基于FvCB模型的叶片光合生理对环境因子的响应研究进展

为提高叶片光合速率并更好地理解叶片光合生理对环境因子变化的响应机制,FvCB模型(C_3植物光合生化模型)常用于分析不同环境条件下CO_2响应曲线并预测叶片活体内光合系统的内在变化状况。系统介绍了FvCB模型的建立、发展过程和拟合方法等基本理论,综述了该模型在叶片光合生理对光、CO_2、水、温度和N营养等环境因子变化的响应机制中的应用研究。为进一步完善FvCB模型并更好地理解叶片活体内光合系统对环境因子变化的响应机制,未来拟加强以下研究:1)羧化速率与光合电子传递速率之间的联系;2)叶肉导度的具体组分及其对FvCB模型参数估计的影响;3)叶片气孔导度和叶肉导度对环境因子变化的调控机制。     

5种木本植物对NaHCO_3胁迫的光合生理响应

以5个抗盐性不同的树种白榆、新疆枸杞、南蛇藤、小叶丁香、樟子松的一年生实生苗为实验材料,研究光合生理参数作为植物抗盐性评价指标的有效性。结果表明:5个树种的抗盐性由强到弱依次为新疆枸杞、白榆、南蛇藤、小叶丁香、樟子松。5个树种对NaHCO_3胁迫有一致的光合响应,即净光合速率(P_n)、蒸腾速率(T_r)、气孔导度(G_s)、细胞间隙CO_2浓度(C_i)和气孔限制值(L_s)等光合参数均呈下降趋势。与对照相比,重度胁迫下白榆、新疆枸杞、南蛇藤、小叶丁香、樟子松P_n分别下降33.97%、31.40%、54.97%、71.18%和72.25%,5个树种苗木P_n下降幅度顺序为樟子松小叶丁香南蛇藤白榆新疆枸杞;重度胁迫下5个树种苗木T_r分别比对照下降36.18%、48.49%、46.07%、53.55%和71.82%,5个树种苗木T_r下降幅度顺序为樟子松小叶丁香新疆枸杞南蛇藤白榆;重度胁迫下5个树种苗木G_s分别比对照下降58.73%、72.16%、19.82%、48.22%和74.15%,5个树种苗木G_s下降幅度顺序为樟子松新疆枸杞白榆小叶丁香南蛇藤。研究表明,在低NaHCO_3胁迫下白榆和新疆枸杞叶片光合下降的原因是气孔限制,在高NaHCO_3胁迫时,则为非气孔限制;南蛇藤和樟子松为气孔限制因素;小叶丁香为非气孔因素。在NaHCO_3胁迫条件下,抗性较强的白榆和新疆枸杞净光合速率降低的程度明显小于抗性较弱的小叶丁香和樟子松。     

生长光强和冬季低温对三种亚热带木本植物生理特性的影响

种植于１００％、４０％和１６％自然光下的荷木、黧蒴和黄果厚壳桂幼苗叶片,在冬季低温期中细胞电解质未发生明显泄漏．强光下的黄果厚壳桂的叶绿素荧光Ｆｖ／Ｆｍ只有０．３４．离休叶园片经５℃弱光处理,Ｆｖ／Ｆｍ下降．黄果厚壳桂在三种光下叶片的ｃｈｌａ／ｂ、可溶性糖／蛋白质和Ｆｖ／Ｆｍ皆比荷木和黧蒴低．显示其对高光和低温较为敏感．４０％光比其他两种光强较有利于三种植物中有机物的合成．     

