The Potential of Bacterial Strains of Luteovulum sphaeroides W22 and W47 for Producing δ-Aminolevulinic Acid to Improve Soil Quality, Growth and Yield of Saline-Irrigated Rice Cultivated in Salt-Contaminated Soil

Abstract

The present study aimed to identify the abilities of the δ-aminolevulinic acid (ALA) producing purple non-sulfur bacteria (PNSB), Luteovulum sphaeroides W22 and W47, to reduce the Na+ concentration, and to ameliorate the soil fertility, nutrients uptake, growth and yield of rice on the salt-contaminated soil. A two-factor experiment was conducted following a completely randomized block design. The factors were the frequency of applying saline irrigation (zero, one, two, three and four times) and the ALA-producing PNSB supplementation (applying only W22, only W47 and mixed W22 + W47). The results revealed that supplying the PNSB mixture not only reduced the proline content but also increased the plant height, number of panicles per pot, percentage of filled seeds, contents of NH4+, PO43−, total N, P uptake and grain yield. The mixed PNSB application also reduced the Na content and the total Na uptake in plants. L. sphaeroides W22 and W47 decreased the proline content by 31.3% and increased the grain yield by 27.2% in the condition of applying 5‰ saline irrigation four times.