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1.
2001～2002连续两年在大田生产条件下研究了10个烤烟基因型气孔密度和气孔导度的变异情况及其与抗臭氧伤害的关系;2002年在控制条件下采用低温加臭氧的方法处理烟草植株,研究分析了烟草叶片遭受臭氧伤害后抗氧化酶活性的变化及其与抗臭氧伤害的关系。结果表明：烤烟不同基因型对臭氧伤害的抗性存在显著的差异。烟草叶片下表皮气孔密度和气孔导度与臭氧伤害引起的气候斑点病具有相关关系,在烟株下部叶中,其相关性分别达到显著（R2001＝0.68,R2002＝0.65）和极显著水平（R2001＝0.87,R2002＝0.80）。因此,下部叶气孔密度和气孔导度可以作为抗病育种的选择指标。在控制条件下的试验结果表明：只有低温加臭氧复合因子才能诱发烟草叶片产生臭氧伤害症状。烟草叶片低温下遭遇臭氧伤害后,超氧化物歧化酶（SOD）活性升高,升幅与气候斑点病病情指数负相关,过氧化氢酶（CAT）活性略有升高,过氧化物酶（POD）活性急剧下降。抗性较差的烟草基因型抗氧化酶反应不敏感,臭氧伤害症状严重,抗性较强的烟草基因型抗氧化酶反应敏感,臭氧伤害症状较轻。低温和臭氧同时作用明显影响了活性氧清除系统,致使系统中酶活性比例失调,POD活性急剧下降,可能是烟草叶片产生臭氧伤害的原因之一,SOD和CAT活性升高对消除臭氧伤害具有一定的防御作用。 相似文献
2.
近地面大气中臭氧(O3)对植物生长发育和产量会产生不良影响。工业和交通排放的增加使得全球地面O3浓度逐年增加,不断升高的O3浓度已开始影响到我国的粮食产量。O3对植物的影响是由于其进入植物体内发生生化反应所引起的,所以需要建立一种考虑到植物生理生态状况的评估指标来评估O3对植物的影响。其中基于O3通量(特别是植物气孔吸收)的评价指标和方法,被认为比传统的基于O3浓度的评价指标和方法更符合O3对植物的影响机理。介绍了O3对生态系统影响评估方法和评价指标,重点评述了生态系统尺度O3通量观测和气孔吸收估算的主要方法以及在不同生态系统上的研究进展分析了我国关于O3对植物和生态系统影响的研究现状,并对未来的研究工作进行了展望。 相似文献
3.
以荒漠生态系统典型植物白刺(Nitraria tangutorum Bobr)叶片为研究对象,利用数码图像显微镜处理系统,研究了不同人工模拟增雨处理下的白刺叶片气孔密度及形态特征的变化情况。结果表明,荒漠植物固有特征决定了白刺叶片下表皮气孔密度大于上表皮,上表皮、下表皮气孔密度对增雨响应差异不显著(P0.05)。增雨处理上表皮、下表皮气孔密度与对照差异显著(P0.05)。相同增雨季节,50%处理下叶片气孔密度高于100%处理;不同增雨季节,气孔密度对生长季后期增雨响应更明显。白刺叶表皮气孔分布遵循\"一细胞间隔(one cell spacing rule)\"法则。增雨后叶片上表皮和下表皮气孔长度、宽度均有不同程度的增加,气孔形态特征对100%处理的响应较50%处理更为明显,且生长季后期增雨对叶片气孔形态特征的影响更大。 相似文献
4.
光诱导的气孔动力学响应快慢是影响植物叶水分利用效率的重要因素,为探索黄土高原不同演替阶段树种水分利用效率差异的生理机制,该研究以黄龙山林区典型树种(演替早期种山杨和白桦、演替后期种辽东栎)的幼龄实生苗为材料,采用盆栽试验,研究了叶片光诱导的气孔导度动力学参数差异及其与气孔特征、叶长期水分利用效率的关系。结果表明：(1)山杨和白桦气孔开放过程中气孔导度(gs)增加的时间常数(Ki)小于辽东栎,但气孔关闭过程中气孔导度降低的时间常数(Kd)则大于辽东栎,表明山杨和白桦气孔开放更快,而辽东栎的气孔关闭更快。同时,气孔开放过程中山杨和白桦的gs响应幅度均大于辽东栎,气孔关闭过程中山杨的gs响应幅度亦大于辽东栎。(2)3种树种中,辽东栎的气孔密度最大,气孔最小,气孔指数最大,辽东栎气孔特征无法解释其慢速的气孔开放过程。 (3)山杨和白桦具有高的光合速率、最大羧化效率和最大电子传递速率,3种树种碳同位素比率(δ13C)表征的长期水分利用效率表现为山杨>白桦>辽东栎。研究认为,演替早期种山杨和白桦的高水分利用效率与其快速的气孔开放有关,而演替后期种辽东栎快速的气孔关闭并未增加其水分利用效率,且长期水分利用效率低于山杨和白桦,可能与辽东栎慢速的气孔开放限制了其光合速率有关。 相似文献
5.
