Abstract
Leaf blades, petioles and stems of 8 healthy and 10 witches' broom diseased sweet potato plants were analyzed for 13 elements including N, P, K, Ca, Mg, Fe, Mn, Zn, B, Mo, Cu, Na and Al. The concentrations of N, K, B and Cu in the leaf blade, of K, Ca, Mo and Cu in the petiole, and of N and Mg in the stem of healthy sweet potato plants were significantly higher than those of witches' broom diseased ones.
Among the three plant parts, the N and Mn concentrations of the leaf blade were significantly higher than those of the other two plant parts in both healthy and witches' broom diseased sweet potato. There was not significant difference in the Zn concentration among the leaf blade, petiole and stem of both healthy and witches' broom diseased plants. The other 10 elements showed different tendencies of distribution between healthy and witches' broom diseased plants.
Relationships of element concentrations were studied between the leaf blade, petiole and stem of sweet potato plants. The concentrations of K, Ca, Zn, Fe, Mn and Na were significantly correlated between the leaf blade and petiole, between the leaf blade and stem, and between the petiole and stem in both healthy and witches' broom diseased plants. In general, more elements were correlated between the potiole and stem than those between other plant parts in both healthy and witches' broom diseased plants.
Possibilities of using plant analysis were discussed in order to diagnose witches' broom disease infection of sweet potato plants.
