| Cut rose hybrida, 'Samantha' is red variety and 'Belami'is pink variety. Their process of opening to senescence is different in postharvest during vasing. The former opening floral is quick and full, the later is slow and often becomes stereotyped. With the two varieties, the content of soluble protein, the content of free amino acid, the EP activities and the effects of deficit water stress on these physiology indexes of petals and leaves during vasing were studied. The characteristic of Ep in quality and quantity was studied also. In order to seek the probable reasons" of difference of the process of opening to senescence between 'Samantha' and 'Belami', the relations between senescence and EP were probed. The flowing results were obtained:1. There is a growing period of from youth to senescence in postharvest of cut rose, corresponding, there is a transform of the soluble protein from taking synthesis as the dominant way (the former period) to taking degradation as the dominant way (the later period).The ratio of synthesis and degradation in petals and leaves of 'Belami' is larger than in that of 'Samantha' during the former vasing. This is one of likely reasons that flower opening of 'Belami' is slower and often stereotyped.2.The optimum temperature of EPs is 37'C in petal and leaf of 'Samantha' and 'Belami'. There is at least a serine proteinase in leaf, it's optimum pH is pH 10, it's molecular weight is about 52 kD. The optimum pH of petal's EP is different because of different varity, the optimum pH of EP of 'Samatha'petals is pH 10, 'Belami' petals pH 6 and pH 10. There are at least three kinds of EP in petal: thiol-proteinase, metallo-proteinase , serine proteinase. They gather at the site between 43 kD and 66.2 kD (about 52 kD) on the substrate gel electrophoresis. The optimum pH of thiol-proteinase, metallo-proteinase is pH 6, which are looked as acid EP, the serine proteinase has two forms, one is acid EP (pH 6), and the other is alkali (pH 10). So serine proteinase is both acid EP and alkali EP. The changes of these endopeptidase are different during the former vasing of 'Samatha' and 'Belami'. The main EPs in petals of 'Samatha' are the acid thiol-proteinase, metallo-proteinase and the alkali serine proteinase and the main EPs in petals of 'Belami' are the acid thiol-proteinase and serine proteinase. During the later vasing the acid metallo-proteinase and the alkali serine proteinase become main EPs in petals of 'Samatha' and 'Belami'. The difference of EPs during the former vasing is one of likely inner reasons that the process of opening to senescence is different between 'Samatha' and 'Belami'.3. The changes of EP activities of petal are more complicated than those of leaf during vasing. From beginning to end, the EP activities of the optimum pH 10 of 'Samatha' petal is higher by far than added values those of the optimum pH 6 and the optimum pH 10 of the 'Belami' petal.This is one of likely reasons that 'Samatha' can open quickly and fully duringvasing.4. During vasing of 'Samanthas'and 'Belami', the process of opening to senescence is speeded up and the flower diameter increase rate is enlarged after deficit water stress. But the effects of deficit water stress on 'Belami' is more outstanding than those of 'Samantha'. The content of soluble protein is also increased after deficit water stress, but the increasing of 'Belami' is more significant than that of 'Samantha'.5. After deficit water stress, in 'Samantha'petals, the metallo-proteinase activities of the optimum pH 6 and the serine proteinase activities of the optimum pH 10 are increased markedly, the thiol-proteinase activities of the optimum pH 6 is decreased markedly. While, in 'Belami' petals, the metallo-proteinase and the thiol-proteinase activities of the optimum pH 6 and the serine proteinase activities of the optimum pH 10 are also increased markedly.6. There are very close relations between the rapidly decreasing of the soluble protein content, the sweetly enhancing of EP activities, the quckly increa...
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