几种野生报春花的光合特性初探

 采用LI-6400便携式光合作用系统分析昆明室外栽培3年生的几种野生报春花光合作用特性.光补偿点(μmol·m^-2·s^-1)以被灯台报春最高(28),其余3种相近且较低(8～15).光饱和点以四季报春最低(80),其光合速率也最低,2种灯台报春的光饱和点(500)和光合速率均最高,灰岩报春居中.光合作用CO₂补偿点(μmol·mol^-1),灰岩报春54,桔红灯台报春64,粉被灯台报春69,四季报春80.光合速率和蒸腾速率日变化均呈单峰曲线,前者的峰值出现在10:00左右,后者的峰值出现在13:00左右;中午到下午光合速率降低的主要原因是气孔阻力增大,但17:00以后则主要是羧化阻力增大所造成.光合速率主要与叶片水分导性、蒸腾速率、光照强度和胞间CO₂浓度及气压相关.     

蒜头果(Malana oleifera)幼苗的光合生理生态特征

利用C02光合测定仪分析了引种栽培的蒜头果幼苗叶片的光合补偿点和饱和光强,通过控制叶室的光合有效辐射、C02浓度、温度和相对湿度,分析了叶片的羧化效率和CO2补偿点,并进行光合有效辐射、温度或相对湿度对光合速率影响的研究.蒜头果幼苗叶片光补偿点的光强为8.1μmol.m-2.s-1,饱和光强约为750μmol.m-2.s-1.叶片的羧化效率为0.022 67,CO2补偿点为53.2μmol.mol-1.叶片光合速率在25℃时达到最大值,最适温度为18~31℃.相对湿度在20%~80%的范围内,叶片光合速率随湿度增加而增大,最适相对湿度条件在50%以上.     

转SOD基因烟草的光合特性初探

 以转基因Fe-SOD,Mn-SOD高表达、转基因Mn-SOD反义低表达烟草及非转基因品系为供试材料,比较CO₂光强对烟草光合作用和蒸腾作用的影响及不同叶位叶片的光合差异.在相同条件下,Mn-SOD高表达烟草CO₂补偿点最高(105μmol·mol^-1),Mn-SOD低表达烟草最低(78μmol·mol^-1),CO₂浓度对非转基因烟草蒸腾作用的影响比对其他三个转基因品系的影响要强.Mn-SOD低表达烟草的光补偿点最高(45μmol·m^-2·s^-1),而Mn-SOD高表达烟草最低(25μmol·m^-2·s^-1),并且强光对非转基因烟草的光合作用抑制大,转基因品系对强光具有较强的耐受力.同一叶位叶片,转基因烟草的光合速率、蒸腾速率更强.但转基因SOD高表达烟草在整体上并没有表现出明显的光合作用优势.     

潢川金桂夏季光合特性分析

采用Li-6400XT便携式光合作用测定仪对潢川金桂成年树光合特性进行研究。结果表明:夏季潢川金桂净光合速率日变化呈明显的双峰型,最高峰出现在9:00,其净光合速率为10.05μmol/(m~2·s),次高峰出现13:00,其净光合速率为8.980μmol/(m~2·s),有明显的光合午休现象。根据光响应曲线可以得出潢川金桂的光饱和点(LSP)为1290μmol/(m~2·s),光补偿点(LCP)为74.21μmol/(m~2·s),表观光量子效率为0.0267,由CO_2响应曲线可以得出CO_2饱和点(CSP)为530μmol/mol,CO_2补偿点为61.24μmol/mol,羧化效率为0.0433。潢川金桂具有较高的CO_2补偿点和光饱和点说明潢川金桂是喜光的阳性植物。     

束花石斛和黄花石斛的光合特性研究

研究了大花组的束花石斛和黄花石斛的光合生理,结果表明,2种石斛叶片的解剖结构为异面叶,气孔仅分布在下表面,具气孔盖,叶脉维管束鞘不含叶绿体,无花环型结构,具C3植物特征.2种石斛的光补偿点(LCP)和光饱和点(LSP)分别为5～10μmol/(m2.s)和850～900μmol/(m2.s),最大光合速率(Pn)约为6μmol/(m2.s);CO2补偿点和饱和点分别为80～90μmol/mol和800μmol/mol;光合作用的最适温度在26～30℃.Pn日变化为双峰型曲线,首峰出现在11:00左右,最大光合速率在5～6μmol/(m2.s),次峰出现在15:00左右,夜间不吸收CO2.PEPCase活性低,RuBPCase和GO酶活性较高.以上结果表明,束花石斛和黄花石斛光合作用碳同化途径属C3植物类型,具有半阴生植物的特点.     

