BCI 50 hm2森林大样地2010年活立木空间结构分析

[目的]以BCI 50 hm²大样地为研究对象,利用空间结构参数一元分布和二元分布,量化评价BCI 50 hm²大样地活立木整体、冠层和下层的空间结构特征。[方法]以巴拿马BCI 50 hm²森林大样地（2010年第7次调查）中所有胸径（DBH）≥ 1 cm的活立木数据为材料,采用基于相邻木关系的空间结构参数方法对其整体、冠层和下层活立木的空间结构进行分析。[结果]表明：BCI大样地第7次调查整体活立木的平均角尺度（W）为0.504,样地大部分林木处于极强度混交状态（M_i=1）,比例为74.7%。样地的冠层和下层的状态与整体林分的状态相同,均处于随机分布、强度混交和中庸偏劣势的状态。冠层中几乎没有林木个体处于零度混交（M_i=0）状态。下层的大部分林木处于中高度大小比数和中高度混交度等级的组合上。样地中大部分活立木为小径级个体（1 cm ≤ DBH < 20 cm）,使得样地中大部分林木处于劣势状态。无论在整体、冠层和下层,活立木的混交度（M_i）都处于极高水平,在参照树周围的最近4株相邻木中同种个体的比例（M_i=0.00,M_i=0.25）极低。[结论] BCI大样地整体、冠层和下层活立木空间结构呈随机分布,林木的混交度极高,样地中同种个体在最近4株邻体这样的小尺度上呈现聚集分布的情况几乎不存在。     

大兴安岭森林沼泽类型与火干扰对土壤微生物群落影响

[目的]研究森林沼泽演替与火干扰条件下土壤微生物结构与多样性变化,为进一步揭示土壤微生物群落在森林沼泽保护与恢复中的作用提供依据。[方法]采用磷脂脂肪酸法与BIOLOG方法,研究大兴安岭南瓮河国家自然保护区内主要森林沼泽类型(兴安落叶松-狭叶杜香-藓类沼泽、兴安落叶松-兴安杜鹃-藓类沼泽、兴安落叶松+白桦-苔草沼泽)与2006年受不同火强度干扰沼泽(重度火烧的兴安落叶松-兴安杜鹃-藓类沼泽和中度火烧的兴安落叶松+白桦-苔草沼泽)土壤微生物群落特征,探讨沼泽主要发育阶段与火干扰强度对土壤微生物群落的影响。[结果]研究区域土壤微生物群落以16:00(16.29±5.62 nmol·g^-1)、甲烷氧化菌(18:1ω8t)(9.89±8.61 nmol·g^-1)与16:1ω7c(9.79±3.24 nmol·g^-1)的微生物为优势种群。土壤微生物总PLFAs含量、革兰氏阳性菌(G⁺)中a15:0、i16:0、i17:0、革兰氏阴性菌(G^-)中的cy19:0、真菌中的18:2ω6c、甲烷氧化菌(18:1ω8t)与森林沼泽发育阶段、火干扰明显相关(p<0.05)。一般饱和直链脂肪酸/单烯饱和脂肪酸比(Sat/Mon)偏低,其比值随沼泽发育呈现增加趋势,受到火干扰后明显增加(p<0.05);真菌/细菌比(F/B)与革兰氏阳性菌/革兰氏阴性菌(G⁺/G^-)未随着沼泽发育呈现出规律性变化,其比值受火干扰后明显发生改变(p<0.05)。土壤细菌与真菌对6类碳源的利用能力明显不同(p<0.001),其中土壤细菌对α-D-Lactose与L-Threonine利用存在差异性(F_α-D-Lactose =2.87 p=0.080,F_L-Threonine=3.00 p=0.078),土壤真菌对D-Mannitol、D-glucosaminic Acid利用存在差异性(F_{Tween 80}=2.75,p=0.088, F_D-Mannitol=3.53 p=0.047, F_{D-glucosaminic Acid}=4.67 p=0.022),但沼泽类型与火干扰未对土壤微生物功能多样性产生影响(p>0.05)。[结论]土壤微生物量与沼泽发育阶段相关;沼泽发育与火干扰改变土壤微生物群落结构。土壤细菌与真菌对碳源利用方面具有选择性。     

