THE USE OF CHLOROPHYLL FLUORESCENCE TO IDENTIFY CHEMICAL AND ENVIRONMENTAL STRESS IN LEAF TISSUE OF THREE OAK (QUERCUS) SPECIES
Glynn C. Percival
Abstract: During their lifetime, urban trees are susceptible to a range of environmental and chemical stresses that can result in tree decline. Chlorophyll fluorescence has been used as a nondestructive and noninvasive means of quantifying damage to the leaf photosynthetic system of deciduous and evergreen trees. Aims of this investigation were to determine whether there were unique chlorophyll fluorescence profiles for different chemical (salt, herbicide) and environmental (heat) stresses in leaf tissue of three oak (Quercus) species. Results demonstrate that alterations in the OJIP curve as a measure of electron transport within the leaf plastoquinone pool of photosystem II could be used to identify tree decline due to herbicide and heat but not to salt damage. The benefits of this system to make rapid, stress-specific diagnosis in the field for professionals involved in urban tree management are discussed.
Keywords: English oak; evergreen oak; heat; herbicide; leaf tissue damage; red oak; salinity; stress detection; Quercus ilex; Quercus robur; Quercus rubra.