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概要

Post-Harvest Physiology and Technology in Orchids

De LC, Vij SP and Medhi RP

Orchids account for a large share of global floriculture trade and are estimated around 10% of international fresh cut flower trade. They have taken a significant position in cut flower industry due to its attractiveness, diversity in forms, shape and color, high productivity, right season of bloom, and easy packing and transportation. Postharvest life of orchid cut flowers is influenced by pre-harvest factors like varietal or species differences, light intensity, sugar level of flowers, temperature and water loss. It is also affected by harvest factors such as time and stage of harvest and postharvest factors viz. ethylene production, precooling, pulsing, use of preservatives, packaging and storage.
The hybrids of Dendrobium, Vanda and Mokara remain perfect from 7 days to 30 days. The flowers of Cattleya and Phalaenopsis remain fresh for 1 to 4 weeks whereas Aranda lasts for 18 to 28 days. Higher sugar levels of flowers improve longevity of cut flowers. The optimum harvesting stage of commercial orchids is fully open and mature flowers. In Cymbidium hyb. ‘PCMV’, harvest at two buds opened stage had maximum vase life (66.8 days). Ethylene is the main factor responsible for early senescence. In Cymbidium hybrid ‘Red Princess’ pulsing with 5% sucrose increases vase life upto 56 days. Pulsing with 4 mM STS for 10 minutes in Aranda and 0.5 mM STS for 24 hours in Phalaenopsis blocks the deleterious effect of ethylene.
In tropical orchids like Dendrobium and Oncidium, AgNO3 (10-30 ppm) and HQS (50-100 ppm) extends vase life and bud opening of cut flowers. In Cymbidium, 1-MCP and AVG are superior to STS in prolonging the vase life of cut flowers. In Cymbidium ‘PCMV’, highest per cent of fully opened buds (75%) and maximum vase life (45 days) were recorded with the chemical combination of sugar 4% + salicylic acid 200 ppm.
In orchids, cut spikes are inserted in tube containing water or water with preservatives and bunch of 5 or more or individual spikes are placed inside the CFB box in alternate fashion. Cool growing orchids are stored at lower temperature even at 5°C in cold chambers whereas tropical and subtropical orchids are stored at 7-10°C and 90-95% relative humidity.