عنوان مقاله [English]
Introduction: Management of rose plant structure plays an important role in flower production throughout the year and determines the amount of rose plant life span and influence plant development and quality of cut flowers (length, diameter and weight). In the past, roses were planted in a row, and their structure was in the form of long vertical hedges, with annual pruning often involving, disbudding and pinching. Rose growers tend to bend non-producing shoots to increase light absorption and build more photosynthetic assimilates and increases the quality of the produced cut flowers. In this study was investigated for proper management of pruning of cut rose bud with an emphasis on degrees of shoot bending.
Materials and Methods: The cutting's media were prepared from a combination of Cocopeat and Perlite at 50% equilibrium. The cuttings were planted in two-meter-long boxes 18 cm apart. From day 4, nutrient solution was injected into the substrates. Nutrient solution volume per plant was 550 ml per day, which was injected 11 times into the culture medium. In order to select the best plant structure architecture for producing the highest quality of the cut flowers, a factorial experiment was conducted based on a completely randomized design with two shoot pruning and bending treatments. During the bending process to increase the accuracy of the experiment, two bent shoots were counted for all cuttings, six days after bending treatment the dormant buds were activated in the primitive part of the stem and began to grow. Pruning of the buds was done in two levels of 50% pruning and without pruning. 45 days after bud removal, flower shoots were harvested, and samples were transferred to the laboratory for post-harvest evaluation. Chlorophyll and carbohydrate concentration, photosynthesis index, physiological, morphological and photosynthetic parameters were measured as well as vase life trait.
Results and Discussion: Pruning of buds at 1% probability level was important on carbohydrate content and bending at 5% probability level on carbohydrate and vase life. Furthermore, the interaction between the two pruning treatment and bending at 1% probability level was significant on the carbohydrate content and vase life. In general, it could be concluded that by bending the shoots, the light penetrates into the plant structure, which ultimately increased photosynthesis and the amount of carbohydrates in flower buds. It could be concluded from the observations that bent shoots with appropriate angles could consume their carbohydrates for bud flower production. In other words, bending branches plays the role of factories which task is to deliver the photosynthetic production in the bending branches to the flower branches that are the most important consumer. The results showed that bending of branches (45 and 90 degree), with increasing light absorption and making more photosynthetic assimilates and changing their flow from bent branches to shoots, caused their proper growth and 30% increasing in the fresh and dry weight traits. The diameter of the bud and the length of the flower shoot increased post-harvest quality of the cut flower. Furthermore, the interaction of bud pruning and bending had a positive effect on carbohydrate content of flower shoots. On the other hand, the vase life were evaluated, which showed that the bending 45 degree had the highest vase life (22.5) and 120 degree had the lowest vase life. At treatment 120 degree (lowest postharvest survival), non-pruned treatments showed longer vase life (16 days) and lower pruned treatments after harvest (13.5 days). It also showed the highest fresh weight, dry weight, peduncle diameter and flower length are 45 degree. No significant difference was observed in the photosynthesis rate of a bent branch near the bed and vertical branches above the bed. By bending the branch at the right angle, it made the bent light branch more efficiently utilized and maintained its photosynthetic rate, although bending stress, at the high levels and in the manufacture of carbohydrates and other products. Photosynthesis for helping the plant eventually gained more carbohydrates from its vertical branches (flowering), and increasing carbohydrates will lead to a relative increase in quality, bud diameter and flower length and eventually vase life of the cut flower.
Conclusion: The results of the bending treatment showed that the accuracy of the bending time and degree of 45° and 90° subsequently resulted in an increase in the quality of production.