Data from: Photochemical and non-photochemical chlorophyll fluorescence dynamics in reproductive structures of semi-arid rangeland perennial bunchgrasses

These data were collected in a field study at the USDA-ARS Northern Great Basin Experimental Range, Oregon, USA, aimed at assessing the photochemical efficiency and ability of florets and flag leaves of two important sagebrush steppe bunchgrasses -- Crested wheatgrass (Agropyron cristatum), and Bluebunch wheatgrass (Pseudoroegneria spicata) -- to dissipate excess light energy over the 2025 plant reproductive period. Chlorophyll fluorescence measurements were made on flag leaves and distal and basal florets at night to determine dark-adapted baseline (Fo) and maximum fluorescence yields (Fm) and to calculate maximum photosystem II quantum efficiency (Fv/Fm = (Fm-Fo)/Fm). The same florets were then measured again the following morning when exposed to full incident ambient photosynthetic photon flux densities to determine light-adapted steady state fluorescence (Fs), maximum fluorescence yields (Fm') and light-adapted photosystem II quantum efficiency (PhiPSII = (Fm'-Fs)/Fs). Fs, Fm and Fm’ were used to estimate the quantum yield of non-photochemical energy loss (NPQ) in PS II that is physiologically regulated (PhiNPQ = (Fs/Fm’)-(Fs/Fm)) and unregulated (PhiNO = Fs/Fm). Data was collected five times over the entire reproductive cycle (pre-anthesis, anthesis, and post-anthesis), with concurrent average daily volumetric soil moisture at 10 cm soil depth (Vsm) from six Vsm observations made daily.

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  "005:18"
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{
  "fn": "Hamerlynck, Erik P.",
  "hasEmail": "mailto:erik.hamerlynck@usda.gov"
}

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    "title": "FPBData.xlsx",
    "format": "xlsx",
    "mediaType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
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[
  "Bluebunch wheatgrass",
  "Chlorophyll fluorescence",
  "Florets",
  "Fv/Fm",
  "PhiPSII",
  "Reproduction",
  "crested wheatgrass",
  "flag leaves",
  "non-photochemical quenching (NPQ)"
]

[
  "005:040"
]

{
  "name": "Agricultural Research Service",
  "@type": "org:Organization"
}

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