Compare The Effects Of Two Kinds Of Yeasts On The Postharvest Diseases Of ’Red Fuji’ Apples

Apples (Malus domestica Borkh) are the most important fruit in the world, and one of the economic crops in China.’Red Fuji’ apple is widely cultivated in China. As a non-damaging physical treatment, biological control has been applied to control insect pests and disease, to modify fruit responses to other stresses, and to maintain fruit quality during storage. Red Fuji apples are one of the most important apples varieties in China, and would be investigated in this paper. The yeast P. guilliermondii and C. laurentii were examined for its ability to control the blue mold, gray mold, and anthracnose disease on Fuji apples during storage. The contents and results are as follows:1. The effects of two kinds of yeasts on the postharvest diseases of Red Fuji apples.The results showed that two kinds of antagonist yeasts at1×108CFU/mL can effectively control the infection of the three kinds of diseases, when the C. laurentii was more inhibitory effect than P. guilliermondii (P<0.05). The C. laurentii has better inhibitory effect on the three kinds of diseases than P. guilliermondii at1×108CFU/mL to control the blue mold, gray mold, anthracnose disease on Fuji apples during post-harvest storage (P<0.05).2. Researching the growth of two yeast in fruit wound and dynamic interaction between pathogen and yeast.The results show that C. laurentii grew faster than P. guilliermondii in the wound. At the fourth day, the quantity of C. laurentii is at the maximum level, prophase C. laurentii can reproduce rapidly, with strong nutrition space competitive advantage. It shows that C. laurentii can better adapt to "Red Fuji" apple fruit wound environment. Through the SEM observation, we boserved the interaction between C. gloesporiodes and pathogen in apple fruit wound, it was found that the yeast cells vigorous growth, multiply, form clear and complete structure, adherent to pathogen mycelia. At the same time C. laurentii is much stronger than P. guilliermondii of adsorption grow ability.3. The comparion of the induction of host defense reponse by yeasts in’Red Fuji’ apple. The fruit inoculated with C. laurentii demonstrated greater changes in lignin determination, PPO, POD and PAL than P. guilliermondii. C. laurentii can significantly increased lignin in Apples fruit. At the fourth day after treatment, C. laurentii can induce an increase more significantly in PPO, POD activity than P. guilliermondii. After one day of the treatment, C. laurentii can induce more PAL activity than those in P. guilliermondii.4. Researching two kinds of antagonism yeast volatile substance. The results showed that C. laurentii and P. guilliermondii all have inhibitory effect on B. cinerea, P. expansum, C. gloesporiodes by volatile substances when growing on PDA. Dectecting by the Electronic nose, we can fine the difference between the two kinds of yeasts.