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United States Department of Agriculture

Agricultural Research Service

Title: Variation of Photosynthetic Quantum Yield in Ecophysiological Studies

Authors
item Singsaas, E - PLANT BIOLOGY UOFI URBANA
item Ort, Donald
item Delucia, E - PLANT BIOLOGY UOFI URBANA

Submitted to: Oecologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 16, 2000
Publication Date: N/A

Interpretive Summary: While low genetic variability in the intrinsically high efficiency of photosynthesis in herbaceous crop plants is well established, many published reports of low and highly variably efficiencies in natural habitats suggest that there may be a fundamental difference between wild and cultivated species. Using a consistent set of state-of-the-art techniques we measured photosynthetic efficiencies in various wild species as well as critically assessed the data and techniques from published studies. Our work shows that when measured properly, non-stressed wild species have the same invariantly high photosynthetic efficiency as common cultivated crop plant species. This work points out important experimental deficiencies in a substantial body of work relevant to the areas of forestry and conservation biology and challenges a long held and erroneous premise about photosynthetic efficiency of wild species.

Technical Abstract: Photosynthetic efficiency is often quantified as the maximum, or light-limited, quantum yield in ecophysiological studies. Four comparative studies have found that photosynthetic efficiency varies little between plant species of widely diverse origins, and quantum yields were near the maximum attainable value calculated from theory. However, we have found examples in the literature which contradict with this conclusion, reporting quantum yields as low as 30 percent of those found in the comparative studies. This has been interpreted in some cases to mean that certain plants, particularly wild plants growing outdoors, may have intrinsically low photosynthetic efficiencies. In response to this, we compiled quantum yield data from a survey of thirty papers and compared those with data from two comparative quantum yield studies. We also included quantum yield observations we made on ten species. We conclude that many quantum yield values reported in the literature are affected by one or more of these errors, and the intrinsic efficiency of photosynthesis is invariant among plants. This emphasizes the importance of the measurement and data analysis protocols in obtaining accurate and reliable quantum yield data.

Last Modified: 12/20/2014
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