该研究利用植物制片技术,以中国青藏高原和内蒙古高原典型草地常见种或优势种植物的叶片为研究对象,通过比较分析叶片哑铃型气孔器和肾型气孔器的特征及其与环境因子的关系,揭示植物叶片两类气孔器对环境因子的响应策略。结果表明:(1)叶片哑铃型气孔器气孔指标的变异系数小于肾型气孔器。(2)叶片哑铃型气孔器气孔指标与环境气候指标的关系弱于肾型气孔器。(3)叶片哑铃型气孔器气孔特征与环境关系在叶片上下表面之间存在显著差异,而肾型气孔器气孔特征与环境因子的关系在叶片上下表面之间无显著差异。(4)叶片哑铃型气孔器的气孔特征与降水关系密切,而肾型气孔器气孔特征与温度关系密切。(5)同一种气孔器的气孔特征在两个地区(青藏高原和内蒙古高原)间存在显著差异。研究认为,肾型气孔器和哑铃型气孔器的气孔特征及其与环境之间的关系存在差异,在分析气孔特征时有必要将肾形与哑铃形保卫细胞形成的气孔器加以区分,该研究结果有助于进一步理解中国草地植物叶气孔特征对气候变化的响应与适应策略。 相似文献
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气孔调节着植物光合、蒸腾作用的平衡及其相互耦合过程,其在植物适应环境变化中起着关键作用。以若尔盖高原纳勒乔沼泽水位下降模拟控制实验平台为依托,研究木里薹草的叶片气孔性状以及光合性状对水位下降的响应,探讨木里薹草气孔性状与光合性状之间的变异与权衡关系。结果表明:(1) 水位下降后,木里薹草的气孔数量 (NS) 、气孔密度(SD)、净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、叶绿素含量(Chl)显著减少(P＜0.05);气孔面积(SA)、叶片厚度(LT)、胞间CO2浓度(Ci)显著增加(P＜0.05);维管束面积(VA)、导管面积(CA)、筛管面积(STA)没有显著差异(P＞0.05)。(2)木里薹草气孔性状、光合性状中所有性状均显著相关(P＜0.05),但解剖性状只有CA与VA和STA呈显著正相关关系(P＜0.05);解剖特征与气孔特征、光合特征之间不存在显著相关关系(P＞0.05)。但气孔特征与光合特征紧密联系,NS和SD均与Gs、Pn和Tr呈极显著正相关(P＜0.001),SA与Gs、Pn和Tr呈极显著负相关(P＜0.001)。(3)气孔特征与光合特征存在一定的协同变异关系,这种关系并非在不同水位条件下都存在。(4)此外,随着湿地水位下降,木里薹草由快速投资回报策略向缓慢投资回报策略转变。综上表明,木里薹草在适应低水位环境中展现出高度可塑性,气孔特征与光合性状之间的协同变异关系充分体现了木里薹草的权衡策略,反映了若尔盖高寒高原湿地植物叶片结构和功能对水位变化的适应性,有助于木里薹草在变化的环境中生存和繁衍。 相似文献
7.
乙酰胆碱与蚕豆气孔运动的关系 总被引：11，自引：0，他引：11
在蚕豆（ViciafabaL）幼苗中,很尖的切除可以引起植株蒸腾速率的逐渐下降;而在这一过程中植株地上部水势保持不变;外施乙酰胆碱可以使蒸腾速率基本恢复到断根前的水平。利用气质联动技术对乙酰胆碱的内源性进行了鉴定,结果表明蚕豆的类乙酰胆碱提取物具有与人工合成的乙酰胆碱和高等动物脑组织中类乙酰胆碱提取物相同的质谱谱线,说明乙酰胆碱是蚕豆中的一种内源物质。为了对乙酰胆碱进行快速而准确的测定,建立了测定乙酰胆碱的热裂解的气相色谱法。利用这种方法测定的结果表明,在从根的切除到不定根重新长成的整个过程中,叶片下表皮中乙酰胆碱的含量与叶片的蒸腾速率及根的存在和生长状态密切相关,表明内源的乙酰胆碱可能参与调控植物的气孔行为;这一推论又为乙酰胆碱对表皮条中气孔开度的刺激效应和乙酰胆碱酯酶抑制剂neostig－mine可以增加气孔对乙酰胆碱的敏感性的实验进一步证实。 相似文献
8.
