CO2浓度对大豆叶片气孔特征和气体交换参数的影响

利用可精准控制CO₂浓度的大型气候箱设置7个CO₂浓度处理(400、600、800、1000、1200、1400和1600 μmol mol ^-1), 对大豆进行CO₂浓度富集的室内培养试验。结果表明, CO₂浓度升高显著减小大豆叶片近轴面的气孔密度和远/近轴面的气孔面积指数。当CO₂浓度为400 μmol mol ^-1时, 远轴面气孔分布最规则, 提高CO₂浓度导致远轴面气孔的不规则分布; 与远轴面相反, CO₂浓度升高导致近轴面气孔的空间分布更加规则, 即在较高CO₂浓度处理下的Lhat(d)最小值均低于对照组。不同叶面(远/近轴面)气孔特征对大气CO₂浓度变化的响应存在明显差异, 但大豆可以通过调整气孔形态特征和气孔空间分布格局进一步改变叶片的气体交换参数。研究结果有助于从气孔特征响应的角度深入理解CO₂浓度对大豆叶片气体交换过程产生的影响。     

大气CO2浓度升高背景下冬小麦冠层光谱特征和地上生物量估算

本研究旨在探究大气CO₂浓度升高对冬小麦全生育时期冠层光谱特征的影响,并基于筛选的敏感波段建立地上生物量(AGB)与光谱参数的定量关系。为此,在2021—2022年的冬小麦生长季,利用开放式CO₂富集系统(Mini-FACE),设定大气CO₂浓度(ACO₂,(420±20)μL L^-1)和高CO₂浓度(ECO₂,(550±20)μL L^-1)两个处理水平,分析了高CO₂浓度下光谱特征变化,基于连续投影算法(SPA)、逐步多元线性回归(SMLR)和偏最小二乘法回归(PLSR)筛选AGB敏感波段并构建估算模型。结果表明:CO₂浓度升高使冬小麦拔节期和开花期AGB显著增加。红边和近红边反射率及红边面积在拔节期增加,在开花期和灌浆期降低,蓝边、黄边和红边位置在不同生育时期均发生移动;AGB的敏感光谱波段主要分布在红边和近红边区域,CO₂浓度升高缩小了AGB...     

高温条件下CO2对黄瓜叶片光合速率和气孔特性的影响

探索高温条件下,施加CO₂对黄瓜叶片的光合速率、气孔长度、气孔宽度、气孔密度、气孔开张比和气孔开度的影响。采用LI-6400测定光合速率,结果显示高温条件下,经CO₂处理的14、21、28、35和42d的黄瓜叶片光合速率显著增加,分别比常温处理增加30.8%、49.7%、34.5%、32.1%和32.1%。利用软件Motic Images Advanced 2.0分析表明,高温结合CO₂处理后黄瓜气孔长度、宽度、密度、开张比和开度均显著增加,在处理35、28、42、14和28d时分别比常温处理增加了36.4%、38.8%、37.7%、30.2%和36.9%。     

CO2浓度升高条件下不同氮素水平对小叶章光合特性和生长的影响

为阐明大气CO₂浓度升高和不同氮素水平对湿地植物光合生理特性和生长的影响,本研究以三江平原湿地优势植物小叶章(Calamagrostis angustifolia)为研究对象,通过野外原位控制试验,利用开顶式气室(OTC)模拟环境大气CO₂浓度变化,设置E₀(380 ±20 µmol/mol)、E₁(550 ±20 μmol/mol)和E₂(700 ± 20 μmol/mol)3个CO₂浓度;在每个OTC内设置 N₀(0 g N/m²)、N₁(4 g N/m²)和N₂(8 g N/m²)3个氮素水平。结果表明,N₀条件下,与E₀处理相比,E₁和E₂处理（72 天）后小叶章叶片净光合速率分别降低11%和12%(P<0.05),其叶片可溶性蛋白含量、氮素含量（CO₂熏蒸72 天）、小叶章株高（CO₂熏蒸86 天）均显著低于E₀处理(P<0.05);N₁条件下,与E₀处理相比,E₁和E₂处理（72 天）后小叶章叶片净光合速率降低5%(P>0.05)和10%(P<0.05),其叶片氮素含量(P<0.05)、小叶章株高均低于E₀处理;N₂条件下,E₁和E₂处理（72 天）小叶章净光合速率均呈稍增加的趋势(P>0.05),其叶片可溶性蛋白含量显著增加(P<0.05),氮素含量和小叶章株高无显著变化(P>0.05)。N₀、N₁和N₂条件下,CO₂浓度升高均显著增加了小叶章叶片可溶性糖含量。本研究表明长期CO₂浓度升高可能通过降低小叶章叶片光合酶活性,进而降低了其净光合速率,而施加高浓度的氮肥可以缓解长期高CO₂浓度对湿地植物光合及生长的负面影响。     

