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Rapid Determination of Chloride Content of Vegetation for Assessment of Air Pollution Injury from Hydrogen Chloride. D. S. Shriner, Graduate Assistant, Department of Plant Pathology, The Pennsylvania State University, University Park 16802, Present address of senior author: 5204 Boulder Road, Frederick, Maryland 21701; N. L. Lacasse, Assistant Professor, Department of Plant Pathology, The Pennsylvania State University, University Park 16802. Phytopathology 62:427-429. Accepted for publication 9 November 1971. DOI: 10.1094/Phyto-62-427.

Twenty-eight-day-old tomato plants (Lycopersicon esculentum ‘Bonny Best’) and rooted cuttings of chrysanthemums (Chrysanthemum morifolium ‘Neptune’) were exposed to hydrogen chloride (HCl) gas at concentrations ranging from 2 to 18 ppm for time periods ranging from 1 to 3 hr. Relative humidity of the exposure environment was maintained between 65 and 75%, and a light irradiance of 3.9 × 10⁴ ergs/cm² per sec was provided. Water extracts of macerated plant tissues were titrated with a chloridometer. Large increases in chloride content were recorded for all aboveground parts of fumigated plants as compared to control plants and plant parts. Greatest increases in tomato occurred in those leaves which were not yet fully expanded. Greatest increases in chrysanthemum occurred in immature upper leaves. The pattern of the uptake of chlorides in tomato and chrysanthemum is similar to that reported for fluorides. The procedure has potential usefulness as a diagnostic tool in assessment of air pollution injury from HCl gas.