Study on the postharvest life of Eustoma grandiflorum (Raf.) Shinn. cut flowers

Postharvest physiology of Eustoma grandiflorum cut flowers in relation to ethylene and pollination and their postharvest chemical treatment were investigated. Ethylene is involved in natural and pollinated flower senescence in Eustoma. Factors affecting the vase life of pollinated flowers were investigated. Cultivar variation was observed in the distance from stigma to anther and in the rate of natural pollinated flowers. The rate of pollinated flowers was negatively correlated with the distance from stigma to anther, suggesting easier pollination of flowers with shorter distance. Senescence of Eustoma flowers was significantly accelerated by all-area and 1/8-area pollination compared with the control and all-area pollinated flowers tended to senesce faster than 1/8-area pollinated ones, suggesting that the pollinated area of the stigmatic surface also affects the vase life of pollinated Eustoma flowers. Cultivar variation was also observed in the vase life of unpollinated and pollinated Eustoma flowers. In unpollinated and pollinated flowers, the flower diameter of short-lived cultivars tended towards a greater reduction compared to that of long-lived cultivars after ethylene treatment. These results suggest that the sensitivity of flowers to ethylene is likely related to cultivar variations in the vase life of unpollinated and pollinated flowers. Sugar application is very effective for promoting bud opening and petal pigmentation as well as extending the vase life of cut Eustoma flowers; however, it can also cause leaf damage. High sucrose concentration and excessive uptake of sucrose solution resulted in an increased rate of leaf damage. The addition of abscisic acid (ABA) to the sucrose solution reduced sucrose accumulation in leaves and prevented leaf damage. Cut Eustoma flowers were treated with silver thiosulfate complex, an ethylene action inhibitor, 4% sucrose and ABA for pulse treatment, followed by 1% sucrose for transport. These treatments extended the vase life of foliage and flowers and promoted bud opening by simulated transport and in practice.