The effect of shading and branch position on the quality of cut flowers and photosynthetic parameters of roses

This experiment was conducted to investigate the effects of shading treatment (full light intensity, 25, 50, and 65 percent shade) and branch position (bent and upright) on the quality of cut flowers and photosynthetic parameters of flowers of the Avalanche cultivar. The experiment was conducted in split plots, in a completely randomized block design, with 4 replications with 2 samples per experimental unit. During the experiment, qualitative traits including bud emergence time after branch bending, flowering branch length, flower diameter, flowering branch diameter, fresh weight, dry weight, leaf area, specific leaf area, chlorophyll index and photosynthetic parameters including photosynthesis, stomatal conductance and transpiration were investigated. The results showed that shading treatment reduced branch diameter, flower diameter, fresh and dry branch weight and increased the number of days until bud emergence. However, it had no significant effect on branch length and leaf area. With increasing shading, leaf specific area increased, with the highest leaf specific area observed in 65% shade. In this experiment, branch position also affected some traits. Flowering branch length, flower diameter and fresh and dry branch weight increased in the bent position compared to the upright position. However, no difference was observed in bud emergence time and branch diameter between both branch positions. In this experiment, shading treatment had a significant effect on photosynthetic parameters, such that with increasing shading, the photosynthetic parameters and chlorophyll index decreased. The highest photosynthesis rate was observed in control plants and the lowest in 65% shade. Measurement of photosynthetic parameters and chlorophyll index in different layers of the canopy showed that the amount of chlorophyll and photosynthetic parameters increased with increasing canopy depth and followed a specific pattern. The results of this experiment also show that there is no difference in photosynthesis, transpiration, stomatal conductance and chlorophyll index between upright and bent positions.