PHYSIOLOGICAL AND ECOLOGICAL ASPECTS OF THE INTERACTIONS BETWEEN PLANT-ROOTS AND RHIZOSPHERE SOIL

The rhizosphere soil of six different plant species grown in a factorial combination with four different types of soil was analysed to gain information about the amount of organic metabolites and their origin in the rhizosphere. Amino-acids, sugars, CO2 evolution and some enzyme activities were measured quantitatively. The results were compared using various statistical methods such as multiple correlation, factor analysis, principal component analysis, and cluster analysis. The amounts of sugars and amino-acids, and the enzyme activities of some metabolites behave in an interdependent way, suggesting a very close interrelationship of the involved organisms. In most cases the soil was the dominating factor in the combination. Some plants were able to predominate certain soil factors. Emphasis is laid on the importance of such physiological investigations as a diagnostic tool for the assessment of the biological state of various natural agricultural soils.