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PHOTOSYNTHETIC SENSITIVITY TO TEMPERATURE IN POPULATIONS OF TWO C 4 BOUTELOUA (POACEAE) SPECIES NATIVE TO DIFFERENT ALTITUDES
Author(s) -
Bowman William D.,
Turner Lee
Publication year - 1993
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1993.tb13814.x
Subject(s) - photosynthesis , biology , bouteloua gracilis , poaceae , photosynthetic capacity , altitude (triangle) , botany , grazing , geometry , mathematics
The relationships between photosynthesis, flowering, and growth temperatures were examined experimentally in four populations of the C 4 grass genus Bouteloua. Field‐collected plants were grown under two temperature regimes, cool (20 C day/6 C night) and warm (30/16), representative of the extreme populations. Populations collected from the warm climates had significantly lower photosynthetic capacity when grown in the cool chamber relative to the warm chamber, while photosynthetic capacity in the cool climate populations did not differ between the growth conditions. Additionally, exposure to a 2‐day cold temperature treatment (10/‐2), representative of late‐season frosts in high altitude sites, resulted in further reductions in photosynthesis in the warm climate plants, but not in the cool climate plants. This effect was greater for plants grown in the cool growth chamber. Flowering was reduced by 70% in the warm climate plants grown in the cool chamber, and was correlated with photosynthetic inhibition following the short‐term cold temperature treatment. These results indicate that genetic differentiation for photosynthetic temperature sensitivity has occurred in the cool climate populations, and that long‐term exposure to cool temperatures coupled with short‐term relatively extreme low temperatures results in greater photosynthetic inhibition in nontolerant populations.