The fate of markerAzospirillum lipoferum inoculated into rice and its effect on growth, yield and N2 fixation of plants studied by acetylene reduction,15N2 feeding and15N dilution techniques

Autor: I. Watanabe, Jagdish K. Ladha, D. N. Nayak
Rok vydání: 1986
Předmět:
Zdroj: Biology and Fertility of Soils. 2:7-14
ISSN: 1432-0789
0178-2762
DOI: 10.1007/bf00638955
Popis: A spontaneous mutant ofAzospirillum lipoferum, resistant to streptomycin and rifampicin, was inoculated into the soil immediately before and 10 days after transplanting of rice (Oryza sativa L.). Two rice varieties with high and low nitrogen-fixing supporting traits, Hua-chou-chi-mo-mor (Hua) and OS4, were used for the plant bacterial interaction study. The effect of inoculation on growth and grain and dry matter yields was evaluated in relation to nitrogen fixation, by in situ acetylene reduction assay,15N2 feeding and15N dilution techniques. A survey of the population of marker bacteria at maximum tillering, booting and heading revealed poor effectivety. The population of nativeAzospirillum followed no definite pattern. Acetylene-reducing activity (ARA) did not differ due to inoculation at two early stages but decreased in the inoculated plants at heading. In contrast, inoculation increased tiller number, plant height of Hua and early reproductive growth of both varieties. Grain yield of both varieties significantly increased along with the dry matter. Total N also increased in inoculated plants, which was less compared with dry matter increase.15N2 feeding of OS4 at heading showed more15N2 incorporation in the control than in the inoculated plants. The ARA,15N and N balance studies did not provide clear evidence that the promotion of growth and nitrogen uptake was due to higher N2 fixation.
Databáze: OpenAIRE
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