A New Micropropagation Technology of Tilia amurensis:In VitroMicropropagation of Mature Zygotic Embryos and the Establishment of a PlantRegeneration System

Tilia amurensis is an economically valuable broadleaf tree species in Northeast China.The production of highqualityT.amurensis varieties at commercial scales has been greatly limited by the low germination rates.Thereis thus a pressing need to develop an organogenesis protocol for in vitro propagation of T.amurensis to alleviate ashortage of high-quality T.amurensis seedlings.Here,we established a rapid in vitro propagation system forT.amurensis from mature zygotic embryos and analyzed the effects of plant growth regulators and culture mediain different stages.We found that Woody plant medium(WPM)was the optimal primary culture medium formature zygotic embryos.The highest callus induction percentage(68.76%)and number of axillary buds induced(3.2)were obtained in WPM+0.89μmol/L 6-benzyladenine(6-BA)+0.46μmol/L kinetin(KT)+0.25μmol/Lindole-3-butryic acid(IBA)+1.44μmol/L gibberellin A_(3)(GA_(3)).The multiple shoot bud development achievedthe highest percentage(83.32%)in the Murashige and Skoog(MS)+2.22μmol/L 6-BA+0.25μmol/L IBA+1.44μmol/L GA_(3).The rooting percentage(96.70%)was highest in 1/2 MS medium+1.48μmol/L IBA.Thesurvival percentage of transplanting plantlets was 82.22%in soil:vermiculite:perlite(5:3:1).Our study is the firstto establish an effective organogenesis protocol for T.amurensis using mature zygotic embryos.

Optimal ultrasonic extraction condition and determination of polysaccharides in Tilia amurensis flowers

Seven extracting temperatures （25, 35, 45, 55, 65, 75, 85℃） and extracting time （30, 40, 50, 60, 70, 80, 90 min） were designed for selecting the optimal extracting time and extracting temperature for ultrasonic extraction of T. amurensis flowers. Polysaccharides from T. amurensis flowers were isolated and determined by spectrophotometry. Results show that the optimal ultrasonic temperature was 75℃ and ex tracting time 52 min. The content of polysaccharides in T. amurensis flowers measured by anthrone--H2SO4 colorimetry under 580 nm, was 9.74% with 0.47% of relative standard deviation （RSD, n=3）. This study demonstrated that ultrasonic extraction method was simple, and the color of the treated samples was stable in 4 h. The average recovery value for the polysaccharides measured was 99.48%±1.01%, with 0.112% of RSD （n=3）.

山葡萄(Vitis amurensis Rupr)晚秋叶施^(15)N-尿素的吸收、运转、贮藏及再分配的研究

本文研究了山葡萄对晚秋叶施^(15)N-尿素的吸收、运转、贮藏及再分配利用的特点。结果表明,山葡萄幼树晚秋叶施尿素后可很快被叶吸收并运到树体各部分,Ndff从叶运到根中(距离40cm)只需48小时,且运到根中后即部分形成蛋白质。休眠期80.02％的Ndff贮藏在根中,特别是细根,52.39％Ndff以蛋白态形式贮藏。翌春葡萄开始生长后,Ndff较总N优先用于新梢和叶片等新生器官的生长。不同时期,Ndff％最高的器官不同,一般生长活跃器官的Ndff％高。次年秋季,叶中Ndff仍可部分回流到树体内,第3年春天仍有小量Ndff重新分配到新生器官。Ndff可被山葡萄重复利用3年。

地形因子对天然落叶阔叶林不同年龄紫椴(Tilia amurensis)胸径生长的影响

以集安市林业局热闹林场天然落叶阔叶林为对象,运用树木年轮学方法,分析27块样地121根紫椴树芯样本数据,了解地形条件对不同年龄紫椴胸径生长的影响.结果显示:在调查范围内,以800~900 m海拔紫椴胸径生长过程占优势,各海拔区内的紫椴胸径连年生长量均随年龄的增加表现为先快速降低后缓慢下降的趋势;缓坡紫椴胸径生长量最大,斜坡紫椴胸径连年生长最稳定;不同坡度间紫椴胸径生长在10 a后开始出现差异;前45 a紫椴胸径生长量以阳坡最佳,其次为半阴坡、半阳坡、阴坡,不同坡向间的影响差异出现在10~40 a和50~70 a;坡中、坡下紫椴生长优于坡上,不同坡位间的紫椴胸径连年生长量差异表现在20 a后.

