| Summary: | 碩士 === 國立臺灣大學 === 農業化學研究所 === 90 === One system being studied is the symbiotic, nitrogen-fixing infection of host legumes by rhizobia. The nitrogen-fixing symbiosis is a complex infection process in which the soil bacteria provide fixed nitrogen and the plant provides a source of carbon, energy, and electrons. The study is to compare the amount of rhizobia (Sinorhizobium fredii RO、TU6)incubated in two different medium, which one is ABJ (Alfalfa brown juice) which is the co-product during purifying leaf protein, and the other is YEM (Yeast extract mannitol) which is usually used as the growth medium for rhizobia. After 30 hours in incubating rhizobia(Sinorhizobium fredii RO、TU6) by ABJ and YEM, the amount of rhizobia using ABJ as medium are 1.8 and 1.9 times higher than YEM. Before being infected with rhizobia, we immerse the soybean root in ABJ for 40 minutes, and we find that the number of nodules and the dry weights of these nodules are 1.5 and 1.6 times higher than untreated soybean roots, respectively. The soybean infected with rhizobia, which incubates in ABJ has the number of nodules and dry weights 2.8 and 3.2 times higher than which is incubated in ABJ .In addition to the amounts and dry weight of nodules, the specific adsorption is also increased. The maximum adsorption of rhizobium incubated in YEM medium, which infects the soybean root immersed in ABJ after 120 minutes is better than the ones without ABJ. According to the above results, either treating the root with ABJ or using ABJ as the growth medium for rhizobia can increase the numbers of nodules and also make the root hair curling at the initial infection.
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