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REGULATION OF ISOPRENE EMISSION RESPONSES TO RAPID LEAF TEMPERATURE FLUCTUATIONS
Citation:
Singsaas, E. L. AND T. D. Sharkey. REGULATION OF ISOPRENE EMISSION RESPONSES TO RAPID LEAF TEMPERATURE FLUCTUATIONS. PLANT, CELL, AND ENVIRONMENT. Blackwell Science, Oxford, 21(11):1181-1188, (1998).
Description:
Isoprene emission from leaves is temperature dependent and may protect them from damage at high temperatures. We measured the temperature of white oak (Quercus alba L.) leaves at the top of the canopy. The largest changes in leaf temperature were associated with changes in solar radiation. During these episodes leaf temperature changed with a 1 min time constant. We imposed leaf temperature fluctuations to study their effect on isoprene emission. Leaf temperature changed with a 16 s time constant; isoprene responded more slowly with a 37 s time constant. This time constant was slow enough to cause a lag in isoprene emission when leaf temperature fluctuated rapidly. Isoprene emission changed quickly enough to follow the large temperature changes we saw in the oak canopy. This is consistent with our theory that isoprene functions to protect leaves from periods of high temperature. Time-constant analysis also revealed that there are two processes that cause isoprene emission to increase with leaf temperature. The fastest process is likely to reflect the influence of temperature on reaction kinetics, while the slower process may reflect the activation of an anzyme.