Ectomycorrhizal communities associated with Tilia amurensis trees in natural versus urban forests of Heilongjiang in northeast China

The deciduous linden tree （Tilia amurensis Rupr.） is protected at National Level II in China as a species of ecological and economic importance. The objective of this study was to assess and compare the ectomycorrhizal communities associated with T. amurensis in natural versus urban forests of central Heilongjiang Province. The percentage of T. amurensis colonisation by ectomycorrhiza was more than 60 % in urban forests, compared to 34-49 % in natural forests. Use of a combi- nation of morphological and molecular methods docu- mented 18 ECM （ectomycorrhizal） types among three sites; 12-13 ECM species were identified in the natural sites versus 9 species in the urban site. Four ECM species （Boletus sp., Tuber sp., Inocybe sp.2, Leccinum sp.1） were the dominant mycorrhizal symbionts, and Cenococcum geophilum and Russula sp. were found only in the natural forests.

Biomass allocation and assimilation efficiency of natural Tilia amurensis samplings in response to different light regimes

Biomass allocation and assimilation efficiency of natural Amour linden (Tilia amurensis) samplings in different light regimes were analyzed in the paper. The results showed that shoot increment of samplings in gap was the highest and that of samplings under canopy was the least. Samplings in gap expressed apical dominance strongly but samplings in full sun and under canopy behaved intensive branching. Lateral competition or moderate shading was favored to bole construction. The patters of biomass allocation of samplings in different light environment were rather similar. The biomass translocated to stem was more than that to other organs, and about one half of photosynthate was used to support leaf turn over. On the contrary, photosynthates of samplings in full sun were mostly consumed in leaves bearing and energy balancing. The carbon assimilation for leaves of samplings in gap was the most efficient, and more carbons were fixed and translocated to non-photosynthetic organs, especially to stemwood.

Fallen wood decomposition of Pinus koraiensis and Tilia amurensis

Fallen wood decomposition rate ofPinus koraiensis andTilia amurensis in broadleaved Korean pine forest was studied in this paper. The result showed that decomposition rate of fallen wood was different from that of little diameter wood and coarse woody debris for the same tree species. Fallen wood decomposition was generally rotten from outside to inside. And decomposition speed of fallen woods was different according to tree species and site, and it was also related to diameter of fallen woods. Decomposition depth ofTilia amurensis fallen wood for 17 years was 14 cm, but that ofPinus koraiensis in the same condition was less than 7 cm.Tilia amurensis was decomposed faster thanPinus koraiensis. For same tree species, if the diameter was small, the decomposition speed was quick.

Study on Tissue Culture and Rapid Propagation of Tilia amurensis

To explore the establishment of a tissue culture and rapid propagation system of Tilia amurensis,the effects of basic medium and concentrations and ratios of plant growth regulators on tissue culture and rapid propagation of T.amurensis were studied.The results showed that 1/2 MS medium was the most suitable proliferation medium,and the proliferation coefficient could reach 13.5 after adding 0.05 mg/L 6-BA and 0.03 mg/L IBA;MS medium was the most suitable medium for strong plantlets and rooting,and the best medium for strong plantlets was MS+0.1 mg/L 6-BA+0.1 mg/L IBA+0.03 mg/L GA_(3),with which the average plantlet height reached 5.15 cm;and the best rooting medium was MS+1.0 mg/L6-BA+0.05 mg/L NAA,with which the rooting rate was 93.3%and the number of roots was 5.7 roots.

