翅果油树及其群落中7种优势木本种类的叶性特征比较

Taking Elaeagnus mollis Diels and seven dominant woody species in its community from Yicheng County of Shanxi Province as research objects, leaf traits including specific leaf area (SLA), nitrogen content in leaf per unit area ( Narea ) , leaf dry matter content ( LDMC ) and photosynthetic nitrogen use efficiency ( PNUE ) were compared, and correlations of SLA value with LDMC and PNUE values were analyzed. The results show that there are different degree variations in four indexes of leaf traits of E. mollis, Vitex negundo var. heterophylla ( Franch.) Rehd., Broussonetia papyrifera ( Linn.) L' Hér. ex Vent., Lespedeza bicolor Turcz., Caragana microphylla Lam., Rosa xanthina Lindl., Amygdalus davidiana ( Carrière) de Vos ex Henry and Periploca sepium Bunge, in which, SLA value with the largest coefficient of variation ( 404%) , and LDMC value with the lowest coefficient of variation ( 103%) . Compared with other tested species, SLA and PNUE values of E. mollis are the lowest ( 103 cm-2 · g-1 and 108 μmol · mol-1 · s-1 , respectively) , while its Narea value is the highest ( 0243 g · m-2 ) , and its LDMC value is also relatively high ( 0380 g·g-1 ) . SLA value of eight tested species show an extremely significant positive correlation ( P<001) with PNUE value, and a significant negative correlation ( P<005 ) with LDMC value, correlation coefficient are 0923 and -0718, respectively, indicating that SLA value is an important parameter of leaf photosynthetic capacity and resource utilization ability. It is suggested that compared with other dominant woody species, E. mollis is more sensitive to environmental change, and has a poor environmental adaptability.     

长期施肥对水稻光合特性及水分利用效率的影响

在实施了27年的长期田间定位试验区,研究了长期不同施肥对红壤区水稻光合特性及水分利用效率的影响.结果表明:在不施肥(CK)、无机肥(N、NP、NPK)、有机肥(猪粪+紫云英绿肥,M)和无机肥与有机肥配施(NPKM)处理中,长期施用肥料,特别是有机肥与无机肥配施提高水稻各生育期剑叶叶绿素含量、净光合作用速率、气孔导度、蒸腾速率、水分利用效率和水稻产量,降低水稻剑叶胞间CO_2浓度;水稻剑叶叶绿素含量、净光合作用速率、气孔导度、蒸腾速率随发育阶段演进而减小,孕穗期>齐穗期>乳熟期,而胞间CO_2浓度相反;水分利用效率以齐穗期为最大;水稻发育阶段叶绿素含量、净光合速率和水稻产量之间均呈显著正相关;长期施用肥料,特别是有机肥与无机肥配施更有利于红壤区水稻的生长发育、产量和水分利用效率的提高.

Abstract：

A field experiment has being conducted for 27 years in Jinxian County, Institute of Red Soil in Jiangxi Province (116°20'24" E, 28°15'30" N) to study the effects of fertilization on the rice photosynthetic traits and water use efficiency. Four treatments were installed,i. e., no fertilization (CK), chemical fertilization (N, NP, NPK), organic fertilization (M), and chemi-cal and organic fertilization (NPKM). Long-term fertilization, especially treatment NPKM, in- creased the flag leaf chlorophyll content, net photosynthetic rate, stomatal conductance, transpi-ration rate, and water use efficiency of rice at its all growth stages and the rice yield, and de-creased the flag leaf intercellular CO_2 concentration. With the growth of rice, the chlorophyll content, net photosynthetic rate, stomatal conductance, and transpiration rate decreased, but the intercellular CO_2 concentration increased. The water use efficiency was the greatest at full-head-ing stage. There were significant positive correlations between the chlorophyll content and net photosynthetic rate at various growth stages and the rice yield, Long-term fertilization, especially the combined chemical and organic fertilization, was favorable to the rice growth and develop-ment, water use efficiency, and yield production in red soil region.     