乙酰胆碱与蚕豆气孔运动的关系 总被引：5，自引：0，他引：5
在蚕豆(Vicia faba L.)幼苗中,根尖的切除可以引起植株蒸腾速率的逐渐下降;而在这一过程中植株地上部水势保持不变;外施乙酰胆碱可以使蒸腾速率基本恢复到断根前的水平。利用气质联动技术对乙酰胆碱的内源性进行了鉴定,结果表明蚕豆的类乙酰胆碱提取物具有与人工合成的乙酰胆碱和高等动物脑组织中类乙酰胆碱提取物相同的质谱谱线,说明乙酰胆碱是蚕豆中的一种内源物质。为了对乙酰胆碱进行快速而准确的测定,建立了测定乙酰胆碱的热裂解的气相色谱法。利用这种方法测定的结果表明,在从根的切除到不定根重新长成的整个过程中,叶片下表皮中乙酰胆碱的含量与叶片的蒸腾速率及根的存在和生长状态密切相关,表明内源的乙酰胆碱可能参与调控植物的气孔行为;这一推论又为乙酰胆碱对表皮条中气孔开度的刺激效应和乙酰胆碱酯酶抑制剂neostigmine可以增加气孔对乙酰胆碱的敏感性的实验进一步证实。 相似文献
9.
对元谋干热河谷人工混交林中9个树种叶片的水势、饱和渗透势、气孔导度、渗透调节和季节变化进行了测定,同时对树高和胸径也进行了比较。水分生理特征表明: 1)随着旱季的深入,除刺槐（Robinia pseudoacacia）、黄荆（Vitex negundo）、滇榄仁（Terminalia franchetii）落叶外,其余常绿树种叶片的气孔导度、水势和饱和渗透势都呈下降的趋势,在最旱的三、四月份,它们适应干旱的方式有4种：①低水势、气孔导度近似关闭的厚荚相思（Acacia leptocarpa）、大叶相思（A. auriculiformis）和肯氏相思（A. cunninghamii）;②低水势、低气孔导度的赤桉（Eucalyptus dulebsis）、娟毛相思（A. holosericea）和车桑子（Dodonaea wiscosa）loserice气孔导度的柠檬桉（Eucalyptus citriodora）和新银合欢（Leucaena leucocephala）;④较高水势、气孔导度近似关闭的马占相思（Acacia mangium）。2)在干旱胁迫过程中,主要渗透调节物质出现的先后顺序是K+、游离脯氨酸、游离氨基酸和可溶性糖, K+和可溶性糖贡献最大,分别在干旱的前后期起渗透调节作用,游离脯氨酸和游离氨基酸在干旱的中期起渗透调节作用。大多数树种适应干热河谷生境的主要抗旱途径是有效的吸水能力和完善的保水机制。 相似文献
10.
【背景】探讨入侵种假臭草不同生境下气孔的变化规律,揭示假臭草种群在不同生境下所采取的生长对策及适应机制,可为入侵生物的防治提供参考。【方法】采取光学显微镜系统观察桉树林、木薯地、弃耕地、公路边4种生境下假臭草叶片的气孔特征。【结果】光照和土壤肥、水条件对假臭草叶片的气孔孔径（横轴方向和纵轴方向）、单个气孔器面积、气孔器总面积、气孔密度及气孔指数的影响显著。低光照及肥沃、湿润土壤生境与高光照及贫瘠、干旱土壤相比,假臭草的气孔孔径（横轴方向和纵轴方向）、单个气孔器面积、气孔器总面积较大,气孔密度及气孔指数较小。【结论与意义】假臭草叶片气孔特征表现可塑性,说明其对异质环境具有一定的生态适应能力。 相似文献
11.
