Improving Postharvest Life, Defoliation, and Stem Length of Woody Cut Stems

Abstract

In the first study, the postharvest life and optimum handling procedures were determined for Buddleia davidii 'Royal Red', Hydrangea quercifolia, Viburnum tinus, Ilex 'Nellie R. Stevens', Ligustrum sinense, Pyracantha coccinea, Buxus sempervirens, Ilex crenata, and Myrica cerifera. In Experiment 1, we investigated pre-treatments of 1-methylcyclopropene (1-MCP), a 10% sucrose pulse, 50°C distillled (DI) and tap water, and 20°C DI and tap water. 1-MCP and 50°C DI water produced the longest vase life for Buddleia. The 10% sucrose pulse and 1-MCP gave the longest vase life for Viburnum. No pre-treatment extended the vase life of Hydrangea, I. 'Nellie R. Stevens', Ligustrum, Pyracantha, Buxus, I. crenata, or Myrica. In Experiment 2, stems were stored wet or dry at 5°C for 0, 1, 2, or 3 weeks in light or dark. Optimal storage conditions by species were: Buddleia— dark, wet (1 week); Hydrangea— cannot be stored; Viburnum— light or dark, wet (1 week); I. 'Nellie R. Stevens' — light, wet (3 weeks); Ligustrum — dark, wet (3 weeks); Pyracantha — any condition (3 weeks); Buxus — any condition (3 weeks); I. crenata — light or dark, wet (3 weeks); and Myrica — light or dark, wet (3 weeks). For Experiment 3, stems were held in foam or without foam, with 0, 2, or 4% sucrose + 8-HQS. Buxus was the only species not adversely affected by foam. Myrica and Buxus performed best in 0% sucrose; Ligustrum performed best in 2% sucrose; and Viburnum and I. 'Nellie R. Stevens' performed best in 4% sucrose. Sucrose concentration had no effect on Buddleia, Hydrangea, Pyracantha, or I. crenata.

In the second study, six defoliants were applied to Ilex verticillata, Celastrus scandens, and Salix matsudana. Defoliants included acetic acid, chelated copper, crop oil concentrate (COC), ethephon, dimethipin, and pelargonic acid. No treatment resulted in defoliation of Ilex. Chelated copper at 800 mg·L-1 provided 100% defoliation of Celastrus. Chelated copper at 400 mg·L-1, ethephon at 1000 mg·L-1, and dimethipin provided up to 80% defoliation of Celastrus. Dimpethipin provided 75% defoliation of Salix. In a second experiment conducted with containerized Salix, irrigation was stopped for 0, 3, or 6 d before defoliants were applied. Dimethipin promoted 90% defoliation, with no subsequent adverse effects on plants.

Cut stems of Callicarpa americana and S. matsudana 'Tortuosa' were held in DI water at 5, 20, or 35°C. No treatment promoted defoliation of Callicarpa. Holding cut stems of S. matsudana at 20°C promoted 68% defoliation, compared to 53 or 28% for 5 or 35°C, respectively.

In the third study, containerized Viburnum trilobum and Ilex verticillata were (a) inoculated with a commercial formulation containing 7 species of vesicular-arbuscular mycorrhizae (VAM), (b) inoculated with Glomus etunicatum, or (c) allowed to remain uninoculated. Phosphorus (P) was applied daily at 0, 25, or 50 mg·L-1. Neither plant species was colonized by any VAM species. Phosphorus supplied at 50 mg·L-1 was optimal for increasing stem number and length of Ilex. For Viburnum, 25 mg·L-1 was optimal for stem growth, but root area, length, and weight were not affected by P concentration.