大气CO_2倍增条件下冬小麦气体交换对高温干旱及复水过程的响应

探究大气CO_2浓度倍增条件下冬小麦气体交换参数对高温干旱及复水过程的生理响应机制,有助于提高生态过程模型的模拟精度,更加准确地预测全球气候变化对农田生态系统初级生产力及其生态服务功能的影响。利用4个可精准控制CO_2浓度和温度的大型人工气候室,研究了CO_2浓度倍增条件下高温干旱及复水过程对冬小麦气孔特征和气体交换参数的影响。结果表明, CO_2浓度倍增(E)导致冬小麦远轴面气孔密度增加、气孔宽度减小、气孔空间分布规则程度降低,但提高叶片的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和水分利用效率(WUE)。高温干旱(HD)使叶片气孔长度、密度、周长和面积减小,导致叶片气体交换参数均显著下降。然而,高CO_2浓度及高温干旱(EHD)导致气体交换参数下降幅度相对较小,表明高CO_2浓度对高温干旱具有一定的缓解作用。此外,干旱复水后,不同处理条件下冬小麦叶片气体交换参数均有所升高,但高温干旱下叶片的气体交换参数仍未能恢复到对照水平,暗示光合器官可能在高温干旱时遭到损伤和破坏。     

臭氧与其他环境因子及其复合作用对植物的影响

综述了臭氧（O₃）浓度升高、太阳辐射减弱、UV-B辐射、CO₂浓度升高及其与O₃复合作用对植物形态特征、光合作用、干物质累积及作物产量等生理生化机制的影响。交互作用的试验条件可以更好地模拟自然环境条件。O₃和UV-B辐射对植物几乎没有积极作用。太阳辐射减弱、CO₂浓度升高都会促进植物营养生长。但太阳辐射减弱降低干物质累积和产量,CO₂浓度升高对其有促进作用。CO₂浓度升高在与O₃复合条件下,可部分缓解太阳辐射减弱对植物造成的伤害。而UV-B辐射与O₃复合对植物造成的伤害更大。     

设施条件下两个石榴品种光合荧光特征参数差异与变化

为明确‘泰山红’和‘突尼斯软籽’石榴设施栽培的光合生理特性,观测了光合和荧光特征参数的差异及变化趋势。本研究结果表明,两个品种光合有效辐射和大气温度随时间的增加均先升高后降低。净光合速率、气孔导度和蒸腾速率日变化均为典型的双峰曲线,存在光合“午休”现象。细胞间CO₂浓度和水分利用效率先降低后升高,水蒸气压亏缺先升高后降低再升高。‘泰山红’净光合速率、气孔导度和蒸腾速率整体上高于‘突尼斯软籽’。F_o随时间的增加先升高后降低,F_m、F_v/F_m、F_v/F_o和PI先降低后升高,Vj先升高后降低再缓慢升高。大气温度与水分利用效率、细胞间CO₂浓度极显著负相关。光合有效辐射与F_o显著正相关,与F_m、F_v F_m、F_v/F_o显著负相关。气孔导度与净光合速率极显著正相关。细胞间CO₂     

增施CO2对马铃薯植株光合特性及产量的影响

为检验增施CO₂对马铃薯组培苗植株光合特性及微型薯产量的影响,选用马铃薯品种夏坡蒂组培苗为试验材料,于2015年在温室条件下进行了两批次试验。结果表明,增加CO₂浓度可显著增加植株的叶面积、叶片净光合速率和胞间CO₂浓度,且CO₂ 750μmol/mol处理>550μmol/mol处理>CK（空气）,但增加CO₂浓度降低了马铃薯植株叶片气孔导度和蒸腾速率。结果还表明,增施CO₂增加了马铃薯单株结薯数、单个薯重和单株产量,其增幅随CO₂量的增加而增加。上述结果充分证明在温室条件下增施CO₂对加速马铃薯微型薯的繁育有积极作用。     

