Effect of leaf surface wetness and wettability on photosynthesis in bean and pea |
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Authors: | Y. T. HANBA,A. MORIYA,& K. KIMURA |
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Affiliation: | Research Institute for Bioresources, Okayama University, Kurashiki 710–0046, Japan |
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Abstract: | Leaf surface wetness that occurs frequently in natural environments has a significant impact on leaf photosynthesis. However, the physiological mechanisms for the photosynthetic responses to wetness are not well understood. The responses of leaf CO2 assimilation rate (A) to 72 h of artificial mist of a wettable (bean; Phaseolus vulgaris) and a non‐wettable species (pea; Pisum sativum) were compared. Stomatal and non‐stomatal limitations to A were investigated. A 28% inhibition of A was observed in the bean leaves as a result of a 16% decrease in stomatal conductance and a 55% reduction in the amount of Rubisco. The decrease of Rubisco was mainly due to its partial degradation. In contrast to the bean leaves, a 22% stimulation of A was obtained in the 72 h mist‐treated pea leaves. Mist treatment increased stomatal conductance by 12.5% and had no effect on the amount of Rubisco. These results indicated that a positive photosynthetic response to wetness occurred only in non‐wettable species and is due to the change in stomatal regulation. |
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Keywords: | Phaseolus vulgaris Pisum sativum CO2 assimilation rate internal conductance Rubisco degradation stomatal conductance vapour pressure deficit |
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