Effects of acidity on growth, structure and physiology of plants with special reference to root cells.

In the past 25 years considerable controversy has taken place over the effect of Hydrogen-ion concentration on plant growth. In 1931 Hoagland (37) expressed the following: "I recall some early experiments with, barley seedlings in California. With considerable surprise it was noted that the plants made better development in a definitely acid solution than in a slightly alkaline one. The impression gained from the literature of that time was to the • effect that most agricultural plants round their most favourable environment in a slightly alkaline medium and were injured by acidity". Following the discrediting by various investigators of this early ·belief of the harmful effects of acidity there was a tendency to treat the Hydrogen-ion concentration of the soils as the prime factor controlling the growth and distribution of plants. [...