Analysis of Genetic Diversity of Vitis amurensis Rupr.(Vitaceae) Germplasm Resources

[ Objective] This study aimed to explore the genetic diversity of Vitis amurensis Rupr. （Vitaceae） germplasm resources. [ Method ] Out of total 245 pairs of primers, 18 were selected for SSR amplification of 360 V. amurensis experimental materials. [Result] The number of bands amplified by each primer ranged from 4 to 13 with a mean of 9.44. The length of bands ranged from 150 to 1 000 bp, concentrated at 200 -750 bp. The 18 pairs of primers amplified 170 bands totally, of which 167 bands were polymorphic with a polymorphism ratio of 98.2%. The Shannon＇s diversity index （I） is 1. 778 051. With the SSR-PCR am- plification of 360 V. amurensis varieties （ strains）, 5 specific bands were amplified by certain primers in several varieties（strains） accounting for 2.95% of the total bands. [ Conclusion] SSR molecular marker technique was an efficient method to detect the genetic diversity of V. amurensis and thereby is an effective tool for pedigree analysis and variety identification of A. amurensis varieties（strains）.

环塔盆地不同山葡萄品种果实品质间的差异

为山葡萄在环塔盆地生态区域的选育、推广应用提供科学理论依据,建立8个新疆山葡萄果实综合评价体系。以2019-2021年田间表现良好的山葡萄‘北冰红’‘双红’‘左优红’‘雪兰红’‘双丰’‘北国红’‘左山1’和‘左山2’为试材,测量果实23项外观及理化品质指标,按照测量结果进行描述性统计和主成分分析,根据综合得分进行排名。结果表明,23项果实品质指标变异程度不同,其中白藜芦醇、果形指数、Zn含量和花色苷变异程度较大,超过50%;果穗质量、原花青素、固酸比和Fe含量变异程度一般,为30%~50%;其他果实品质指标变异程度较小(<30%)。因子分析提取出6个特征根>1的公因子,累计方差贡献率达97.839%,公因子PC1贡献率达22.154%,主要由pH、果实纵径、横径、单果质量、单果体积和果穗质量决定,主要反映果实外观品质;公因子PC_(2)贡献率达20.987%,由可溶性固形物、总糖、糖酸比、固酸比和Mn含量5个因子决定,主要反映果汁的糖度;公因子PC_(3)贡献率为19.820%,由Ca、Mg和Cu含量3个因子决定,主要反映矿质元素含量。公因子PC_(4)贡献率为19.117%,由花色苷、总酸和果形指数3个因子决定,主要反映果汁色泽、酸度和果实形状;公因子PC_(5)贡献率为8.293%,由原花青素和总黄酮2个因子决定,主要反映果实的营养状况;公因子PC_(6)贡献率为7.467%,由白藜芦醇和Zn含量2个因子决定,主要反映白藜芦醇和Zn含量的高低情况。山葡萄果实品质综合得分排序由高到低依次是:‘北冰红’‘左优红’‘雪兰红’‘左山2’‘北国红’‘双丰’‘双红’‘左山1’。

