| Summary: | 碩士 === 國立屏東科技大學 === 農園生產系所 === 105 === The Roselle(Hibiscus sabdariffa L.) calyx is one of the most important medicinal plants in many parts of the world for its edible, medicinal uses as health foods. Roselle calyx can produce considerable amounts of antioxidant such as, polyphenols, flavonoids and anthocyanins. Arbuscular mycorrhizal fungi (AMF) are a beneficial microorganism in the terrestrial ecosystem , It can enhance the absorption of nutrients and improve the secondary metabolite accumulation in crops. In this study, these are six species of AMF, such as Glomus clarum, G. etunicatum, G. fasciculatum, Gigaspora sp., G. mosseae, and Acaulospora sp. are used to screened out which one is the optimal mycorrhizal fungi and also to evaluate the effects of secondary metabolites and antioxidant capacity of Roselle calyx.
The results showed that all six AMF species are able to form mycorrhizal structure with the host Roselle, the mycorrhizal formation rates from 71.67% to 78.89%, indicating that these AMF present high compatibility with the host roselle. After cultivation 210 days, the plant height inoculated with AMF was from 154.98 cm to169.98 cm, which was enhanced by inoculating with Gm, Asp, Gg, Ge, Gc, and the stem diameter of plant inoculated with AMF from 12.23 mm to 14.74 mm, which was enhanced through inoculating with Gg, Asp, Gm, Gf, Ge. In pot trials for screening AMF species, Asp, Gg species were screened out and mixed with 1: 1 for next experiments.
In following study, Roselle was inoculated with mix AMF(Gigasporasp.,Acaulosporasp.), after cultivation 210 days, the mycorrhizal formation rates were AMF 93.33%, control 0.00%; the plant heights were AMF 153.88 cm, control 134.57 cm and the stem diameters were AMF 22.13 mm, control 15.17 mm, they indicated that the treatment of mycorrhizal fungi increased significantly. And the total chlorophyll contents were AMF 2.26 mg/g, control 1.71 mg/g; the soluble carbohydrate contents were AMF 5.06 mg/g, control 3.04 mg/g; soluble protein contents were AMF 17.59 mg/g, control 10.46 mg/g. It illustrated that the Roselle leaves with AMF inoculation had substantially higher chlorophyll content as well as soluble carbohydrate and soluble protein compared with those in control group. The Roselle calyxes of polyphenols contents were AMF 27.37 mg/g, control 20.53 mg/g; the total flavonoids contents were AMF 8.03 mg/g, control 7.40 mg/g; total anthocyanin contents were AMF 11.58 μmole/g, control 9.77 μmole/g, all significantly enhanced by inoculating with AMF. The phenylalanine ammonia lyase (PAL) activities of inoculated and control groups were 0.96 OD290˙30min-1g-1 FW and 0.68 OD290˙30min-1g-1 FW.
In the antioxidant capacity of the methanol extraction, the DPPH radical scavenging ability of Roselle residue obtained the highest ability 90.95% at a concentration of 1 mg/ml of inoculation AMF treatment, and control were 89.90%, enhanced significantly by inoculating with AMF. In the antioxidant capacity of the methanol extract, the DPPH radical scavenging ability of Roselle residue obtained the highest ability 0.418 at a concentration of 1 mg/ml of inoculation AMF treatment, and control were 0.316, enhanced significantly by inoculating with AMF.
The Roselle calyxes with AMF inoculation also had substantially higher secondary metabolite contents such as polyphenols, lavonoids, and anthocyanin, and substantially higher PAL activities and antioxidant ability. Therefore, AMF can be used to develop for Roselle cultivation and production.
Keyword : antioxidant capacity, arbuscular mycorrhizal fungi (AMF), phenylalanine ammonia lyase(PAL), Roselle(Hibiscus sabdariffa L.)
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