The Isolation Of Ericoid Mycorrhiza And Its Effects On The Growth And Fruit

Blueberry (Vaccnium) is one of the most important newly developing fruit trees. It spreads widely, especially in Jilin province and southwest area of our country. Blueberry is used as fruit and also contains anthocyanin and antioxidation substance that can cure some kinds of diseases. So it is a multifunction fruit tree with highly economic value. Blueberry is suit to live in the acid soil and fit to being cultivated in the red soil of our country. To develop the blueberry industry in polluted area can meliorate the soil and put the virescence and afforestation into practice. At present, a lot of seedlings are produced in a short term with the succeeded tissue culture technique of rabbiteye blueberry. However, to boost up the growth and improve the quality of micropropagated blueberry plantlets is still a key issue waitting for us to solve.Ericaceous plants, especially the blueberry, has feeble assimilate ability for having no root hair in root system. In the wild, blueberry has intergrowth with EM fungi to form mycorrhiza. In doing so, the nutritional status of blueberry, including nutrition and moisture absorption has been improved, as well as the metabolism and resistant activity built up. Therefore, to integrate the tissue culture and mycorrhizal technology is an item with great economy benefit worthing to research. The use of EM fungi is one of the way necessary to facilitate the growth and improve the output of blueberry now widely adopted abroad, whereas, little in China, if any. It needs to point out that the inoculation of the EM fungi suitable to local natural conditions is important in producing healthy seedlings.In the experiment, typical EM fungi strains were isolated from Jinyun mountain in Chongqing where wild Vaccinium ashei Reade was very popular. And the effects of EM fungi on the growth, nutrition absorption of seedlings in vitro and in the field, and the beneficial component in fruits of blueberry were also studied in the same time.The object of the research is to supply techniques to cultivate seedlings with advantageous EM fungi for planting trees in acid soil area.The results are as follows:The production and cultivation of micropropagated blueberry plantlets in our country is underway. Researchers are feeling for the mycorrhizal technology on micropropagated plantlet s. So isolating the beneficial EM fungi plays a key role on the study. The isolation of EM fungi is usually carried out by mycorrhizal tissue method, lixiviated soil solution method and unicellular isolation method for the spores with different shapes of EM fungi are very diffi cult to pick out.The results showed that different fungi were isolated by distinct means:the f ungi apart from lixiviated soil solution method mainly formed white colony developed rapidl y;the mycorrhizal tissue methods with different exterior sterilize means separated fungi coloni es varied in shape and number.Therefore,adopting manifold methods in isolation assay could separate more EM fungi we wanted.Test selecting the optimum medium is necessary to be carried out because every fungus has its optimum medium for their different nourishment demand. The isolated strains had better growth potential and mycelium developed strongly and rapidly on PDA medium, while they grew slowly and poorly on the others. It indicated that PDA medium was the optimum medium in EM fungi isolation and cultivation. But it had a little opacity matter remnant after filtrated, as liquid medium it would influence the observing of the results. So modified MMN medium which was easy to make and had known ingredient was selected as the liquid medium of isolated EM fungi. The results showed that modified MMN medium was fit for the spread of strains. Mycelium grew well and developed faster in this medium than on solid ones.Some researches have showed that inoculating micropropagated plantlets with beneficial microorganism had some effects on the growth and development of host But it is a long time to form EM and the infection rate is also low in natural conditions. The production of blueberry seedlings by inoculating mycorrhizal fungi is absolutely required. In this experiment, the effects of EM fungi on growth and development of micropropagated plantlets were studied. As a results, the growth quantity and absorption ability to sorb mineral elements of seedlings in vitro or ex vitro were greatly promoted. The isolated EM fungi, especially the SWAU0309 and SWAU0313 were excellent strains to symbiose with blueberry.In general, there is great discrepancy between the field surroundings and the tissue culture environment which would lead to the different behaves of EM fungi on the host. But in the experiment, the results showed that the functions of the fungi on the micropropagated plantlets and seedlings in the field were almost the same. The mineral elements absorption of host in the field was meliorated to different extent. Certainly, different EM fungi inoculated manifested varied effects on the different varieties. The nitrogen and phosphor contents in inoculated Gardenblue and Darrow...