Studies On Physiological Mechanisms Of Lily Bulb Stored At Different Cold Temperatures For Breaking Dormancy

This paper is about physiological and biochemical analysis for dormancy release of lilybulb(L.×Prato). In this dissertation, the morphological changes and the contents of total sugar,starch, 4 hormones (ABA, GA₃, IAA, ZR) and phenolic compounds and the activities of 3enzymes (POD, PPO, PAL) related to phenols in lily bulb were determined during the coolingstorage of bulbs. In addition, the type and content of phenolic compounds in middle bulbs oflily were identified by HPLC analysis, Correlation and regression analyses of substancemetabolism in lily bulb during cold treatment for dormancy release. The purposes of theseexperiments are to provide academic basis for making clear dormancy mechanism and makinganniversary production of lily to be come true. The main results are as follows.(1) Morphological change and endogenesis substance metabolism in middle bulb of lilywere studied during cold treatment for dormancy release. The bulb released from dormancyrespectively in 7 weeks and 4 weeks stored at 5℃and 0℃for 1 week and then turn to 5℃.Fresh weight and content of starch reduced gradurally when dormancy released, and thecontent of soluble total sugar peaked at the point of dormancy released and then decrease nextweek.(2) Phenolics metabolism in middle bulb of lily was studied during cold treatment fordormancy release. Along with the dormancy release, POD activity, PAL activity and phenoliccompound content decreased, PPO activities increased. The result shows that: phenoliccompound is an inhibitor of lily bulb dormancy, and the decreasing of POD and PAL activitiescould be responsible for the decrease of phenolic compounds. So they are maybe one of thekey enzymes for bulb dormancy controlling.(3) The type and content of phenolic compounds in middle bulbs of lily were identified byHPLC analysis during cold treatment for dormancy release. There are 6 phenolic compounds inthe middle of lily bulb. Threeof them were identified, which were hydroquinone, resorcinol,and catechol. And the content of hydroquinone and resorcinol increased during break ofdormancy, while catechol decreased gradually. So we presumed hydroquinone and catecholwere likely to be the main promoters that promoted dormancy breaking, and catechol may bethe main inhibitor of the phenolic compounds in lily bulb. Breakage of dormancy may berelative to cooperating control of these two kinds of phenolic compounds, which need morestudy.(4) Variation Of endogenesis hormonal content and ratio in lily bulb were determinedduring cold treatment for dormancy release, and correlation of them was analyzed. The 4hormones varied sharply during the first one week or three weeks, so it is the key periods of breakage of dormancy for lily bulb. Correlation analysis of hormones content and ratio showsthat GA₃ and ABA play the central role in dormancy controlling.(5) Correlation and regression analyses of substance metabolism in lily bulb during coldtreatment for dormancy release. The result shows that, for 5℃, the content of phenoliccompounds is correlative with PAL activity and ABA content. PAL activity is correlative withABA, and PPO activity is correlative with ZR. While for 0℃for one week and then turn to 5℃,the content of phenolic compounds is correlative with POD activity and ABA content. PAL andPPO activity is correlative with ABA.