基于功能性状评价5种植物对热带珊瑚岛环境的适应性

植被新建是保护和改善热带珊瑚岛生态系统的关键环节,热带珊瑚岛极端干旱生境是影响植物存活和定居的主要限制因子之一,因此选取适生植物对热带珊瑚岛植被新建至关重要。通过测定在海南省文昌市苗圃和热带珊瑚岛上的草海桐(Scaevola taccada)、厚藤(Ipomoea pescaprae)、木麻黄(Casuarina equisetifolia)、花生(Arachis hypogaea)、椰子(Cocos nucifera)5种植物的光合/水力相关功能性状,探讨植物对热带珊瑚岛生境的适应性。研究发现:与对照(文昌苗圃)相比,热带珊瑚岛上的草海桐、厚藤、木麻黄最大光合速率(A_(max))均显著升高;除椰子外,其余4种植物的比叶面积(SLA)降低,长期水分利用效率升高(其中木麻黄和花生升高显著);5种植物的叶片碳含量(LC)均有不同程度降低。此外,厚藤、木麻黄、椰子的叶片导水率(K_(leaf))显著升高;厚藤和花生的叶片膨压丧失点(Ψ_(tlp))显著降低;厚藤和木麻黄的气孔导度(g_s)显著升高。研究结果表明草海桐、椰子、花生主要通过非气孔调节方式(提高K_(leaf),降低Ψ_(tlp)、SLA等)适应热带珊瑚岛干旱环境;而厚藤和木麻黄同时通过气孔调节(降低g_s)及非气孔调节(提高K_(leaf),降低Ψ_(tlp)、SLA等)两种方式促进植物碳同化和水分利用。综上所述,草海桐、厚藤、木麻黄具有更高的光合能力和水分利用效率,能有效协调碳同化和水分利用,表现出良好的适应能力,适合用于热带珊瑚岛的植被新建。     

漓江水陆交错带植物叶性状对水淹胁迫的响应及经济谱分析

以漓江水陆交错带为研究区,分两个条带分别量测了适生植物的5个叶性状指标:最大净光合速率(A_(max))、比叶重(LMA)、单位质量叶片全氮含量(N_(mass))、单位质量叶片全磷含量(P_(mass))、单位质量叶片全钾含量(K_(mass))。研究重度淹没带与微度淹没带不同功能型植物叶性状间的差异,分析并讨论重度淹没带叶性状间的关系与全球尺度是否存在差异,探究重度淹没带植物对水淹生境的生理响应机制。结果如下:(1)重度淹没带植物叶片的A_(mass)、N_(mass)、P_(mass)显著高于微度淹没带。(2)乔木、灌木叶片的LMA均显著高于草本植物,而A_(mass)、PPUE均显著低于草本植物。(3)重度淹没带草本叶性状指标的N_(mass)、P_(mass)、PNUE均显著高于微度微度淹没带,而乔木、灌木的叶性状在两个条带的差异则不显著。(4)重度淹没带植物叶性状关系与全球尺度基本一致,其植物叶片具有低LMA,高A_(mass)、Nmas s、P_(mass)。分析可知,重度淹没带植物在出露期提高叶片光合效率及相关营养水平可能是其适应水淹胁迫特殊生境的关键策略之一;不同功能型植物对同一环境的适应能力存在一定的差异,草本对于水淹环境的响应更为积极,适应能力更好;重度淹没带也存在叶经济谱,其植物在经济谱中属于"快速投资-收益"型物种。     

