Funding for this column is provided by the ASCFG Research Committee.

Effect of S-carvone on Vase Life

S-carvone, a compound found in caraway and dill seeds, can prevent or reduce wound healing when applied to plant tissues exogenously. The target wound in this experiment was the harvest cut. As that “wound” heals, cut stems develop water deficit stress, typically caused by occlusion of xylem conduits, physiological plugging and air emboli (an air bubble). The researchers, at the University of Queensland in Australia, hypothesized that a vase solution with S-carvone would increase vase life and possibly display antibacterial activity.

The cut species used in the trial were: Acacia holosericea, Baeckea frutescens, Chaelaucium uncinatum and Chrysanthemum sp. Treatments included concentrations of 0.318mM S-carvone and 0.636mM S-carvone, prepared in deionized water and tap water. Another treatment involved removing 1 cm from the stem base every two days.

The S-carvone treatments significantly increased the vase life of B. frutescens and C. uncinatum; however, the vase life of A. holosericea and Chrysanthemum sp. was not increased. Recutting the stems resulted in prolonged vase life for all the species tested.

No evidence of antibacterial activity was observed in the S-carvone vase solutions allowing the research to attribute the prolonged vase life of B. frutescens and C. uncinatum to inhibited wound repair induced by the presence of S-carvone. Further studies will try to determine which specific wound repair compounds are inhibited by S-carvone.

Damunupola, J.W., T. Quian, R. Muusers, D.C. Joyce, D.E. Irving, U. Van Meeteren. 2010. Effect of S-carvone on vase life parameters of selected cut flower and foliage species. Postharvest Biology and Technology. 55:66-69.

Adding Value with Edible Dyes

Research at the Navsari Agricultural University, in India, assessed the use of edible dye on candytuft (Iberis umbellate L.) to develop a value-added product to capture more revenue from the consumers. Dye concentration and duration of immersion were to two treatments applied to vase life and flower quality.

Seven colors were tested at 0.5%, 1.0%, and 1.5%: yellow, orange red, falsa blue, apple green, pink rose, tomato red and kalakhatta (a shade of purple). Immersion durations were half-hour intervals from 0.5 hours to 3.0 hours. The shade of dyed flower was recorded immediately following treatment and at the end of the vase life.

The shade of color deepened as the dye concentration and time of immersion increased. This result suggests that more dye was translocated up to the central buds of an inflorescence without affecting physiological processes at the maximum concentration and immersion period tested.

There was no significant difference in observed vase life among the treatments. Therefore, the authors of this study concluded that there were no adverse effects of the dye concentration, time of immersion or combination of treatments on flower vase life and quality.

Patil, S.D., H.E. Patil. 2008. Value addition of candytuft (Iberis umbellate L.) cut flowers coloured with edible dyes. Asian Journal of Biological Science. 3(1):163-167.

Effect of Colored Shade Nets on Cut Flower Growth

Seven cultivars of four cut flower species (lisianthus, sunflower, trachelium and ornithogalum) were grown under four different colored nets (black, red, yellow and blue). The black shade netting was considered the control. Compared to the control, three lisianthus and two sunflower cultivars grown under red and yellow shade nets displayed significant increased stem length. The red netting also caused a shorter time to flowering in ornithogalum. The blue netting resulted in shorter stem length in two sunflower cultivars and trachelium. Blue netting also produced smaller inflorescence in trachelium, sunflower and ornithogalum.

Ovadia, R., I. Dori, A. Nissim-Levi, Y. Shahak, M. Oren-Shamir. 2009. Coloured shad-nets influence stem length, time to flower, flower number and inflorescence diameter in four ornamental cut-flower crops. The Journal of Horticultural Science & Biotechnology. 84(2): 161-166.

Freesia Sneak Virus Reported in Virginia

In the spring of 2008, two freesia cultivars, ‘Honeymoon’ and ‘Santana’, were grown in Virginia and analyzed for disease by the USDA-ARS Floral and Nursery Plants Research Unit in Beltsville, Maryland. The plants displayed coalescing, interveinal, chlorotic, whitish, necrotic spots on leaves. Twenty-five percent of the plants, scattered within the planting exhibited symptoms. Plants were collected from March to May for analysis. Using genetic testing techniques (amino acid sequencing), the disease in question was confirmed to be freesia sneak virus, the first report of this disease in the United States. Freesia sneak virus may pose a new soilborne threat for ornamental bulbs, as it is likely soilborne through the plant pathogen Olpidium brassicae.

Vaira, A.M., M.A. Hansen, J. Hammond. 2009. First Report of Freesia sneak virus in Freesia sp. in Virginia. Plant Disease. 93(9): 965.

Effect of Calcium on Cut Gladiolus

Three vase solutions were tested on cut stems of the gladiolus cultivar ‘Mascagni’: calcium acetate, ethylene glycol bis-amino tetmacetate (EGTA), or water. The opening rate and the vase life were greatest in the vase solution containing 2 mol/Liter of calcium acetate. Further tests indicated that the solution containing calcium acetate in resulted in increased endogenous calcium in the gladiolus. The researchers concluded that the calcium acetate stabilized the membrane structure of the cut gladiolus and activates and calcium-binding protein that controls the endogenous hormonal levels and transports soluble sugar into petals, ultimately contributing to a longer vase life.

JiGang, B., X. PeiLei, Z. ChengShun, W. CaiYun. 2009. Effects of exogenous calcium on some postharvest characteristics of cut gladiolus. Agricultural Sciences in China. 8(3):293-303.