四種綠肥根瘤菌的分泌物及其溶磷特性之研究

Studies on the Exudate and Characteristics of the P-solubilization of Rhizobia from Four Green Manure

楊秋忠(Chiu-Chung Young) ； 洪麗蓉(Li-Jung Hung) ； 陳立夫(Lih-Fu Chen)

《土壤與環境》 1卷1期 (1998/03) Pp. 7-17

https://doi.org/10.30058/SE.199803.0002

摘要

本研究以台灣重要綠肥作物田菁（Sesbania roxburghii）、太陽麻（Crotalaria juncea）、苕子（Vicia dasycarpa）與黃花羽扇豆（Lupinus luteus）等綠肥為材料，從根瘤中分離出各該綠肥作物之根瘤菌，分別測定其固氮及溶解無機磷酸鹽的能力，期篩選出具優良固氮與溶磷能力者，並研究探討不同菌種之間溶磷能力上的差異，以及此種差異與有機酸的種類與生成量之關係。經分離之綠肥根瘤菌（S85、C13、V19及L12）純化後，再接種回原綠肥植物觀測根瘤生成及測定乙炔還原能力，結果發現L12菌株固氮能力最佳，且固氮能力與根瘤數目多寡無關。四菌株於含磷酸三鈣之液體培養基中測得之最大溶磷量依次為58.2、69.6、75.1和86.4 μg mL^(-1)。在培養初期，溶磷量與菌株族群大小成比例，其後則有降低之趨勢。綠肥根瘤菌所分泌之有機酸的分析，以S85和L12菌株產生較相同種類的有機酸，且L12菌株極可能藉分泌葡萄醣酸（gluconic acid）而成為優良溶磷者。在菌液培養基中之離子養分會促進萵苣胚莖生長，而根瘤菌菌株分泌液則助於萵苣胚根生長。

關鍵字

綠肥根瘤菌 ； 溶磷作用 ； 有機酸 ； 生物分析

並列摘要

The objectives of this study were to take important green manure crops including sesbania (Sesbania roxburghii), sun hemp (Crotalaria juncea), vetch (Vicia dasycarpa) and yellow lupin (Lupinus luteus), to isolate the green manure rhizobia from the nodules of these crops and determine the acetylene reduction activity and P-solubilizing abilities of the green manure rhizobia. This study also endeavors to further understand the different P-solubilizing ability of various isolates and their connection to the amount of P-solubilization and organic and compounds.The results revealed that L12 showed the best acetylene reduction activity of the rhizobia tested which were isolated individually from the field soil of green manure specimens. There was no significant relationship between the number of nodules and the N2-fixation ability. The maximum amount of soluble phosphate of S85, C13, V9 and L12 were 58.2, 69.6, 75.1 and 86.4 μg mL^(-1), respectively after inoculating in a liquid tricalcium phosphate medium. Furthermore, the amount of soluble phosphate appears to have a direct correlation with the population of isolates. The assay of organic acid excreted by the rhizobia showed that S85 and L12 produced similar kinds of organic acid, and that the isolate L12 appears to be the superior P-solubilizing isolate. This may be due to the production of gluconic acid. The results of the bioassay revealed that the ions in the liquid tricalcium phosphate medium had a better effect on the epicotyl growth of lettuce seedlings and that the rhizobial excreted organic acid which promoted the growth of the radicals significantly.

並列關鍵字

rhizobia of green manure ； p-solubilization ； organic acid ； bioassay