The Study Of Development Of AM And Soil Microenvironment In Orchard Of Peach, Pear And Grape Trees

Arbuscular mycorrhizal fungus (AMF) attracts much attention because it can form a kind symbiotic relationship with many host plants and help plants absorb mineral nutrients, water of soil and improve stress resistance, disease resistance of host plants. The influence of AM in citrus has been researched in many aspects, and there are some reports about influence of AM in grape trees, thus little attention on peach, pear. This study deals with peaches, pears and grapes in order to explore the development of AM in peach, pear and grape trees in yellow brown soil, so as to provide valuable reference for application of AMF in peaches, pears and grapes. The main contents and results are as follows:(1) Development of AM in peach, pear and grape treesModel AM structure including vesicles, arbuscles, hyphaes were observed in roots of peach, pear and grape trees. This showed that peach, pear and grape trees belonged to AM plants. The AM colonization was 23.43%-74.06% in peach trees,35.08%-60.29% in pear trees, and 31.03%-84.68% in grape trees. The range of AM spore density was 556.7 num/100g dry soil to 1216.7 num/100g dry soil in peach trees,163.3 num/100g dry soil to 600.0 num/100g dry soil in pear trees, and 123.3 num/100g dry soil to 456.7 num/100g dry soil in grape trees. The AM colonization of the three kinds of fruit trees was all the highest in spring, followed by autum, the lowest in winter. Vesicles developed well in the most suitable temperature range and vice versa. The development of arbuscular of the three fruit trees was different. AMF spore density of the three fruit trees was all the highest in summer and the lowest in winter.(2) Vertical distributions of root in peache, pear and grape treesUnder the condition of yellow brown soil in Wuhan, within a distance of 100 cm from the soil surface, roots whose diameter was smaller than 2 mm are for 67 percent of total roots, followed by roots whose diameter is between 2 mm to 5 mm in the three kinds of fruit trees. More than 60 percent roots were mainly distributed within a distance of 30 cm from the soil surface of peach and grape trees, and 30 cm to 80 cm from the soil surface of pear trees.(3) Factors on development of AM in peach, pear and grape treesAlkali-hydrolyzed nitrogen had positive correlation with AM colonization. There was no significant relationship between soil available phosphorous and AM colonization. Soil sucrose and acid phosphatase may inhibit AM colonization, however, soil urease could help AMF colonize host plants. There was no obvious relationship between AM colonization and spore density. Soil urease, fungi number, alkali-hydrolyzed nitrogen, available potassium, available phosphorus and organic matter had significant negative correlation with AM spore density. Soil pH value, soil catalase and soil available magnesium had significant positive correlation with AM spore density.