不同O2和CO2浓度梯度对酥梨采后生理及果实褐变的影响

以酥梨为试材,研究了(0±0.5)℃条件下不同O₂浓度梯度和CO₂浓度梯度的气调贮藏对酥梨采后生理及果实褐变的影响。结果表明:在贮藏期内,当CO₂浓度为0%时,随着O₂浓度的降低,在一定程度上可以延缓酥梨果肉组织相对电导率的升高、酚类物质的下降、多酚氧化酶活性的上升及色泽的转黄;但当O₂浓度为1.5%时,会对酥梨果实造成伤害,引起多酚氧化酶活性上升,果心褐变指数升高;当O₂浓度为5%时,CO₂浓度的升高有效保持了果实的硬度、色泽;但当CO₂浓度为8%时,会导致酥梨果实相对电导率增幅加大,果心、果肉酚类物质氧化加剧,果心褐变指数升高。综上所述,酥梨适宜的气调指标阈值为CO₂<2%,O₂为3%~5%。     

外源亚精胺对烤烟幼苗干旱胁迫的缓解效应研究

为揭示外源亚精胺（Spd）对不同干旱胁迫程度烤烟幼苗的缓解效应,以云烟87为供试材料,探究叶面喷施0.40mmol/L Spd对不同干旱胁迫程度下烤烟幼苗生物量、光合特性、根系活力、渗透调节物质含量、膜质过氧化物和抗氧化酶活性的影响。结果表明,干旱胁迫抑制了烤烟幼苗的生长发育,尤以重度干旱抑制效果最为显著。轻度干旱胁迫下喷施外源Spd能够显著提高烤烟幼苗的生物量、净光合速率（P_n）、蒸腾速率（T_r）、气孔导度（G_s）和叶绿素含量,同时增强抗氧化酶（SOD、POD和CAT）活性和根系活力,提高渗透调节物质（可溶性蛋白、脯氨酸）含量,降低胞间CO₂浓度（C_i）、丙二醛（MDA）含量和O^-₂·产生速率,有效缓解轻度干旱胁迫造成的损害,而重度干旱胁迫下,喷施外源Spd对于提高烤烟幼苗生物量和光合能力没有显著效果。综合来看,叶面喷施0.40mmol/L Spd能够有效提高烤烟幼苗的抗旱能力,尤其对轻度干旱的烤烟幼苗作用最为显著。     

Water-use efficiency, leaf area and leaf gas exchange of cowpeas under mid-season drought

Ten cowpea (Vigna unguiculata L. “Walp.”) genotypes were grown in a growth chamber under well-watered conditions up to early flowering and were then either subjected to water deficit or were continually well-watered. Water deficit was induced by withholding irrigation until the soil water potential was −75 kPa, which was then maintained for 10 days. Variation in water use efficiency (WUE), leaf area, specific leaf area (SLA), leaf area ratio (LAR) and leaf gas exchange (i.e. assimilation, transpiration, stomata conductance and internal CO₂ concentration) in response to water deficit were investigated. Water deficit treatment reduced mean water use by 21%. This caused between 11 and more than 40% reduction of biomass across the genotypes. Reductions in biomass were due to decline in leaf gas exchange and leaf area during water deficit. Water deficit improved the WUE of two genotypes (IFH 27-8 and Lobia) by approximately 20%, but caused moderate to huge reductions in most genotypes. High relative water content (RWC) of leaves was maintained in some of the genotypes by stomata closure and a reduction of leaf area. Drought avoidance by maintaining high leaf water content was negatively associated with leaf area as well as SLA. High assimilation rate under water deficit was associated with high RWC. Decline in assimilation rate were due mainly to stomata closure, however, some evidence of non-stomatal regulation were also found. WUE and instantaneous water use efficiency (IWUE, a molar ratio of assimilation to transpiration) were not directly associated, but IWUE and leaf internal CO₂ concentration (c_i) were negatively related while c_i was also moderately related with SLA. Overall, significant genotypic variations in leaf gas exchange parameters were found, which can give some indications of superiority when comparing cowpea genotypes for agronomic fitness under drought. The lack of relationship between WUE and IWUE was due to the instantaneous measurement of leaf gas exchange, which can be corrected by calculations to reflect the entire season.     

