共查询到18条相似文献，搜索用时 968 毫秒
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以天山地区收集的600个无性系中优选得到的18个新疆野苹果无性系为试材,在生长季节采用Li-6400XT光合仪和Porket PEA高速连续激发式荧光仪对各无性系光合和叶绿素荧光参数进行了动态变化测定和分析。结果表明:不同月份影响光合的主导因素存在差异,6月份影响净光合速率(Pn)的主导因素为气孔导度(Gs),7、8月份均为胞间CO2浓度(Ci),9月份影响Pn的主导因子为蒸腾速率(Tr)、Gs,10月份Tr、Gs、Ci对Pn的影响因差异不明显;叶绿素荧光年动态分析表明,初始荧光(Fo)、最大荧光(Fm)、最大荧光发出时间(Tfm)、单位面积的热耗散(DIO/CSO)、单位面积反应中心的数量(RC/CSO)、单位面积为基础的性能指数(PIcs)、荧光诱导曲线和F=Fm之间的面积(Area)均与Pn达到极显著相关水平,说明光化学反应对Pn的影响较大。不同月份间光合速率差异不显著;无性系间存在显著差异,1号无性系年平均光合速率显著高于其它无性系。 相似文献
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几个三角梅品种光合作用日变化的比较研究 总被引：1，自引：0，他引：1
运用美国产CI-340便携式光合测定系统和OS1-FL便携式叶绿素荧光仪,比较研究了5个三角梅品种的光合作用日变化特征,包括净光合速率、光合有效辐射、温度、空气湿度、大气二氧化碳浓度、蒸腾速率、气孔导度、叶间二氧化碳浓度等因子及叶绿素荧光动力学参数。结果表明:不同三角梅品种的光合速率日变化都呈现不对称的双峰曲线,有明显的"午休"现象;气孔导度、蒸腾速率和净光合速率变化均成正相关,影响三角梅光合速率下降的主要因素是气孔限制。荧光动力学参数变化表明,5个品种光合作用器官在中午光强和温度较高下其光合活性受到了暂时的抑制,光合器官并没有受到损伤,随着光强和温度的下降其光合功能得到恢复,说明这些三角梅品种能较好地适应强光辐射及高温栽培条件,品种之间差异不明显。 相似文献
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强光胁迫下外源NO对霍山石斛叶绿素荧光和抗氧化系统的影响 总被引：5，自引：1，他引：4
以兼性景天酸代谢(CAM)植物霍山石斛为材料,研究强光胁迫条件下,外源NO对其叶绿素荧光和抗氧化系统的影响。结果表明： 0. 1 mmol·L-1硝普钠(SNP)处理提高了石斛光合系统Ⅱ(PSⅡ)的光能转换效率和潜在活性,增加了过剩光能的非光化学耗散,缓解了光抑制的发生,同时通过增强抗氧化系统的活性氧清除能力,有效保护了光合机构免受强光胁迫的伤害,PSⅡ反应中心得以较快恢复。而经0.5 mmol·L-1SNP处理后,霍山石斛的光能转换系统未能通过有效的光能转换和非光化学反应耗散过剩的光能,降低了抗氧化系统中SOD、POD和CAT的活性,加剧了PSⅡ反应中心光抑制的发生。 相似文献
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为了探讨赤霉素(GA)对黄瓜在根区亚低温下氮(N)吸收和代谢的影响机理,以营养液栽培的‘中农26’黄瓜为试材,研究了外源GA对黄瓜在根区亚低温下叶片叶绿素荧光参数、光合参数和碳(C)、氮代谢平衡调节酶活性的影响。结果表明:与根区适温处理相比,根区亚低温使黄瓜幼苗生长受抑,叶片光系统Ⅱ(PSⅡ)的光化学活性、光合放氧速率、净光合速率(Pn)、磷酸烯醇式丙酮酸羧化酶(PEPCase)和蔗糖磷酸合成酶(SPS)活性等降低,单株C与N积累量的比值(C/N)升高,N代谢消耗的能量减少。外源GA处理缓解了根区亚低温对黄瓜生长的抑制,使PSⅡ光化学活性、光合放氧速率、Pn、PEPCase和SPS活性都有不同程度的提高,C/N值和N代谢消耗的能量恢复至与根区适温处理相当的水平。表明,外源GA可以通过增强光能捕获和CO_2同化能力,调节N、C代谢平衡,促进根区亚低温下黄瓜对N的吸收与代谢。 相似文献
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以南京师范大学植物园生长的7a生银杏苗木为试材,选择银杏植株当年生新梢叶片和同株多年生枝条叶片为研究对象,分别测定了新梢叶片与老枝叶片叶绿素含量、光合及荧光参数,研究了银杏新梢叶片的光合特性.结果表明:与老枝叶片相比,银杏新梢叶片叶绿素a、b含量相对低,但是Chl a/b的比值较高;新梢叶片的净光合速率(Pn)比老枝高,光合日变化显示新梢和老枝叶片具有光合“午休”现象,主要原因是气孔因素导致;叶绿素荧光方面表现为,新梢叶片具有更高的最大光化学效率(Fv/Fm)和PSⅡ潜在活性(Fv/Fo). 相似文献
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This paper analyses the effect of different air temperatures (10, 20 and 30 °C) on the response of sweet pepper plants (Capsicum annuum L. cv. Herminio) to foliar urea applications after growing plants for 20 day with and without nitrogen (N) applied to the growing substrate. Leaf CO2 assimilation, chlorophyll fluorescence, root respiration, lipid peroxidation and antioxidative enzymes were analysed. Spraying plants with urea increased leaf CO2 assimilation of N-deficient plants when applied at 20 or 30 °C, compared with non-sprayed plants. When plants were sprayed with urea at 10 °C chlorophyll fluorescence of leaves was similar to that of plants that were supplied with full N in the nutrient solution. Root respiration was not affected by urea sprays whilst leaf NO3− concentration was increased by urea but only when it was sprayed at 10 or 20 °C. Lipid peroxidation and ascorbate peroxidase in N-deficient plants were reduced significantly by urea sprays, especially when plants were sprayed at 20 °C with N-limitation in the growing substrate. This study shows that N-limitation in the growing substrate induces a temperature-dependant increase in the activities of antioxidant enzymes in leaves of pepper and applications of foliar urea can be optimised, when applied at the appropriate temperature, to partly replace the N supplied to the roots of sweet pepper. 相似文献