不同山葡萄品种CO_(2)响应模型拟合及评价

为探索不同山葡萄品种叶片CO_(2)响应特征差异,以5 a生山葡萄‘北冰红’‘北国红’‘双红’和‘雪兰红’为试材,采用Li-6400便携式光合仪,测定果实膨大期山葡萄叶片光合-二氧化碳响应曲线(photosynthetic CO_(2)response curve,P_(n)-C_(i))以及胞间CO_(2)浓度(intercellular CO_(2)concentration,C_i)、气孔导度(stomatal conductance,G_s)、水分利用率(water use efficiency,WUE)和蒸腾速率(transpiration rate,T_r)等气体交换参数,基于直角双曲线模型、Michaelis-Menten模型和直角双曲线修正模型3种模型拟合山葡萄叶片P_(n)-C_(i)响应曲线。结果表明,直角双曲线修正模型拟合的山葡萄P_(n)-C_(i)响应曲线,其拟合参数与实测值最为接近,可直接计算CO_(2)饱和点(CO_(2)saturation point,CSP)。随大气CO_(2)浓度(atmospheric CO_(2)concentration,C_a)的增加,4个山葡萄品种C_i呈线性递增趋势;G_s和T_r总体呈先升后降趋势;WUE先降后升,呈“U”型变化趋势。主成分分析提取出2个主成分,累计贡献率达84.613%。综合评价‘雪兰红’得分最高,光能转化利用率最高,在低C_a环境下的适应性最佳;‘双红’在不同C_a水平下均可保持较高光合效率,排名第2。综上所述,直角双曲线修正模型拟合山葡萄叶片P_(n)-C_(i)响应曲线效果最优。

植被控制对人工更新紫椴幼树根系性状的影响

全光条件下紫椴(Tilia amurensis)更新困难,植被控制通过改变光照条件和土壤质量能够促进目的树种生长,研究植被控制强度对紫椴幼树根系性状和土壤因子的影响,为紫椴人工林培育提供支撑。以株行距为1.5 m×1.5 m的紫椴人工林(5年生)为对象,设置不同植被控制强度:幼树半径75 cm内所有灌草去除(T_(75))、半径50 cm范围灌草去除(T_(50))、半径30 cm范围灌草去除(T_(30))和不去除灌草(CK),测定不同植被控制强度下紫椴幼树吸收根和运输根的形态学性状、全量养分和非结构性碳水化合物等指标及土壤理化性质,揭示植被控制对根系性状和土壤因子的影响。植被控制显著改变了紫椴幼树所处环境中光照强度,其中,T_(75)处理下光照强度最大,光照强度随着植被控制强度减弱而显著降低(P<0.05)。植被控制均显著降低了土壤全碳、全氮、速效氮和有效磷含量。随着植被控制强度的减弱,细根的直径、碳磷比、可溶性糖和淀粉含量均减小,比表面积、比根长、全碳、全氮和全磷含量均增加。土壤因子对紫椴幼树吸收根和运输根根系性状的变异的解释度分别为43.2%和37.9%。植被控制强度越大,紫椴幼树获得的光照强度越大,紫椴幼树根系形态、化学计量和生理特征随植被控制强度的变化均发生适应性改变,通过提高紫椴根系比表面积、比根长、全碳、全氮和全磷含量以增强幼树对低光条件的适应。植被控制强度变化下光照条件和土壤因子的改变可能是解释紫椴幼树根系性状变化的两个主要因素。