底泥养分富集条件下11种水生植物的光合氮利用效率

为揭示水生植物对富营养化河涌底泥的生理生态适应性及其净化能力,选取11种水生挺水植物(包含6种本土植物和5种外来植物)结合河涌底泥进行试验。通过测定试验一年后植物叶片的光饱和光合速率(P_(sat),μmol m~(-2)s~(-1))、比叶面积(SLA,m~2/kg)、总氮含量(TN,mg/g)和光合作用氮利用效率(PNUE,μmol mol~(-1)s~(-1)),比较分析物种间生理与结构特性及其相互关系。结果表明:种间的SLA层次比较分明,最高的大叶皇冠草(20.31±0.30)与最低的鸢尾草(7.22±0.31)相差近3倍。种间的P_(sat)在(3.76±0.57)(鸢尾草)—(21.53±1.20)(水罂粟)之间,水罂粟比鸢尾草高81.79%。种间的PNUE从42.53±8.42(鸢尾草)至655.8±100.93(天使花),美人蕉、水罂粟、风车草和香蒲的PNUE值均较高,且差异不明显(P0.05),这些植物的PNUE显著高于较低PNUE的种类(包括菖蒲、蓝花草和鸢尾草)(P0.05)。种间SLA分别与PNUE和P_(sat)(μmol kg~(-1)s~(-1))呈显著的正相关,SLA和P_(sat)(μmol m~(-2)s~(-1))分别与TN(mmol/m~2)呈显著负相关(P0.05)。外来植物类群的PNUE、SLA、P_(sat)和TN均显著高于本地植物类群(T-test,P0.05),说明外来水生植物在养分富集化环境下能更有效地利用资源,具有潜在的高生长速率和种间竞争优势。     

气孔特征与叶片功能性状之间关联性沿海拔梯度的变化规律——以长白山为例

气孔是陆生植物与外界环境进行水分和气体交换的主要通道,控制着植物的光合作用和蒸腾过程。植物往往通过多种性状的组合来适应变化的环境,叶片功能性状之间的紧密关系已经在不同尺度得到证实。然而,植物气孔特征与叶片其它功能性状是否存在关联性以及这种关联性是否会受到环境变化梯度的影响仍鲜少报道。沿长白山北坡6个海拔梯度,测定了150种植物的气孔特征和叶片功能性状。结果发现,气孔密度(SD)与比叶面积(SLA)负相关,与单位面积的叶氮含量(N_(area))正相关;除了SLA和N_(area)外,气孔长度(SL)与SLA、叶片厚度(LT)和单位质量的叶氮含量(N_(mass))均存在显著的相关性(P0.05)。然而,气孔特征与叶片功能性状的相关性只在部分海拔梯度存在。此外,发现SD与SL之间存在稳定一致的负相关关系。这些结果表明,植物气孔特征与叶片形态和化学特征对环境变化的适应存在一定的协同变异性,但这种关系不具有普适性,主要与气孔特征和叶片功能性状的选择压力存在差异以及物种分布范围相关。未来仍需要在更多物种和不同区域内来验证气孔特征与植物功能性状之间的关联关系。     

Variations and interrelationships of foliar hydraulic and photosynthetic traits for Larix gmelinii北大核心CSCD

Aims: Variations and potential trade-offs of leaf hydraulic and photosynthetic traits are essential for assessing and predicting the effect of climate change on tree survival, growth and distribution. Our aims were to examine variations and interrelationships of leaf hydraulic and photosynthetic traits in response to changes in site conditions for Dahurian larch (Larix gmelinii)-a dominant tree species in Chinese boreal forests. Methods: This study was conducted at the Maoershan Forest Ecosystem Research Station. A transect of 27 year-old Dahurian larch plantation was established that consisted of five plots extending from the valley to the ridge of a slope. The predawn leaf water potential (ψpre), area- and mass-based leaf hydraulic conductance (Karea and Kmass, respectively), resistance to embolism capacity (P50), leaf mass per area (LMA), net photosynthetic rate (A), and leaf nitrogen content (N) were measured in August 2016. Important findings: The ψpre, Karea, Kmass, P50, A, LMA, and N all varied significantly among the plots (p < 0.05), indicating significant intra-specific variations in these traits in response to the changes in site conditions. The P50 was significantly (p < 0.05) correlated with ψpre, Karea or Kmass, suggesting that a trade-off between hydraulic efficiency and safety exist within the species to some degree. There were significant (p < 0.05) pairwise correlations between A, LMA, and N. Nevertheless, there was no significant (p < 0.05) correlation between the measured photosynthetic traits and hydraulic traits. We concluded that the intra-specific variations and multiple interrelationships of the leaf hydraulic and photosynthetic traits for the larch reflect the plasticity of its leaf traits and strategies of its survival and growth as a result of its acclimation to diverse site conditions.     

