微生物環境としての水稲根圏
Rice Rhizosphere as an Environment of Microbial Growth

Makoto KIMURA, Hidenori WADA, Yasuo TAKAI
1983 Tsuchi to biseibutsu  
Most of the studies on rhizosphere have been c ( )ncerned with the plants grown in the upland soils, Even a few studies which dealt with rhizosphere of rice plants disregarded the speci 丘c physiological properties of the rice plants and reduced condition of thc submerged paddy soils , In order to know the general characteristics of rice rhizosphere , RIS ratios were 丘rst measured with rice plant grown ill Hooded soils and abnormally low R/S ratios were obtained for aerobic heterotrophs. As the
more » ... terotrophs. As the causes ofabnormally low R ! S rati 〔〕 s , 〔 i)gene し ical characteristics of rice plant, ( ii )10w concentration of microbial substrates exuded from rice roots , and ( iii )reduced condition Df flooded soils were considered . But the results that RIS ratios of rice plant during upland nursery stage were as high as those of Llpland plants, that the R 〆 S ratiQs Qf anaerobic microorgarlisms were very high during 日ooded stage and that thc cDncentrati (m of exuded sugars , arrlino acids alld organic acids were higher during fiooded stage than during uPland nursery stage denied the above ( D and ( ii }considerations . The numbers of aerobic microorganisms decreased as the soil Eh dccreased in both rhizosphere and non − rhizosphere soils . 八 旺( >re reduced condition at each stage ill the rhizosphere caused the low R 〆 S ratios , though the numbers of aerobic microorganisms were higher in the rhizosphere at the same Eh leve1 , The degree of Eh decrease and the physiological properties of rice plant also irif ! uenced the successiol ユ of microorgan 三 sins and precipi し ation . redissQlution of iron oxides on root surfaces and n ユicrobial activities ill the rhizosphere . The disapPearances of Poi) wn } vrα grami " is like Drganis エ ns ( P. gramin is 孟 s a strict aerobe )and precipitation − redisso 】 utioll of irQn oxides occurred around maximum tmering stage and this phenomena did not change wlth dif 〔 erent soil treatments . Several gases were produced successive [ y froln the rhizosphere
doi:10.18946/jssm.25.0_45 fatcat:ardgq63hp5ezna23jjuw3cpjmu