宁夏六盘山香水河小流域华北落叶松人工林乔木层生物量的坡面变化和尺度效应

生物量受坡面环境条件变化影响而有坡面变化与尺度效应。本文在六盘山半湿润区的香水河小流域选择了33 a生华北落叶松人工林的一个斜坡长480 m,水平长398 m的典型坡面,在整个坡面上建立了宽30 m的调查样带,均匀分为空间连续的16个样地,在2014年生长季中期调查不同坡位的样地生物量,分析其坡面变化规律。结果表明:生物量存在明显的坡位差异。坡面生物量t·hm^-2平均值为118.59,其变化范围为96.19 139.18,变幅为42.99,变异系数为0.12;随着离坡顶距离的增加,生物量总体上呈现先升高后降低的变化趋势,在坡面的中上部(水平坡长为87.71 m)达到最大。生物量存在坡面空间尺度效应,即随着相对坡长(X₁)的增加,生物量的顺坡滑动平均值(Y₁)先增大后减小,其回归关系式为:Y₁=23.004X₁³-60.834X₁²+31.786X₁+123.43(R²=0.84),坡面尺度效应表现为每100 m水平坡长生物量变化的数值为6.12 t·hm^-2;各样地生物量与整个坡面平均值的比值(Y₂,小数)随相对坡长有很好的非线性关系,基本上呈先增加后下降、后趋于稳定的变化趋势,其关系式为Y₂=1.722 6X₁³-2.844 5X₁²+1.033 8X₁+1.000 1(R²=0.57),可基于此将特定坡位样地的生物量换算成整个坡面的估算值。造成生物量坡面变化的主要原因是太阳辐射和光照时间随海拔的变化等多种因素造成的。     

栎树林分因子与栗山天牛危害程度的风险分析

研究了13个与栗山天牛危害程度有关的林分因子,并对这些林分因子与栗山天牛危害林地有虫株率进行逐步回归分析,从中筛选出林地坡位、栎树胸径和主林层郁闭度3个关键因子。结果表明:栗山天牛危害林地有虫株率(y)与坡位(x₁)和胸径(x₆)呈显著正相关关系,与主林层郁闭度(x₄)呈显著负相关关系,依此建立多元回归模型:y=0.071 2+0.691 8x₁-0.507 4x₄+0.561 3x₆,经检验,平均差异程度为0.174 2。因此,可用该模型对栗山天牛危害程度进行风险评估。     

I－69杨胶合板用材林密度及立地效应研究

以胶合板材为培育目标,研究了I-69杨胶合板用材林平均单株材积与造林密度和优势高的关系。分别不同林龄(6～11a)建立了平均单株材积与造林密度及优势高的模型V=a₀N^a₁ H₀^a₂,通过生产弹性分析、边际产量分析,研究了密度效应及优势高效应,计算出了不同林龄林分的生产弹性值和边际产量,并且根据立地及密度效应模型研究了造林密度、林龄、立地指数对林分蓄积的影响。认为在长江中、下游地区营造I-69杨胶合板用材林密度应适当减小,选择造林地时以立地指数大于等于20m林地为佳。     

