Saline Aerosol: Some Effects on the Physiology ofPhaseolus vulgaris

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Abstract
Experiments were performed to determine some of the chemical and physiological changes accompanying exposure of bean plants (P. vulgaris ''Topcrop'') to saline aerosol. Plants were exposed to various dosages of salt (0-150 .mu.g 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; 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 N, 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 N 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.