Photosynthetic responses in spring wheat grown under elevated CO2 concentrations and stress conditions in the European, multiple-site experiment ‘ESPACE-wheat’

Spring wheat cv. Minaret crop stands were grown under ambient and elevated CO₂ concentrations at seven sites in Germany, Ireland, the UK, Belgium and the Netherlands. Six of the sites used open-top chambers and one used a controlled environment mimicking field conditions. The effect of elevated CO₂ for a range of N application regimes, O₃ concentrations, and growth temperatures on flag leaf photosynthesis was studied. Before anthesis, flag leaf photosynthesis was stimulated about 50% by 650 compared with 350 μmol mol⁻¹ CO₂ at all sites, regardless of other treatments. Furthermore, there was no evidence of a decrease in photosynthetic capacity of flag leaves due to growth at elevated CO₂ before anthesis, even for low N treatments. However, photosynthetic capacity, particularly carboxylation capacity, of flag leaves was usually decreased by growth at elevated CO₂ after anthesis, especially in low N treatments. Acclimation of photosynthesis to elevated CO₂ therefore appears to occur only slowly, consistent with a response to changes in sink–source relationships, rather than a direct response. Effect of elevated CO₂ on stomatal conductance was much more variable between sites and treatments, but on average was decreased by ˜10% at 650 compared with 350 μmol mol⁻¹ CO₂. Carboxylation capacity of flag leaves was decreased by growth at elevated O₃ both before and after anthesis, regardless of CO₂ concentration.     

Interactive effects of elevated atmospheric CO2 concentrations and plant available soil water content on canopy evapotranspiration and conductance of spring wheat

The present study was conducted to investigate the possible interactive effects of rising atmospheric CO₂ concentration [CO₂] and drought stress on water use of wheat. Spring wheat (Triticum aestivum cv. “Minaret”) was grown either in 1 m diameter lysimeters with 0.4 m soil depth (1998) or in the field (1999) in open-top chambers under two CO₂-concentrations (ambient, ambient + 280 ppm) and two watering regimes (well-watered = WW with a plant available water content PAW > 40 mm and drought stressed = DS, 10 mm < PAW < 30 mm) beginning after first node stage. Canopy evapotranspiration (E_C) was measured continuously from first the node stage until the beginning of flag leaf senescence using four open-system canopy chambers (0.78 m³). Seasonal changes of the absorption of photosynthetically active radiation (APAR) of the canopy and root growth (1999) were also measured.

In both growing seasons leaf area index increased in response to elevated [CO₂] in both water treatments. The related effects of [CO₂] on canopy radiation absorption (APAR) were, however, smaller. E_C was linearily related to APAR in both growing seasons. While elevated [CO₂] reduced the slope of this relation under WW conditions by ca. 20% in both growing seasons, it was not reduced (1998) and even increased (1999) under drought. Canopy conductance (G_C) calculated as E_C divided by vapour pressure deficit of air, showed a non-linear relationship to APAR that was best explained by saturation curves. Under WW conditions, elevated [CO₂] reduced the initial slope of G_C versus APAR as well as G_C at saturating light conditions (ca. −30%), while under DS conditions no effect of elevated [CO₂] could be detected. Under high light conditions (PAR > 400 μmol m⁻² s⁻¹) a critical “threshold value” of PAW (T_PAW, ca. 40 mm) could be identified above which G_C did not respond to PAW. While in 1998 G_C did not respond to elevated [CO₂] at PAW < T_PAW, it was slightly increased at low PAW values in the field experiments of 1999. The reduction of T_PAW by elevated [CO₂] may be explained by enhanced root growth (1999) that would have given the plants better access to soil water resources. The present results suggest that below a critical soil water content elevated [CO₂] will not reduce canopy water loss of wheat or may even enhance it.     

