Application Of Endophytic Fungus'metabolites And PP₃₃₃ In Cut Carnation Fresh Keeping

Based on principle of plant microecology, the present research analyses the endophytic mycoflora of carnation (dianthus caryophyllus) cut flowers; discusses the fresh keeping effect of endophytic fungi so as to find out fresh-keeping fungus and biological agents suitable for camation; combines biological preservative agents with other agents to enhance fresh-keeping function by means of hurdle technology. Major findings are as follows:1. Thirty seven strains of endophytic fungi are collected from scape, petal and leaf of carnation, 22 of which do not sporulate. Fungi populations from different parts of carnation present evident difference. Dominant populations differ from scape, petal and leaf. Comparatively more common endophytic fungi are found in petal and leaf, which indicates a wide spread of endophytic fungi in different parts and tissues of plants. Experiment also shows that the amount of fungi populations peculiar to specific part of carnation is very few.Through the identification, 16 strains of fungi are classified into following 5 genera: Aspergillus Micheli ex Fr., Alternaria Nees ex Wallr., Penicillium LK. ex Fries, Fusarium LK. ex Fr., Rhizoctonia DC.ex Fr.2. Under the same experimental condition, fungi strain crude extracts F1, F5, F14 and L 14 can well preserve the freshness of carnation cut flowers, which indicates the existence of fresh-keeping endophytic fungi. Antibacterial and antioxidant analyses shows that chloroform crude extracts of fungi strain F5 is a good choice for preservative agent ingredient, for it can not onlv generate antibacterial substances but also eliminate superoxide ion. Therefore, the research adopts hurdle technology to conduct two-factor experiment with chloroform crude extracts of fungi strain F5 at five concentration level (0, 0.5%, 1%, 2%, 3%) and PP₃₃₃ at six concentration level (0, 25, 50, 100, 200, 500mg/L). Results shows that under the same condition, exclusive use of fungi strain extracts of low concentration have good performance in expanding the vase life of the cut flower, increasing flower diameter, improving water maintenance in the flower. Extract of 0.5% shows the best effect. While extracts of high concentration have negative impact on the cut flowers in reducing flower diameter, reducing fresh weight, making vase liquid turbid, lowering admiration quality and even breaking the middle of the scape. While exclusive use of PP₃₃₃ has the similar fresh-keeping effect. PP₃₃₃ of high concentration can shorten the vase life, reduce the flower diameter and lower the freshness. However, limpid vase water proves good antibacterial function.The result of mulriple experiment shows that 100mg/L+0.5% have the best effect to carnation. But the vase indices between 0.5% treatment and 100mg/L+0.5% treatment do not have distinctive differences.3. Analysis also shows that Mixture of PP₃₃₃ of 100mg/L and fungi strain extracts of 0.5% can slow down the progress of soluble protein degradation and restrain the generation of O₂^-, thus keep high SOD activity of the cut flower. At the same time, the isoenzyme bands of POD is lighter and narrower than comparison through the whole vase life. This indicates that the preservation can prevent lipid peroxidation of cut carnation.4. The cut carnation vase life is 15.9 days in 0.5% fungi strain extracts preservation, which is longer than comparison. While cut carnation can hold 13.2 days in 100moiL PP₃₃₃ preservation and 100mg/L+0.5% preservation can hold 16.1 days. These results shows that fungi strain extracts and PP₃₃₃ do not have the best cooperative function. The cause and new preservation mixture's filtration need further studies.