水稻根际促生细菌促生生理活性评价

Evaluation of physiological activities of plant growth-promoting rhizosphere bacteria of rice

为了考察水稻特异性PGPR菌株各生理活性对水稻幼苗初生根数、次生根数、茎干重和根干重的影响,筛选优良PGPR菌株,采用改良的CAS检测法、Salkowski比色法、钼蓝比色法和1-氨基环丙烷-1-羧酸(ACC)脱氨酶检测法分别测定菌株产铁载体、产吲哚乙酸(IAA)、溶磷能力和ACC脱氨酶活性,利用Hoagland半固体培养基和土壤盆栽法培养水稻幼苗。结果表明,IAA产量低的菌株对水稻幼苗初生根数、次生根数和茎干重的增长有明显的促进效果;根干重明显随铁载体产量增加而增加;溶磷活性高的菌株对水稻幼苗茎干重和根干重的增加均有明显的促进作用;低ACC脱氨酶活性的菌株促进水稻幼苗初生根的生长,活性高的菌株促进次生根数的增加。根据半固体试验结果,选择7株具有明显促生效果的菌株进行盆栽试验,结果证实,这些菌株均具有显著的促生效应。

In order to select excellent PGPR strains, various physiological activities of specific strains of rice were evaluated to test their effects on the number of primary roots and secondary roots as well as stem dry weight and root dry weight of rice seed- lings. The modified CAS assay, the Salkowski colorimetry, molybdenum blue method and ACC deaminase assay were used to measure production of siderophores and IAA, phosphate solubilizing capacity and ACC deaminase in the tested strains. Rice seedlings were cultivated both in Hoagland semi-solid medium and pot soil. The results indicated that the strains producing low concentration of IAA showed promoting effect on the primary root numbers, lateral root numbers and the stem dry weights of rice seedling. The strains with high concentrations of siderophore had significant promoting effect on the root dry of rice seedling, and the root dry weights were increased significantly with the high production of siderophore. Strains with high phosphorus solu- bilizing activities had significant growth promoting effects on the dry weights of both stem and root of rice seedling. The primary root numbers of rice seedlings were promoted when ACC deaminase at low activities, while the lateral root numbers were promo- ted when ACC deaminase activities stronger. According to the results of semisolid experiments, pot experiments were conducted on 7 strains, the results confirmed that these strains possess significant growth-promoting effect.