Contribution of Individual Bent Shoot Layers to Cut Flower Productivity in Shoot-bending ‘Asami·Red’ Roses

Abstract

We estimated the contribution of individual shoot layers in a multi-layered bent canopy to the cut flower productivity of roses ('Asami·Red'). A two-layered bent shoot canopy was established and upper-or lower-layer bent shoots were replaced with artificial replicas of shoots. Replacing upper-layer shoots with replicas facilitated leaf abscission of lower-layer shoots, resulting in severe reduction in the total dry weight of cut flowers (TDWF) compared with plants having two intact bent shoots. When lower-layer shoots were replaced with replicas, the leaf area of upper-layer shoots increased and consequently the excision of lower-layer shoots had little influence on the TDWF. In another experiment, when a three-layered bent shoot canopy was established and light interception by lower-layer shoots was restricted completely by placing a shading film between two of the three layers, the leaf area of the uppermost shoots increased to compensate for the decreased leaf area due to leaf abscission of lower-layer shoots. The excision of lower-layer shoots resulted in more severe reduction of the TDWF than shading. These results suggest that in a multi-layered bent shoot canopy of roses, upper-layer shoots contribute to cut flower yield of plants, primarily through their current photosynthesis with high light interception. However, lower-layer shoots also contribute to cut flower yield by exporting assimilates retained previously, and hence these shoots should remain on plants until they die spontaneously.

Effects of Harvest Shoot Stage on Partitioning of Photosynthates Originating from Bent Shoots in the Modified Arching Technique of Cut Rose Production

“…In fact, the number of cut flowers produced using the MA technique is higher than that of the A technique by 20-30% without reducing the cut flower quality (Mercurio, 2007). Shimomura et al (2003) and Doi et al (2009) investigated the relationship between the productivity of cut flowers and trimming management and clarified that increasing the number of harvested shoots promoted their sink ability.…”