| Organic phosporus is an important P source in soil,but it is not able to be used by plant directly.Therefore,decomposing of organic phosphorus in soil is essential to its utilization by plants.Enhancing the decomposing of organic phosphorus in soil is of great significance in agriculture,and it has become a hot research topic in plant nutrition.Oat is an important crop in Inner Mongolia,phosphorus bioavailability is often a limiting factor for oat production.The main purpose of this research is to investigate if there is any bacteria in the rhizosphere of oat,which can dissolve the organic phosphorus.The results showed that five strains of organic-phosphorus-dissolving bacteria were isolated from rhizospheres of oat in Siziwang Inner mongolia.Two of them with higher capacity of dissolving organic phosphorus were selected for further study on their morphology and growth.Both YM-4 and YM-2 are bacilli without capsule and positive in gram reaction,after 4～5 days of culture,they all produced spores.Two strains, especially strain YM-2 proved tolerant to salt in the experiment and grow well in media with 1% NaCl.The data on effects of different pH on the bacteria growth showed that neutral or alkaline culture media is prefered by the bacteria,acid media is not good for their growth.Along with the growth of both strains of bacteria,the media pH grdually decreases.This implies that growth and propagation of these two strains of bacteria in the soil can not only dissolve organic phosphorus,but probably also enhance the solubility of inorganic phosphates in alkine soil and therefore benefit P absorption by oat,which are usually planted in alkine soil.This suggests the strains of bacteria isolated from rhizosphere of oat may have great potential for use in practice.In this research,sorts of carbon resources were also compared in cultural media,the result showed that glucose is better than starch,sucrose,and lactose for the bacteria growth.This is important for slecting C resource when conducting propagation of the bacteria,and it also provides important information for utlization of these strains. |