Zhaozhong Feng Patrick Büker Håkan Pleijel Lisa Emberson Per Erik Karlsson Johan Uddling 《Global Change Biology》2018,24(1):78-84
Tropospheric ozone is considered the most detrimental air pollutant for vegetation at the global scale, with negative consequences for both provisioning and climate regulating ecosystem services. In spite of recent developments in ozone exposure metrics, from a concentration‐based to a more physiologically relevant stomatal flux‐based index, large‐scale ozone risk assessment is still complicated by a large and unexplained variation in ozone sensitivity among tree species. Here, we explored whether the variation in ozone sensitivity among woody species can be linked to interspecific variation in leaf morphology. We found that ozone tolerance at the leaf level was closely linked to leaf dry mass per unit leaf area (LMA) and that whole‐tree biomass reductions were more strongly related to stomatal flux per unit leaf mass (r2 = 0.56) than to stomatal flux per unit leaf area (r2 = 0.42). Furthermore, the interspecific variation in slopes of ozone flux–response relationships was considerably lower when expressed on a leaf mass basis (coefficient of variation, CV = 36%) than when expressed on a leaf area basis (CV = 66%), and relationships for broadleaf and needle‐leaf species converged when using the mass‐based index. These results show that much of the variation in ozone sensitivity among woody plants can be explained by interspecific variation in LMA and that large‐scale ozone impact assessment could be greatly improved by considering this well‐known and easily measured leaf trait. 相似文献
12.
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。 相似文献
13.
Isoprene and nitric oxide (NO) are two volatile molecules that are produced in leaves. Both compounds were suggested to have an important protective role against stresses. We tested, in two isoprene-emitting species, Populus nigra and Phragmites australis, whether: (1) NO emission outside leaves is measurable and is affected by oxidative stresses; and (2) isoprene and NO protect leaves against oxidative stresses, both singularly and in combination. The emission of NO was undetectable, and the compensation point was very low in control poplar leaves. Both emission and compensation point increased dramatically in stressed leaves. NO emission was inversely associated with stomatal conductance. More NO was emitted in leaves that were isoprene-inhibited, and more isoprene was emitted when NO was reduced by NO scavenger c-PTIO. Both isoprene and NO reduced oxidative damages. Isoprene-emitting leaves which were also fumigated with NO, or treated with NO donor, showed low damage to photosynthesis, a reduced accumulation of H(2)O(2) and a reduced membrane denaturation. We conclude that measurable amounts of NO are only produced and emitted by stressed leaves, that both isoprene and NO are effective antioxidant molecules and that an additional protection is achieved when both molecules are released. 相似文献
14.
Alessandro Anav Qiang Liu Alessandra De Marco Chiara Proietti Flavia Savi Elena Paoletti Shilong Piao 《Global Change Biology》2018,24(1):235-248
Plant phenology plays a pivotal role in the climate system as it regulates the gas exchange between the biosphere and the atmosphere. The uptake of ozone by forest is estimated through several meteorological variables and a specific function describing the beginning and the termination of plant growing season; actually, in many risk assessment studies, this function is based on a simple latitude and topography model. In this study, using two satellite datasets, we apply and compare six methods to estimate the start and the end dates of the growing season across a large region covering all Europe for the year 2011. Results show a large variability between the green‐up and dormancy dates estimated using the six different methods, with differences greater than one month. However, interestingly, all the methods display a common spatial pattern in the uptake of ozone by forests with a marked change in the magnitude, up to 1.9 TgO3/year, and corresponding to a difference of 25% in the amount of ozone that enters the leaves. Our results indicate that improved estimates of ozone fluxes require a better representation of plant phenology in the models used for O3 risk assessment. 相似文献
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Y. Hoshika M. Watanabe E. Carrari E. Paoletti T. Koike 《Plant biology (Stuttgart, Germany)》2018,20(1):20-28
- Stomatal ozone flux is closely related to ozone injury to plants. Jarvis‐type multiplicative model has been recommended for estimating stomatal ozone flux in forest trees. Ozone can change stomatal conductance by both stomatal closure and less efficient stomatal control (stomatal sluggishness). However, current Jarvis‐type models do not account for these ozone effects on stomatal conductance in forest trees.
- We examined seasonal course of stomatal conductance in two common deciduous tree species native to northern Japan (white birch: Betula platyphylla var. japonica ; deciduous oak: Quercus mongolica var. crispula ) grown under free‐air ozone exposure. We innovatively considered stomatal sluggishness in the Jarvis‐type model using a simple parameter, s , relating to cumulative ozone uptake (defined as POD : phytotoxic ozone dose).
- We found that ozone decreased stomatal conductance of white birch leaves after full expansion (?28%). However, such a reduction of stomatal conductance by ozone fell in late summer (?10%). At the same time, ozone reduced stomatal sensitivity of white birch to VPD and increased stomatal conductance under low light conditions. In contrast, in deciduous oak, ozone did not clearly change the model parameters.
