水田及水稻根部微生物固氮之研究

Studies of the Microbial Nitrogen-fixation in Rice Roots and Rice Paddies

林錫錦(Chyi-Jiin Lin)

《中華農業研究》 33卷1期 (1984/03) Pp. 44-52

https://doi.org/10.29951/JARC.198403.0006

摘要

水稻根部微生物固氮力弱，供試8個品種間固氮能力於每次採樣時品種間固氮活性之高低無一固定的傾向，水稻抽穗前之固氮活性較其他生長期高，70年第一期稻作之固氮活性較69年第二期稻作低。施用氮肥(120kg/ha)抑制根部微生物之固氮活性。由水稻根部分離到一種普遍存在於根上之革蘭氏陰性短桿固氮菌。
水田田土固氮力微弱，田水無固氮力。種值水稻之水田田土之固氮力比不種植水稻者高些，尤其以水稻抽穗前最顯著，在水稻生育期中，根圈土之固氮活性比底土者高。由水田田土分離到固氮藍綠藻Anabaena sp.及Nostoc sp.，以及一種廣泛存在於水田田土之革蘭氏陰性短桿固氮細菌。接種十種不同的固氮藍綠藻對盆栽水稻生長效應之研究，發現固氮藍綠藻HN 801品系對水稻之株高、穗數及穀產量之肥效約等於或超過施用半量化學氮肥(N 60kg/ha)者。

並列摘要

The N2-fixation rate of the excised rice root was low. The difference of N2-fixation rate among the eight rice varieties varied in every samplings during rice growth stages, and none have shown a definite trend of higher N2-fixation rate in every samplings. The nitrogenase activity was highest in the booting stage. The N2-fixation rate during the first rice crop-season of 1981 was lower than that of the second rice crop-season of 1980. The microbial nitrogenase activity of the rice root was inhibited with the application of 120 kg/ha of N fertilizer. A gram negative rod bacterium which is widely existed on the rice root and responsible for the nitrogen-fixation in the rice root was isolated.
Nitrogen-fixation rate in the rice paddies was very low. No nitrogenase activity was observed in the paddy waters. The nitrogenase activity of the paddy fields grown with rice was higher than that of the paddy fields without grown with rice, it was significantly different in the booting stage. In general, nitrogenase activity in the rhizosphere soil was higher than that of the subsurface soil. Nitrogen-fixing blue green, algae such as Anabaena sp. and Nostoc sp. were isolated from the rice paddies, and a gram negative rod nitrogen-fixing bacterium which is widely distributed in the rhisosphere soil was isolated. Greenhouse experiment was conducted to investigate the effect of ten strains of N2-fixing blue green algae on the growth response of rice plant. Inoculation of N2-fixing blue green algae HN 801 was found to give grain yield equal to/or higher than that of the yield of applying 60kg/ha of chemical N fertilizer.