Evaluation of ethylene sensitivity and postharvest treatments to improve the vase life of four Campanula species

The genus Campanula is composed of over 300 species but only few of them are used as cut flowers. In order to diversify the production and to exploit local plants with potential ornamental characteristics, ethylene action and three treatments for extending the vase life were evaluated in Campanula barbata L., C. latifolia L., C. rapunculoides L. and C. trachelium L. Cut stems were subjected to the following treatments: 1-methylcyclopropene (1-MCP), recut in tap water at 90°C, Chrysal Clear®, or ethylene and compared to one control in tap water. Pre-treatment with 2.74 μL/L 1-MCP, an inhibitor of ethylene action, for 6 h increased the vase life based on visual check for symptoms of senescence alterations, without any visible toxic effects. In particular, in C. barbata the average flower longevity was 4.2 days, twice longer than the other preservative treatments. In this species, 1-MCP treatment preserved more also the petal color (L*=-1.50, a*=-1.07, b*=4.41), measured by means of a spectrophotometer. However, exogenously applied ethylene did not decrease bellflowers vase life and gas chromatography analysis did not detect any endogenous ethylene production. This suggests that Campanula cut flowers are ethylene responsive but more sensitive protocols for studying ethylene action are needed. Considering the different species, C. rapunculoides resulted the most promising bellflower for its intrinsic ornamental and physiological characteristics.