岩黄连光合与蒸腾特性及其对光照强度和CO2浓度的响应

采用LI-6400便携式光合测定系统(Li-CorInc.,USA)对岩黄连叶片的气体交换进行了测定。结果表明(1)岩黄连叶片的光饱和点(LSP)为329.18μmol.m-2.s-1左右,光补偿点(LCP)为12.76μmol.m-2.s-1,最大净光合速率为2.96μmol.m-2.s-1,暗呼吸速率(Rd)为0.17μmol.m-2.s-1。光饱和点和光补偿点都比效低,表明岩黄连对光照的要求不高,属于阴生植物。(2)4月份,岩黄连Pn随CO2浓度升高而逐渐增大。当CO2浓度由50μmol.mol-1增加到600μmol.mol-1,Pn几乎呈直线上升,600~1000μmol.mol-1范围内逐渐缓和,到1000μmol.mol-1以后Pn变化平稳。由曲线估算CO2饱和点(CSP)大约在1000μmol.mol-1左右。CO2的补偿点为68.80μmol.mol-1。羧化效率为0.0308μmol.m-2.s-1。(3)岩黄连叶片水分利用率(WUE)随有效光辐射强度(PAR)的增强呈抛物线状变化,PAR在200μmol.m-2.s-1内呈直线上升,到200μmol.m-2.s-1时WUE达最大值,大于200μmol.m-2.s-1后WUE呈逐渐下降趋势。     

喷钙对芍药花茎品质及叶片光合特性的影响

以5年生芍药盆栽苗为试材,研究了喷钙措施对芍药花茎品质、花茎机械强度及叶片光合参数的影响.结果表明,喷钙处理(4％,w/v)显著提高了花茎的机械强度,增幅达24.3％,花茎中纤维素、半纤维素、木质素及果胶含量均较对照显著增加,其中纤维素含量为456.54 μg·g-1,较对照增加了28.5％,增幅最大.喷钙处理还使芍药叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和水分利用效率( WUE)增加,至处理28 d时,Pu为17.07 μmol·m-2·s-1,较对照增加29.6％,Gs较对照提高了55％,为0.31 mol·m-2·s-1,Tr较对照提高了20％,达到2.61 mmol · mol-1,WUE为6.54 mmol · mol-1,较对照增加7.6％.另外,喷钙使芍药叶片最大净光合速率(Pmax)达到20.71 μmol·m-2·s-1,较对照提高24.6％,光饱和点为902.5 μmol·m-2·s-1,较对照增加7.5％,而光补偿点则显著降低,为7.27 μmol·m-2·s-1,较对照降低34.5％.     

蜡梅光合与蒸腾速率日变化的初步研究

对野生蜡梅在不同天气中的净光合速率 (Pn)和蒸腾速率 (Tr)日变化及其与环境因子的关系进行了初步研究 ,结果如下 :(1)蜡梅在晴天和阴天的 Pn日进程均呈一双峰型曲线。但晴天的两个峰值比在阴天出现要早 ,Pn的总体水平要高于阴天 ,且在午后发生明显的光合“午休”现象。 (2 )Tr在晴天的日变化呈单峰型曲线 ,在午后强光和高温条件下 ,Tr可高达 10 mmol H2 O m-2 s-1以上。在阴天 ,Tr日进程波动很小 ,且蒸腾作用微弱 ,全天大多保持在 0 .8mmol H2 O m-2 s-1以下的水平。(3)在光合有效辐射 (PAR)为 80 0～ 90 0 μmol m-2 s-1、大气温度 (TA) 2 8℃左右、相对湿度 (RH)约75%的条件下 ,野生蜡梅的 Pn可高达 2 3.6 μmol CO2 m-2 s-1。但蜡梅的光饱和点与光补偿点均较低 ,分别约为 90 0μmol m-2 s-1和 2 0μmol m-2 s-1。 (4 ) PAR和 TA是影响蜡梅光合与蒸腾速率日进程的主导生态因子。蜡梅对强光和高温反应敏感 ,在超过光饱和点且气温高达 4 2℃以上时 ,其蒸腾作用强烈 ,能量转换与水分利用效率 (WUE)大大降低 ,光合能力减弱 ,导致 Pn急剧下降     

