| Herbacious penoies(Paeonia lactiflora Pall.)are traditional plants native to China,which have significant features with a great variety, long vase period and ornamental value. The fresh-cut penoies production has been one of the most important branches in peony commercial production which basis on property cultivars and can be insured by the intergrative post-harvest technology.Low temperature storage is the most direct way in the preservation of cut flowers,which is also a very important means of preservation technology. Polyamines(PAs) are low molecular weight cations synthesized in almost all biological systems including plants. A number of reports available show the role of PAs in delaying senescence. However the effects of polyamines in cut flowers are controversial, since there are also studies that got the opposite result.The herbaceous peony cut flowers ‘taohuafeixue', ‘qihualushuang' and ‘yangfeichuyu'was used as materials in the paper. The studies of vase life, the rate of flower bloom, the rate of in feetion, the rate of fresh weightand relational physiologic charaeteristies in the case of low temperature storage were eondueted inherbaceous peonycut flower. By spraying the exogenous polyamine spermidine(Spd) and the polyamine biosynthesis inhibitor D-argimine(D-Arg) in herbaceous peony cut flowers, the dynamic change of superoxide dismutase(SOD), catalase(CAT), malondialdehyde(MDA), soluble protein and endogenous polyamines, IAA, ZR, ABA, GA3 and the relationship between polyamines and hormones were studied.1. Herbaceous peony cultivars ‘Qihualoushuang', ‘Yangfeichuyu', ‘Taohuafeixue'after the storage at 3?~5? were tested. The results showed that the rate of flower bloom and vase life were gradually decreased with the storage time. The fresh weight of cut flower decreased continually and the water loss caused water deficiency stress during storage, so the water uptake decreased, the balance of water was broken. ‘Qihualushuang' and‘Taohuafeixue' Chinese herbaceous peony had a longer storage life. The rate of flower bloom in 60 d is more than 70%,which means 60 d is best storage time for‘Qihualoushuang' and‘ Taohuafeixue'.40 d is the best storage time for‘Yangfeichuyu'.2. The effect of exogenous polyamines and polyamine inhibitors could significantly affect the content of the vase life, which Spd decreased the vase life of flowers 1.4 d. D-Arg extended the vase life 1.8 d SOD activity increased within the first four days to 235.61u·kg-1·min-1, and then decreased rapidly. During the process of the flower blooming and senescence, SOD activit y with the D-Arg treatment has been higher than the control group,while that with the Spd treatment was lower than the control group. The CAT activity in the flower senescence had the same change trend with SOD activity, which first rose up then decline, and the peak value is 121.67 U·kg-1·s-1. The results show that the SOD, CAT activity with D-Arg treatment were higher than the control group, while that with the Spd treatment is lower than the control group, which means, the D-Arg treatment is helpful for keeping up the SOD, CAT have higher ability of removing radicals. The content of soluble protein was increased in the 2 d, the value is 51.23 g·kg-1, but decreased at mid-later stage, soluble protein content in the petals enhanced progressively with D-Arg over control,while the Spd treatment decrease the protein content. The MDA content in the three treatments increased after 2 d of vase life. However, it was 5.6% lower in treatment with D-Arg comparison with that of the control and Spd treatments. The results indicate that D-Arg decreased the MDA content in the cut herbaceous peony flowers.3. The contents of endogenous IAA content, showing a trend of decline after rising first,emerged a peak on the second day, and decreased 89.4%. The contents of endogenous GA3 kept reducing to a minimum level, only 13% of the early stage, and endogenous ZR decreased constantly, and the lowest content decreased to 46.89 ug·kg-1. The content of endogenous ABA accumulated during the process, which is 154.62 ug·kg-1 at last. The D-Arg treatment reduced the content of ABA by 27.2%.4. The major polyamines in the cut flowers of herbaceous peony petals were putrescine and spermidine. As senescence progressed, a increase in putrescine level was noted, the value of Spd was 117.49 nmol·g-1, and then decreased. The spermidine level was substantially greater than that of putrescine. The contents of endogenous Spd kept reducing to a minimum level, and the content of Spd in last stage was 21.8% lower than the first stage.The variation trend of Put was the same between Spd-treated and control. The values of Put with D-Arg treatment was higher than control, The effect of Spd and D-Arg might control the flower senescence through the way of affecting the hormones by affecting the endogenous polyamines or through the way of affecting the hormones and endogenous polyamines directly. By spraying 0.1mM D-Arg would delay the senescence of cut flowers of herbaceous peony. |
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