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Ecology and Epidemiology

Saline Aerosol: Some Effects on the Physiology of Phaseolus vulgaris. J. F. Petolino, Graduate student, Department of Plant Pathology, N. J. Agricultural Experiment Station, Rutgers University, New Brunswick, NJ 08903; I. A. Leone, professor, Department of Plant Pathology, N. J. Agricultural Experiment Station, Rutgers University, New Brunswick, NJ 08903. Phytopathology 70:229-232. Accepted for publication 16 August 1979. Copyright 1980 The American Phytopathological Society. DOI: 10.1094/Phyto-70-229.

Experiments were performed to determine some of the chemical and physiological changes accompanying exposure of bean plants (Phaseolus vulgaris ‘Topcrop’) to saline aerosol. Plants were exposed to various dosages of salt (0–150 μg Cl^–/cm²) when the primary leaves were approximately one-quarter expanded (7–8 days old). Respiration, photosynthesis, and transpiration rates were determined after salt exposure. There was an increase in the respiration rate of salted plants as compared to the unsalted controls. Photosynthesis apparently was not affected by saline aerosol when the rate of O₂ evolution was expressed on an area or a dry weight basis; however, the rate increased when expressed on a unit chlorophyll basis. Transpiration rate decreased with exposure to saline aerosol. When the primary leaves were fully expanded (15–17 days old) they were analyzed for contents of chloride, water, total nitrogen, total chlorophyll, total free amino acids, soluble sugar, and starch. The chloride content increased linearly with increased exposure. Water content per unit area or per unit fresh weight increased upon exposure to salt although the relative turgidity of the tissue did not change. As the chloride content increased, the total nitrogen content decreased. Chlorophyll and amino acid contents increased until symptoms appeared, then they decreased. With increased exposure to salt total soluble sugar content increased, but there was no significant change in the starch content of the leaves.