Effect ofWater-soluble Zinc from Different Sources on Lettuce (Lactuca sativa L.) Seed Germination and Seedling Development

Purpose:Zinc (Zn) is an essential micronutrient for crops and its availability in alkaline soils is very limited. In this study, the possible growth-promoting effects of soluble Zn present in an alkaline soil to which different Zn treatments have been applied are investigated.
Research Method: Four Zn chemicals (ZnSO₄, ZnO-NP, Zn-EDTA or Zn-EDTA with humic and fulvic acids, Zn-EDTA+AC) at three different concentrations (2.5, 5 or 10, mg Zn kg¹) were applied to soil. The effect of soluble Zn solutions extracted from soil on the final germination percentage of lettuce (Lactuca sativa L.) seeds, radicle and shoot length and shoot dry weight in seedlings after eight days of incubation were evaluated.
Findings and Values: The results indicated that Zn EDTA and Zn EDTA+AC treatments showed a high effectiveness in providing soluble Zn in the soil solution (up to 17.8 times that of the control). Although no significant differences in germination percentage were observed between treatments, the highest radicle growth was observed with the Zn EDTA-2.5 treatment (1.3 times the control). The ZnSO₄ treatments showed a dose-dependent promoter effect. Radicle growth under ZnO-NP and Zn EDTA+AC treatments did not show a consistent relationship with Zn concentrations, indicating a non-dose-dependent effect. The results of this study suggest that Zn EDTA extract alone is more effective in promoting seed growth than when combined with humic and fulvic acids.