Abstract

Y. Cwala1, C. P. Laubscher1, P. A. Ndakidemi* and A. H. Meyer2

A hydroponic trial was carried out to assess the effect of inoculating tomato plants with AM fungi, in the presence and absence of a mycorrrhizal stimulant (Mycotech). Four treatments were applied: (1) AM inoculant, (2) mycorrhizal stimulant, (3) AM + Stimulant and (4) Stimulant alone. Arbuscular mycorrhizal treated plants were 14% root colonized, whilst AM + Stimulant treated plants, were 25% colonized. No colonization was observed in non -AM and non-AM + Stimulant treated plants. However, AM + Stimulant treated plants did not show any significant improvement over AM treated plants, in either the plant nutrient concentrations, except Cu, or the growth of the plants, despite a root colonization advantage. In general, there was also no improvement in colonized plants over non- colonized plants, possibly due to the abundant supply of nutrients. However, Stimulant treated plants performed better than the other plants in terms of their P, K, Ca, Mg and Mn nutrition. The causes of this increase remain unknown. This study has shown that the combined use of mycorrhizal stimulant and AM have a definite advantage for improving root colonization levels, but more research with regard to nutrient supply in the system, is required to ensure further benefits to the plants.