共查询到19条相似文献，搜索用时 828 毫秒
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用光声光谱仪检测结果表明，暗适应叶在光诱导期间出现非常复杂的光声瞬态放氧，产生了一种称为氧峰(oxygengush)的现象.该文利用自制的光声仪对暗适应菠菜叶在光诱导期间出现的光声瞬态放氧与暗适应时间关系，远红光、饱和光预处理以及高浓度CO2对光声瞬态放氧的影响，光声热信号与光声放氧信号之间的关系作了初步研究.推测由两个组分组成的氧峰与其动力学可能反映光系统Ⅱ的状态. 相似文献
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fandayong@ibcas.ac.cn 《勤云标准版测试》2006,(5)
利用光声光谱技术可以精确研究暗适应叶在光诱导期间出现的放氧动态、光热动态、能量储存动态。用光声光谱技术测量了在非胁迫条件以及高CO2下暗适应叶在光诱导期间出现的光声动态,包括放氧动态,气体吸收动态,光热动态和能量储藏动态。研究发现放氧动态与叶绿素荧光曲线有一定关系。第一个放氧峰可能反映PSII的电子传递的瓶颈现象。一开始出现的能量储藏极小值可能反映了诱导期间PSI的环式电子传递或非线性电子传递。诱导期间高浓度CO2诱导产生巨大的气体吸收信号,可能各种类型的Mehler反应是其中的原因之一,另一个原因是CO2的迅速液化。 相似文献
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广州白云山主要林分的生产力及吸碳放氧研究 总被引：5，自引：0，他引：5
对广州白云山风景区主要林分类型的生产力及吸碳放氧功能进行了初步研究.各主要林分总生物量、总吸碳量和总释氧量大小顺序为木荷石栎混交林>木荷林>中华锥林>大叶相思林>马尾松林>马占相思林>黧蒴林>降真香林>尖叶杜英林>加勒比松林.各林分生产力、年均吸碳量和年均释氧量大小顺序均为马占相思林>黧蒴林>大叶相思林>木荷石栎混交林>木荷林>尖叶杜英林>中华锥林>降真香林>加勒比松林>马尾松林.表明速生阔叶林的吸碳放氧能力比针叶林强;处于速生期的阔叶树人工林的吸碳放氧能力比天然次生近熟林强. 相似文献
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氧电极测定水稻叶片光合放氧的技术探讨 总被引：3，自引：1，他引：3
自从薄膜氧电极出现后,国内外已应用于植物光合与呼吸强度的测定。我们参照有关资料,用氧电极法对水稻离体叶片的光合放氧进行了测定。发现该法具有操作简便、测定时间短,且适于对各种材料进行离体测定等优点,现将测定方法与各种因素对光合放氧的测定结果报告如下。材料与方法实验材料用盆栽水稻,品种为中粳80—4,同一处理用同一植株同位叶,在拔节期测 相似文献
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用２ｍｍｏｌ／ＬＬａＣｌ３、ＰｒＣｌ３处理菠叶片，促进新，老叶片光合放氧速率，ＬａＣｌ３的作用较为明显。０．１５ｍｍｏｌ／Ｌ的ＬａＣｌ３对光激活的Ｃａ＾＋＋－ＡＴＰ酶活性有较明显的促进作用，ＰｒＣｌ３则对光激活的Ｃａ＾＋＋－ＡＴＰ酶和ＤＴＴ激活的Ｍｇ＋＋－ＡＴＰ酶同时具有较大促进作用。 相似文献
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B型烟粉虱危害对烟草叶片光系统II的影响 总被引：1，自引：0，他引：1
【目的】研究B型烟粉虱取食危害对烟草光系统II的影响,为明确烟粉虱对寄主植物光合作用的影响机制提供依据。【方法】通过测定烟草叶片叶绿素荧光快速诱导曲线,使用JIP-test分析技术进行参数分析,研究B型烟粉虱危害烟草后对烟草的局部虫体叶和系统叶光系统II（PSII）的影响。【结果】B型烟粉虱危害烟草后虫体叶和系统叶上的最大光化学效率（φpo）和光化学性能指数（PIABS）与对照相比均明显升高（P＜0.05）,表明处理烟草植株的局部叶和系统叶的原初光化学反应受到较大的伤害。B型烟粉虱危害烟草后虫体叶和系统叶PSII反应中心的电子传递均受阻,放氧复合体受到严重破坏。B型烟粉虱危害烟草后系统叶的单位反应中心吸收的能量（ABS/RC）和单位反应中心热耗散掉的能量（DIo/RC）增加,单位反应中心捕获的能量（TRo/RC）下降;B型烟粉虱危害的虫体叶中ABC/RC没有变化,DIo/RC增加,TRo/RC 下降。B型烟粉虱危害烟草后虫体叶和系统叶的单位面积反应中心数量（RC/CS）均明显降低（P＜0.05）,而光系统PSⅡ反应中心的关闭程度（1-qP）却明显升高,分别较各自对照升高了69.83%和142.58%（P＜0.05）。【结论】B型烟粉虱的危害严重影响了烟草叶片的光系统Ⅱ（PSII）,主要是由于PSII反应中心的失活和关闭以及对PSII电子传递的抑制,电子传递中受抑制的位点包括放氧复合体和QA到QB间的电子传递过程,同时B型烟粉虱危害影响了烟草叶片光系统的能量流动,且烟粉虱对烟草叶片PSII的影响具有系统传导性。 相似文献
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钝顶螺旋藻(Spirulia platensis)经特定电磁波(简称 TDP)逐日辐射处理0.5小时,能明显增加螺旋藻的叶绿素含量,提高光合放氧速率,促进藻体生长,从而增加藻体生物产量。 相似文献
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Greenbaum E 《Science (New York, N.Y.)》1977,196(4292):879-880