花楸幼苗光合特性及其影响因子分析

使用Li-6400光合测定系统研究了生态因子对花楸(Sorbus pohuashanensisHedl.)二年生幼苗叶片的光合生理特性的影响.结果表明:花楸幼苗净光合速率日变化曲线均呈单峰型,无午休现象,且峰值(18.7μmol/(m2.s))出现在12:00,净光合速率的变化是由非气孔因素决定的;花楸光合作用受多因子交互作用的影响,交互作用对净光合速率的影响大于单一因子,其中光合有效辐射对净光合速率的影响最大;正常大气条件下,花楸幼苗叶片光饱和点为1 268.4μmol/(m2.s)、补偿点为31.9μmol/(m2.s),CO2饱和点为998.82μmol/mol、CO2补偿点为51.87μmol/mol.     

贡嘎山地区黄背栎的光合特性

应用Li-6 400光合测定系统研究了贡嘎山地区不同海拔黄背栎(Quercus pannosa)幼树的光合生理特性。结果表明:(1)在8月晴天,不同海拔生长的黄背栎叶片净光合速率日变化均呈比较平稳的单峰曲线,无光合午休现象,随着海拔的升高,叶片净光合速率、蒸腾速率和水分利用效率均降低,而叶片气孔导度增加,有利于高海拔地区植物光合作用气体交换;(2)不同海拔试验点叶片净光合速率对光合辐射的响应有较大的差异,叶片光补偿点为39.16~68.06μmol/(m2.s),光饱和点为1 124.78~1 754.88μmol/(m2.s),表观光量子利用效率为0.028 12~0.031 73。随着海拔的升高,叶片光补偿点、光饱和点和最大净光合速率增加;(3)叶片CO2补偿点为68.47~105.21μmol/mol。随着海拔的升高,CO2补偿点降低,有利于植物对高海拔地区低CO2分压环境的适应。CO2饱和点在700μmol/mol左右,羧化效率为0.035~0.038。     

3种兜兰属植物光合特性的比较研究

通过研究硬叶兜兰(Paphiopedilum micranthum)、带叶兜兰(P.hirsutissimum)和长瓣兜兰(P.dianthum)3种兜兰属植物的光合特性,为其种质资源保育及引种栽培提供理论依据。以广西雅长兰科植物国家级自然保护区内3种兜兰属植物为试验材料,测定其叶片的光响应曲线、CO₂响应曲线以及叶绿素含量,比较3种兜兰光合特性的差异。结果表明：硬叶兜兰、带叶兜兰和长瓣兜兰的最大净光合速率(P_max)分别为2.719 μmol·m^-2·s^-1、1.836 μmol·m^-2·s^-1、2.015 μmol·m^-2·s^-1,光饱和点(LSP)分别为578.74 μmol·m^-2·s^-1 、467.72 μmol·m^-2·s^-1、481.25 μmol·m^-2·s^-1,光补偿点(LCP)均较低,分别为15.65 μmol·m^-2·s^-1、12.79 μmol·m^-2·s^-1、10.34 μmol·m^-2·s^-1,是典型的阴生植物。硬叶兜兰的最大净光合速率(P_max)、CO₂饱和点(CSP)、羧化效率(CE)均显著高于长瓣兜兰和带叶兜兰(P<0.05),硬叶兜兰对CO₂的利用能力更强。叶片叶绿素相对含量(SPAD值)表现为硬叶兜兰(58.13)>长瓣兜兰(55.12)>带叶兜兰(51.88)。3种兜兰属植物的光合能力较弱,对光的利用范围狭窄,在引种栽培时应注意增加荫蔽度。     

