂多糖,其中葡萄糖占比最大达到了55.01%。与正常喂养组(CK)相比,灵芝多糖低、中、高剂量组均显著延长了小鼠的爬杆时间和负重游泳时间(P<0.05),同时还显著增加了小鼠体内HG和MG的含量(P<0.05),并减少了BLA、BUN、MDA的含量,此外,还显著增加了LDH和抗氧化酶(SOD、GSH-Px、CAT)的活性(P<0.05)。结论:灵芝多糖能够增加小鼠体内HG和MG的储备,降低机体内BLA和BUN水平,同时还可提高小鼠清除自由基和活性氧的能力,提高抗氧化酶活性进而降低了细胞的脂质过氧化,具有较好的抗疲劳能力,从而缓解运动性疲劳对机体造成损伤。

遗传算法结合响应面优化超声提取松杉灵芝三萜工艺及其质谱分析

研究松杉灵芝三萜最佳提取工艺条件,对其三萜类化合物进行分析鉴定。采取单因素实验和响应面法分析超声辅助提取时间、提取次数、液料比和乙醇浓度对松杉灵芝三萜提取率的影响,结合Matlab遗传算法筛选最佳工艺参数;利用高效液相色谱-电喷雾质谱联用技术(HPLC-ESI-MS)对松杉灵芝中三萜类化学成分进行分析鉴定。结果显示:最佳工艺条件为料液比1∶33(g/mL)、乙醇浓度88%、提取次数4次、提取时间1.0 h、超声功率200 W、超声温度50℃;三萜提取率为(1.210±0.002)%;从松杉灵芝中鉴定出7种三萜类化合物,分别为灵芝酸I、灵芝酸C、赤芝酸C、赤芝酮A、灵芝酸B、灵芝酸A、赤芝酸A。实验结果表明,遗传算法结合响应面筛选松杉灵芝三萜的提取工艺参数准确可靠,可用于松杉灵芝三萜的生产制备;松杉灵芝中具有多种三萜类成分,可为松杉灵芝药理作用的进一步研究提供一定理论基础。

松杉灵芝中总三萜的提取工艺研究

目的研究松杉灵芝中总三萜的最佳提取工艺。方法采用乙醇回流提取,以松杉灵芝内三萜类化合物的含量为指标,通过单因素结合正交试验考察松杉灵芝的最佳提取工艺。结果影响松杉灵芝三萜回流提取的因素顺序为:乙醇浓度>料液比>提取时间,乙醇浓度和料液比具有显著性,70%乙醇浓度和1∶14料液比提取效果最佳,提取时间不具有显著性,提取1.5 h效果最佳。结论松杉灵芝最佳的提取工艺为14倍量70%的乙醇回流提取2次,每次1.5 h,该工艺较为稳定,具有简单、可行的特点。

不同光照下土壤水分胁迫对长苞铁杉幼苗的作用

于2004—2005年研究了在不同光照下(100%、50%、25%、10%全日照)水分胁迫(土壤含水量30%、25%、20%、15%)处理30 d后的长苞铁杉幼苗存活率、叶片光合色素含量及比例、MDA含量、SOD活性、POD活性和Pro含量的变化.结果表明:在光照与土壤干旱协同作用对幼苗的影响方面,强光照(100%全日照)加重了干旱对幼苗的伤害,遮阴可以降低不利因素的影响;在光照与土壤过湿协同作用对幼苗的影响方面,强光照(100%全日照)和弱光照(10%全日照)加重了土壤水分过多引起的伤害,中等强度光照(50%和25%全光照)可以降低不利因素的影响;在50%和25%全日照条件下,长苞铁杉幼苗对土壤水分过多和干旱胁迫的忍耐能力较强.

长苞铁杉天然林群落种内及种间竞争关系研究

通过各种竞争指数的比较筛选,得到较能客观反映长苞铁杉种内、种间竞争关系的竞争指数,定量地分析了长苞铁杉种内和种间竞争强度。结果表明:长苞铁杉种内竞争随胸径的增大而逐渐减少;种间与种内竞争关系顺序为:长苞铁杉-长苞铁杉>猴头杜鹃-长苞铁杉>青冈栎-长苞铁杉>其它树种-长苞铁杉。竞争强度与对象木的胸高直径服从双曲线回归关系,利用模型预测了长苞铁杉种内、种间的竞争强度。

九龙山珍稀濒危植物南方铁杉种群数量动态

针对九龙山国家级自然保护区南方铁杉(Tsuga tchekiangensis)种群的分布特点,设置了10个具有代表性的样地。以种群生命表及生存分析理论为基础,编制了南方铁杉种群的静态生命表,绘制了存活曲线、死亡率曲线、消失率曲线、生存率曲线、累计死亡率曲线、种群死亡密度曲线和危险率曲线,分析了种群数量特征;同时结合谱分析方法,分析了南方铁杉种群数量的动态变化。结果表明:1)南方铁杉种群结构存在波动性,幼年阶段的个体较丰富,成年个体数量相对较少,种群趋于DeeveyⅡ型。2)南方铁杉种群死亡率和消失率曲线变化趋势基本一致,均出现两个高峰,一个出现在第5龄级阶段,另一个出现在第15龄级阶段。3)南方铁杉种群的生存率单调下降,累计死亡率单调上升,生存率下降趋势前期高于后期,累计死亡率则相反。4)4个生存函数曲线表明,南方铁杉具有前期稳定、中期锐减和后期衰退的特点。5)种群动态的谱分析显示,南方铁杉种群动态除受基波影响外,还存在着明显的小周期波动,谐波A3处周期的波动与南方铁杉的高生长有关;A6处周期的波动与外界环境变化有关;A8处周期的波动与南方铁杉进入生理衰退期有关。

长苞铁杉林乔木层优势种群种间关联及尺度效应研究

通过设定不同尺度的样方面积,根据2×2联列表,运用方差分析、联结系数AC、2统计量度量、 Ochiai指数系列技术,测定天宝岩国家级自然保护区长苞铁杉群落乔木层10个优势种群间的总体联结关系、 种对间联结显著性和关联系数。结果表明:长苞铁杉群落乔木层10个优势种群的总体种间关联性均呈正关 联,反映该群落处于稳定的顶极阶段;10个优势种群的种间联结关系中,有26个种对在不同尺度样方设计中 均未达到一般显著水平,种对间的相互独立性较强;样方设计为100 m2时,各项指标上规律性比较明显,它的 研究结果与实际情况相吻合。群落虽处于比较稳定的顶极阶段,但应适当调整群落结构,为长苞铁杉的生长 更新提供良好的生态环境。