As like other C4 plants, optimum temperatures range from 30-40 degrees C. 3. B. Mineral requirements and pH toxicity 1. Interspecific differences in growth response to amaranths to N application have been found. Shown to be essential in C4 plants. In A. tricolor , Na deficiency was shown to reduce growth and chlorophyll content.
High levels can be toxic.
Growth is gradually reduced by increasing salinity. Al is antagonistic to soil potassium, which is required by amaranth in moderate amounts. Low pH increases Al and Mn solubility, which could become toxic. Important limiting factors when liming is not possible. Dormancy and Germination A. Seed dormancy 1.