赣县稀土采矿区巨桉林地土壤抗蚀性评价

通过野外调查与室内分析相结合,应用主成分分析法,从衡量土壤抗蚀性的16个指标中,优化得到赣县稀土采矿区巨桉林地土壤抗蚀性7个最佳评价指标：分散系数（X₁）、团聚度（X₂）、>0.25 mm水稳性团聚体含量（X₃）、>0.5 mm水稳性团聚体含量（X₄）、<0.05 mm粉黏粒含量（X₅）、>0.25 mm团聚体破坏率（X₆）和<0.001 mm黏粒含量（X₇）,并以此为变量分析比较不同林龄巨桉林地土壤抗蚀性变化规律。结果表明：不同林龄巨桉林地土壤抗蚀性综合指数大小为：1年生林地>2年生林地>4年生萌芽1 a林地>裸露地。在此基础上,以上述7个评价指标为自变量,以土壤抗蚀性综合指数（Y）为因变量,进行回归分析,得出稀土采矿区土壤抗蚀性综合评价方程为：Y=0.309 X₁+0.038 X₂ -0.161 X₃ -0.643 X₄ +0.491 X₅ -0.032 8 X₆ +0.129 X₇ +41.637,因子决定系数R²=0.991 5,F=49.84,各因子间显著相关,方程拟合较好,可为构建稀土采矿区土壤抗蚀性评价指标体系提供依据。     

长白山典型森林土壤黑碳含量及不同组分中的分布特征

[目的]通过实地采样对黑碳进行量化研究。[方法]利用相对密度分组方法探讨了长白山典型森林土壤黑碳含量及在不同有机碳组分中的分布特征。[结果]表明:黑碳(BC)含量在表层(A₁₁)、亚表层(A₁₂)分别为6.39~16.55 g·kg^-1、1.44~6.16 g·kg^-1,随土壤深度的增加而显著下降(p﹤0.01)。在A₁₁、A₁₂层中,轻组有机碳(LFOC)平均含量分别为66.66 g·kg^-1、6.65 g·kg^-1,轻组黑碳(LFBC)平均含量分别为5.63 g·kg^-1、1.21 g·kg^-1,同时,LFBC/LFOC在A₁₂层(10.02%~34.89%)显著高于A₁₁层(6.99%~14.45%)(p﹤0.01);A₁₁、A₁₂层重组有机碳(HFOC)平均含量分别为49.16 g·kg^-1、36.55 g·kg^-1,重组黑碳(HFBC)平均含量分别为2.69 g·kg^-1、1.44 g·kg^-1,HFBC/HFOC在A₁₁层(3.36%~8.08%)和A₁₂层(3.21%~7.58%)之间没有显著差异(p>0.05)。另外,土壤中LFBC/LFOC显著高于HFBC/HFOC(p﹤0.01),LFBC/BC显著高于HFBC/BC(p﹤0.01)。[结论]长白山典型森林土壤中黑碳的含量、比例均较高;土壤表层(A₁₁)有机碳、黑碳含量及各组分有机碳、黑碳含量均高于亚表层(A₁₂),均随着土层加深而显著降低;轻组、重组有机碳中均含有一定比例的黑碳,黑碳主要分布在轻组分中;轻组、重组有机碳与组分中黑碳均显著相关,轻组中相关系数大于重组。     

无患子天然居群遗传多样性研究

[目的]通过我国无患子主要分布区的居群样本,研究无患子天然居群的遗传多样性和遗传结构.[方法]采用ISSR分子标记技术,利用12条ISSR引物分析18个天然居群的265株个体样本.[结果]表明无患子遗传多样性水平较高,物种和居群水平上的多态位点百分率 (PPB)分别为95.37%和57.82%,Shannon's信息指数(I)分别为0.256 9和0.199 8,Nei's遗传多样性指数(H)分别为0.390 9和0.298 0.AMOVA分析表明,18个居群间出现一定程度的遗传分化,且遗传变异主要发生在居群内.UPGMA聚类和Mantel检验结果表明,18个天然居群可分为2大组群,且居群间的地理距离与遗传距离之间不存在显著相关性(r=0.066 7,P=0.541 7>0.05).[结论]无患子以自交为主,其天然居群遗传多样性丰富,居群内的遗传多样性高于居群间.研究结果可为无患子育种策略的科学制定和种质资源的有效保护及利用提供理论依据.     