植被控制对人工更新紫椴幼树叶片性状和生长量的影响

【目的】紫椴是我国北方地区特有树种,具有重要的生态和经济价值,全光条件下紫椴更新困难,植被控制通过改变光照条件和土壤质量能够促进目的树种生长,研究植被控制强度对紫椴叶片性状和幼树生长量的影响,探讨最适宜于其更新的植被控制强度。【方法】以株行距为1.5 m×1.5 m的紫椴人工林(5年生)为对象,设置不同植被控制强度T30、T50、T75(清除幼树周围半径30、50、75 cm的所有植被)的处理组和对照组(CK),测定叶片的形态、气体交换参数、光合色素和养分含量及幼树生长量等指标,通过方差分析揭示植被控制强度对叶片形态、光合和生理性质及幼树生长量的影响。【结果】光照强度与植被控制强度呈线性正相关(P<0.05),光照强度在T75组最大(84.43±7.30×10^(3)lx)。紫椴叶片形态指标(叶长、叶宽、单叶面积和比叶面积)均在CK组最大,随着植被控制强度的增加而减小,在T75组达到最小。叶片净光合速率在T30组最大(12.12±1.28μmol·m^(-2)·s^(-1)),胞间CO_(2)浓度在CK组最大(263.14±8.77μmol·mol-1),均随植被控制强度增大而减小。叶片气孔导度和蒸腾速率则随植被控制强度的增大而增加,分别在T75组达到最大(0.17±0.02 mol·m^(-2)·s^(-1)和7.02±1.21 mmol·m^(-2)·s^(-1))。植被控制对紫椴幼树叶片的全碳、全氮和全磷含量具有显著影响(P<0.05),但对叶碳氮磷化学计量比没有显著影响。植被控制提高了叶片中可溶性糖和淀粉的含量,降低了叶片中叶绿素a和叶绿素b的含量,促进了地径生长量,抑制了树高生长量。【结论】随着植被控制强度的变化,紫椴叶片形态、化学计量和生理特征均发生适应性变化,低光条件下,紫椴幼树增加叶片面积、比叶面积、光合色素及营养元素的吸收来提高对光能的捕获能力,增强其光合作用,促进幼树生长。紫椴幼树在T30处理下,净光合速率和地径生长量最大,生存竞争力最强,因此,以幼树为中心对半径30 cm范围的植被控制,是促进紫椴幼树人工恢复的最佳方式。

不同气候情景下小兴安岭3个珍稀易危树种的潜在分布预测

【目的】水曲柳、黄菠萝和紫椴为小兴安岭地区亚顶极群落主要建群树种,分析水曲柳、黄菠萝和紫椴在全球气候变化的背景下的潜在分布区,揭示气候变化对植物分布格局影响,进而为森林质量精准提升和国家储备林建设提供依据。【方法】基于19个气候因子、土壤以及海拔数据,运用MaxEnt模型预测了小兴安岭地区3个珍稀易危树种当前、未来(2021—2040年、2041—2060年、2061—2080年和2081—2100年)4种气候变化情景(ssp126、ssp245、ssp370和ssp585)下潜在分布情况。【结果】1)MaxEnt模型拟合效果良好,AUC值均大于0.7;2)水曲柳重要环境因子依次为年降水量、最热季度的平均温度、最湿月份降水;黄菠萝重要环境因子依次为年降水量、最冷季度的平均温度、最冷季降水;紫椴重要环境因子依次为年平均温度、年降水量、最冷季度的平均温度;3)未来气候变化条件下,水曲柳适生区面积波动较大;黄菠萝在ssp370气候情景下,适生区面积缩减程度最大,其他情况适生区面积趋于平稳;紫椴适生区面积为21 769.87~25 579.46 km^(2),变化范围小,适生区面积有减小趋势。4种气候变化下3个树种核心区中心海拔升高31~222 m。【结论】为使小兴安岭地区森林质量提升,以适地适树为原则,可在伊春市大力种植黄菠萝,在黑河市南部和伊春市北部大力种植紫椴。气候变化对水曲柳影响较大,适生区存在面积小,并且适生区等级降低面积大,建议加大对水曲柳保护力度。

东北阔叶红松林4种树木幼苗光合荧光特征对氮添加的响应

【目的】从光合荧光角度探究阔叶红松林不同演替阶段的4个主要树种幼苗对氮添加的响应差异,为氮沉降加剧背景下东北地区人工造林树种应用提供一定参考,并对未来氮沉降浓度增加情况下森林演替做出推测。【方法】选取阔叶红松林4个演替阶段的代表树种白桦、蒙古栎、紫椴、红松为研究对象,在吉林省舒兰市地区人工造林,设置空白对照(0 kg/(hm^(2)·a)),低氮(50 kg/(hm^(2)·a))和高氮(100 kg/(hm^(2)·a))3种氮梯度模拟自然氮沉降,测定不同氮处理下植株光合参数、光谱反射参数、荧光参数等指标,进行方差分析与均值多重比较。【结果】白桦的净光合速率在不同氮条件下均保持最高,且各项数值受氮影响较小;蒙古栎的净光合速率在低氮下由于叶绿素含量上升而显著提高,在高氮下受气孔、电子传递能力减弱等限制显著下降;紫椴最大光化学效率Fv/Fm较低,电子传递受阻,受到光抑制较强,净光合速率在不同氮条件下均最低,且不同氮处理下无显著差异;红松的净光合速率在施氮条件下由于电子传递速率减弱而下降。【结论】因此推测在低氮浓度下蒙古栎的生长会占据很大优势;氮浓度过高时阔叶红松林前期仍以白桦为主,而中期蒙古栎会受到抑制,紫椴占据优势,后期红松的生长会受到高氮抑制。

