英文摘要 |
Platycerium wandae Racif. is a large epiphytic fern of great ornamental value. Growers are anxious to reduce the production time by enhancing the slow growth of young plants. Effects of light intensity (100, 200, or 300μmolm-2s-1 photosynthetic photon flux density, PPFD) and nutrient solution concentration (0%, 25%, 50%, or 100% Johnson’s solution once per week) were studied on growth and photosynthesis of young plants with two sizes, namely with 2-3 sterile fronds or bending sterile fronds grown at 25/20℃. Results showed that plants without fertilization produced the smallest leaf size with the lowest SPAD-502 value and net photosynthetic rate. Plants grew well with 50% Johnson’s solution under 100 or 200μmolm-2s-1 PPFD conditions, whereas maximum leaf size, stomatal conductance, and net photosynthesis were recorded in plants with 2-3 sterile fronds applied with 100% Johnson’s solution under 300μmolm-2s-1 PPFD conditions. Leaf SPAD-502 value increased with increased nutrient concentration. Light compensation point was estimated between 21.9 and 35.5μmolm-2s-1 in plants with 100% Johnson’s solution under 100-300μmolm-2s-1 PPFD conditions. Plants grown with 100μmolm-2s-1 PPFD had the lowest dark respiration rate but the highest light compensation point. Plants under 300μmolm-2s-1 PPFD without fertilization had the highest values of non-photochemical quenching (qN) and minimal fluorescence in darkness (Fo) and the lowest quantum efficiency of photosystemⅡphotochemistry (Fv/Fm), while other plants had maximum Fv/Fm of 0.75-0.85. |