米槠人促更新林皆伐火烧后初期土壤CO2通量动态

[目的]为科学评价皆伐、火烧对中亚热带常绿阔叶林不同深度土壤有机碳吸存的影响,[方法]以福建省中亚热带36年生米槠人促更新林为研究对象,采用非散射红外CO₂浓度探测仪和Licor-8100土壤碳通量系统,并结合Fick扩散法计算并分析0~80 cm不同深度土层CO₂通量的日动态特征。[结果]表明:(1)火烧地(RB)和皆伐地(RR)不同土层CO₂浓度均出现明显下降,其中,对照(CK)地土壤CO₂浓度值(0~80 cm)分别是RB和RR的1.9、1.3倍;(2)各试验地土壤CO₂通量(0~80 cm)表现为RB(1.99 μmol·m²·s^-1)>RR(0.99 μmol·m²·s^-1)>CK(0.96 μmol·m²·s^-1),除2040 cm土层外,RB土壤各层CO₂通量均显著高于RR和CK(P<0.05);(3)试验地不同土层CO₂通量(0~80 cm)日变化幅度表现为RB>RR>CK,其中,RB土壤各层的变化幅度均显著大于RR和CK(P<0.05),而RR与CK间的差异表现在0~5、10~20、20~40 cm土层(P<0.05);(4)拟合分析表明,各试验地不同深度土壤CO₂通量与土壤温度呈显著相关,且 RB的决定系数(R²)显著高于RR和CK;不同试验地各土层温度、含水量的双因素模型拟合效果均优于单因素模型;Q₁₀值显示,皆伐、火烧后初期土壤各层的温度敏感性得到明显提高。     

Large electro-fused protoplasts ofPopulus alba selected by a micromanipulator: Techniques and some characteristics of cells and their regenerants

An improved method for selection of large electro-fused protoplasts ofPopulus alba by a micromanipulator was developed. The conditions for electric cell fusion treatment were optimized. For the best result, protoplasts with a cell density of 5 × 10⁵/mL were treated with an alternate current (1 MHz, 200 V/cm) and pulsed with a direct current (2 kV/cm) for 100μs in 2.5 mM CaCl₂ and 0.55 M mannitol. The electo-fused protoplasts were cultured in NH₄NO₃-free Murashige and Skoog’s medium containing 0.6 M of mannitol, 0.09 M sucrose, 1μM of 2,4-dichlorophenoxyacetic acid and 0.1μM of benzyladenine, the same medium used for protoplast culture, but at a very low cell density of 5–10 × 10²/mL in a well of a 96-well culture plate. When cell aggregates derived from individual fused protoplasts were transferred to fresh medium with 0, 0.3 or 0.6 M mannitol, large colonies developed. In the shoot differentiation medium, the reaction of the calluses derived from large fused protoplasts towards the growth regulators differed from the non-fused ones. In medium containing 1μM each of naphthalene acetic acid andN-(2-chloro-4-pyridyl)-N′-phenylurea, growth of callus from electro-fused ones was not reduced by much compared to the control, but shoot differentiation was inhibited. Gibberellic acid (0.1–10μM) was beneficial to shoot regeneration; however, irregularly shaped leaves appeared at high gibberellic acid concentrations. Shoots regenerated were rooted in Murashige and Skoog’s medium containing 4μM of indole-3-butyric acid. Some plantlets obtained had a varied morphology. Based on the characteristics of growth, some cells derived from electro-fused protoplasts appear to be physiologically different from the non-fused one.     