低温胁迫时间对4种幼苗生理生化及光合特性的影响

以盐肤木(Rhus chinensis)、假连翘(Duranta repens)、老鸭嘴(Thunbergia erecta)和葛藤(Pueraria lobata)4种幼苗为试验材料,研究了人工模拟下的低温胁迫环境(6℃)对幼苗叶片生理生化及光合特性的影响.结果表明:(1)随低温胁迫的延长,假连翘幼苗的叶绿素含量先升后降,其余3种幼苗持续下降,低温解除后均显著回升;4种幼苗的脯氨酸含量持续上升或波动;葛藤幼苗的可溶性蛋白质含量先升后降,其余幼苗显著上升,且低温解除后有所增加;4种幼苗叶片可溶性糖含量以及丙二醛含量呈增加趋势,SOD活性持续上升或先升后降.低温解除后,盐肤木幼苗的SOD活性略有上升,其余幼苗显著下降.(2)随低温胁迫的延长,4种幼苗的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)均持续下降,假连翘的胞间CO2浓度(Ci)持续上升,其余幼苗先降后升.低温解除后4种幼苗叶片Pn、G、Tr均有不同程度的回升,Ci有不同程度的下降.低温胁迫和恢复48 h期间,4种幼苗的脯氨酸、可溶性糖、可溶性蛋白质含量的增加和SOD活性的稳定或增加,减轻了幼苗叶片细胞的膜脂过氧化程度,维持了细胞膜的完整性,是幼苗对低温胁迫适应性反应的重要调节机制.恢复48 h时的Pn、Gs和Tr均有不同程度的回升,Ci有不同程度的下降,说明4种幼苗有一定的抗寒能力.(3)用主成分分析法分别对生理生化指标和光合生理指标进行分析,均得出4种幼苗的抗寒性顺序为葛藤＞盐肤木＞老鸭嘴＞假连翘,这一结果可为采矿石废弃地生态恢复的植物筛选提供科学依据.     

4种木本植物叶片的光合电子传递和吸收光能分配特性对光强？…

以气体交换和叶绿素荧光测定相结合的方法研究了亚热带自然林乔木荷树、黧蒴和林下灌木九节、罗伞幼苗的光合电子传递及激发能利用的分配对生长光强的适应特性。４种植物生长于１００％、３６％和１６％的自然光下８个月,叶片的光化学速率和热能耗散速率随光强增大而提高,热能耗散占总的光能吸收的比例也因光强不同而改变,１６％光下的相对热耗散率约为４０％－４５％,１００％自然光下增大至５０％－７５％。叶片总的非环式电子     

生物结皮对3种荒漠草本植物光合生理特性的影响

通过人工去除生物结皮实验,研究古尔班通古特沙漠生物结皮对3种荒漠草本植物生理特性的影响,根据生物结皮对土壤养分和水分的影响,综合分析生物结皮对3种草本植物光合生理特性的影响。结果表明,生物结皮对3种荒漠草本植物光合生理的影响基本一致,在植物生长早期,生物结皮区的尖喙牻牛儿苗（Erodium oxyrrhynchum M.Bieb.）、条叶庭荠（Alyssum linifolium Steph.ex Willd.）和琉苞菊（Hyalea pulchella（Ldb.） C.Koch）的叶片相对含水量（RWC）、净光合速率（P_n）、气孔导度（G_s）、蒸腾速率（E）、水分利用效率（WUE）、PSⅡ最大光化学量子效率（F_v/F_m）、PSⅡ实际光化学效率（φ_PSⅡ）和叶绿素（Chl）含量均高于去除生物结皮区;但是,在植物生长后期,却是去除生物结皮区的各项生理指标高。生物结皮对3种荒漠草本植物光合生理过程的影响与其对植物生长的影响基本一致,这与土壤养分和水分状况的变化密切相关。     

台湾桤木引种的光合生理特性研究

以台湾桤木 Alnusformosana 引种2年生苗木为研究对象,探讨了台湾桤木的光合生理生态特性.结果表明: 1 叶片净光合速率 Pn 具有明显的日变化.中部叶Pn日变化在生长中期表现为双峰曲线型,高峰分别出现在9:00和15:00左右,峰值分别为15.03μmol·m-2·s-1和12.97μmol·m-2·s-1;在生长初期和末期为单峰曲线型.不同部位叶片Pn大小为:中部叶>顶部叶>基部叶. 2 不同部位叶片Pn表现出不同的季节变化特征.中部叶和顶部叶一年有两个高峰,高峰均出现在6月和8月;基部叶只有一个高峰,出现在6月.光合作用具有较广的温度适应范围.自然条件下叶片最大净光合速率为17.67μmol·m-2·s-1;人工条件下为20.2μmol·m-2·s-1,在新的环境条件下表现出较强的光合适应能力. 3 叶片LCP为33.32～67.47μmol·m-2·s-1,LSP为1332～1656μmol·m-2·s-1,具有较低的光补偿点和较高的光饱和点,表现出较强的弱光利用能力和强光利用潜力. 4 台湾桤木CO2补偿点为54.17～74.98μmol·mol-1,CO2饱和点在800μmol·mol-1左右;羧化效率为0.0270～0.0468.表现出较大光合作用潜力和较广的生存适应能力. 5 通径系数分析表明,Cond、Ci、Vpdl和RH是影响叶片光合速率变化最主要的直接作用因子.     

