Study On Senescence Of Vegetative Mycelium Of Agaricus Bisporus

Agaricus bisporus is an edible basidiomycete,it is cultivated in more than 70 countries and is one of the most commonly and widely consumed mushrooms in the world.With the gradually increasing the amount of cultivation,the requirements of quantity and quality of the mushroom spawn have been increased. However, due to poor management,lack of knowledge,bad preservation conditions causes spawn senescence is a serious problem.Senescence affect directly the quality of spawn,therefore the production of Agaricus bisporus also could be affected. With the growth of spawn age,activity and other physiological characteristics are relatively decreased that the mycelium become senescence. Thus inquired the mechanism of mycelium senescence, delayed the mycelial senescence and detected senescence morphology of mycelium is the question of the practice or scientific research which is urgent need to be resolved,and it provide the theoretical basis to study on senescence of vegetative mycelium of Agaricus bisporus. The main results are illustrated as followed:1.By seting different moisture of wheat medium(35%,40%,45%,50%,55%),different content(0.1%,0.3%,0.5%,0.7%,0.9%)of FeSO4,Ca(H2PO4)2,MgSO4,CaCO3,KH2PO4,and different content fermental cow dung(15%,20%,25%,30%,35%,40%) to study the impact of senescence on the mycelium. The result shows that the moisture of 45% of wheat medium has the most significant effects on delaying senescence of mycelium; 5 kinds of inorganic salt on the mycelium have some inhibitory effects of senescence, the 0.9% Ca(H2PO4)2 and 0.1%~0.9% MgSO4 has the most significant nhibitory effects on senescence of mycelium; fermental cow dung has less significant inhibitory effects on senescence of mycelium.2. Study on the microstructure of vegetative mycelium of Agaricus bisporus,it will found that essential characteristic of the senescence vegetative mycelium.The investigation shows that the morphological changes occurr in senescence vegetative mycelium of Agaricus bisporus in different period. The result shows that the period of senescence occurs from 50 to 60 days after inoculation. The sign of senescence is swelling and vacuole-like in the mycelium and the cell walls become coarse and irregular.With the growth of spawn age, senescence become more serious.The cell walls have swelled or even fragmented, and mycelium have eventually lose their shape to breakup.3.Study on the activity of mycelium and content of RNA of vegetative mycelium of Agaricus bisporus, it will found that essential characteristic of the aged vegetative mycelium. The results show that the mycelial growth rate decrease as the time of mycelial germination increases: inoculated age of 30d of spawn has growth rate of 1.8cm/d,as inoculated age of 150d of spawn has growth rate of 0.96cm/d; inoculated age of 30d of spawn has he time of mycelial germination of 1.5d,as inoculated age of 150d of spawn has he time of mycelial germination of 5d.And the content of RNA decrease while spawn age grow more older: inoculated age of 30d of spawn has the content of RNA of 2231.2ng/μl,as inoculated age of 150d of spawn has the content of RNA of 438.9 ng/μl4.Study on the activity of POD,CAT,SOD and ACP of different aged vegetative mycelium of Agaricus bisporus, the result shows that the activity of POD,CAT and SOD has less significant regular change on spawn age.The activity of ACP has decrease while spawn age grow more older: inoculated age of 30d of spawn has the activity of ACP of 1.91nmole/g.min,as inoculated age of 150d of spawn has the activity of ACP of 0.52 nmole/g.min.