Effects of Preharvest Conditions and Postharvest Handling on Postharvest Characteristics of Cut Lilies, Roses, Sunflowers, and Zinnias
Studies were conducted to determine the effects of preharvest humidity and water stress levels during production on cut Lilium L. and Helianthus L. stems and various postharvest procedures on cut Rosa hybrida L., Helianthus L., and Zinnia Jacq. stems. Subjecting Lilium âDazzleâ and âVermeerâ stems to high humidity during production did not reduce cut flower vase life but increased stem length and production time. In Helianthus, vase life, water uptake, stem length, stem diameter, and head diameter of cut âSunbrightâ stems were positively correlated with production time in high humidity. Applying water stress to âDazzleâ, âVermeerâ, and âSunbrightâ during production did not affect vase life at the treatment level; however, water potential readings during the last five days before harvest were negatively correlated with vase life in âVermeerâ, and water potential readings from up to 36 days before harvest were positively correlated with vase life in âSunbrightâ. Bud number in âVermeerâ was positively correlated with stem diameter, and stem diameter in âDazzleâ and âVermeerâ was reduced as soil moisture deficit increased. Quality of cut âSunbrightâ stems was reduced as soil moisture deficit increased. Vase life in cut âVermeerâ and âSunbrightâ stems was negatively correlated with the change in fresh weight in both humidity and water stress preharvest experiments.
Postharvest studies determined that R. hybrida vase life was influenced by cultivar and vase solution, where commercial preservative solutions resulted in longer vase lives and smaller changes in fresh weight than the controls, but also less water uptake. Exogenous ethylene did not affect vase life but decreased water uptake. Application of the anti-ethylene agent silver thiosulfate (STS) significantly improved vase life in a majority of the rose cultivars tested, but 1-methylcycloprepene (1-MCP) did not improve vase life over the control. Both vase life and water uptake were reduced when more than one stem was placed in a vase, where placing ten stems in a vase decreased vase life by 1.4 days and water uptake by up to 10.6 mL/stem/day. Leaving stems dry before placing in vases reduced vase life, but recutting immediately before placing in vases minimized the decline. Rose stems responded positively to increasing the amount of stem removed, where cutting from 1 to 15 cm off the end improved vase life.
Drying stems of Helianthus âSunbrightâ for up to 48 hours did not significantly reduce vase life when stems were recut after drying time; however, vase life was affected by storage temperature such that the longest vase life of 13.2 days occurred when stems were stored for 3 days at 5Â°C. Placing more sunflower stems in a vase did not statistically affect vase life.
Vase life of cut Zinnia âBenary Giant Deep Redâ stems was reduced when stems were recut compared to stems that were not recut. However, if stems were recut, a period of desiccation before placing in vases improved vase life. Vase life was improved by 2.1 days with the use of Floralife Professional as a pulse solution versus tap water and by 2.2 days when stems were stored in a bleach solution versus tap water. Storage temperature affected vase life with 5 hours of storage at 5Â°C followed by 2 days of storage at 1Â°C resulting in the highest vase life of 13.0 days. Short vase lives occurred as storage temperature increased, with a low of 6.5 days with 2 days of storage at 20Â°C. Varying the number of stems per vase did not significantly affect vase life.
Advisor:Dr. Sylvia M. Blankenship; Dr. Brian E. Whipker; Dr. John M. Dole
School:North Carolina State University
School Location:USA - North Carolina
Source Type:Master's Thesis
Date of Publication:04/28/2008