紫椴红松林群落主要乔木树种种间关系

以吉林松花江三湖国家级自然保护区紫椴红松林为研究对象,采用总体相关性检验(VR)、χ^(2)检验、联结系数(AC)、共同出现百分率(PC)和点相关系数(Ф)分析群落主要乔木树种在5个层级(Ⅰ级幼苗、Ⅱ级幼树、Ⅲ级小径树、Ⅳ级中径树、Ⅴ级大树)的种间关系。结果表明:主要乔木树种总体相关性为显著正联结,各层级VR介于0.84~1.59;χ^(2)检验结果显示,紫椴-红松在各层级均为不显著联结,二者在Ⅰ、Ⅲ、Ⅳ层级为正联结,在Ⅱ和Ⅴ层级为负联结。主要树种种间关系大多不显著,由Ⅰ级幼苗至V级大树不显著联结种对数占比增加;在Ⅱ和Ⅳ层级,负联结种对数占比最大;AC、PC和Ф值也均表明,紫椴-红松间虽然存在一定联结但联结程度较弱,其他主要树种种间关系多数处于松散的独立状态。总体而言,紫椴红松林群落主要乔木树种已建立了良好的种间关系,可相对稳定地共同利用林地资源。

吉林蛟河针阔混交林红松和紫椴个体生长的影响因素

【目的】以吉林蛟河针阔混交林优势树种红松、紫椴为研究对象,探究叶性状的种间差异,不同叶性状间的相关性,以及生物(邻域竞争、初始胸径、叶片性状)与非生物因素(地形因子)对树木生长速率的影响。【方法】利用Welch-ANOVA方差分析量化红松、紫椴叶性状的种间差异;利用主成分分析及斯皮尔曼相关系数评估性状间的相关性;利用普通最小二乘模型计算不同因素对红松、紫椴生长速率的相对影响。【结果】红松的光饱和净光合速率、暗呼吸速率显著高于紫椴;紫椴的光饱和气孔导度、比叶面积显著高于红松。红松的光饱和净光合速率与光饱和气孔导度、比叶面积呈正相关;紫椴的光饱和净光合速率与光饱和气孔导度呈正相关,与比叶面积呈负相关。初始胸径、邻域拥挤指数、坡度对红松年均胸径生长量有显著负效应。初始胸径对红松年均生物量生长量有显著正效应,邻域拥挤指数、坡度有显著负效应。初始胸径对紫椴年均胸径生长量有显著负效应,对紫椴年均生物量生长量有显著正效应。海拔对紫椴年均胸径生长量、年均生物量生长量均有显著负效应。【结论】红松、紫椴叶性状表现出显著的种间差异,两物种叶片性状的相关性呈现不同规律。紫椴的生长受初始胸径、海拔的影响。初始胸径越大,年均胸径生长量越低,而年均生物量生长量越高;海拔越高,年均胸径生长量与年均生物量生长量越低。红松的生长受初始胸径、邻域拥挤指数和坡度的影响。初始胸径越大,年均胸径生长量越低,而年均生物量生长量越高;邻域拥挤指数、坡度越大,年均胸径生长量与年均生物量生长量越低。

