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Irrigating one-year-old sour orange seedlings in black polyethylene bags containing a clay-loam soil with saline water (up to 4500 p.p.m. salt (NaCl + CaCl2)) reduced leaf total chlorophyll and chlorophyll-a concentrations compared with controls (irrigated with tap water) but did not affect chlorophyll-b concentration. Inoculating the seedlings with Glomus intraradices increased total chlorophyll and chlorophyll-b concentrations in the first season of the trial (1991) and chlorophyll-a concentration in the second (1992). Salinity reduced peroxidase activity in leaves, but did not affect polyphenol oxidase [catechol oxidase] activity. Mycorrhizal infection increased polyphenol oxidase activity, but did not affect that of peroxidase. Starch and total carbohydrate concentrations in leaves and roots were generally reduced by saline irrigation, but sugar concentrations were increased in some cases. Mycorrhizal infection generally increased leaf and root sugars and carbohydrate concentrations.
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