Studies On Optimization Of Culture Formulation And Physiological-biochemical Characteristics For Pleurotus Nebrodensis

The research on the culture of Pleurotus nebrodensis, a kind of high-quality rare fleshy agarics , will promote a sound and steady growth of the p. nebrodensis industry. This thesis mainly focuses on the nutrition condition and the physiological-biochemical index in the growth period, including the optimization of composition and the C/N ratio of culture medium, the optimal culture days and temperature of the hyphal postripeness, the variation rules of ectoenzyme activity, respiratory enzymes activity and the ion flux at the surface of hyphae during the growth period of p. nebrodensis. The results were as follows:1. 15 formulas were designed by the method of mixture, using sawdust, cotton seed shell, corn cob, wheat bran as main material. Through the data statistical analysis,the ingredient regression equations between the main material and the yield were established, and as well the equations between the main material and cultivation period. And according to the regression equations, the yield and cultivation period of the different formulas can be estimated. The results showed that the optimized formulation for the maximal yield was composed of wheat bran 27.8%, cotton seed hulls 36.2%, corn cob 19.7% , saw-dust 9.3%, corn flour 5%, gypsum 1% and lime 1%; the optimized formulation for shortest fruiting period was composed of wheat bran 14.0%, cotton seed hulls 18.6%, corn cob 9.3% , saw-dust 51.2%, corn flour 5%, gypsum 1% and lime 1%; the high- profit formulation was composed of wheat bran 27.4%, cotton seed hulls 29.1%, corn cob 19.8%, sawdust 19.8%, corn flour 5%, gypsum 1% and lime 1%.2. Using urea and wheat bran as a supplementary nitrogen source, 14 cultivation formulas were designed in the experiment. By analyzing the experimental data, the appropriate range of the C/N ratio of medium is 30:1 to 51:1 for mycelia growth, but mycelia growth rate is faster when added CO(NH2)2 than wheat bran in the culture substrate. Particularly when the C/N ratio is below 25:1, fruiting rate is very low or non-fruiting;The inverse correlation between the biological efficiency and the C/N ratio in the added wheat bran formulas. Then the C/N ratio of urea formulas is 36:1, has the highest biological efficiency.3. The results of different time treatment in hyphal postripeness period showed that mulberry-like phase was extended when shorted the postripening period, but the growth period shorten significantly. When hyphal postripeness period was controlled to 30 days or 35days, fruiting rate and biological efficiency were 96.77%, 100% and 52.27%, 36.22%. The optimal temperature of hyphal postripeness phase cultivation was 25℃.4. The results of studies on the ectoenzyme activities at various stages of growth and development of p. nebrodensis showed that the variation of activity of ectoenzyme had some clear periodic steps. The activity of Laccase was high at the hyphal growth stage, while declining tendency at the other stages, but increased rapidly after fruiting body harvested. The activity of cellulose and hemiceluase increased rapidly when fruiting bodies were growing, and further declined after they were harvested. The amylase activity was low throughout the cultivation cycle, although it would be fluctuant at the hyphal postripeness, under temperature stimulation or when fruiting body growing.5. Studies on the enzymes relating to respiratory metabolism, MDH, G-6-PDH and 6-PGDH, at various stages of growth and development indicated that their activities changed consistently. The activities were high at the hyphal postripeness stage, under temperature stimulation stage or when fruiting body growing.6. H⁺, K⁺, Ca²⁺ fulx at the surface of the hyphae had been determined by the NMT,. The data suggested that Ca²⁺ influx at mycelium growing stage and from the hyphal postripenes stage to the fruiting body growing stage. When the fruiting bodies were harvested, the rate of efflux would be accelerated. H⁺ efflux rate increased significantly at the primordium initiation time. The C/N of medium has a significant correlation with Ca²⁺ flux, K⁺ flux at the hyphal growth stage. With C/N radio decreaseing, Ca²⁺ influx was significantly accelerated. The correlation of K⁺ flux with C/N radio was second related significantly, and K⁺ efflux rate was slowest when C/N was 30. The culture temperature affected the rate of H⁺ flux,Ca²⁺ flux at the hyphal surface significantly, but not to K⁺.