Plant Hormones and Mineral Nutrition

Abstract

The concn. of growth hormone in the shoot tips of Helianthus annuus and Nicotiana tabacum was measured for plants grown in sand cultures and in the field, under varying conditions of mineral nutrition. Hormone concn. was high when an abundance of N was supplied to the plants, irrespective of the supply of other elements; it was low in the absence of supplied N. Variations of 1/3 to 3 atmospheres in the osmotic pressure of the nutrient solution did not affect hormone concn. There was no evidence to determine whether hormone concn. was the cause or effect of different rates of growth.