EVALUATION THE EFFECT OF PRESERVATIVE SOLUTIONS AND STORAGE CONDITIONS ON SHELF LIFE OF SUNFLOWER INFLORESCENCES

Two separated experiments were conducted at the Postharvest Lab of Ornamental Plants and Landscape Gardening Res. Dept., Hort. Res. Inst., Giza, Egypt during 2012 and 2013 seasons to study the response of the fresh inflorescences/heads of sunflower (Helianthus annuus L. cv. Sunrich Orange) either to some preservative solutions under the ambient conditions, viz. distilled water (control), sucrose at 10, 20 and 30 g/l levels, glucose at 3, 8 and 15 g/l levels, chelated calcium at 20, 30 and 50 g/l levels and glucerol at 20  and 50 g/l levels in the first experiment or to the main 3 important factors of transportation, storage system (wet or dry), cool storage temperature (0 or 5 °C) and storage period (5 or 7 days) in the second one. The previous 3 factors were combined factorially to obtain the different interactions among them. The flowering stalks after wet or dry storage were held in graduated cylinders filled with about 350 ml of deionized water under the room temperature till the end of shelf life.
The obtained results of the first experiment indicated that all preservative solutions improved the means of water uptake, the percent of change in flower head fresh weight, flower head diameter, vase life and total soluble sugars content in petals with various significant levels as compared to control means in both seasons. However, the superiority was for holding in 50 g/l chelated- Ca solution, that gave in the two seasons the utmost high values over the other solutions in most parameters mentioned before. The second position was occupied by preserving the flowering stems in 30 g/l sucrose solution, which improved means of some characters to values closely near to those of the super treatment. So, for elongating the vase life and keeping quality of sunflower cv. Sunrich Orange heads, it is recommended to holding them either in 50 g/l chelated Ca or in 30 g/l sucrose one.
In the second experiment, the results have shown that dry storage system recorded better results than wet storage one, especially in water uptake and flower head diameter traits. Storing the flowering stems at 0 °C raised water uptake and vase life means to be more than those of storage at 5 °C in the two seasons, while storage at 5 °C caused only a higher increment in flower head diameter. In general, storage for 7 days scored higher means of water uptake, the percent of change in flower head fresh weight, flower head diameter and vase life than storage for 5 days in both seasons. Regarding the total soluble sugars content in the petals, it was not affected markedly by storage system, temperature and period with few exceptions in the two seasons. On the other hand, effect of interaction treatments on the previous stated parameters was fluctuated, where dry storage at 0 °C for 7 days recorded the highest means of water uptake and vase life, while dry storage at 5 °C for 7 days gave only the widest diameter of flower head. The wet storage at either 0 or 5 °C for 7 days scored the highest content of total soluble sugars, while the wet storage at 0 °C for 5 days registered the highest percent of change in flower head fresh weight. Hence, it can be advice to store the cut heads of sunflower cv. Sunrich Orange, dry at 0 °C for 5 or 7 days at long-space transportation without noticeable reduction in their vase life and quality.