A study of the absolute photoproduction of hydrogen by autotrophically grown Chlorella vulgaris with single-turnover flashes of light indicates that (i) while the Emerson and Arnold photosynthetic unit has the value chlorophyll: oxygen approximately 1700 : 1, the hydrogen analog of this unit has the value chlorophyll: hydrogen approximately 1400 : 1, and (ii) whereas the yield of oxygen from dark-adapted algal cells is zero on the first flash and then undergoes damped oscillations of period 4 about the steady-state value, the corresponding yield of hydrogen is fixed at the steady-state value from the first flash onward. These observations suggest that in the molecular mechanism of photosynthetic hydrogen evolution (i) the light reaction is at least 60 percent as efficient as the corresponding oxygen evolution reaction as measured by the ability to utilize absorbed visible quanta, and (ii) there are no sequential, photoproduced, metastable intermediates as there are in the case of oxygen evolution. Therefore, a minimum of two reducing equivalents from two different photosystems must have access to a common pool in producing molecular hydrogen if these photosystems each produce one electron per single-turnover flash. 相似文献
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Harvesting light to produce energy and oxygen (photosynthesis) is the signature of all land plants. This ability was co-opted from a precocious and ancient form of life known as cyanobacteria. Today these bacteria, as well as microscopic algae, supply oxygen to the atmosphere and churn out fixed nitrogen in Earth's vast oceans. Microorganisms may also have played a major role in atmosphere evolution before the rise of oxygen. Under the more dim light of a young sun cooler than today's, certain groups of anaerobic bacteria may have been pumping out large amounts of methane, thereby keeping the early climate warm and inviting. The evolution of Earth's atmosphere is linked tightly to the evolution of its biota. 相似文献
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氧气对蚕豆叶肉细胞光抑制现象的影响 总被引：1，自引：0，他引：1
随无CO_2细胞悬浮液中氧浓度的提高,预照强光对细胞光合碳固定活性的伤害加重。预照光光强愈高,照射时间愈长,这种伤害作用愈明显。HCO_3~-存在时,细胞的光抑制作用有一定程度的减轻。 相似文献
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The evolution of oxygenic photosynthesis and ensuing oxygenation of Earth's atmosphere represent a major transition in the history of life. Although many organisms retreated to anoxic environments, others evolved to use oxygen as a high-potential redox couple while concomitantly mitigating its toxicity. To understand the changes in biochemistry and enzymology that accompanied adaptation to O2, we integrated network analysis with information on enzyme evolution to infer how oxygen availability changed the architecture of metabolic networks. Our analysis revealed the existence of four discrete groups of networks of increasing complexity, with transitions between groups being contingent on the presence of key metabolites, including molecular oxygen, which was required for transition into the largest networks. 相似文献