束花石斛和黄花石斛光合特性研究

以大花组的束花石斛（Dendrobium chrysanthum）和黄花石斛（D. dixanthum）为材料,对它们的光合生理等进行了系统研究.2种石斛叶片的解剖结构为异面叶,气孔仅分布在下表面,具气孔盖,叶脉维管束鞘不含叶绿体,无花环型结.2种石斛的光强、CO2浓度和温度的响应研究表明,它们的光补偿点（LCP）和光饱和点（LSP）分别为5～10μmol/(m2?s) 和850～900μmol/(m2?s),最大光合速率（Pn）在～6μmol/(m2?s);CO2补偿点和饱和点分别为80～90 μmol/mol和800 μmol/mol;光合作用的最适温度在26～30℃.2种石斛兰的Pn日变化为双峰型曲线,首峰出现在12:00左右,最大光合速率在5～6μmol/(m2?s),次峰出现在15:00左右,夜间不吸收CO2.2种石斛的PEPCase活性极低,具有较高的RuBPCase和GO酶活性.以上的研究结果表明,束花石斛和黄花石斛光合作用碳同化途径属C3植物类型,具有半阴生植物的特点.     

3种观赏性石斛的光合特性比较研究

为探明3种观赏性石斛属Dendrobium Sw.植物在光合生理方面的差异,为其栽培及规模化种植提供理论依据。本研究以3种观赏性石斛(叠鞘石斛D.denneanum Kerr.、流苏石斛D.fimbriatum Hook.和束花石斛D.chrysanthum Wall.ex Lindl.)为材料,测定其叶片的光响应曲线、CO₂响应曲线及叶绿素相对含量(SPAD值),探究其光合特性。结果表明,叠鞘石斛、流苏石斛和束花石斛3种石斛属植物的光补偿点(LCP)分别为2.15 μmol·m^-2·s^-1、3.74 μmol·m^-2·s^-1、1.79 μmol·m^-2·s^-1,光饱和点(LSP)分别为995.09 μmol·m^-2·s^-1、679.44 μmol·m^-2·s^-1、712.28 μmol·m^-2·s^-1,LCP均低于5 μmol·m^-2·s^-1,LSP均低于1 000 μmol·m^-2·s^-1,属于典型的阴生植物,具有较强的耐阴性;3种石斛的最大净光合速率(P_max)分别为3.54 μmol·m^-2·s^-1、3.86 μmol·m^-2·s^-1、4.03 μmol·m^-2·s^-1,表观量子效率(AQY)分别为0.042,0.044和0.051,束花石斛的P_max和AQY最大,光合作用能力较强。3种石斛的CO₂响应曲线中,最大净光合速率(A_max)大小依次为叠鞘石斛(11.99 μmol·m^-2·s^-1)、流苏石斛(10.87 μmol·m^-2·s^-1)、束花石斛(4.75 μmol·m^-2·s^-1),叠鞘石斛利用CO₂进行光合作用的能力最强;3种石斛的CO₂饱和点(CSP)无显著性差异,在CO₂浓度不大于2 000 μmol·mol^-1时均未到达饱和点;CO₂补偿点(CCP)具有显著性差异,CCP分别为100.12 μmol·m^-2·s^-1、158.02 μmol·m^-2·s^-1、134.44 μmol·m^-2·s^-1,其中叠鞘石斛的CCP最低,对低浓度CO₂的利用能力最强。3种石斛叶片的SPAD值分别为51.09,56.93和58.06,其高低与其净光合速率的大小有一定程度的相关性。在3种石斛中,束花石斛的光合作用能力最强,对弱光的利用能力较强;流苏石斛对弱光的利用能力较弱,光照适应范围狭窄;叠鞘石斛对强光的利用能力较强,光合作用适应范围较广。此外,3种石斛均具有较强的耐阴性,对CO₂的耐受性也较强,在种植时应提供适当的遮阴和增加CO₂浓度来提高石斛的光合作用能力。     

Effect of CO<Subscript>2</Subscript> concentrations on the activity of photosynthetic CO<Subscript>2</Subscript> fixation and extracelluar carbonic anhydrase in the marine diatom <Emphasis Type="Italic">Skeletonema costatum</Emphasis>

