Abstract

Humic acid (HA) may facilitate plant growth by improving the nutrient uptake as well as through hormonal effects. Studies were conducted to investigate the effect of a mixture of calcium and HA on Oriental lily, which is sensitive to calcium deficiency. Two levels of Ca (3.5 and 7.0 meq/L) were combined with 500 mg/L HA and applied to the nutrient solution of the Lilium Oriental hybrid ‘Sorbonne’. The plant growth, physiological response and the macro- and micro-nutrient contents of the leaves, stems and roots were measured. The results show that low Ca (3.5 meq/L) and HA significantly promoted plant growth and root development. The flowering period started eight days earlier as compared to the treatment CK and the active absorbing area of the root surface was 29.41% higher. Also, low Ca increased the leaf chlorophyll content, and the proline content dramatically increased when low Ca was combined with HA. The application of Ca effectively increased the potassium and iron content of the leaves and increased the phosphorus content of the stems. The nitrogen in the leaves and the zinc in the roots were remarkably enhanced by HA.

Key words: Lilium Oriental hybrid, calcium, humic acid, plant growth, nutrient uptake.

Abbreviation

HA, Humic acid; DAP, days after planting; DM, dry matter; MB,methylene blue.