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草业学报 ›› 2015, Vol. 24 ›› Issue (7): 60-67.DOI: 10.11686/cyxb2014322

• 研究论文 • 上一篇    下一篇

苜蓿根瘤菌对不同形态磷利用效率的研究

刘卢生1, 玉永雄1*, *, 郭蕾2, 胡艳1, 周磊1, 王荣1   

  1. 1.西南大学动物科技学院,重庆市高校草食动物工程中心,重庆 400715;
    2.农民日报社,北京 100089
  • 收稿日期:2014-07-21 出版日期:2015-07-20 发布日期:2015-07-20
  • 作者简介:刘卢生(1979-),男,四川仁寿人,讲师。E-mail:liulushengl@163.com
  • 基金资助:
    国家支撑计划资助项目(2011BAD36B02,2011BAD36B03),中央高校基本科研业务费项目(DXJK2010C098)和948 项目(2014-Z31)资助

Utilization of different forms of phosphorus by Sinorhizobium meliloti

LIU Lu-Sheng1, YU Yong-Xiong1, *, GUO Lei2, HU Yan1, ZHOU Lei1, WANG Rong1   

  1. 1.Key Laboratory of Forage and Herbivore,College of Animal Science and Technology,Southwest University,Chongqing 400715, China;
    2.Farmer Daily, Beijing 100089, China
  • Received:2014-07-21 Online:2015-07-20 Published:2015-07-20

摘要: 为研究酸性土地区耐酸苜蓿根瘤菌对难溶性磷的利用,采用固体培养和液体培养方法在含不同形态磷(酵母膏有机磷、无机可溶性磷、磷酸钙、磷酸铝和磷酸铁),初始pH分别为4.1,7.0和9.0的培养基中进行了苜蓿根瘤菌的培养,观察并测定了不同固体培养基上的菌落形态和大小,液体培养基中根瘤菌的吸光度、培养液中有效磷含量和培养液pH。结果显示,在各pH条件下,无磷对照CK中的根瘤菌生长最差,其固体培养基上的菌落直径显著低于酵母膏有机磷对照(CKYE-P)和无机磷对照(CKP),同时,无磷对照液体培养中根瘤菌吸光度也远低于CKYE-P和CKP,说明在本试验条件下有效磷是影响根瘤菌生长的关键因素。固体培养基上4个不同难溶性磷处理中,植酸磷处理(TPhy-P)菌落直径在各pH条件下皆为最大,磷酸钙处理(TCa-P)次之,而磷酸铝处理(TAl-P)和磷酸铁处理(TFe-P)在各条件下的菌落直径都较小。根瘤菌经液体培养后,TPhy-P和TCa-P的培养液在酸性和中性条件下有效磷含量和根瘤菌吸光度较高,但碱性条件下则较低;TAl-P和TFe-P在各pH条件下的有效磷含量和根瘤菌吸光度皆较低。根瘤菌的接种培养使所有处理的pH下降,其中中性和酸性条件下的TCa-P以及中性条件下的TPhy-P培养液pH变化相对较小。未接种对照中,TPhy-P和TCa-P的有效磷含量在酸性条件下最大,随pH值升高而迅速降低,碱性条件下植酸钙镁几乎不溶;TAl-P和TFe-P在3种pH条件下的有效磷没有明显变化。与未接种对照比,除酸性条件下的TPhy-P和TCa-P外,其他接种处理的有效磷含量皆有不同程度的升高,碱性处理的升高幅度最大。苜蓿根瘤菌能较有效的利用植酸钙镁和磷酸钙中的磷,但在碱性条件下,对二者的利用大幅下降;根瘤菌很难利用磷酸铝和磷酸铁中的磷。培养液pH对植酸钙镁和磷酸钙的有效性影响较大,而对磷酸铝和磷酸铁影响较小。根瘤菌的生长会导致培养液pH的降低,促进难溶性磷中磷的释放,提高有效磷含量,但提高程度随磷形态而异。

Abstract: To study the utilization of different forms of phosphorous by acid-tolerant Sinorhizobium meliloti, rhizobia were cultured under three pH conditions; pH of 4.1, 7.0 and 9.0.Solid and liquid culture were used to investigate the growth of rhizobia in different phosphorus media [phosphorus free control (CK), organic phosphorus with yeast extract (CKYE-P), inorganic phosphorus with K2HPO4 (CKP), phytin (TPhy-P), calcium phosphate (TCa-P), aluminum phosphate (TAl-P) and iron phosphate (TFe-P)]. The colony morphology, diameter on solid media, absorbance and available phosphorous and pH in liquid medium were measured. Under all pH conditions, the rhizobia growth in CK was the poorest. Both the colony diameter of CKYE-P and CKP in solid media and the absorbance in liquid media were significantly higher than that in CK, suggesting that phosphorous was the key factor influencing the growth of rhizobia in this experiment. The colony diameter of rhizobiain thephytin treatment (TPhy-P) was largest in all media and pH levels; the aluminum phosphate treatment (TAl-P) and the iron phosphate treatment (TFe-P) produced the smalled colonies. After liquid culturing, the available phosphorus and rhizobia absorbance of TPhy-P as well as TCa-P in neutral and acid medium were much higher than those in alkaline medium. The available phosphorus and rhizobia absorbance of TAl-P and TFe-P were low in all media. The growth of rhizobia led to decreased pH in all media. When compared to the non-inoculated control, available phosphorus enhancement in the inoculated treatment was variable. The results shows that alfalfa rhizobia could effectively utilize phosphorous in the form of phytin and calcium orthophosphate, but that the availability of phosphorous under alkaline conditions declined dramatically. The phosphorous inaluminum phosphate and ironic phosphate was unavailable to alfalfa rhizobia. Media pH had a big influence on the availability of phytin and calcium orthophosphate but had little effect on the availability of aluminum phosphate and iron phosphate. Rhizobia growth could result in decreased media pH and increased available phosphate, but this was affected by phosphorus form.