| Triazole is a kind of fungicides that not only be used as the efficient and broad-spectrum fungicide, but also can work as non-traditional plant growth regulator in morphology and physiology. Additionally, triazole is regarded as plant multi-protectants for protecting plants from several stresses. In this research, the novel synthesized derivative of triazole, hexaconazole-Cu (hexaconazole modified with copper) complex, has been used to identify its antifungal activities and interaction with DNA. Moreover, the avtivities of complex on plant growth regulation in Triticum aestivum seedlings was investigated under salt stress, and the functional characteristics of complex were evaluated.(1) The antifungal activities were tested according to growth rate method which measures the size of fungi colony. Therefore, five fungi were tested. They were, fusarium graminerum,macrophoma kawatsukai,alternaria solani,pear colletotrichum gloelsporioides, and aternaria alternate. The results indicate that hexaconazole-Cu can effectively inhibit fungi growth and have higher antifungal activities than hexaconazole. Based on these results, hexaconazole-Cu shows the highest antifungal activity on pear colletotrichum gloelsporioides. EC50 of hexaconazole-Cu was 0.113 μmol·L-1 while hexaconazole’s was 0.154 μmol·L-1.(2) Hexaconazole-Cu effectively inhibited Triticum aestivum seedlings growth and elongation, meanwhile decreased shoot height and increased root-shoot ratio. Compared to the control,0.06 mmol·L-1 of hexaconazole-Cu reduced the shoot height by 40.38% and increased the root-shoot ratio by 40.82%, and chlorophyll was increased by 49.21%. Proline, the osmoprotectant, was found 73.91% higher in seedlings pretreated by 0.10 mmol·L-1 of hexaconazole-Cu. Furthermore, hexaconazole-Cu significantly restrained accumulation of malondialdehyde (MDA). MDA in hexaconazole-Cu (0.06 mmol·L-1) pretreated seedlings was 52.54% lower than that of control. Activity of SOD reached highest level after pretreated by 0.06 mmol·L-1 of hexaconazole-Cu, which was 52.29% higher than control. The highest activity of POD was observed after pretreated by 0.04 mmol·L-1 hexazonazole-Cu, and it was 44.91% higher than control. According to these physiological indexes, hexaconazole-Cu displayed characters on Triticum aestivum plant growth regulation. (3) Under 100 mmol·L-1 NaCl stress, proline content in Triticum aestivum seedlings was increased from 2.20 μg·g-1 to 5.42 μg·g-1 in 24 h.. Whereas the proline content in 0.06 mmol·L-1 hexaconazole-Cu treated seedlings was increased from 3.49 μg·g-1 to 8.79 μg·g-1 during 0～24 h’s NaCl stress. In addition, hexaconazole-Cu caused inhibition on MDA accumulation under 100 mmol·L-1 NaCl stress. MDA content was increased from 1.55 『mol·g-1 to 1.70 μmol·g-1 in the control but changed from 1.33 μmol·g-1 to 1.45 μmol·g-1 after hexaconazole-Cu treatment. Furthermore, 0.06 mmol-L"1 hexaconazole-Cu enhanced antioxidant system significantly. The activity of POD was found 9.48% higher in the treated plants under 24 h’s stress. The SOD activity in hexaconazole-Cu pretreated seedlings was improved significantly in 24 h’s stress, and it was 102.01%,156.03%, and 229.59% higher than untreated seedlings after 6,12 and 24 h respectively. However, the activity in control reached highest value at 3 h’s stress, then drcreased.p5cr and p5cs are the two key enzymes genes (△1-pyrropline-5-carboxylate reductase and △1-pyrropline-5-carboxylate synthetase) in proline biosynthesis; sosl and nhexllc are plasma membrane Na+/H+antiporter and vacuolar Na+/H+antiporter genes. Results of real-time quantification PCR depicted enhanced expression levels of p5cr and p5cs. In the period of 3～ 24 h’s NaCl stress, the relative expression of p5cr in untreated plants was about 1.93-fold greater compared with original level, while 5.92-fold greater in hexaconazole-Cu treated plants. The p5cs expression level after hexaconazole-Cu treatment was enhanced from 1.61-foder to 3.11-folder. However, expression in control was first upgraded followed bydescendance, and the tendency was in accordance with proline content. For sosl, NaCl decreased the expression to 0.63,0.22,0.25 and 0.26-fold of the original level after 3,6,12 and 24h’s stress. Hexaconazole-Cu can ameliorate the negative results caused by NaCl and maintain sosl expression at the original level.100 mmol·L-1 NaCl also rapidly reduced expression level of nhexl1c obviously during 3～24 h. However, the expression level of nhexl1c was enhanced and up-regulated by 3.81-fold at 24 h’s stress in hexaconazole-Cu treated seedlings.(4) Transition metal complex which has plane structure is regarded as ribozyme that can cleave DNA. The results of DNA cleavage experiments showed that the supercoil pMD 18T DNA disappeared gradually and linear DNA appeared after 60 min water bath. The amount of linear DNA was higher in the cleavage production of hexaconazole-Cu treatment than that of hexaconazole at 0.25 mmol·L-1. At 2.00 mmol·L-1 concentration, hexaconazole-Cu thoroughly cleaved pMD 18T DNA into linear DNA, but there was still supercoil DNA in hexaconazole cleavaged production.There would be different DNA in cleavaged production due to the different water bath time. After 120 min of water bath, the supercoil DNA disappeared thoroughly when cleaved by 1.00 mmol·L-1 hexaconazole-Cu. Whereas in hexaconazole cleaved production, supercoil DNA existed through out the whole period of...
|
PDF Full Text Request