Effects of the Hot Water Extract and Its Residues of Chlorella Cells on the Growth of Radish Seedlings and the Changes in Soil Microflora

Effects of the Hot Water Extract and Its Residues of Chlorella Cells on the Growth of Radish Seedlings and the Changes in Soil Microflora.


Abstract

The effects of hot water extract and extracted residues of Chlorella cells on the growth of radish seedlings in relation to chages in soil microflora and microbial activity were studied. In particular, actinomycetes spp.isolated from the soil amended with hot water extract of chlorella cells were screened for their productivity of plant growth regulators and antibiotic substances on a plant pathogen, Fusarium oxysporum f.sp.raphani. The hot water extract promoted the growth of 6 species of streptomyces which generally inhabit the soil. The repeated amendment of hot water extract and its residues of chlorella cells to soil promoted the growth of radish seedling and increased the population of actinomycetes and bacteria in soil. The most significant positive correlations were observed between the growth of seedlings and the population of actinomycetes in these soils. Most actinomycetes spp.isolated from the soil amended with hot water extract produced plant growth regulators and also had antagonistic effects on the plant pathogen, Fusarium oxysporum f.sp.raphani. The hot water extract promoted the production of plant growth regulators and the growth of 3 actinomycetes spp.tested. Repeated soil amendment of the hot water extract increased the population of indigenous Fusarium oxysporum f.sp.raphani-antagonists in the soil. These results indicated that the plant growth-promotive effects of the hot water extract and its residues of chlorella cells were due to the increase in the amount of plant growth regulators in soil and the enhancement of soil fungistasis by increasing in the poulation of such profitable actinomycetes in soil.

from : http://ci.nii.ac.jp/naid/110001747407/en/