- The consideration of both ozone‐induced stomatal closure and stomatal sluggishness improved the model performance to estimate stomatal conductance and to explain the dose–response relationship on ozone‐induced decline of photosynthesis of white birch. Our results indicate that ozone effects on stomatal conductance (i.e . stomatal closure and stomatal sluggishness) are crucial for modelling studies to determine stomatal response in deciduous trees, especially in species sensitive to ozone.
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Knowledge of responses of photosynthesis, respiration, and stomatal conductance to cumulative ozone uptake (COU) is still scarce, and this is particularly the case for adult trees. The effect of ozone (O(3)) exposure on trees was examined with 60-year-old beech trees (FAGUS SYLVATICA) at a forest site of southern Germany. Trees were exposed to the ambient O(3) regime (1 x O(3)) or an experimentally elevated twice-ambient O(3) regime (2 x O(3)). The elevated 2 x O (3) regime was provided by means of a free-air O(3) canopy exposure system. The hypotheses were tested that (1) gas exchange is negatively affected by O(3) and (2) the effects of O(3) are dose-dependent and thus the sizes of differences between treatments are positively related to COU. Gas exchange (light-saturated CO(2) uptake rate A(max), stomatal conductance g (s), maximum rate of carboxylation Vc (max), ribulose-1,5-bisphosphate turnover limited rate of photosynthesis J (max), CO(2) compensation point CP, apparent quantum yield of net CO(2) uptake AQ, carboxylation efficiency CE, day- and nighttime respiration) and chlorophyll fluorescence (electron transfer rate, ETR) were measured IN SITU on attached sun and shade leaves. Measurements were made periodically throughout the growing seasons of 2003 (an exceptionally dry year) and 2004 (a year with average rainfall). In 2004 Vc(max), J(max), and CE were lower in trees receiving 2 x O(3) compared with the ambient O(3) regime (1 x O(3)). Treatment differences in Vc (max), J (max), CE were rather small in 2004 (i.e., parameter levels were lower by 10 - 30 % in 2 x O(3) than 1 x O(3)) and not significant in 2003. In 2004 COU was positively correlated with the difference between treatments in A (max), g (s), and ETR (i.e., consistent with the dose-dependence of O(3)'s deleterious effects). However, in 2003, differences in A(max), g (s), and ETR between the two O(3) regimes were smaller at the end of the dry summer 2003 (i.e., when COU was greatest). The relationship of COU with effects on gas exchange can apparently be complex and, in fact, varied between years and within the growing season. In addition, high doses of O(3) did not always have significant effects on leaf gas exchange. In view of the key findings, both hypotheses were to be rejected. 相似文献
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近地层臭氧(O3)已严重威胁到作物生产,而施肥可以调节土壤的养分平衡,进而促进作物生长。以两个水稻品种(徽两优898和南粳9108)为研究对象,利用开顶式气室,设置2个O3浓度处理(NF:环境大气为对照;NF40:环境大气+40 nmol/mol O3),每个O3处理下嵌套设置3个肥料处理(Ino:施无机肥处理,270 kg N hm-2 a-1;Red:减施无机肥30%处理,189 kg N hm-2 a-1;Com:有机无机肥配施处理,Red+有机肥鸡粪5000 kg hm-2 a-1),通过测定不同生育期水稻光合参数,探究不同肥料处理下O3对水稻不同生育阶段光合生理的影响。结果表明,NF40对水稻营养生长阶段的饱和光合速率(Asat)没有显著影响,而显著地降低了水稻灌浆期的Asat。基于两个水稻品种的Asat和相对叶绿素含量(SPAD)相对减少量与O3累积剂量关系的斜率,发现杂交稻徽两优898(Asat和SPAD的斜率:-1.55和-0.98)比常规稻南粳9108(Asat和SPAD的斜率:-0.92和0.06)对O3更敏感。此外,基于不同O3处理下水稻的气孔导度(gs)和胞间二氧化碳浓度(Ci),可以看出O3造成南粳9108光合速率降低的主要是非气孔因素,而徽两优898光合的降低是由气孔因素和非气孔因素共同限制。与Ino处理相比,Red处理主要通过降低叶片SPAD进而显著地抑制两种水稻品种的Asat,但Ino处理和Com处理间Asat没有显著差异,说明有机无机肥配施能部分缓解减施无机肥造成水稻光合的降低。O3和肥料处理对两个水稻的所有光合参数都没有显著的交互影响,表明短期有机无机肥配施并不能有效缓解O3对作物造成的负面影响。在O3污染背景下,研究结果可以为通过合理的农田氮肥管理措施减缓O3造成的作物减产提供理论依据。 相似文献