RESPONSES OF TWO LETTUCE CULTIVARS TO IRON DEFICIENCY

Abstract

SUMMARYA comparative study of two lettuce varieties (Lactuca sativa: ‘Romaine’ and ‘Vista’) was conducted to understand the effect of iron deficiency on growth, biomass allocation, chlorophyll fluorescence and root and leaf enzymatic activity. After 15 days of growth in hydroponic solution under Fe-deficient and Fe-sufficient conditions, leaf chlorophyll concentration, activities of ribulose 1.5-bisphosphate carboxylase/oxygenase (Rubisco) in leaves extract, ferric chelate reductase (FCR) and phosphoenolpyruvate carboxylase (PEPC) in root extracts were measured. We found that there were significant differences in fresh matter accumulation and pigment concentration between the varieties. Fresh weight and total leaf area and leaf number were significantly reduced under iron deficiency. There was also a significant decrease in photosynthetic pigment concentration in both varieties. In response to Fe deficiency, ‘Vista’ variety showed higher FCR and PEPC activities compared to ‘Romaine’ variety. Moreover, this increase was accompanied by an enhanced accumulation of phenolic compound in roots of ‘Vista’ variety. These findings show that ‘Romaine’ was more affected by iron deficiency than ‘Vista’.