肥披碱草叶片光合特性研究

以大田生长的肥披碱草为试验材料,利用Li-6400型光合作用测定系统监测其叶片光合生理生态特性及其环境因子日变化,并利用相关分析和逐步回归分析法探讨了净光合速率和蒸腾速率与生理生态因子间的关系.结果表明:(1)肥披碱草叶片的净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)的日变化均呈双峰曲线,具有明显的光合"午休"现象;叶片水气压亏缺(VPD)和Tr及Gs的峰值出现时间不同步,胞间CO2浓度(Ci)不随气孔的降低而减小,抑制其光合速率的因子为非气孔限制;水分利用率(WUE)的变化呈单峰型,并且其上午WUE明显高于下午.(2)自然条件下,影响肥披碱草叶片Pn的主要因子是Tr和Ca(大气CO2浓度),影响Tr的主要因子是Gs和Ta(气温).(3)在干旱与半干旱自然条件下,肥披碱草的光补偿点(12.45 μmol·m-2·s-1)、光饱和点(1 750 μmol·m-2·s-1)、最大净光合速率(65.125 μmol·m-2·s-1)、表观光量子效率(0.128 9 μmol·mol-1)都较高,表现出较强的光环境的适应性和光能利用能力,是典型的阳性植物.     

入侵植物马缨丹(Lantana camara)及其伴生种的光合特性

马缨丹(Lantana camara L.)是粤东地区的入侵植物之一.采用LI-6400光合作用仪对马缨丹及其常见主要伴生种鬼针草(Bidens pilosa L.)、肖梵天花(Urena lobata L.)、土牛膝(Achyranthes aspera L.)在不同有效光合辐射(PAR)和不同CO2浓度下的光合生理指标进行测定,结果表明:(1)马缨丹的光饱和点(LSP)与光补偿点(LCP)分别为1225、13.58 μmol·m-2·s-1,均低于伴生种,且和伴生种差异达到显著水平,光饱和点时的最大净光合速率(Pmax)为13.89μmol·m-2·s-1,表观量子效率(AQY)为0 0503 μmol·m-2·s-1,与土牛膝相当,而显著高于肖梵天花;(2) 马缨丹的CO2饱和点(CSP)与CO2补偿点(CCP)分别为1350、61.78 μmol·mol -1,CO2饱和点时马缨丹的最大净光合速率(Pmax)为20.08 μmol·mol-1,显著高于土牛膝,马缨丹的表观羧化效率(CE)与鬼针草相当,为0.0424 μmol·mol -1;(3)有效光合辐射与CO2浓度的增加,对马缨丹气孔导度(Gs)、蒸腾速率(Tr)影响不明显,但大大提高了其水分利用率(WUE),提示马缨丹对于环境中光强和CO2的变化具有良好的适应能力.这些信息对马缨丹生理生态学特性的认识是一个补充,并能为马缨丹入侵机制的研究提供一些有价值的参考.     

遮荫对月季光合特性及生长发育的影响

采用人工遮荫法研究不同程度遮荫(75%、50%和25%全光照,以全光照为对照)处理对月季的生长发育、光合特性及叶绿素荧光参数的影响。结果表明:(1)随着遮荫程度的增加,月季的叶片厚度、花径、成花率均呈降低趋势,叶绿素含量呈增加趋势;净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、胞间CO2浓度(Ci)降低,气孔限制值(Ls)升高,Pn下降的主要原因可能为气孔限制。(2)月季在遮荫条件下的光饱和点和光补偿点、暗呼吸速率下降,表现出其对光照降低的生理适应机制;其光饱和点在600~1 200μmol·m-2·s-1,光补偿点在29.89~62.95μmol·m-2·s-1,CO2补偿点在78.16~89.41μmol·mol-1,CO2饱和点在1 100μmol·mol-1左右,潜在光合能力13.06~25.63μmol·m-2·s-1,其对光的适应范围较宽,光照和CO2浓度对其光合能力的影响较大。(3)各处理条件下叶绿素荧光参数显示,月季在自然光和低光下(50%和25%全光照)叶片PSⅡ受到了明显伤害,光合作用原初反应过程受到抑制,光合电子传递受到影响。研究发现,月季虽是阳生植物,但光照生态幅较宽,轻度遮荫(75%全光照)能促进其光合作用效率,减少光抑制,植株长势好,成花率高。     

