Present address: Department of Biology, Colorado State University, Fort Collins, CO 80523, USA.
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Seasonal variation in photosynthetic capacity of montane conifers
Article first published online: 8 DEC 2004
DOI: 10.1111/j.0269-8463.2004.00909.x
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How to Cite
NIPPERT, J. B., DUURSMA, R. A. and MARSHALL, J. D. (2004), Seasonal variation in photosynthetic capacity of montane conifers. Functional Ecology, 18: 876–886. doi: 10.1111/j.0269-8463.2004.00909.x
Publication History
- Issue published online: 8 DEC 2004
- Article first published online: 8 DEC 2004
- Received 13 January 2004; revised 14 June 2004; accepted 16 June 2004
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Keywords:
- chlorophyll fluorescence;
- Fv/Fm;
- model parameterization;
- temperature
Summary
- 1The capacity to perform photosynthesis, given appropriate environmental conditions, is reflected by measurements of the maximum quantum yield of photosystem II (Fv/Fm). The seasonal course of Fv/Fm may help define the length of the annual photosynthetic period in temperate evergreen forests.
- 2Fv/Fm was measured 31 times from September to May on six conifer species located along an altitudinal gradient between 400 and 1400 m a.s.l. in northern Idaho, USA. The species were Western Redcedar (Thuja plicata Donn ex D. Donn), Douglas Fir (Pseudotsuga menziesii (Beissn.) Franco), Engelmann Spruce (Picea engelmannii Parry), Grand Fir (Abies grandis (Dougl.) Lindl.), Ponderosa Pine (Pinus ponderosa Laws.) and Lodgepole Pine (Pinus contorta Dougl.).
- 3Species differed in mean Fv/Fm, in magnitude of response to maximum and minimum temperature, and in altitude effects other than temperature. For two species Fv/Fm in spring differed from that in autumn, even when measured at the same air temperature. Regardless of temperature, most species maintained some photosynthetic capacity all winter.
- 4A lag of several days to 2 months was observed in the response of Fv/Fm to ambient temperature. The lag differed among species. It was not observed in Grand Fir, and was as long as 2 months in Western Redcedar. Over all species combined the best overall correlation was with a moving average of maximum temperature over the previous 30 days.
- 5The correlation between Fv/Fm and maximum temperature was generally stronger than that with minimum temperature (average root mean-squared error was reduced by 10%), presumably because maximum temperatures better reflect daytime photoinhibitory conditions.
- 6A reduced model predicted Fv/Fm based on species and maximum temperature; this model can be used to parameterize models describing the annual cycle of photosynthetic capacity for the six conifer species included in this study.