四种菊科植物开花期构件生物量及表型可塑性比较

本文对粤东地区菊科2种入侵植物三叶鬼针草(Bidens pilosa)、加拿大蓬(Conyza canadensis)以及2种本土植物宽叶鼠曲草(Gnaphalium adnatum)、夜香牛(Vernonia cinerea)3种生境下的构件生物量、生物量分配及变异趋势进行了研究,对株高与各构件之间的关系建立了定量化描述模型,以揭示4种菊科植物在不同小生境中各构件的变异大小及生殖分配策略;对4种植物繁殖与营养构件之间的关系进行相关性、回归分析和生长趋势分析,以确定入侵种是否存在较高的表型可塑性。结果表明:三叶鬼针草在贫瘠、干燥的生境中,茎生物量分配显著增大,叶和花序生物量分配有减小的趋势;加拿大蓬在肥沃、潮湿的生境中其茎、叶、花序及总生物量显著大于其他2个生境(P0.01);宽叶鼠曲草和夜香牛在肥力较差、干燥的环境中,根生物量分配增大,茎和花序生物量分配有减小的趋势;三叶鬼针草、加拿大蓬和夜香牛各构件生物量的变异系数宽叶鼠曲草;相关性检验和生长趋势分析显示,三叶鬼针草、加拿大蓬和夜香牛繁殖与营养构件之间为异速生长。因此,三叶鬼针草、加拿大蓬和夜香牛具有较高的表型可塑性,以增强对多样环境的耐受性和适应性。     

金沙江干热河谷新银合欢(Leucaena leucocephala)的光合与荧光特征干湿季对比研究

为了研究引进树种对干热河谷环境的适应性,以生长于干热河谷野外环境中的新银合欢(Leucaena leucocephala)为研究对象,研究分析了其在湿季(7月)和干季(11月)的光合生理特征和叶绿素荧光特征。结果表明:(1)在P_n-C_i响应曲线中,当C_i150μmol/mol,干季的净光合速率(Net photosynthetic rate,P_n)高于湿季,而当C_i150μmol/mol,干季的P_n低于湿季;(2)相较于湿季,干季的初始羧化效率(Initial carboxylation efficiency,CE)、光合能力(Photosynthetic capacity,A_(max))、CO_2补偿点(CO_2 compensation point,Γ)、光呼吸速率(Photorespiration rate,R_p)、最大羧化速率(Maximum carboxylation rate,V_(cmax))、最大电子传递速率(Maximum electron transport rate,J_(max))、磷酸丙糖利用率(Triose phosphates utilization rate,TPU)、J_(max)/V_(cmax)、气孔限制值(Stomatal limitation,L_s)和叶片饱和水汽压差(Vapor pressure deficit,VPD)均显著下降(P0.05),而暗呼吸速率(Dark respiration rate,R_d)、胞间CO_2浓度(Intercellular CO_2 concentration,C_i)、气孔导度(Stomatal conductance,G_s)、蒸腾速率(Transpiration rate,T_r)、饱和光下最大净光合速率(Light-saturated net photosynthetic rate,P_(nmax))和水分利用效率(Water use efficiency,WUE)则显著上升(P0.05);(3)干季的PSII实际光化学效率(Actual photochemical efficiency of PSII,Ф_(PSII)),光化学猝灭系数(Photochemical fluorescence quenching,qP),电子传递效率(Electron transport rate,ETR)较湿季出现显著下降(P0.05),非光化学猝灭系数(Non-photochemical fluorescence quenching,NPQ)显著增加(P0.05);(4)叶绿素荧光参数的Ф_(PSII)、NPQ、ETR与各光合生理指标相关性较强。在干热河谷地区,气孔限制是影响新银合欢湿季光合速率的主要因素;而非气孔限制是影响其干季光合速率的主要因素。     