盐胁迫对Frankia 生长和生理生化特性的影响

研究了盐胁迫(10～50 g·L-1 NaCl)对从杨梅[Myrica rubra (Lour.) Sieb. et Zucc.]、木麻黄(Casuarina spp.)、桤木(Alnus spp.)和福建胡颓子(Elaeagnus oldhami Maxim.)根瘤中分离出的11株Frankia菌株的生长和生理生化特性的影响.结果表明,在离体培养条件下,分离自木麻黄和桤木根瘤的Frankia菌株耐盐性最强,其次是来源于福建胡颓子根瘤的Frankia菌株,而从杨梅根瘤中分离得到的Frankia菌株耐盐性最弱.在盐胁迫条件下, Frankia菌株的形态和生理生化特征也发生相应变化孢囊和泡囊数量增加、菌丝变细或变粗、固氮酶活性增加、营养源利用率下降.     

四种常见树木叶片光合模型关键参数对臭氧浓度升高的响应

随着城市化进程的加快, 臭氧(O₃)已经成为中国夏季首要大气污染物。已有研究表明O₃通过气孔进入叶片显著抑制光合作用, 影响陆地生态系统碳水循环过程。但是O₃浓度升高对植物光合和气孔导度模型关键参数影响的研究仍然缺乏。该研究利用开顶式气室, 设置两个O₃处理(CF, 过滤空气; E-O₃, 未过滤空气+ 60 nmol·mol^-1 O₃), 选用4种常见的树木(茶(Camellia sinensis)、复叶槭(Acer negundo)、栾树(Koelreuteria paniculata)和蒙古栎(Quercus mongolica)), 通过测定叶片气体交换参数, 探究O₃浓度升高对植物光合和气孔导度模型关键参数的影响。结果表明: O₃浓度升高显著降低了4种植物的饱和光合速率和光合生化模型参数叶肉导度, 但是O₃对光合生化模型参数最大羧化速率和最大电子传递速率的负效应在不同树种间存在差异。此外, 不同植物气孔导度对O₃的响应也存在差异。通过对最优化气孔导度模型进行参数化, 结果表明O₃显著提高了蒙古栎和复叶槭的斜率参数(g₁), 并显著增加了茶的气孔导度模型截距参数(g₀), 但降低了复叶槭的g₀。在不同O₃处理下4种树木的内源水分利用效率与g₁呈显著线性负相关关系。综上所述, O₃浓度升高显著影响光合生化和气孔导度模型关键参数。     

新疆阿勒泰地区8种生态型罗布麻光合生理及生长特性研究

为明确新疆阿勒泰地区不同生态型罗布麻生物学性状的稳定性和差异性,以8种生态型罗布麻为材料,对其外部形态、光合生理特征及生长特性(株高、分枝数、地径和叶干重等)进行评价。结果表明:(1)除白麻宽叶外,其余生态型罗布麻在移栽3年后株型、叶型、叶色和花色等形态特征均保持稳定。(2)8种生态型的光合生理特征在不同生长时期和不同时间段存在差异;各生态型罗布麻均存在光合"午休"现象,Pn在上午时最高(17.8~30.1μmol·m-2·s-1),中午时较上午降低6%~45%,并以白麻紫斑和大叶白麻降幅最大,白麻白花降幅最小。(3)多数生态型的Pn、Tr和Ci/Ca值与Gs的变化特征具有较好的一致性,说明光合和蒸腾"午休"主要受气孔因素影响,但白麻粉秆的光合"午休"与之不同,受非气孔因素的影响较明显。(4)相对而言,大叶白麻、白麻青秆、白麻红秆、白麻粉秆生态型为低蒸腾高光合高水分利用效率型,罗布红麻为低蒸腾低光合高水分利用效率型,白麻白花为低水分利用效率型且在上午表现为低蒸腾低光合型,而在中午和下午表现为高蒸腾高光合型,白麻紫斑则与白麻白花相反。(5)白麻粉秆和白麻白花的株高(110cm)、地径(8.2mm)、单株叶干重(22.6g)均较高;大叶白麻的茎节最长(6.5cm)。可见,多数生态型罗布麻在长期进化中形成适应其生长环境的稳定性状;白麻白花较其他生态型具有更好的耐受高光强、高温和对弱光利用的能力,而白麻紫斑、大叶白麻和白麻粉秆的这种能力较差;罗布红麻和白麻白花可作为产叶型,白麻红秆和白麻粉秆可作为产叶及产纤维型进行培育,而大叶白麻不适合在北疆种植。     

