Photosynthesis and Growth of Single-node Cutting Rose `Red Velvet' and `Vital' by Nutritional Control in a Plant Factory

Plant factory is a new plant production system that enables high quality, year-round, and planned production by controlling the environment. However, the recirculation of the nutrient solution leads to several problems because of unstable condition by nutrient uptake. The concentrations of nutrients in the recirculating solution should be kept at the required levels, since an optimum nutrition is determined by the specific concentrations of an element and mutual ratio to other nutrients in the root zone. Consequently, the nutrient solution is required adjustments based on regular analysis of the drain water and relationships among nutrient uptake, growth stage, and environmental factors for plant quality. This study was conducted to examine the effect of mineral nutritional control by five different methods on growth and photosynthesis of single-stemmed rose `Red velvet' and `Vital' in a plant factory. The nutritional control of nutrient solution was as following: the control of electrical conductivity (EC), N, P, and K elements (NPK), macro elements (M), macro and micro elements (MM) to target ranges in root environment, and the supplement of nutrient solution (S). The growth of single-node cutting rose `Vital' and `Red velvet' was higher in the M and MM than that of other control systems. Although M and MM system showed no significant difference, the photosynthetic rate, stomatal conductance, and transpiration rate were higher than those with other systems. The maximal efficiency of photochemistry (Fv/Fm) was higher in the M and MM control system, which showed the highest root activity. These results could be attributable for modelling the mineral nutritional control system, which reduces the use of fertilizers and increases the productivity of single-stemmed rose.