The growth and activity of photosynthetic CO2 uptake and extracellular carbonic anhydrase (CAext) of the marine diatom Skeletonema costatum were investigated while cultured at different levels of CO2 in order to see its physio-logical response to different CO2 concentrations under either a low (30 靘ol·m-2·s-1) or high (210 靘ol·m-2·s-1) irradiance. The changes in CO2 concentrations (4—31 靘ol/L) affected the growth and net photosynthesis to a greater extent under the low than under the high light re-gime. CAext was detected in the cells grown at 4 mol/L CO2 but not at 31 and 12 靘ol/L CO2, with its activity being about 2.5-fold higher at the high than at the low irradiance. Photo- synthetic CO2 affinity (1/ K1/2(CO2)) of the cells de-creased with increased CO2 concentrations in culture. The cells cultured under the high-light show significantly higher photosynthetic CO2 affinity than those grown at the low-light level. It is concluded that the regulations of CAext activity and photosynthetic CO2 affinity are dependent not only on CO2 concentration but also on light availability, and that the de-velopment of higher CAext activity and CO2 affinity under higher light level could sufficiently support the photosyn-thetic demand for CO2 even at low level of CO2.     

Diurnal and monthly variations of carbon dioxide flux in an alpine shrub on the Qinghai-Tibet Plateau

Long-term flux observation is an efficient approachto collect CO2 emission or assimilation data in an ecosys-tem. In cooperation with a series of international coopera-tion programs including those sponsored by IGBP (Inter-national Geosphere-Biosphere Program), WCRP (WorldClimate Research Program), IHDP (International HumanDimension of Global Environment Change), GCTE(Global Change and Terrestrial Ecosystem) and LUCC(Land Use and Land Cover Change), a lot of researchwork conce…     

Changes of photosynthetic capacity of some plant species under very high CO2 concentrations in Biosphere 2

Conclusions The initial slope of A/ light curve became steep under high CO₂ (700 μmol · mol^-1) compared with that under low CO₂ (350 μmol · mol^-1) for the C₃ species growing in very high CO₂(>2 200 μmol · mol^-1) for a long period. The light compensation points remained unchanged, but the light saturation points were found increased. The ϕ_m,_app and A_max of the C₃ species increased respectively by 79 % and 80 %, while those of C₄ species decreased by 10% and 14%, respectively. The shape of A/light curve of C₄ species did not change. Such results indicated that C₃ species increased the capacity of photosynthesis, while C₄ did not change, otherwise it decreased a little. This work only compared the changes of capacity in photosynthesis of some species under different CO₂ levels in Biosphere 2. We need further investigation on the effects of high CO₂ on the same species outside Biosphere 2, in order to fully undertand the effects and mechanism of response of plants to the elevated CO₂.     

Comparative study of the net exchange of CO<Subscript>2</Subscript> in 3 types of vegetation ecosystems on the Qinghai-Tibetan Plateau

Using the eddy covariance method, from 1 July 2003 to 30 June 2004, we conducted the observation and analysis of ecosystem CO2 flux in 3 types of alpine meadow vegetation （Kobresia humilis, Potentilla fruticosa shrub and Kobresia tibetica swamp meadows） on the Qinghai-Tibetan Plateau. The results show that the Kobresia humilis meadow, the shrub meadow and the swamp meadow＇s highest CO2 uptake rates are 16.78, 10.42 and 16.57 μmol·m^-2·-s^-1 respectively, while their highest CO2 release rates are 8.22, 7.73 and 18.67μmol·m^-2·-s^-1 respectively. The Kobresia humilis meadow and shrub meadow＇s annual atmospheric uptakes are 282 g CO2/m^2 and 53 g CO2/m^2, respectively, while swamp meadow＇s annual atmospheric release is 478 g CO2/m^2. This proves that the Kobresia humilis meadow and the shrub meadow on the Qinghai-Tibetan Plateau have relatively low potential for CO2 uptake and release compared to C4 grasslands, a number of lowland grasslands, and forests. Moreover, swamp meadow has relatively high release potential. This, in turn, reveals clear differences in carbon source/sink between different types of vegetation in the Qinghai-Tibetan Plateau alpine meadow ecosystem. These differences are mainly brought by differences in the vegetations＇ photosynthetic capacity and soil respiration.     