林木直径大小多样性量化测度指数的比较研究

[目的]为了客观恰当地量化表达林分水平上的林木直径大小多样性。[方法]采用6块定位样地数据,对比分析基于直径分布的Simpson(D_N)、Shannon(H_N)及单木断面积Gini系数(GC),基于直径大小分化度的Simpson(DT)、Shannon(HT)及其均值(T-)这6种林木直径大小多样性量化测度指数,筛选出符合逻辑排序且具有较好辨别能力的直径大小多样性量化测度指数。[结果]6块样地的林木直径大小多样性逻辑排序为吉林胡桃楸针阔混交林经营样地吉林胡桃楸针阔混交林对照样地甘肃锐齿栎阔叶混交林经营样地甘肃锐齿栎阔叶混交林对照样地北京油松落叶松人工混交林样地北京侧柏人工纯林;林木直径大小多样性为天然林高于人工林,更为成熟的吉林老龄林样地高于甘肃中龄林样地,经过至少5年结构化经营的样地高于对照样地,人工混交林样地高于人工纯林样地。基于直径分布的DN、HN和GC测度的6块样地林木直径大小多样性排序结果与逻辑排序不一致;基于直径大小分化度的D_T、H_T和珔T测度的各林分林木直径大小多样性排序与逻辑排序一致。[结论]基于直径分布的D_N、H_N和GC量化测度指数不能恰当地表达林木直径大小多样性。基于直径大小分化度的D_T、H_T和珔T量化测度指数能恰当表达林木直径大小多样性;相对D_T和H_T,珔T是一个连续型变量的测度指数,而且能从林分整体水平上量化林木间的大小分化程度,易于解释其生物学意义。因此,认为珔T是恰当表达及区分各林分林木直径大小多样性的最优量化测度指数。     

A new iridoid from Adenosma caeruleum R. Br.

A new iridoid glycoside, adenosmoside (1), together with five known phenylpropanoids, crenatoside, verbascoside, cistanoside F, campneoside I, and campneoside II and two known flavonoids, apigenin 7-O-β-d-glucuronopyranoside and apigenin 7-O-β-d-glucopyranoside, were isolated from the aerial parts of Adenosma caeruleum R. Br. Their structures were elucidated by spectral evidence.     

Effects of temperature on reproductive capacity and longevity of Trissolcus simoni, an egg parasitoid of Eurygaster integriceps

In order to understand the effects of temperature on Trissolcus simoni, some parameters of the life tables of adult parasitoids were investigated under laboratory conditions. The following parameters were measured (the values in parentheses were obtained at 20, 26, and 32 °C temperatures, respectively): net reproductive rate (R_o=37.785, 40.301, and 58.299), intrinsic rate of population increase (r_m=0.111, 0.221, and 0.325), generation time (T=32.77, 16.60, and 12.49 days), doubling time (DT=6.245, 3.136, and 2.133), and finite rate of increase (=1.117, 1.247, and 1.385). Fecundity increased with increasing temperature. The values for total number of eggs deposited per female were 50.1, 64.1, and 68.1, and average female longevity was 24.2, 13.8, and 11.1 days at 20, 26, and 32°C, respectively. Temperature had a significant effect on longevity and oviposition and post-oviposition periods. The results of the study are discussed and compared with life-table parameters of other scelionids.     

Postbuckling of thin wood-based sandwich panels due to hygroexpansion under high humidity

This study was carried out to investigate the postbuckling behavior of thin wood-based sandwich panels under high humidity. Using the Rayleigh-Ritz method based on the von Karman nonlinear theory for the panel, the solutions for both the approximate and the closed form for postbuckling of orthotropic panels were derived to evaluate the deflection for the boundary condition of all clamped edges. The results suggested that the edge movement be considered for evaluation of a critical moisture content and deflection of thin wood-based panels fixed on the core with an adhesive. The numerical solution obtained from the derived model showed some discrepancy with the experimental results. The predicted results overestimated the center deflection of the panels because creep and plastic deformation might be caused by considerable in-plane stress on panels.Appendix: Abbreviations and symbols total potential energy of panel - A _ij ,D _ij extensional and bending stiffness, respectively - _x , _y midplane strains inx andy directions, respectively - _xy midplane shear strain inxy plane - N _x ^M , N _y ^M hygroscopic forces inx andy directions, respectively - h panel thickness - a, b panel length inx andy directions, respectively - x, y, z coordinate system - u, v, w displacement inx, y, andz directions, respectively - MC moisture content change - a _x ,a _y coefficient of linear expansion inx andy directions, respectively - LE linear expansion (MC) - s arc length - R radius of curvature - N _x ,N _y resultant in-plane forces per unit length inx andy directions, respectively - N _n nondimensional loadN _x ^M b ²/E ₂ h ³ - N _cr nondimensional critical load,N _x,cr ^M b ²/E ₂ h ³ - ratio of the core to the total width,a _c /a + a _c - E _c effective core MOE,E +E (i.e., the summation of MOE parallel to the grain and perpendicular to the grain) - h _c core thickness     