羌塘高原降水梯度植物叶片、根系性状变异和生态适应对策

叶片和根系是植物获取资源的最重要的器官,其性状随环境梯度的变化反映了植物光合碳获取和水分与养分的吸收能力及其对环境变化适应的生态对策。羌塘高原降水梯度带高寒草地群落叶片和根系成对性状关系研究不仅能揭示环境梯度对植物性状的塑造作用,也可为理解寒、旱和贫瘠等极端环境下植物的适应策略提供依据。为此,选择3组具有代表性的叶片和根系成对性状:比叶面积(SLA)和比根长(SRL);单位质量叶氮含量(LN_(mass))和单位质量根氮含量(RN_(mass));单位面积叶氮含量(LN_(area))和单位长度根氮含量(RN_(length)),分析不同优势植物地上、地下成对性状变异特征及其与环境因子的关系,探讨植物性状对高寒生态系统水分和养分限制因素的适应策略。研究表明,区域气候和土壤环境导致的叶片性状变异大于根系性状的变异,干旱端的植物既具有高的SRL,又具有高的叶片和根系的养分含量(LN_(mass),LN_(area)和RN_(mass))。SLA-SRL、LN_(mass)-RN_(mass)、LN_(area)-RN_(length)均表现为权衡关系,在干旱端(年降雨量MAP 400 mm)的高寒草原、荒漠草原和极湿润端(MAP 600 mm)的高寒草甸这种权衡关系更为明显,而中间区域(400 MAP 600 mm)的高寒草甸养分和水分限制不是很强烈,叶片和根系性状更多地表现出协同关系。从植物功能类群来看,苔草和禾草类植物叶片和根系成对性状之间具有更强烈的权衡关系。干旱端植物通过增加SRL和叶片、根系养分含量来提高水分和养分的吸收能力,同时通过叶片高的氮含量提高光合碳获取能力,保障了根系生长的物质来源,表现出地上和地下同时投入的策略。干旱端植物保持较高的养分含量是抵御和适应严酷的寒、旱和贫瘠的环境胁迫的重要策略。而在湿润端植物则采取增加SLA,维持地上光合生产力的生态策略。     

Do higher resource capture ability and utilization efficiency facilitate the successful invasion of native plants?

The great damage caused by native invasive species on natural ecosystems is prompting increasing concern worldwide. Many studies have focused on exotic invasive species. In general, exotic invasive plants have higher resource capture ability and utilization capacity, and lower leaf construction cost (CC) compared to noninvasive plants. However, the physiological mechanisms that determine the invasiveness of native plants are poorly understood. We hypothesized that native invaders, like exotic invaders, may have higher resource capture ability and utilization efficiency compared to native noninvaders. To test this hypothesis, ecophysiological traits including light-saturated photosynthetic rate (A_max), specific leaf area (SLA), photosynthetic nitrogen use-efficiency (PNUE), photosynthetic energy-use efficiency (PEUE), and mass-based and area-based leaf construction cost (CC_mass and CC_area) were measured. We compared the above traits between three pairs of native invasive and noninvasive native species, and between three pairs of exotic invasive and noninvasive species in Guangzhou, southern China. Our results showed that the native invaders had higher A_max, SLA, PNUE, PEUE and lower CC_mass, CC_area, compared to native noninvaders and that these traits were also found in the exotic invaders. PNUE and PEUE in the native invaders were 150.3 and 129.0% higher, respectively, than in noninvasive native species, while these same measures in exotic invaders were 43.0 and 94.2% higher, respectively, than in exotic noninvasive species. The results indicated that native invaders have higher resource capture ability and resource utilization efficiency, suggesting that these traits may be a common biological foundation underlying successful invasion by both native and exotic invasives.     

