ผลของธาตุอาหารพืชต่อการเจริญเติบโตของทิวลิปในระบบไฮโดรโพนิกส์

Abstract

The effects of nutrients on tulip growth in hydroponic system were studied in 2 experiments as follows; Experiment 1: the effects of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe) and boron (B) deficiency on the tulip growth was carried out. In this experiment, tulip bulbs ‘Orange Juice’ with an average circumference of 12 cm were grown in a double pots hydroponic system and kept in a plant factory under the controlled atmosphere with an average temperature of 20±2 °C, an average light intensity of 442 µmol m-2s-1, and relative humidity of 80-90%. A completely randomized design with 9 treatments 4 replications/treatment was used. In particularly, in treatment 1, plants were grown in deionized water; Treatment 2, plants were grown in Hoagland and Arnon (1950) solution as control treatment. treatment 3 to treatment 9, N, P, K, Ca, Mg, B, and Fe-deficient solutions with the same amount of other essential elements were used, respectively. The results showed that 4 weeks after transplanting, plants grown in Ca-deficient solution had shorter roots length compared to other treatments except the plants grown in deionized water. However, no differences was found in leaves area and fresh weight among treatments. The plants grown in Mg-deficient solution showed the lowest photosynthetic rates. As for flower quality, it was found that plants grown in deionized water and Ca-deficient solution showed the lowest flower longevity, and both treatments resulted stem topple system in 58% and 42% of all plants in each treatment, respectively. In addition, non-flowering tulips were found with 17% and 8% of plants grown in P-deficient and N-deficient nutrient, respectively. Experiment 2: the effects of electrical conductivity (EC) of nutrient solution on growth and flower quality of tulip grown in hydroponics system was studied. Tulip bulbs with an average of 12 cm circumference were grown in a hydroponics system using double pots system under a plant factory with an average temperature of 20±2 °C, average light intensity 442 µmol m-2s-1 and 80-90% RH. The experimental design was completely randomized design (CRD) with 5 treatments and 4 replications. Plants were supplied with five EC levels i.e., 0, 1.0, 1.5, 2.0 and 2.5 mS/cm Plant growth, photosynthesis rate, flowers and new bulbs quality were measured. The results showed that there were not significantly different between treatments on days to flowering and stalk diameter parameters. Plants supplied with EC levels at 0, 1.0 and 1.5 mS/cm, photosynthesis rate and transpiration rate were not significant different among treatments. However, plants height, stalk length, total fresh weight, photosynthesis rate and transpiration rate were decreased when the plant was supplied with high EC levels at 2.0 and 2.5 mS/cm but bulb fresh weight, bulb circumference and number of new bulbs per plant were not significant different among treatments. Plants supplied with 0 mS/cm of nutrient solution showed 66.6% of stem topple characteristics, while plants supplied with 2.5 mS/cm showed 22.2% of flower abortion.