Seasonal changes in the relationship between photochemical reflectance index and photosynthetic light use efficiency of Japanese larch needles

Abstract

We investigated seasonal changes in the photochemical reflectance index (PRI) and its relation to the diurnal profile of photosynthetic light use efficiency (LUE) in mature Japanese larch (Larix kaempferi Sarg.) forest throughout the growing season from June to October 2003. The daily mean value of needle PRI showed seasonal variation, strongly correlated with the chlorophyll concentration and carotenoid/chlorophyll ratio of the needles. During the green period from early June to late September, the hourly values of both PRI and LUE showed significant midday depression, and were positively correlated. In late October, however, because the PRI of yellowing needles tended to increase slightly at midday in contrast to the LUE, this correlation became negative. Even before autumn senescence, the sensitivity of PRI to LUE changed with the season. Correlation analysis indicated that the slope and intercept of the regression line of the PRI-LUE relationship increased during summer, with peaks in July and August, respectively. The seasonal change in slope was strongly correlated with the foliar photosynthetic pigment concentration, nitrogen concentration, air temperature and the daily mean value of the normalized difference vegetation index (NDVI). The value of the intercept was positively correlated with the daily mean PRI. These results suggest that although diurnal change in LUE cannot be estimated quantitatively from PRI on its own throughout the growing season, the combined use of PRI and other variables such as foliar pigments or NDVI could improve the remote evaluation of seasonal changes in LUE of deciduous tree leaves.

Gross primary production estimation from MODIS data with vegetation index and photosynthetically active radiation in maize

“…Results indicated that the LUE could be estimated by spectral VIs [e.g., photochemical reflectance index, normalized difference spectral index in bands 710 and 410 nm (NDSI [710,410] ), and Medium Resolution Imaging Spectrometer terrestrial chlorophyll index] derived from in situ measurements [Gamon et al, 1997;Nakaji et al, 2006;Inoue et al, 2008;Wu et al, 2009], airborne optical remote-sensing systems [Nichol et al, 2000], and spaceborne satellite observations [Drolet et al, 2005]. These results demonstrated that certain indices could be reliable proxies of LUE.…”

Parallel Seasonal Patterns of Photosynthesis, Fluorescence, and Reflectance Indices in Boreal Trees

“…The initial fall decrease in the PRI to values lower than the normal winter background may have been attributed to the breakdown of chlorophyll during senescence [43]; the more rapid breakdown of chlorophylls than carotenoids during senescence [44] alters chlorophyll/carotenoid ratios, to which the PRI is sensitive. The lower values of the PRI seen in L. laricina during winter periods compared to the broad-leaf deciduous species was likely due to the persistence of leaf litter on the top of the pots following senescence, causing lower values than was seen with bare soil.…”

Response of green reflectance continuum removal index to the xanthophyll de-epoxidation cycle in Norway spruce needles

“…A strong PRI 70 reduction was observed simultaneously with severe LUE reduction during midday in 71 long-living and slow-growing evergreens having a higher maximal capacity for 72 flexible thermal dissipation due to a higher VAZ pigment possession (Peñuelas et al, 73 1995;Peguero-Pina et al, 2008). On the other hand, several studies applying PRI at 74 canopy level showed that the relationship between photosynthetic efficiency and PRI 75 is inconsistent over time, likely due to the changes in foliar pigment content and 76 canopy architecture changing ratio between sunlit and shaded leaves (Barton and 77 North, 2001;Filella et al, 2004).…”

“…On the other hand, several studies applying PRI at 74 canopy level showed that the relationship between photosynthetic efficiency and PRI 75 is inconsistent over time, likely due to the changes in foliar pigment content and 76 canopy architecture changing ratio between sunlit and shaded leaves (Barton and 77 North, 2001;Filella et al, 2004). It has been shown that the degradation of foliar 78 chlorophylls generally reduces PRI as a result of the relative reflectance increase at 79 570 nm (Moran et al, 2000;Nakaji et al, 2006;Sims and Gamon, 2002). This PRI 80 dependency on foliage chlorophyll content and on the chlorophyll/carotenoids ratio 81 (Chl a+b/ Car x+c) was eventually used to track seasonal alterations in 82 photosynthetic activity (Filella et al, 2009;Stylinski et al, 2002).…”