采收方式对云南红豆杉药用原料林枝构件种群特性的影响

以云南省马关县6年生云南红豆杉药用原料林为研究对象,比较采收主干及其上部枝条、保留主干采收其上部枝条、保留主干采收其下部枝条3种采收方式3个采收强度(1/4、2/4、3/4树冠长度)下枝条收获量,分析不同的枝条采收方式与强度对云南红豆杉枝构件种群生长的影响。结果表明:采收强度的增大促进了枝构件种群的生长,3/4树冠长度的枝条采收强度使老枝萌新枝比例、新枝数量、新枝长度与体积均显著或极显著高于对照;从当年生的新枝长度和新枝体积大小来看,采收树冠上部枝条对枝构件种群的促进作用远大于采收下部枝条;采收主干更有利于去除顶端优势,且在植株剩余的树冠上生长出更多的萌枝。为获取尽可能多的枝条,同时保证药用原料林的长期可持续利用,建议将采收主干及上部3/4树冠长度的枝条采收处理作为最佳枝条采收方案。     

DNA barcoding herbaceous and woody plant species at a subalpine forest dynamics plot in Southwest China

Although DNA barcoding has been widely used to identify plant species composition in temperate and tropical ecosystems, relatively few studies have used DNA barcodes to document both herbaceous and woody components of forest plot. A total of 201 species (72 woody species and 129 herbaceous species) representing 135 genera distributed across 64 families of seed plants were collected in a 25 ha CForBio subalpine forest dynamics plot. In total, 491 specimens were screened for three DNA regions of the chloroplast genome (rbcL, matK, and trnH‐psbA) as well as the internal transcribed spacers (ITS) of nuclear ribosomal DNA. We quantified species resolution for each barcode separately or in combination using a ML tree‐based method. Amplification and sequencing success were highest for rbcL, followed by trnH‐psbA, which performed better than ITS and matK. The rbcL + ITS barcode had slightly higher species resolution rates (88.60%) compared with rbcL + matK (86.60%) and rbcL + trnH‐psbA (86.01%). The addition of trnH‐psbA or ITS to the rbcL + matK barcode only marginally increased species resolution rates, although in combination the four barcodes had the highest discriminatory power (90.21%). The situations where DNA barcodes did not discriminate among species were typically associated with higher numbers of co‐occurring con‐generic species. In addition, herbaceous species were much better resolved than woody species. Our study represents one of the first applications of DNA barcodes in a subalpine forest dynamics plot and contributes to our understanding of patterns of genetic divergence among woody and herbaceous plant species.     