黄刺玫叶片光合生理参数的土壤水分阈值响应及其生产力分级

在半干旱黄土丘陵区,以3年生天然次生灌木黄刺玫为材料,研究了叶片光合生理参数对土壤水分(RWC)的响应特征及光合生产力分级。结果表明:当RWC在33.8%—81.3%时,叶片净光合速率(Pn)和蒸腾速率(Tr)的变化曲线为明显的双峰曲线;上午阶段(11:00时之前)Pn的下降主要是气孔限制引起的,下午以非气孔限制为主;随着RWC的增加,Pn、Tr第1峰值出现的时间延后;在此水分范围内,Pn日均值一直维持在较高水平,Pn最高值((8.5±1.8)mmol·m-2·s-1)出现在RWC为71.7%时。水分利用效率(WUE)对RWC的响应有所差异,当RWC大于47.1%时,WUE呈不明显的双峰曲线,第1峰值出现在13:00时,并且前后时段WUE变化不大。RWC为47.1%时,WUE维持在最高水平,日均值为(2.72±0.59)μmol/mmol。根据Pn、Tr、WUE和RWC的定量分析,以及从黄土丘陵区生态、经济效益同时考虑,适合黄刺玫生长的RWC在33.8%—71.7%之间。以光合生理参数为指标对黄刺玫土壤水分有效性及生产力进行分级与评价,确定RWC90.4%或RWC33.8%时为"中产中效水";RWC在71.7%—81.3%和47.1%—71.7%时分别为"高产中效水"和"高产高效水",!其中RWC在57.4%左右时为"最优产效水";RWC在18.8%—26.5%时为"低产低效水"。     

半干旱黄土丘陵区天然次生灌木山桃（Prunus davidiana）与山杏（Prunus sibirica L.）叶片气体交换参数日动态差异

以半干旱黄土丘陵区5年生天然次生灌木山桃(Prunus davidiana)及山杏(Prunus sibirica L.)作为研究材料,系统比较了两树种叶片气体交换参数的日变化特征,分析了其光合作用和蒸腾作用与环境因子的关系.结果表明:山桃叶片气体交换参数日变化特征与山桃有所差异,山桃除蒸腾速率(Tr)外其它生理参数呈单峰曲线,山杏的日变化类型均呈双峰曲线.两树种光合速率(Pn)在下午明显下降,其原因主要是受到非气孔限制.山桃Pn的日均值((7.64±3.69) μmol · m-2 · s-1)比山杏((5 29±2.97) μmol · m-2 · s-1)高出46%,Tr的日均值((2.21±1.02) mmol · m-2 · s-1)比山杏((1.58±0.57) mmol · m-2 · s-1)高出40%左右,水分利用效率(WUE)的日均值相差不大,分别为(2.89±1.52) μmol · mmol-1,(2.54±1.37) μmol · mmol-1.多元回归及相关分析表明,影响光合作用与蒸腾作用的最重要因子是光合有效辐射强度,其次是大气CO2浓度;光合作用与蒸腾作用参数之间也有明显的相关性.结论:山桃与山杏表现出具有较高光合速率,较低蒸腾速率和较高水分利用效率的生理特征,因而在半干旱黄土丘陵区都有较好引种栽培与开发利用潜力.     

