Study On Sugar And Abscisic Acid In Preservation Mechanism Of Cut Lilium

Lilium, with its straight flower stem, big flower, gorgeous color, and long florescence, wasone of the four famous cut flowers all over the world. Lilies greatly favored Chinese consumersdue to its implication of "together for centuries","noble and pure", etc. But cut flowers'postharvest quality was serious declined because of improper harvesting time and postharvesttreatment. Sugar, as one of basic formula of preservatives, had been a great deal applications. Butits mechanism was unclear. Abscisic acid, who had caused stomatal closure and kept leavesgreen, began to be added into the preservative. But there was little report. Even can't been foundin its applied to lily cut flowers. Lilium orential 'Sorbonne' was used in this research. The role ofsucrose and abscisic acid played in the preservation of lily cut flowers from several aspects: typesof sugar source, concentration and processing method of sugar, concentration of ABA, sucroseand ABA treatment, and harvest stages of cut flowers were discussed in this thesis. Theconclusions as follows:(1)The preservation effects of glucose, mannose, sucrose and maltose holding treatments oncut Lilies was discussed. The results showed that: The optimal concentration of sugar source wasdifferent from types. Generally, low concentration was better than high. High concentrationtreatments shortened the vase life of cut lilies, and leaded leaves yellow obviously at the sametime. The optimal concentrations of glucose, sucrose, maltose were2.5,5,1g L^-1. But thepreservation effects of each concentration mannose treatment were not significant. It mayberelative to whether sugar can be metabolised or not. The preservation effects of sucrose andglucose which prolonged vase lives, increased diameters of flowers and enhanced fresh weightwere better than maltose.(2) Suitable concentrations of sucrose and treatments were discussed. The results showedthat: the proper concentration sucrose processing extended the vase lives of cut flowers,enhanced fresh weight and improved the flower color. But high concentration of sucrosetreatments whether pre-or holding treatments made leaves ornamental worse, increasedmembrane permeability of petal, especially holding treatment. For comprehensive evaluationindexes, the effect of5g L^-1sucrose holding treatment was the best.(3)The effects of the different concentrations of ABA pretreatment on the cut lilies wereinvestigated. The results showed that the addition of low ABA (0.1,0.5,2mg L^-1) extended vaselife, increased flower diameter, and improved water balance.0.1mg L^-1ABA was the optimalconcentration. But ABA of high concentration shortened the vase life of cut lilies, decreased thepostharvest quality and had more serious water deficit.(4)The addition of low concentration ABA(0.1,0.5mg L^-1) extended vase life, increasedflower diameter, and improved water balance, alleviated the loss of chlorophyll in leaves, solubleprotein and sugar,anthocyanins in petals. At the same time the activity of SOD kept at a highlevel. The MDA declined rapidly. The high concentration ABA(10,50mg L^-1) had the oppositeeffects. It shortened the vase life of cut lilies and decreased depressed growth of the bud, andspeed up leaves' yellowing. Sucrose, sucrose and ABA mixed treatment delayed the first peak ofethylene production. (5)The effects of sucrose and abscisic acid pretreatment on the differents harvest stages ofcut Lilies were investigated. The result showed that:30g L^-1sucrose pretreatment enhanced freshweight significantly for all kinds of harvest stages flowers. For early harvest of cut flowers,because of its low development level, the accumulation of their own energy was less. Treatmentincluding sucrose insured the blooming rate, increased diameters of flowers and moved up thefull flowering stage. The addition of ABA, based on sugar solution, eased leaves yellowing. Forintermediate state of cut flowers, sugar and ABA individual treatment has certain effect onpreservation, but no significant effect of mixed treatment. For the latest harvest of cut flowers,ABA, ABA and sucrose mixed pretreatment preservation effects were remarkable. It promotedthe absorption of sucrose, and improved and the content of soluble sugar in petals.