干旱区不同品种中华钙果光合特性比较研究

不同中华钙果品种在西北干旱区叶片形态及光合特性的研究可为该区域高产优质节水品种筛选提供理论依据。通过测定叶片光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和胞间CO₂浓度(Ci)等光合性能指标及形态,分析不同中华钙果品种的叶片形态特征与光合特征及其相关关系。结果表明：（1）不同中华钙果品种叶长和叶宽均存着较大差异,叶面积大小表现为‘农大5号’>‘农大7号’>‘农大6号’>‘生态晚熟种’>‘生态早熟种’;（2）‘农大7号’的净光合速率及蒸腾速率均最大,其净光合速率显著高于‘农大6号’和‘生态早熟种’,蒸腾速率均显著高于其他品种,5种中华钙果的气孔导度及胞间CO₂浓度均无显著性差异;（3）5种中华钙果净光合速率、蒸腾速率、气孔导度与叶面积之间存在正相关线性关系,胞间CO₂浓度与叶面积之间存在负相关线性关系;（4）5种中华钙果的光合速率与气孔导度、蒸腾速率、叶片蒸汽压亏缺、叶片温度呈极显著正相关,与胞间CO₂浓度呈极显著负相关。     

Photosynthetic and stomatal responses of potatoes grown under elevated CO2 and/or O3—results from the European CHIP-programme

The physiological effects of elevated CO₂ and/or O₃ on Solanum tuberosum cv. Bintje were examined in Open-Top Chambers during 1998 and 1999 at experimental sites across Europe as part of the EU ‘Changing Climate and Potential Impacts on Potato Yield and Quality’ programme (CHIP). At tuber initiation (≈20 days after emergence, DAE) elevated CO₂ (680 μl l⁻¹) induced a 40% increase in the light saturated photosynthetic rate (A_sat) of fully expanded leaves in the upper canopy. This was 16% less than expected from short-term exposures of plants grown under ambient CO₂ (360 μl l⁻¹) to elevated CO₂, indicating that photosynthetic acclimation began at an early stage of crop growth. This effect resulted from a combination of a 12% reduction in stomatal conductance (g_s) and a decline in photosynthetic capacity, as indicated by the significant reductions in the maximum carboxylation rate of Rubisco (Vc_max) and light-saturated rate of electron transport (J_max) under elevated CO₂. The seasonal decline in the promotion of photosynthesis by elevated CO₂ reflected the concurrent decrease in g_s. Vc_max and J_max were both reduced in plants grown under elevated CO₂ until shortly after maximum leaf area (MLA) was attained. Although non-photorespiratory mitochondrial respiration in the light (R_d) increased during the later stages of the season, net photosynthesis was consistently increased by elevated CO₂ during the main part of the season. Photosynthetic rate declined more rapidly in response to elevated O₃ under ambient CO₂, and the detrimental impact of O₃ was most obvious after MLA was attained (DAE 40–50). Several exposure indices were compared, with the objective of determining the critical ozone level required to induce physiological effects. The critical O₃ exposure above which a 5% reduction in light saturated photosynthetic rate may be expected (expressed in terms of cumulative exposure above 0 nl l⁻¹ O₃ between emergence and specific dates during the season (AOT0-cum)) was 11 μl l⁻¹ h; however this value should only be extrapolated beyond the CHIP dataset with caution. The interaction between O₃ and stomatal behaviour was more complex, as it was influenced by both long-term and daily exposure levels. Elevated CO₂ counteracted the adverse effect of O₃ on photosynthesis, perhaps because the observed reduction in stomatal conductance decreased O₃ fluxes into the leaves. The results are discussed in the context of nitrogen deficiency, carbohydrate accumulation and yield.     