独叶草的光合生理生态特性

应用CI-301PS便携式光合测定仪对独叶草(Kingdonia uniflora)营养叶的光合生理生态特征进行了研究.结果表明:独叶草的净光合速率(Pn)日变化曲线呈双峰型,峰值出现在13:30和16:30左右,具有明显的光合"午休"现象;其叶片的蒸腾速率(Tr),水分利用率(WUE)的变化也呈双峰型.自然条件下,独叶草叶片净光合速率与光合有效辐射(PAR)、蒸腾速率、气孔导度(Gs)之间都具有多项式回归关系,R2分别为0.2082、0.2016和0.0582(n=129,P＜0.05),但独叶草叶片净光合速率与空气温度(Ta)相关性不显著(P＞0.05).独叶草叶片的光补偿点(LCP)、光饱和点(LSP)分别为14.93和215.76 μmol·m-2·s-1,只能适应较窄的光照环境.     

冠层部位和叶龄对红松光合蒸腾特性的影响

利用Li-6400便携式CO2/H2O红外气体分析仪测定了红松不同冠层部位和叶龄针叶的光合蒸腾特性及其环境影响因子.结果表明:冠层部位和叶龄显著地影响最大净光合速率(Pmax)、光饱和点(LSP)、光补偿点(LCP)、表观最大量子效率(α)、蒸腾速率(Tr)和比叶面积(SLA),但对水分利用效率(WUE)影响不显著.随着冠层部位的下降和叶龄的增加,红松针叶的Pmax逐渐下降,其平均值变动在6·55～9·05μmol·m-2·s-1之间.不同冠层部位和叶龄针叶的LSP和LCP的差异很大,以树冠中部针叶对弱光和强光的利用能力最大.Tr随着冠层部位的下降而降低;不同叶龄针叶的Tr在1·37～1·59mmol·m-2·s-1之间变化.不同部位和叶龄红松针叶的Tr和光合有效辐射存在极显著正相关关系(R2=0·967).红松的WUE与净光合速率紧密相关(R2=0·860).随冠层部位的上升和叶龄的增大,红松针叶的SLA递减,分别在6·61～8·41m2·kg-1和6·65～8·38m2·kg-1之间波动.     

三种松树的生理生态学特性研究

测定南亚热带丘陵地马尾松、湿地松和加勒比松光合速率、蒸腾速率、日同化量和水分利用效率的变化．结果表明,３种松树光合速率和蒸腾速率都具有明显的日变化和季节变化,夏季的光合速率和蒸腾速率最高,冬季最低;加勒比松的平均日同化量为９．３４ｇ·ｋｇ－１、平均水分利用效率为１５９．７５μｍｏｌＣＯ２·ｇ－１Ｈ２Ｏ,高于其它树种;湿地松最低．加勒比松是很好的引种树种,更适合在当地推广     

Agitation rate effects on plasmid stability in immobilized and free-cell continuous cultures of recombinant E. coli.

Escherichia coli B/pTG201 recombinant cells were immobilized by entrapment in a carrageenan gel and cultivated in nonselective media to investigate the effect of agitation rate on plasmid stability, biomass concentration, and enzyme productivity. These parameters were studied in continuous cultures for free and immobilized cells, respectively. Immobilized recombinant cells exhibit an increase in the stability of the plasmid pTG201 compared to free cells, even under conditions where the tendency of plasmid stability for free cells decreased generally more rapidly under a higher agitation rate. Intensive agitation, resulting also in a strong shear stress, greatly reduced cell concentration within gel beads throughout the course of growth. Higher enzyme expression of catechol 2–3, dioxygenase was also obtained in leaked cells due to better maintenance of plasmid stability and higher plasmid copy number with regard to free cells. Enzyme productivity of leaked and free cells in minimal medium decreased with the increase in agitation rate, due to decreased plasmid stability; however, in LB medium, it increased in the presence of higher agitation rate related to important cell concentration.     