唐古特白刺叶功能性状沿气候梯度的变异特征

叶功能性状与植物的生长对策及资源利用效率密切相关,研究叶功能性状沿气候梯度的变异特征能为理解植物对气候变化的响应机制提供一种简便可行的测定指标。以我国西北荒漠地区广泛分布的唐古特白刺（Nitraria tangutorum）为研究对象,对其比叶面积（SLA）、单位质量和单位面积叶氮含量（N_mass、N_area）、单位质量和单位面积叶建成成本（CC_mass、CC_area）进行测定,分析这些叶功能性状及性状相关关系沿气候梯度的变异特征。结果表明,唐古特白刺叶功能性状（CC_area除外）在气候梯度下存在显著差异,其中,温度是决定唐古特白刺SLA变化的主要因子,SLA随着温度的增加而增加;降水和温度对唐古特白刺N_mass、N_area和CC_mass均有显著影响,N_mass和N_area随着降水和温度的增加而降低,而CC_mass呈增加趋势。沿气候梯度,唐古特白刺SLA-N_mass、CC_mass-N_mass和CC_area-N_area的线性正相关关系发生平移,导致在相同SLA、CC_mass和CC_area下,降水和温度较低的地区具有更高的N_mass和N_area。这一结果表明唐古特白刺能通过调节叶功能性状之间的关系来适应气候的变化,并形成性状间的最佳功能组合。     

混交比例对桉树-乡土树种混交林优势树种叶片资源获取性状的影响

桉树-乡土树种混交林在提高林分生产力和生态系统功能等方面具有较大潜力。该研究以南亚热带4种桉树-乡土树种混交林(桉树与乡土树种混交比例分别为5:5、6:4、7:3、8:2)和桉树纯林为研究对象,研究了3种优势乡土树种华润楠(Machilus chinensis)、阴香(Cinnamomum burmannii)、灰木莲(Manglietia glauca)和速生树种尾叶桉(Eucalyptus urophylla)的叶片生理、结构和化学性状在不同比例混交林中的差异。结果表明,4优势造林树种的叶片性状存在明显的种间差异,其中灰木莲的比叶面积(SLA)、光合磷利用效率(PPUE)、单位质量叶片最大光合速率(A_mass)和蒸腾速率(T_mass)以及叶片养分含量最高,说明灰木莲采取资源获取型的生态策略;尾叶桉的SLA、A_mass、T_mass及叶片养分含量最低,但具有最高的PPUE,说明尾叶桉兼顾了资源获取型和保守型的物种特征。灰木莲与尾叶桉在SLA、A_mass、T_mass     

木兰科常绿与落叶物种叶片构建策略的差异

为探究木兰科(Magnoliaceae)常绿与落叶物种叶片构建的生理生态策略,选取黄山木兰(Yulaniacylindrica)、玉兰(Y.denudata)和鸡公山玉兰(Y. jigongshanensis) 3种落叶物种,以及荷花玉兰(Magnolia grandiflora)、含笑花(Michelia figo)、石碌含笑(M. shiluensis) 3种常绿物种,对其叶片构建成本和叶片寿命相关的性状进行比较。结果表明,木兰科3落叶种的单位叶片面积成本(CCarea)显著低于3常绿种,但落叶和常绿物种的叶片质量成本(CCmass)差异不显著。落叶物种的叶氮、磷含量(Nmass,Pmass)和比叶面积(SLA)均显著高于常绿物种,而叶片寿命(LLS)显著低于常绿物种。CCarea与LLS呈显著正相关,Nmass、Pmass和SLA均与LLS呈显著负相关。这说明木兰科玉兰属落叶物种单位面积叶片构建成本小于常绿物种;落叶物种叶片寿命短,但采取低成本构建策略,提高比叶面积获得更多光资源,增加营养积累,也揭示了玉兰属落叶物种适应北亚热带较短的生长季和较低水热条件的生理生态策略。     

不同光照和水分下三叶鬼针草与本地种金盏银盘生长特征的比较研究

为探讨三叶鬼针草(Bidens pilosa)成功入侵机制,利用盆栽试验对不同光照和水分条件下三叶鬼针草与本地种金盏银盘(B.biternata)的生长特征进行了比较研究。结果表明,两物种对光和水的变化均具有较大可塑性,但与金盏银盘相比,在有利环境下三叶鬼针草具有较大的株高、叶面积、生物量;在不利环境下,三叶鬼针草具有较大的比叶面积和叶面积比;除叶面积比和叶生物量比外,三叶鬼针草各生理参数的可塑性指数均高于本地种。这说明三叶鬼针草具有较强的表型可塑性和入侵适应性,这些特性促进了其成功入侵。     

