Monitoring migration and measuring biomass in benthic biofilms: the effects of dark/far-red adaptation and vertical migration on fluorescence measurements
Monitoring migration and measuring biomass in benthic biofilms: the effects of dark/far-red adaptation and vertical migration on fluorescence measurements
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DOI：
10.1023/b:pres.0000028397.86495.b5
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发表时间：
2004-07-01
影响因子：
3.7
通讯作者：
Paterson, DM
中科院分区：
文献类型：
--
作者：
Consalvey, M;Jesus, B;Paterson, DM
脉冲调制荧光已越来越多地被用作一种生态学工具，用于检查河口沉积物上层内微底栖植物细胞垂直分布的变化（最常用的是使用最小荧光量F-O），以及指示群落的健康（使用最大PS II量子效率F-v/F-m）。然而，实地测量的实用性通常要求必须使用较短的暗适应时间（类似于15分钟）。在自然迁移的底栖微植物生物膜和人工非迁移的底栖生物膜中研究了远红光作为暗适应的替代。长时间的黑暗（类似于24小时）不足以获得“真实”的F-O和F-v/F-m的测量，这需要Q(A)的完全氧化和非光化学猝灭（NPQ）的完全逆转。在某些情况下，只有使用远红光才能达到稳定值。长时间暴露于暗红光/远红光下导致细胞在自然组合中向下迁移，这可以从F-O和最大荧光产额（F-m）的降低中看出。在非迁移生物膜中，Fm在暗光和远红光处理下增加，表明NPQ逆转，而F-O在远红光下减少，但在暗光下增加。结果表明，远红光和暗光对NPQ逆转和Q(A)氧化之间的平衡有不同的影响，从而导致测量到的F-O产率。本文讨论了远红光作为暗适应的替代方法的使用，并讨论了原位使用短时间（例如15分钟）暗适应时间对沉积物生物膜内细胞垂直迁移的影响。
Pulse modulated fluorescence has increasingly been used as an ecological tool to examine changes in the vertical distribution of microphytobenthic cells within the upper layers of estuarine sediments (most often using the minimum fluorescence yield F-O) as well as to indicate the health of the community (using the maximum PS II quantum efficiency F-v/F-m). However, the practicalities of in situ measurements, often dictates that short dark adaptation periods must be used (similar to15 min). The use of far-red light as an alternative to dark adaptation was investigated in natural migratory microphytobenthic biofilms and artificial non-migratory biofilms. Prolonged periods of darkness (similar to24 h) were not adequate to achieve 'true' measurements of F-O and F-v/F-m, which require complete oxidation of Q(A) and full reversal of non-photochemical quenching (NPQ). In some instances, stable values were only achieved using far-red light. Prolonged exposure to dark/far-red light led to a downwards migration of cells in natural assemblages, as seen by a reduction in both F-O and the maximum fluorescence yield (F-m). In non-migratory biofilms, Fm increased in the dark and far-red treatments, indicating a reversal of NPQ, whereas F-O decreased in far-red light but increased in the dark. It is suggested that far-red light and darkness differentially affected the balance between NPQ reversal and Q(A) oxidation that lead to the measured F-O yield. The use of far-red light as an alternative to dark adaptation is discussed and the implications of short (e.g., 15 min) dark adaptation times used in situ are discussed with reference to the vertical migration of cells within sediment biofilms.