Seasonal variations in the vessel size of temperate, diffuse-porous species and its relationship to leaf water potential

• Published in: Forest research, Kyoto Vol. 78; pp. 89 - 95
• Main Authors: OHASHI, Shinta, OKADA, Naoki
• Format: Journal Article
• Language: English
• Published: Field Science Education and Research Center, Kyoto University 28.09.2012
• Subjects: Annual ring; diffuse-porous wood; tree water relation; vessel size
• ISSN: 1344-4174; 2759-3134
• DOI: 10.60409/forestresearch.78.0_89

Vessel lumen area and leaf water potential (ψleaf) at predawn and midday were measured periodically to reveal seasonal variations in the vessel sizes of diffuse-porous species and to determine the factors that cause this variation. Two deciduous species (Cercidiphyllum japonicum and Liriodendron tulipifera) and one evergreen species (Quercus glauca) were studied. In most of the samples, mean vessel lumen area (MVLA) initially increased then eventually decreased after a period, but this period varied among species. In C. japonicum, the decrease in MVLA coincided with a decrease in predawn ψleaf. In contrast, MVLA variations in most samples of L. tulipifera and Q. glauca did not show such a relationship. However, one of the L. tulipifera samples had an earlier decrease in MVLA that coincided with a lower predawn ψleaf. There was no clear relationship between the variation in vessel size and midday ψleaf, because midday ψleaf showed daily variation depending on vapor pressure deficit, which had less seasonality. Thus, we concluded that there are species-specific annual patterns in vessel size variation that are likely determined by internal factors. Low water availability is one of the external factors inducing the formation of narrower vessels.