江苏滨海湿地芦苇和互花米草光合特性对模拟增温的响应

滨海湿地生态系统具有较高的初级生产力,是地球生态系统主要的碳库之一。然而,气候变暖和外来物种入侵通过改变植物光合特征性能使这一碳库的稳定性存在诸多的不确定性。利用在江苏盐城芦苇湿地和互花米草湿地建设的两个增温观测站,采用便携式光合荧光测量系统研究了本土植物芦苇（Phragmites australis）和入侵物种互花米草（Spartina alterniflora）光合特性对模拟增温的响应特征和机制。光合作用日调查变化曲线显示,增温使芦苇的净光合速率（P_n）、气孔导度（G_s）、蒸腾速率（T_r）和水分利用效率（WUE）都发生了显著的下降,但互花米草的各同名参数却表现出相反的变化特征,表明增温使互花米草的生理机能增强,促进了光合作用;根据P_n和胞间CO₂浓度（C_i）的变化趋势推断互花米草和芦苇光合速率变化均为非气孔限制因素驱动。利用直角双曲线修正模型拟合的光响应曲线结果显示,芦苇增温组的光响应曲线位于对照组下方,互花米草增温组的光响应曲线位于对照组上方;增温降低了所研究植物的光补偿点（LCP）,表明增温可提高两种植物利用弱光的能力;增温增加了互花米草光补偿点（LCP）和光饱和点（LSP）间值域范围,从而揭示了增温可有效提高互花米草利用光合有效辐射的能力;增温降低了芦苇的暗呼吸速率（R_d）,芦苇受到增温的胁迫,在减缓新陈代谢的同时也减弱了光合作用,而互花米草表现出相反特征。由此推测增温条件下入侵植物互花米草同化大气CO₂的能力（即碳汇能力）优于本土植物芦苇,这也是互花米草成为入侵物种的主要原因之一。     

不同种源五角枫幼苗叶片N、P化学计量学特征对氮添加的响应

不同土壤氮环境下植物对氮沉降的响应趋势不同,因此研究不同种源地的五角枫(Acer mono)对氮沉降的响应机理具有重要的意义。为了深入了解不同种源五角枫对氮沉降的适应和响应机制,主要通过3个种源的五角枫幼苗氮添加控制实验,分析不同种源的五角枫幼苗比叶面积(SLA)和叶片干物质含量(LMDC)以及叶片N、P含量和N∶P对氮添加的响应规律。结果表明:(1)不同氮添加处理下,内蒙古种源五角枫幼苗(NW)和山西种源五角枫幼苗(SW)的LDMC均显著低于对照,NW和SW在N4条件下表现为显著的促进作用。随着氮添加浓度的增加,NW与北京种源的五角枫幼苗(BW)的SLA在N4条件下显著增加;SW的SLA在N2的水平下显著增加。(2)氮添加下,只有SW的P_(mass)在N1水平下显著增加,N_(mass)在N1和N3水平下表现为显著增加。说明在低氮水平下,能够促进SW对P的吸收,从而增加植物体内对P的积累。同时在低氮和中高氮条件下,能够促进SW对N的吸收,说明SW能较好的适应低氮和高氮环境,使其生存能力更强。(3)分析变异来源及各指标的相关性得出,氮添加条件下,五角枫的SLA、LDMC、P_(area)及N∶P与氮添加处理呈显著的相关关系,而SLA、LDMC、N_(mass)、P_(mass)、Narea、P_(area)和N∶P对氮添加处理和种源的交互作用均未表现出相关关系,说明引起五角枫各性状主要受氮添加处理影响。(4)综合各指标的变化,氮添加条件下,NW的LDMC显著降低,SLA显著增大,同时叶N含量、叶P含量以及N∶P比较高;SW的LDMC显著降低,SLA增大,同时叶N含量、叶P含量表现为显著增大,结合叶经济谱理论分析得出,SW和NW属于"快速投资-收益"型,而BW倾向于"缓慢投资-收益"型。因此,不同种源的五角枫对于氮沉降的响应存在差异,并且持续的氮添加已经改变了五角枫的适应性。     