抽穗后冬小麦旗叶光合特性的变化对产量的影响

为了探讨不同小麦品种之间的光合特性的差异及光合作用与经济产量的关系,本研究选取4个不同冬小麦品种分别在6个生育时期进行了光合特性的测定。结果表明：小麦旗叶6项光合特性指标随发育进程变化的趋势、变化程度基本相同,但不同品种在不同发育时期内光合特性指标的数值、变化程度不同;6项光合特性指标均与籽粒产量正相关;相关程度表现为绿叶面积>气孔导度>胞间CO₂浓度>净光合速率>叶绿素含量>蒸腾速率;不同时期光合特性与籽粒产量的相关性顺序为灌浆中期>灌浆前期>灌浆后期>开花期>抽穗期>灌浆末期;在开花期至灌浆后期,维持和提高旗叶的绿叶面积、叶绿素含量、净光合速率、气孔导度、胞间CO₂是提高小麦产量的基础。因此,在开展小麦高光效育种时,对种质资源材料进行光合特性测定和比较对育种工作具有非常重要的参考价值和指导意义。     

Chlorophyll content of spring wheat flag leaves grown under elevated CO2 concentrations and other environmental stresses within the ‘ESPACE-wheat’ project

Spring wheat cv. Minaret was grown in open-top chambers at four sites across Europe. The effect of different treatments (CO₂ enrichment, O₃ fumigation, drought stress and temperature) on the chlorophyll content of the flag leaf was investigated using the MINOLTA SPAD-502 meter. Under optimum growth conditions the maximum chlorophyll content, which was reached at anthesis, was consistent among the sites ranging from 460 to 500 mg chlorophyll m⁻². No significant effect of elevated CO₂ or O₃ was observed at anthesis. Leaf senescence, indicated by the chlorophyll breakdown after anthesis, was relatively constant in the control chambers. Under control conditions, thermal time until 50% chlorophyll loss was reached was 600°C day. Elevated CO₂ caused a faster decline in chlorophyll content (thermal time until 50% chlorophyll loss was reduced to 500–580°C day) indicating a faster rate of plant development at two experimental sites. The effect of ozone on chlorophyll content depended on the time and dose of O₃ exposure. During grain filling, high O₃ concentrations induced premature senescence of the flag leaves (up to −130°C day). This deleterious effect was mitigated by elevated CO₂. Drought stress led to faster chlorophyll breakdown irrespective of CO₂ treatment.     

Phenological development, leaf emergence, tillering and leaf area index, and duration of spring wheat across Europe in response to CO2 and ozone

Phenological development, leaf emergence, tillering and leaf area index (LAI), and duration (LAD) of spring wheat cv. Minaret, grown in open-top chambers at different sites throughout Europe for up to 3 years at each site, were investigated in response to elevated CO₂ (ambient CO₂×2) and ozone (ambient ozone ×1.5) concentrations.

Phenological development varied among experiments and was partly explained by differences in temperature among sites and years. There was a weak positive relationship between the thermal rate of development and the mean daylength for the period from emergence to anthesis. Main stems produced on average 7.7 leaves with little variation among experiments. Variation was higher for the thermal rate of leaf emergence, which was partly explained by differences in the rate of change of daylength at plant emergence among seasons. Phenological development, rate of leaf emergence and final leaf number were not affected by CO₂ and ozone exposure. Responses of tillering and LAI to CO₂ and ozone exposure were significant only in some experiments. However, the direction of responses was consistent for most experiments. The number of tillers and ears per plant, respectively, was increased as a result of CO₂ enrichment by about 13% at the beginning of stem elongation (DC31), at anthesis and at maturity. Exposure to ozone had no effect on tillering. LAI was increased as a result of CO₂ elevation by about 11% at DC31 and by about 14% at anthesis. Ozone exposure reduced LAI at anthesis by about 9%. No such effect was observed at DC31. There were very few interactive effects of CO₂ and ozone on tillering and LAI. Variations in tillering and LAI, and their responses to CO₂ and ozone exposure, were partly explained by single linear relationships considering differences in plant density, tiller density and the duration of developmental phases among experiments. Consideration of temperature and incident photosynthetically active radiation in this analysis did not reduce the unexplained variation. There was a negative effect of ozone exposure on leaf area duration at most sites. Direct effects of elevated CO₂ concentration on leaf senescence, both positive and negative, were observed in some experiments. There was evidence in several experiments that elevated CO₂ concentration ameliorated the negative effect of ozone on leaf area duration. It was concluded from these results that an analysis of the interactive effects of climate, CO₂ and ozone on canopy development requires reference to the physiological processes involved.