Persistent and advanced reddening of sweetgum leaves after major veins severing

Abstract

The effects of major veins severing on morphological and physiological features of sweetgum (Liquidambar styraciflua L.) leaves were investigated by observing leaf color change and measuring leaf temperature, green/luminance (G/L) value of half-lobes, leaf stomata conductance, and water content in Yamaguchi University, Japan. The palmately veined leaves of sweetgum (Liquidambar styraciflua L.) were found more sensitive to the major vein severing than that of other species.Major veins severing resulted in serious water stresses, as indicated by the persistent reddening and/or advanced reddening of local leaf, lower leaf stomatal conductance, and higher leaf temperature, etc. Severed leaf can be clearly divided into non-severed area, transitional area, and stressed area, which the three areas have different colours and temperature. The major vein barrier can also be seen clearly. The persistent reddening and advanced reddening seem consistent with the phenomenon of red crown top of some sweetgum trees and may have similar mechanism.