黄顶菊对入侵地群落动态及植物生长生理特征的影响

为明确黄顶菊对入侵地植物群落和土著植物生理生长的影响机制,采用同质园试验对入侵和非入侵土壤的植物群落开展了整个生育期动态监测,并分析了黄顶菊入侵对狗尾草、羽叶鬼针草、灰绿藜、地肤4种土著植物生长和生理特征的影响规律。结果表明:黄顶菊入侵土壤植物群落多样性指数低于非入侵地,且有季节性差异,随生育期的推进差异逐渐减小;黄顶菊对本地植物的生长指标有显著影响(P0.05),随时间变化显著,但存在物种差异;4种植物的净光合速率(Pn)、气孔导度(Cd)、蒸腾速率(Tr)在非入侵土壤生长显著高于入侵地土壤(P0.05);而4种植物在入侵土壤生长的比叶面积(SLA)、比根长(SRL)、比根面积(SRA)显著高于本地土壤(P0.05)。综上,黄顶菊入侵抑制了本地植物的光合效率,减少了生物量的积累,导致本地植物群落的生物多样性水平降低,但表现出季节差异;不同物种对黄顶菊入侵胁迫的响应表现种间特异性,为理解入侵种对群落结构影响和实现入侵生境恢复提供了理论依据。     

Photosynthesis,Transpiration, and Water Use Efficiency of Vegetative and Reproductive Shoots of Grassland Species from North-Eastern China

The differences in net photosynthetic rate (P _N), transpiration rate (E), and water use efficiency (WUE) between the vegetative and reproductive shoots of three native grass species from the grassland of northeastern China [grey-green and yellow green populations of Leymus chinensis (Trin.) Tzvel., Puccinellia tenuiflora (Griseb) Scrib & Merr, Puccinellia chinampoensis Ohwi] were compared. The two type shoots experienced similar habitats, but differed in leaf life-span and leaf area. The leaf P _N and WUE for the vegetative shoots were significantly higher than those for the reproductive shoots in the grasses, while their E were remarked lower in the dry season. Relative lower leaf P _N and WUE for the reproductive shoots of grassland grasses may explain the facts of lower seed production and the subordinate role of seed in the grassland renewal in north-eastern China.     

Leaf anatomical structures of <Emphasis Type="Italic">Paphiopedilum</Emphasis> and <Emphasis Type="Italic">Cypripedium</Emphasis> and their adaptive significance

Paphiopedilum and Cypripedium are closely related in phylogeny, but have contrasting leaf traits and habitats. To understand the divergence in leaf traits of Paphiopedilum and Cypripedium and their adaptive significance, we analyzed the leaf anatomical structures, leaf dry mass per area (LMA), leaf lifespan (LL), leaf nitrogen concentration (N _mass), leaf phosphorus concentration (P _mass), mass-based light-saturated photosynthetic rate (A _mass), water use efficiency (WUE), photosynthetic nitrogen use efficiency (PNUE) and leaf construction cost (CC) for six species. Compared with Cypripedium, Paphiopedilum was characterized by drought tolerance derived from its leaf anatomical structures, including fleshy leaves, thick surface cuticles, huge adaxial epidermis cells, lower total stoma area, and sunken stomata. The special leaf structures of Paphiopedilum were accompanied by longer LL; higher LMA, WUE, and CC; and lower N _mass, P _mass, A _mass, and PNUE compared with Cypripedium. Leaf traits in Paphiopedilum helped it adapt to arid and nutrient-poor karst habitats. However, the leaf traits of Cypripedium reflect adaptations to an environment characterized by rich soil, abundant soil water, and significant seasonal fluctuations in temperature and precipitation. The present results contribute to our understanding of the divergent adaptation of leaf traits in slipper orchids, which is beneficial for the conservation of endangered orchids.