| The purpose of this experiment is to investigate the expression patterns of genes encoding ethylene receptors and signal transduction components during flower opening and senescence of cut rose, and the experiment can be divided into two parts as below. 1. The difference in the expressions of genes encoding ethylene receptors and signal transductioncomponents between two cultivars with different ethylene sensitivityFlowers of two cut rose cultivars, ' Samantha' , whose opening process is promoted, and 'Kardinal', whose opening process is inhibited by ethylene, were used as materials and treated with ethylene (10ppm) and its action inhibitor STS (2mM) at 8°C. Ethylene production and expressions of genes encoding ethylene receptors and signal transduction components in petals were determined. Enhancement of ethylene production by ethylene was much more significant in 'Kardinal'than in 'Samantha' . Seven gene fragments, including Rh-ETR (AF441283), Rh-ETR1 (AY953869), Rh-ETR3 (AY953392) , Rh-CTR1, RH-CTR2, Rh-EIN3-J (AF443783) 和 Rh-EIN3-2 (AY919867), were isolated from petals. The expression level of three receptor genes was much higher in 'Samantha' than in 'Kardinal', and was more inducible by ethylene. Among the receptor genes, Rh-ETR was expressed predominantly in control, and Rh-ETR3 was induced most dramatically by ethylene in 'Samantha' . The expressions of Rh-CTRl and Rh-CTR2 were both weaker in 'Samantha' than in 'KardinaP while the expression of Rh-CTR1 was much stronger than that of the latter in both cultivars during flower opening, increased during flower opening, and was enhanced by ethylene especially in 'Kardinal', whereas Rh-CTR2 was expressed constitutively. Rh-EIN3-1 and Rh-EIN3-2 exhibited distinct expression patterns and ethylene induction, and both were expressed in cultivar-dependent manner. These results suggest that the higher level of receptors and its easier being induced by ethylene results in less ethylene sensitivity, for there is an inverse correlation between transcript level of receptors and sensitivity, the relationship between ethylene sensitivity and transcript level of CTR and EIN3 needs further investigation. 2. The induction of flower opening and senescence and influence on expression of genes encodingethylene receptors and signal transduction components by ethylene 1) Pre-identification of ethylene treatment time to initiate flower opening and senescenceFlowers of 'Samantha' were treated continuously with ethylene (10ppm) and its action inhibitor 1-MCP (2mM) respectively at 20 °C. The changes of morphological characters, ethylene production of petals and expression of isolated genes mentioned above were examined. 24h Ethylene treatment accelerated flower opening, shortened vase life, enhanced ethylene production of petals, and enhanced the expression of Rh-ETR3, Rh-CTRl and Rh-CTR2. However, more than 48h treatment could not enhance the expression of these genes, and even lowered that of Rh-ETR3; 1-MCP treatment for 24h prolonged vase life and reduced ethylene production particularly in prophase of flower opening, and lowered the expression of Rh-ETR3, Rh-CTRl and Rh-CTR2. However, the effects of 1-MCP were not amplified when treatment time was prolonged to 48h, and vase life waseven shortened when treated for 72h. The results indicate that 24h is enough for either ethylene or 1-MCP treatment time to induce their respective effects.2) Identification of shortest ethylene treatment time to initiate flower opening and senescenceThe flowers were treated as 1) but the treatment time within 24h was further divided as 6h, 12h, 18h and 24h. 12h ethylene or 1-MCP treatment both could induce obviously changes in morphological characters, vase life and ethylene production of petals. Therefore, 12h is probably the shortest treatment time to initiate flower opening and senescence, thouth the times of ethylene and 1 -MCP treatment for obviously accelerated and inhibited the expression of Rh-ETR3 respectively were more than 12h.3) Reversibility of effects of ethylene on flower opening and s...
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