Using chlorophyll fluorescence to assess the fraction of absorbed light allocated to thermal dissipation of excess excitation
Using chlorophyll fluorescence to assess the fraction of absorbed light allocated to thermal dissipation of excess excitation
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DOI：
10.1034/j.1399-3054.1996.980206.x
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发表时间：
1996-10-01
影响因子：
6.4
通讯作者：
Verhoeven, AS
中科院分区：
文献类型：
--
作者：
DemmigAdams, B;Adams, WW;Verhoeven, AS
在本研究中，我们探讨了评估分配的可能性光系统II（PSII）天线吸收的光子的热能耗散和光合电子传递在几种植物叶片在田间条件下。叶绿素荧光参数的变化进行了测定，在现场的一整天的过程中，在阳光照射的两个物种的叶片具有不同的最大光合速率，向日葵（向日葵）和向日葵主要。还监测了生长在深阴影位置的小红花（长春花）的叶。我们建议使用这些阳光和阴影叶片中开放的PSII中心效率（F-v '/F-m'）的日变化来（a）评估吸收光分配到光化学和热能耗散的日变化，此外，（B）估计热能耗散速率的变化，这是一个类似于光化学速率的表达式。建议由D = 1-F-v ′/F-m ′估算PSII天线中吸收的热耗散的光的分数（D），类似于广泛使用的由P = F-v ′/F-m ′ × q（P）估算PSII光化学中利用的PSII天线中吸收的光的分数（P）（其中q（P）是光化学猝灭的系数; Genty，B.，Briantais，J. M. & Baker，N. R. 1989.生物化学生物Biophys. Acta 990：87-92）。因此，热耗散速率由D × PFD（光子通量密度）给出，再次类似于光化学速率P × PFD，两者都假设光系统I和II的匹配行为。从开放的PSII中心的效率的能量耗散的表征允许在一天中的任何时间从一组测量的评估，这是特别有用的，在现场条件下，完全放松的参考值的变量或最大荧光所需的计算nonphotochemical淬火可能无法使用。与其他目前使用的参数来量化非光化学和光化学叶绿素荧光猝灭的有用性进行比较，上述评估。
In the present study we explored the possibility of assessing the allocation of photons absorbed by photosystem II (PSII) antennae to thermal energy dissipation and photosynthetic electron transport in leaves of several plant species under field conditions. Changes in chlorophyll fluorescence parameters were determined in situ over the course of an entire day in the field in sun-exposed leaves of two species with different maximal rates of photosynthesis, Helianthus annuus (sunflower) and Vinca major. Leaves of Vinca minor (periwinkle) growing in a deeply shaded location were also monitored. We propose using diurnal changes in the efficiency of open PSII centers (F-v'/F-m') in these sun and shade leaves to (a) assess diurnal changes in the allocation of absorbed light to photochemistry and thermal energy dissipation and, furthermore, (b) make an estimate of changes in the rate of thermal energy dissipation, an analogous expression to the rate of photochemistry. The fraction of light absorbed in PSII antennae that is dissipated thermally (D) is proposed to be estimated from D = 1-F-v'/F-m', in analogy to the widely used estimation of the fraction of light absorbed in PSII antennae (P) that is utilized in PSII photochemistry from P = F-v'/F-m' x q(P) (where q(P) is the coefficient for photochemical quenching; Genty, B., Briantais, J.-M. & Baker, N. R. 1989. Biochim. Biophys. Acta 990: 87-92). The rate of thermal dissipation is consequently given by D x PFD (photon flux density), again in analogy to the rate of photochemistry P x PFD, both assuming a matching behavior of photosystems I and II. Characterization of energy dissipation from the efficiency of open PSII centers allows an assessment from a single set of measurements at any time of day; this is particularly useful under field conditions where the fully relaxed reference values of variable or maximal fluorescence needed for the computation of nonphotochemical quenching may not be available. The usefulness of the assessment described above is compared with other currently used parameters to quantify nonphotochemical and photochemical chlorophyll fluorescence quenching.