响应面法优化低共熔溶剂提取紫椴花总黄酮工艺及抗氧化活性研究

目的通过合成不同类型的低共熔溶剂,考察其对紫椴花中黄酮类化合物提取率的影响并优化其工艺,并对其总黄酮的抗氧化活性进行研究。方法在单因素实验基础上,选取对紫椴花总黄酮提取率影响较大的因素,采用响应面试验设计方法,建立以超声功率、超声时间、溶剂含水量为自变量,紫椴花总黄酮提取率为因变量的二次回归模型。根据紫椴花总黄酮对ABTS自由基和DPPH自由基的清除效果判断其体外抗氧化能力。结果紫椴花总黄酮的提取最优条件为氯化胆碱-乳酸(摩尔比1:2),超声功率200 W,提取时间30 min,含水量为50%。在此条件下,具有最高的提取率(10.61%)。紫椴花总黄酮对ABTS自由基、DPPH自由基清除率分别为93.27%和90.85%,IC_(50)值分别为0.021和0.0045 mg/ml,具有较好的抗氧化能力。结论利用响应面法优化紫椴花总黄酮的提取工艺,建立了模拟回归方程,可用于提取工艺的参数优化。抗氧化实验结果表明,紫椴花总黄酮有较好的体外抗氧化活性,可用于开发新的抗氧化药物。

不同采收期北冰红葡萄中总酚含量变化规律研究

为综合评价北冰红葡萄品种特性,以3个采样点(阳坡、阴坡、半阴半阳坡)5个不同采收期(T1、T2、T3、T4、T5)的北冰红葡萄为研究对象,测定单粒果重、可溶性固形物等指标,以福林肖卡法重点考察了果实不同部位(果皮和果籽)总酚含量的变化,旨在研究不同采收期北冰红葡萄果实酚类物质的积累规律.结果表明,3个采样点在T5时期的北冰红葡萄果实中总酚含量分别为88.48 mg/g、88.06 mg/g、78.34 mg/g,均显著(p<0.05)高于其他时期的总酚含量,且单粒果重和可溶性固形物含量随采收期的延长而增长,确定了北冰红葡萄的最适采收期为T5.该研究结果将为实际生产中进一步调控酿酒葡萄总酚物质积累和果实品质提供一定的理论依据.

光强和不同抚育措施对林冠下人工更新紫椴苗木叶绿素和光合特性的影响

以次生林林冠下人工更新的2年生紫椴苗木为研究对象,设置2种光照强度(强光(High light,HL,林隙),弱光(Low light,LL,林冠))和4种排除地下竞争的抚育措施(施肥(F)、切根(T)、切根加施肥(T+F)、对照(CK))处理,测定紫椴苗木叶绿素和光合基本参数,探究光强和排除地下竞争的抚育措施对林冠下人工更新紫椴苗木光合生理的影响。结果表明:HL较LL提高了紫椴苗木的净光合速率、蒸腾速率和气孔导度,其中HL下净光合速率显著高于LL(P<0.05),而胞间CO_(2)浓度呈相反的趋势,HL较LL显著降低了紫椴苗木的胞间CO_(2)浓度(P<0.05)。光强以及切根、施肥和光强的交互作用均对紫椴苗木的叶绿素含量产生显著影响。LL下紫椴苗木叶片叶绿素a、叶绿素b和总叶绿素含量较HL分别显著提高了36.1%、37.3%、36.3%(P<0.05)。8个处理组合中,LL下F、T、T+F、CK处理下紫椴苗木叶片的叶绿素含量均显著高于HL (P<0.05),LL下T和T+F处理较CK处理显著提高紫椴苗木叶片的叶绿素含量(P<0.05)。综上,紫椴苗木在林隙这种强光环境下光合作用较强,在林冠这种弱光环境下会通过增加叶绿素含量适应弱光环境,同时在弱光下切根和切根加施肥能够进一步提高紫椴苗木的叶绿素含量,更快速的提高苗木对弱光的适应能力。