转基因鱼构建模式的研究II.构建转基因鱼的几个影响因素(英文)

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Canopy photosynthetic production in a Japanese larch stand. I. Seasonal and vertical changes of leaf characteristics along the light gradient in a canopy

In an 18 year old Japanese larch stand, leaf characteristics such as area, weight, gross photosynthetic rate and respiration rate were studied in order to obtain basic information on estimating canopy photosynthesis and respiration. The leaf growth courses in area and weight from bud opening were approximated by simple logistic curves. The growth coefficient for the area growth curve was 0.155–0.175 day⁻¹, while that for the weight growth was 0.112–0.117 day⁻¹. The larger growth coefficient in area growth caused the seasonal change in specific leaf area (SLA) that increased after bud opening to its peak early in May at almost 300 cm² g⁻¹ and then decreased until it leveled off at about 140 cm²g⁻¹. The change inSLA indicates the possibility that leaf area growth precedes leaf thickness growth. The relationship between the coefficientsa andb of the gross photosynthetic rate (p)-light flux density (1) curve (p=bI/(1+aI)) and the mean relative light flux density (I′/I ₀) at each canopy height were approximated by hyperbolic formulae:a=A/(I′/I ₀)+B andb=C/(I′/I ₀)+D. Leaf respiration rate was also increased with increasingI′/I ₀. Seasonal change of gross photosynthetic rate and leaf respiration rate were related to mean air temperature through linear regression on semilogarithmic co-ordinates.     

Long-term responses of Melilotus segetalis to salinity. II. Nutrient absorption and utilization

Specific absorption rates (SAR) and specific utilization rates (SUR) of sodium, chloride, potassium, calcium, magnesium and phosphate ions were determined for Melilotus segetalis (Brot.) Ser. (annual sweetclover) grown under both control and salinized conditions (NaCl treatment of CE=15 dS m⁻¹) for a complete life cycle with sequential harvests. The behaviour over time of the SARs and SURs of the mineral elements was in general correlated with relative growth rate (RGR) kinetics, with a parabolic trend during the vegetative phase and a progressive linear decrease during the reproductive stage. Salinity significantly reduced the SARs of K and Mg but did not affect the SARs of Ca and P during the vegetative phase. During the reproductive stage, however, the SARs of K, Ca and P of salt-stressed plants were higher than in control plants. The similar SARs of total cations (TC) found in control and salt-stressed plants may indicate compensatory mechanisms to maintain a constant total cation content. Salt-stressed plants showed lower SURs of K, Ca and P during the vegetative phase, and lower SURs of K and P but a higher SUR of Mg during the reproductive stage. A nutrient imbalance, caused by a lower root efficiency in absorbing K and Mg and a lower leaf efficiency in producing biomass per unit of K, Ca and P, apparently contributed to the salt-induced reduction in growth during the vegetative phase of M. segetalis. The switch to non-reduced, compensated growth during the reproductive phase may have been caused by a higher nutrient demand which increased the root efficiency in absorbing K, Ca and P and the leaf efficiency in utilizing Mg.     

Cardiovascular responses to dreamed physical exercise during REM lucid dreaming.

Previous studies have demonstrated intriguing psychophysiological correspondences when lucid dreamers carried out specific tasks during lucid dreams (e.g., eye movements and EMG activities). But only a few studies have investigated cardiovascular changes during dreamed physical activities. This study tests the hypothesis that physical activity (performing squats) carried out in a lucid dream increases cardiovascular parameters in the sleeping body. Therefore, 5 proficient lucid dreamers experienced with the eye-signaling method during lucidity spent 2 to 4 nonconsecutive nights in a sleep laboratory. Instructed to carry out specific tasks (counting and performing squats) while lucid dreaming, the participants reported becoming lucid and signaling in 11 REM periods recorded. Fourteen complete lucid dream tasks were verified by eye signaling. The results showed a statistically significant increase of heart rate between the preexercise and exercise periods and the postexercise period. The results for respiration rate were less clear. Even though respiration rate during the exercise period was higher than during the pre- and postexercise period, statistical significance was only found for the second comparison. Overall, the results support the hypothesis that lucidly dreamed motor action causes increases at the level of peripheral effectors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chlorophyll a Fluorescence Analysis in Response to Excitation Irradiance in Bean Plants (Phaseolus vulgaris L. and Vigna unguiculata L. Walp) Submitted to High Temperature Stress

