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The Influence of Temperature Upon Physiological Processes in Early-Flowering and Late-Flowering Strains of Thlaspi arvense L.
L. Hume, M. D. Devine and S. Shirriff
International Journal of Plant Sciences
Vol. 156, No. 4 (Jul., 1995), pp. 445-449
Published by: The University of Chicago Press
Stable URL: http://www.jstor.org/stable/2475062
Page Count: 5
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This study was initiated to determine net photosynthesis, respiration, and stomatal conductance for early-flowering (EF) and late-flowering (LF) strains of Thlaspi arvense L., and to determine the relative impact of temperature on these processes in the two strains. The strains have been shown to differ by a single gene. Vernalized EF and LF plants were grown under controlled environments at day temperatures of 15⚬C, 20⚬C, and 25⚬C (16-h photoperiod) each, with 15⚬C nights. During the period of floral initiation for the EF strain, net photosynthesis, respiration, and stomatal conductance were determined in both strains. Plants of the LF strain had higher net photosynthesis rates and lower respiration rates. Net photosynthesis was most efficient at 20⚬C days, while respiration rates increased with increasing temperature. Stomatal conductance was greater in the EF strain, which also had larger stomata than plants of the LF strain. Generally, EF plants grew more quickly in terms of shoot dry weight than LF plants. However, at 25⚬C, the LF plants had significantly more shoot dry weight. We suggest that differential net photosynthesis and respiration rates of the EF and LF strains of T. arvense may influence the relative amounts of carbohydrates and nitrogen available to the shoot apices and therefore affect the time to floral transition.
International Journal of Plant Sciences © 1995 The University of Chicago Press