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The maximum quantum yield of oxygen evolution in deuterated chlorella is found to be 0.075, while normal chlorella showed, in parallel experiments, a value of 0.10. Deuterated Chlorella vulgaris showed a decline in the quantum yield of oxygen evolution ("red drop") beginning at 680 millimicrons and a clear Emerson enhancement effect qualitatively similar to that obtained in normal chlorella cells. However, the ratio of quantumn yield at 680 to that at 710 millimicrons was about 1.5 times higher in normal than in deuterated chlorella cells. Action spectra of the Emerson enhancement effect in deuterated chlorella also are qualitatively similar to those of normal cells. 相似文献
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以自然湖泊沉积物为研究基质,利用微型电机控制溶氧微电极实现纵向精确微位移,在照光与遮光条件下,对典型湿地植物菖蒲幼苗、成株根系根基部起总根长1/4处(根1/4)、根系中部(根1/2)、从根基部起总根长3/4处(根3/4)及根尖(根1)处根系微界面径向溶氧浓度变化进行原位精确测定.结果表明:无论有无光照,菖蒲幼苗、成株根系不同部位均存在从根表面至沉积物氧饱和度由高到低的氧扩散层,其厚度0.18-0.68 mm;根1/2、3/4、1处氧扩散能力菖蒲成株较幼苗显著增强(P＜0.01),根1/4处二者则无显著差异(P＞0.05);光照对菖蒲幼苗、成株根系不同部位氧扩散能力的影响存在差异,光照对菖蒲幼苗根1/2及菖蒲成株根1/2、根3/4处影响显著(照光组显著高于遮光组,P＜0.01),而对菖蒲幼苗根1/4、根3/4、根1及菖蒲成株根1/4、根1处无显著影响(P＞0.05);从根系泌氧空间差异上看,照光条件下菖蒲幼苗、成株分别表现为根1/2＞根3/4≈根1≈根1/4 (P＜0.01,P＞0.05)和根1/2＞根3/4＞根1＞根1/4( P＜0.01),遮光条件下菖蒲幼苗、成株分别表现为根1/2≈根3/4≈根1≈根1/4( P＞0.05)和根1/2＞根3/4≈根1＞根1/4( P＜0.01,P＞0.05). 相似文献
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里塘河亚洲苦草分布特点及光照因子影响分析 总被引：1，自引：0，他引：1
2012年对上海市临港新城里塘河水体状况和亚洲苦草(Vallisneria natans)分布特点进行了调查,并研究了不同光照强度对亚洲苦草生长及光合放氧速率的影响。调查结果表明,里塘河透明度为80~100 cm,苦草生物量按生长在水深20~30 cm、30~60 cm、60~90 cm、90~120 cm 4个范围计算,随水深增加先增大后减小,其中60~90 cm水深范围内亚洲苦草生物量最大。苦草密度与水深成负相关,而平均叶长与水深呈正相关,河道近岸苦草密集,中间最深处无水草生存。室内进一步研究表明,平均每株生物量、分蘖数、平均根长、光合放氧速率均随着光照强度降低而降低(P0.01),10μmol/(m2·s)为临界光照强度,这时亚洲苦草生物量开始出现负增长,其光合放氧速率为10.52μmol/(g·h),仅为80μmol/(m2·s)光照强度组的22.79%。该研究表明河道苦草分布深度与透明度深度相一致,进一步揭示了低光条件下苦草群落难以繁殖扩散的原因。 相似文献
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The rise of oxygen over the past 205 million years and the evolution of large placental mammals 总被引：2，自引：0，他引：2
Falkowski PG Katz ME Milligan AJ Fennel K Cramer BS Aubry MP Berner RA Novacek MJ Zapol WM 《Science (New York, N.Y.)》2005,309(5744):2202-2204
On the basis of a carbon isotopic record of both marine carbonates and organic matter from the Triassic-Jurassic boundary to the present, we modeled oxygen concentrations over the past 205 million years. Our analysis indicates that atmospheric oxygen approximately doubled over this period, with relatively rapid increases in the early Jurassic and the Eocene. We suggest that the overall increase in oxygen, mediated by the formation of passive continental margins along the Atlantic Ocean during the opening phase of the current Wilson cycle, was a critical factor in the evolution, radiation, and subsequent increase in average size of placental mammals. 相似文献