Photosynthetic nitrogen-use efficiency in leaves of woody and herbaceous species

1. Photosynthetic characteristics of an annual herb, Chenopodium album , and an evergreen tree, Quercus myrsinaefolia , were compared to clarify causes of the difference in photosynthetic nitrogen-use efficiency (photosynthetic capacity per unit nitrogen) between leaves of herbaceous and evergreen species.
2. When leaves with the same nitrogen content on an area basis were compared, photosynthetic capacity of C. album was twice as high as that of Q. myrsinaefolia . Gas-exchange measurements showed higher intercellular CO₂ concentration in C. album . Biochemical analyses indicated larger allocation of nitrogen into ribulose-1,5-bisphosphate carboxylase, a key enzyme of photosynthesis, and higher specific activity of ribulose-1,5-bisphosphate carboxylase in C. album . However, these differences were not large.
3. Compositional deviation of ¹³C in leaves of the two species suggested that the drop of CO₂ level between the intercellular space and the chloroplast was slightly larger in Q. myrsinaefolia when compared between the leaves with the same photosynthetic capacity.
4. It is concluded that the difference in photosynthetic nitrogen-use efficiency between C. album and Q. myrsinaefolia is not caused by a sole factor that is markedly different between the two species but by several factors each of which is slightly disadvantageous to Q. myrsinaefolia compared with C. album .     

基于结构方程模型分析林分空间结构对草本物种多样性的影响

林分空间结构的改变直接影响林下草本物种的多样性。以针叶纯林、针阔混交林和常绿阔叶林为研究对象,采用结构方程模型研究了林分空间结构对林下草本物种多样性的影响,并探讨了林分水平空间结构,垂直空间结构以及林木竞争态势对林下草本物种多样性的影响的相对重要性。结果表明,林分水平空间结构对林下草本的物种多样性指数和物种均匀性指数均存在极显著的影响(P<0.001),影响系数高达0.96和0.89,对林下草本物种丰富度存在显著影响(P<0.01),影响系数为0.22;林分垂直空间结对林下草本丰富度和物种均匀性指数均存在极显著的影响(P<0.001),影响系数分别为0.86和0.43,对林下草本物种多样性指数存在显著影响(P<0.01),影响系数为0.16;林木竞争指数与林下草本丰富度和物种多样性指数也均存在极显著的影响(P<0.001),但影响系数较小,分别为-0.47和-0.30,而对林下草本物种均匀性指数未达到显著影响作用(P>0.05),影响系数仅为-0.04。整体上看,林分水平空间结构、垂直空间结构和林木竞争态势均对林下草本物种多样性有较强的影响作用,但从...     

Testing the association of phenotypes with polyploidy: An example using herbaceous and woody eudicots

Although numerous studies have surveyed the frequency with which different plant characters are associated with polyploidy, few statistical tools are available to identify the factors that potentially facilitate polyploidy. We describe a new probabilistic model, BiChroM, designed to associate the frequency of polyploidy and chromosomal change with a binary phenotypic character in a phylogeny. BiChroM provides a robust statistical framework for testing differences in rates of polyploidy associated with phenotypic characters along a phylogeny while simultaneously allowing for evolutionary transitions between character states. We used BiChroM to test whether polyploidy is more frequent in woody or herbaceous plants, based on tree with 4711 eudicot species. Although polyploidy occurs in woody species, rates of chromosome doubling were over six times higher in herbaceous species. Rates of single chromosome increases or decreases were also far higher in herbaceous than woody species. Simulation experiments indicate that BiChroM performs well with little to no bias and relatively little variance at a wide range of tree depths when trees have at least 500 taxa. Thus, BiChroM provides a first step toward a rigorous statistical framework for assessing the traits that facilitate polyploidy.     

基于FvCB模型分析盐分胁迫对棉花叶片光合作用的影响

为深入理解叶片光合特性对盐胁迫的响应机理,以棉花为试验材料,设置5个盐分(NaCl)浓度处理:0(CK)、50、100、150和200 mmol·L^-1,利用FvCB模型分析盐胁迫对棉花幼苗叶片光合特性的影响。结果表明:与CK相比,50和100 mmol·L^-1盐分处理增加了棉花叶片的最大羧化速率(V_{c max})和最大电子传递速率(J_max),但150和200 mmol·L^-1盐分处理显著降低了V_{c max}和J_max。叶片净光合速率(P_n)、叶肉导度(g_m)和暗呼吸速率(R_d)随盐分浓度升高而下降;与CK相比,50和100 mmol·L^-1盐分处理对g_m无显著影响,但P_n和R_d显著降低。150和200 mmol·L^-1盐分处理明显降低了P_n、g_m和R_d,且与0、50和100 mmol·L^-1盐分处理间存在显著差异;利用FvCB模型模拟了不同盐分胁迫下叶片净光合速率。与不考虑g_m的模拟结果相比,考虑g_m提高模拟值和实测值间的决定系数,并降低了平均绝对误差。棉花幼苗耐盐阈值为100～150 mmol·L^-1,随盐分浓度的增加,光合限制因素由叶肉因素转变为光合机构受损;引入g_m可以提高FvCB模型的模拟精度。     