Effects of slope and canopy trees on light conditions and biomass of dwarf bamboo under a coppice canopy

Dwarf bamboo, Pleioblastus chino, grows extensively in abandoned coppice woodlands on the Kanto Plain in central Japan and suppresses other understory plants. In order to clarify the factors determining the growth of P. chino, we considered the effect of light conditions under a coppice canopy and examined its relationship with slope aspect, slope angle, and basal area of the trees. The relative photon flux density under the canopy was highly correlated with canopy coverage (R ² = 0.97). The light conditions under the canopy were almost the same at all sites in the summer leafy season regardless of the stand type, while they were remarkably different among the sites and depended on the basal area of evergreen trees in the winter leafless season. The biomass of P. chino on the forest floor was described by the equation: y = 3.18 x ₁ – 0.05 x ₂ + 3.11 (R ² = 0.77, P < 0.01), where y is the log-transformed value of P. chino biomass (gdrymassm^–2), x ₁ is cos at solar noon at the winter solstice, and x ₂ is the canopy coverage during the winter leafless season. is the angle between the suns rays and the normal to the surface and changes with slope aspect and angle. We concluded that light conditions under the canopy in the leafless season had a great effect on P. chino biomass, and that the basal area of evergreen trees and slope characteristics can provide useful guidelines in the control and management of P. chino.     

A new cerebroside from Gynura divaricata

A new cerebroside, 1-O-β-d-glucopyranosyl-(2S,3S,4R,10E)-2-[(2′R)-2′-hydroxyltricosanoyl-amino]-10-octadecene-1,3,4-triol was isolated from the aerial parts of Gynura divaricata DC.     

Gas exchange,water relations and morphology of yellow-cedar seedlings and stecklings before planting and during field establishment

Information is lacking on how yellow-cedar (Chamaecyparis nootkatensis (D. Don.) Spach) stecklings compare with seedlings in their response to potentially limiting field site environmental conditions. Before planting, yellow-cedar seedlings and stecklings were characterized at 5 and 22°C root temperatures for gas exchange parameters (n=6), root growth capacity (n=12) and plant water movement (n=6) using a fully randomized design in a controlled environment growth room. Seedlings, compared with stecklings (t-test), showed a faster (p=0.01) recovery of net photosynthesis (P_n) and stomatal conductance (g_wv) after root temperature increased from 5 to 22°C. Seedlings had greater (p=0.05) root growth capacity (number of new roots 0.5 cm in length) than stecklings after 14 days at 22°C and after 14 days at 5°C followed by 15 days at 22°C. Seedlings had a lower (p=0.01) resistance to plant water movement measured after 29 days (14 days at 5°C followed by 15 days at 22°C root temperature).Seedlings and stecklings were planted on a coastal British Columbia field site and monitored for 1) morphological development and physiological response to ambient site conditions throughout the first growing season, and 2) physiological response to drought conditions during late summer. Both trials used a fully randomized design and stock type means were compared using t-tests (p=0.10, 0.05, and 0.01). Initially, seedlings were taller (p=0.01) than stecklings but otherwise morphologically similar (n=20). Over a 35 week period after planting, stecklings had greater incremental height growth, while seedlings produced a greater (p=0.01) number of roots extending out of the root plug. Seedlings and stecklings (n=6) had similar P_n and g_wv patterns under late spring environmental conditions. However, seedlings had greater P_n and g_wv under cold temperature (p=0.05 and p=0.1, respectively) and drought conditions (p=0.05 and p=0.01, respectively), but during conditions of high evaporative demand and adequate soil moisture, stecklings had greater (p=0.01) P_n and g_wv. Seedlings had higher (p=0.01) daily integrated shoot water potential values (D) at different times during the growing season, and maintained higher (p=0.05) predawn (_pd) shoot water-potential values, higher (D) (p=0.01) and lower (p=0.01) resistance to plant water movement (R_SPAC) during drought conditions.