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N. T. Welander O. Hellgren 《The Journal of Horticultural Science and Biotechnology》2013,88(2):279-286
SummaryNet photosynthesis, dark respiration and chlorophyll content were studied in plants of Codiaeum when transferred” from a glasshouse to photon flux densities 6, 18, or 66 μE m?2s?1 in growth rooms. The diurnal patterns of daily net photosynthesis and dark respiration were recorded during the first 12 days and 3, 7, 11 and 19 weeks after the transfer. Only plants transferred to 66 μE m?2s?1 reached a positive total net photosynthesis per day within the first 12 days. This was achieved only between the 12th day and 3 weeks when transferred to 6 μE m?2s?1. The rate of net photosynthesis increased until the 11th week and then declined, while dark respiration decreased until the 11th week and then increased. The diurnal patterns of net photosynthesis and dark respiration changed significantly with time of acclimatization. The rate of change in daily net photosynthesis and dark respiration was highest in the plants transferred to the lowest photon flux density. Changes in chlorophyll content of the leaves were similar to those in net photosynthesis. 相似文献
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冬、春田间枇杷叶片光合机构的运转 总被引：13，自引：0，他引：13
冬季枇杷光合作用的最适温度低于春季,光合作用的最适叶温高于环境温度;冬季枇杷的叶绿素含量、净光合速率(Pn)、Rubisco活性、RuBP再生速率、表观量子效率(AQY)、PSⅡ最大光化学效率(Fv/Fm)、光下的光化学效率(Fv'/Fm')、光化学猝灭系数(qP)及电子传递速率较低,PSⅡ反应中心失活或破坏,细胞间隙CO2浓度与环境CO2浓度比值(Ci/Ca)、光呼吸速率与净光合速率比值(Rp/Pn)、光呼吸速率与暗呼吸速率的比值(Rp/Rd)及非光化学猝灭系数(qN)较高。这些结果说明,枇杷光合作用的最适温度与环境温度的变化相适应,低温环境是限制枇杷光合作用的重要因子;光合碳代谢和光化学反应受到低温的限制是冬季光合作用较低的重要原因;在碳代谢中光呼吸所占的比例增加和非辐射能量耗散对光合机构运转有保护作用。 相似文献
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Gas exchange and chlorophyll fluorescence quenching analysis were carried out to investigate the diurnal variations in photosynthesis and light allocation in leaves of soybean. Leaf net CO2 assimilation rate showed a bimodal diurnal pattern and midday depression of CO2 assimilation was observed at 13:00 h. Depression in CO2 assimilation at midday was mostly attributed to non-stomatal limitation since the reduction in net CO2 assimilation rate was not followed by significant reductions in stomatal conductance and intracellular CO2 concentration. Midday depression in CO2 assimilation was found to be associated with reversible inactivation of photosystem II reaction centers and increases of antenna heat dissipation and photorespiration in response to the high light intensity. It is likely that PS II down-regulation, heat dissipation and photorespiration co-operated together to prevent the chloroplast from photodamage. 相似文献
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利用叶绿素荧光预测水蜜桃果实冷害研究 总被引：1，自引：0，他引：1
采用叶绿素荧光技术检测冷藏条件下水蜜桃冷害发生进程中初始荧光（Fv）、最大荧光（Fm）、可变荧光（Fv = Fm/Fo）、光化学效率（Fv/Fm）等叶绿素荧光动力学参数的变化,分析了叶绿素荧光参数与果肉出汁率的相关性以及与呼吸作用的关系。研究结果发现,在冷藏过程中,叶绿素荧光参数都呈下降趋势,冷害发生以后,Fm和Fv/Fm下降速度加快,而中途加温处理能够缓解Fm和Fv/Fm降低。同时,Fm和Fv/Fm与果肉出汁率之间存在显著的正相关,利用测定Fm和Fv/Fm能够初步预测冷害的发生情况。 相似文献