中亚热带常绿阔叶林优势树种幼树光合特性季节动态

基于指数改进模型估算了亚热带常绿阔叶林优势树种米槠(Castanopsis carlesii)、丝栗栲(Castanopsis fargesii)和木荷(Schima superba)生长旺盛期(春、夏、秋季)的光合参数特性。结果表明:米槠、丝栗栲、木荷光饱和点春季最小,分别为1 241.25、1 245.93、1 366.49 μmol/(m²·s); 最大净光合速率夏季均最大,分别为3.78、5.39、7.20 μmol/(m²·s)。木荷春季的光饱和点、光补偿点、最大净光合速率、暗呼吸速率均大于米槠和丝栗栲。在夏季和秋季,木荷和丝栗栲光饱和点均大于米槠; 木荷最大净光合速率均大于米槠和丝栗栲,且在秋季其最大净光合速率仍大于米槠。综合比较得出:木荷具有较强的光合能力和光环境适应能力,其次是丝栗栲,米槠较差。     

The characteristics of CO2 assimilation of photosynthesis and chlorophyll fluorescence in transgenic PEPC rice

With PEPC, PPDK, NADP-ME and PEPC+ PPDK transgenic and untransformed rice (Orysa sativa L.), the activities of related C₄ photosynthesis enzymes, the chlorophyll fluorescence parameters, CO₂ exchange and other physiological indexes were compared, in which the physiological characteristics of PEPC transgenic rice were mainly studied. The results were as follows: (ⅰ) The activities of PEPC in PEPC transgenic rice were 20-fold higher than those in untransformed rice; the light-saturation photosynthetic rates and the carboxylation efficiency of PEPC transgenic rice were increased by 55% and 50% more than those of untransformed rice, respectively, while the CO₂ compensation point decreased by 27%. (ⅱ) The PSⅡ photochemical efficiency (F_v/F_m) and photochemical quenching (q_P) of transgenic PEPC rice decreased less in comparison with those of untransformed rice after the treatment with high light intensity (3 h) or methyl viologen (MV), a photooxidative reagent, which demonstrated that the tolerance of PEPC transgenic rice to photoinhibition and photooxidation was enhanced. (ⅲ) Under the condition of high light intensity, the activity of RuBPCase in PEPC transgenic rice did not obviously vary while the activity induced of carbonic anhydrase (CA) in PEPC transgenic rice increased by 1.8 fold. These results would provide some beneficial enlightment for revealing the mechanism of high photosynthetic efficiency and breeding with high photosynthetic efficiency in rice.     

扭曲椭圆管内超临界CO2冷却换热的数值模拟

为了提高CO₂热泵的传热性能,基于Fluent的数值模拟方法研究了不同质量流量下,扭距为100 mm及无扭曲状态下的水平椭圆管管内超临界CO₂冷却换热特性及二次流的变化规律,并针对竖直椭圆管引入局部换热系数和压降,研究了长短轴比b/a及扭距对扭曲管换热性能的影响。结果表明,低质量流量下扭曲椭圆管内浮升力明显大于椭圆管扭曲结构所产生的浮升力,对于低质量流量G<200 kg/(m²·s²)下的超临界CO₂流体,椭圆管具有更大强度的浮升力所造成的二次流,强化传热更明显;对于高质量流量G>200 kg/(m²·s²)下的超临界CO₂流体时,扭曲椭圆管具有更大强度自身结构所产生的周期性二次流来强化传热;管内的传热系数及压降随着扭曲程度及压扁程度的增大而增大。为扭曲椭圆管在CO₂热泵中的应用提供了重要的理论与数据支持。     

Photoautotrophic Growth and Net Photosynthetic Rate of Sweet Potato Plantlets In Vitro as Affected by the Number of Air Exchanges of the Vessel and Type of Supporting Material

Introduction Micropropagation, a plant tissue culture technique, has contributed to producing virus-free, genetically supe-rior plantlets. However, its commercial application is still limited due to its relatively high production costs. The high costs are…