1. Symptoms of zinc deficiency and toxicity have been studied in guar, brinjal, maize, tobacco and Mosambi (Mozambique) using a sand-culture technique.
2. In zinc-deficient guar plants, depressed vegetative growth and smaller leaves than normal ones were found. Only few flower buds were seen, and there was abscission of leaves at the time of flowering.
3. Chlorosis followed by necrosis and finally the drying up of leaves was the most characteristic deficiency symptom in the case of brinjal; growth was stunted and flowers failed to set fruits.
4. In the newer leaves of maize, intermittent light yellow bands were formed just parallel to the midrib.
5. In the lower leaves of tobacco, chlorosis followed by necrosis was observed; growth was stunted and leaves were small in size.
6. In Mosambi (Mozambique), whitish yellow patches in between the veins were observed; leaves were small, pointed and quite unhealthy.
7. There was an increase in zinc uptake with increased rates of application of zinc.
8. Crude protein increased with increasing zinc supply up to levels beyond the optimum for growth.