Effects of restriction of wild herbivore movement on woody and herbaceous vegetation in the Okavango Delta Botswana

We conducted herbaceous and woody vegetation surveys across Botswana's southern Okavango Buffalo Fence, which separates wildlife management from tribal grazing areas, to determine whether the restriction of herbivore movement by fencing has influenced vegetation composition, diversity and structure. We sampled herbaceous and woody vegetation at twenty paired sites every 2 km along the fence. For the herbaceous layer, ten 0.25 m² quadrats were laid every 10 m perpendicular to the fence; while for the woody vegetation, variable quadrat plots were used. Paired t‐tests were run. Results show little difference in forb or grass composition between the two sides. However, the cover and diversity of many woody species were greatly reduced across most height classes on the wildlife management side. Overall woody cover on the wildlife side of the fence was nearly half that of the tribal grazing side (t = 2.83, P = 0.011, df = 19), while overall wood diversity was also significantly less on the wildlife side (t = 3.29, P = 0.004, df = 19). We conclude that the concentration of wildlife due to the fence, while improving habitat for some herbivore species, is having a detrimental effect on plant diversity in general.     

A proposal for universal formulas for estimating leaf water status of herbaceous and woody plants based on spectral reflectance properties

The present study deals with the relationships between water status parameters of plant leaves and reflectances (R_λ) at characteristic wavelengths, between 522 and 2450 nm, as well as reflectance ratios, R_λ/R₁₄₃₀, R_λ/R₁₆₅₀, R_λ/R₁₈₅₀, R_λ/R₁₉₂₀, and R_λ/R₁₉₅₀, based on the air-drying experimental results of soybean (Glycine max Merr.), maize (Zea mays L.), tuliptree (Liriodendron tulipifera L.) and viburnum (Viburnum awabuki K. Koch.) plants. The water status parameters include leaf water content per unit leaf area (LWC), specific leaf water content (SWC), leaf moisture percentage of fresh weight (LMP), relative leaf water content (RWC) and relative leaf moisture percentage on fresh weight basis (RMP). Effective spectral reflectances and reflectance ratios for estimating the LWC, SWC, LMP, RWC and RMP were identified. With these spectral indices, approaches to estimating LWC, RWC and RMP were discussed. Eventually, an attempt on universal formulas was made for estimating the leaf moisture conditions of both herbaceous and woody plants as mentioned above. Moreover, applicability of these formulas was checked with the field experimental results of soybean and maize grown under water and nutrient stresses. This revised version was published online in June 2006 with corrections to the Cover Date.     

清除优势草本植物对西双版纳飞机草-马唐群落中木本幼苗的影响

在农业弃耕地上通常会出现由草本植物占优势的演替早期群落。为研究优势草本植物对群落中木本幼苗及群落微环境的影响以及外来入侵植物和本地植物对木本幼苗的影响有何差异,在西双版纳地区选取由外来入侵植物飞机草和本地植物马唐共同占优势的演替早期群落,实施物种清除实验,观测样地中木本幼苗的高增长及死亡补充情况,同时对群落微环境进行观测。结果显示,清除优势种显著提高了木本幼苗的高增长,降低了其死亡率,并且使新增幼苗数量有所提高。清除优势种对0-50cm幼苗高增长和死亡率的影响均大于50-100(或200)cm幼苗。清除处理显著提高了样地的冠层下可见天空比例,但对土壤含水量和土壤养分的影响并不显著。飞机草和马唐均能形成浓密的冠层,通过对光的竞争抑制木本幼苗的生长,且这两者的抑制作用没有显著差异。该地区次生林中常见的先锋树种在研究样地内均有幼苗存在,但其生长却受到优势草本植物的强烈抑制。因此,对演替早期群落中草本植物的控制与管理应同时注意外来入侵物种与本地杂草。