Bean plants Phaseolus vulgaris L. (cv. Carioca and Negro Huasteco) and Vigna unguiculata L. Walp (cv. Epace-10) were grown in a growth chamber with a photosynthetic photon flux density of 200 mol m^–2 s^–1 at leaf level and air temperature of 25+1 °C. Fully expanded, first pair leaves of 12-d-old plants were submitted for 90 min to high temperature (25, 30, 35, 40, 45, and 48 °C). Chlorophyll a fluorescence parameters (ETR, q_P, q_N, and F₀) were investigated using a modulated fluorimeter at 25 °C during recovery considered here as 48 h after stress induction period. An accentuated decrease in q_P and an increase in q_N at 48 °C in Carioca and Negro Huasteco was not observed in Epace-10. In response to excitation irradiance a great potential for ETR was found in Negro Huasteco at 25 °C, also demonstrated by net photosynthetic rate. At 48 °C ETR was high for Epace-10 while it was equal to zero for Carioca and Negro Huasteco. Tolerance to high temperature observed in Epace-10 provided important information about the adaptative characteristics of Vigna cultivars to warm climates.     

Post-illumination burst of carbon dioxide inPhaseolus vulgaris L. as affected by leaf temperature

The effect of leaf temperature on the post-illumination burst of CO₂ (PIB) in 15 day-old primary bean leaves (Phaseolus vulgaris L.) was studied by means of infrared gas analysis in a closed gas exchange system. The amplitude and kinetic of PIB was different with its own characteristic course for different temperature steps. The temperature optimum for the PIB at 21% O₂ near the carbon dioxide compensation concentration Λ (150 mg m^-3) was 33 °C while that for net photosynthetic rate (P _N) at 21% O₂ and 600 mg m^-3 CO₂ was 24.5 °C. The PIB was observed to 12…33 s after the darkening of leaves. No PIB was observed at 2% O₂. The applicability of PIB as an estimate of photorespiration rateR _p has been proved by comparing it with extrapolation of the relationship betweenP _n and CO₂ concentration to zero.     

中国北方杂草稻光合与水分生理特性

杂草稻是一类重要的稻属种质资源,具有耐寒、耐旱、耐瘠薄等优良特性.本文以88份中国北方杂草稻资源和4份栽培稻为材料,研究了中国北方杂草稻的光合速率、蒸腾速率、气孔导度等光合与水分生理特性及其相互关系.结果表明: 北方杂草稻资源的光合和水分生理特性存在较大差异,具有丰富的多样性.杂草稻的光合速率变化范围在12.47～28.67 μmol CO₂·m^-2·s^-1,瞬时水分利用效率的变化范围在1.39～3.40 mg·g^-1.光合参数中,胞间CO₂浓度的变异系数最小,气孔导度的变异系数最大.光合速率与蒸腾速率、气孔导度呈极显著的二次曲线关系,光合速率与胞间CO₂浓度呈显著的直线关系,瞬时水分利用效率与蒸腾速率、气孔导度呈极显著的二次曲线关系.可用杂草稻材料的优越性能对栽培稻进行品种改良.     

苋菜的光合特性

宽菜Amaranthus cruentus cv.生长在调控的温室条件。在光强0至800μmol.m~(-2)S~(-1),光合速率(PN,μmol.CO_2m~(-2)、s~(-1))随光强(PFD,μmol、m~(-2)、s~(-1))增高而增大,其关系为PN=56.82 PFD×10~(-3)—2.13。光补偿点为60μmol.m~(-2)、s~(-1)。叶片在1400 μmol.m~(-2)、s~(-1)达到光合光饱和点。在叶温35℃,叶片/空气水蒸汽压陡度20 m Pa、Pa~(-1)和外界CO_2浓度340μ1、1~(-1),光饱和光合速率为51.63±4.90μ mol.CO_2、m~(-2)、S~(-1)。在光强0至600μmol.m~(-2)、s~(-1),气孔传道率随光强增高而增大。光强高于600μmol.m~(-2)、s~(-1),气孔传道率变化较小。细胞间CO_2浓度为120μ1.1~(-1)由于细胞间CO_2浓度在光合速率——CO_2关系曲线的转折点,可能表明光合作用不受气孔限制。结果表明,苋菜适于高光强环境生长,在干旱条件下具有高的光合速率。