STUDIES IN PLANT MINERAL NUTRITION: I. AN INVESTIGATION INTO THE CAUSE OF GRAY SPECK DISEASE OF OATS

摘要

A series of experiments were carried out over a period of three years in which plants ofAvena sativavar. Tama were grown in nutrient solutions which provided variations in iron and manganese concentrations, calcium concentration, and pH. The experiments were conducted under a wide range of growing conditions as regards light intensity and temperature control. The aim of the work was to furnish information regarding the factors associated with the development of the symptoms of gray speck disease. The experimental results indicated that under otherwise favorable culture conditions, manganese deficiency alone will produce gray speck symptoms. Inoculation of the cultures with root material from plants bearing gray speck symptoms had no effect whatever on the incidence of the disease. Variations in the pH of the culture solutions did not affect the development of gray speck symptoms, but the symptoms appeared later in cultures containing a high concentration of calcium than in cultures containing a low concentration of this metal.