【作者】 何亚慧；

【导师】 黄高宝； 郭丽琢；

【作者基本信息】 甘肃农业大学 ， 作物栽培学与耕作学， 2011， 博士

【摘要】 豌豆是干旱、半干旱地区一种重要的轮作倒茬作物,其固定的氮素能改良土壤并为下茬作物提供优质氮源。充分发挥其生物固氮作用,对修复干旱半干旱区的生态损伤和抑制土壤退化具有重要意义。目前在豌豆根瘤菌的基础研究方面,包括豌豆根瘤菌资源调查、采集与筛选的投入较少,限制了对豌豆共生固氮资源的利用。本研究采集甘肃、青海及陕西三省的定西、武威、庆阳、临夏、兰州、互助、格尔木及子洲八个不同生态区域根瘤样品353份,通过分离获得根瘤菌纯培养物364个,经蛭石回接初筛与土壤复筛后对筛选的豌豆根瘤菌进行抗逆、促生及固氮性能评估,同时系统性的研究了不同生态区域土壤因子对豌豆根瘤菌筛选的影响,主要研究结论如下:1、豌豆根系的结瘤状况与当地气候条件有关,庆阳、定西地区根瘤较少,子洲地区难以采集根瘤,而武威、兰州、格尔木地区土壤湿度较大,临夏、互助地区土壤质地疏松且降雨量充足,根瘤数量则较多。在青海互助地区发现球体状有效根瘤,直径达1cm左右。2、接种根瘤菌对豌豆生长具有一定的促进作用,与不接种对照相比,豌豆干物质积累量的增加2.9%-78.5%,其中菌株GDB27、GLC1及QGW19接种燕农2号与绿豌后,增幅达57%以上;且接种豌豆根瘤菌提高了植株收获后土壤氮素的有效性,黄绵土与灌淤土铵态氮含量分别增加25.5与17.7mg/kg,硝态氮增加15.7与7.9mg/kg。3、豌豆根瘤菌抗逆性能与菌株来源地生态环境密切相关,在盐胁迫和干旱胁迫下分离出的豌豆根瘤菌对盐分和干旱胁迫有良好的适应能力。34.5%的菌株可耐4.5%NaCl浓度,以QGW19、GWC7.3、GWWW16及GQZ5耐盐性最强;菌株普遍耐碱,但耐酸能力较弱,以GWC7.3耐碱能力最强,其次为GQZ5、QGW19、GWWW16及GLC1;菌株GLC1耐酸能力最强,其次为QGW19及GDW6;菌株可在渗透势为-0.6mPa—-0.2mPa范围的培养基中生长,当渗透势小于-0.6mPa时,根瘤菌生长明显受到抑制,48.3%菌株可在渗透势为-1.0mPa的培养基中生长,以GDB27与GQZ5耐旱能力表现最强,其次为SY12、GWC7.3、SZ32及GQC1。发现了一株功能复合型抗逆菌株GLC1,同时具备耐酸碱盐及耐旱能力。4、豌豆根瘤菌溶解有机磷能力较弱,但均具备分泌生长素能力。溶磷能力较强的菌株为QGW19与GLC1,其次为SY3.1、XC3.1、GWC7.3及GQZ5;10株豌豆根瘤菌分泌生长素能力较强,分别为QGW19、SY3.1、SY12、XC3.1、GWC7.3、GWWW16、GDB27、GQW28、GQZ5及GLC1。发现溶磷能力及分泌生长素能力较强的菌株QGW19、GLC1及XC3.1。5、豌豆根瘤菌的抗逆、分泌生长素及溶磷能力与其来源地土壤因子紧密相关,高有效氮含量及碱性土壤可以提高菌株耐盐能力,较高的速效钾含量能提高菌株的耐旱性,土壤有机质含量较高可提高菌株的耐酸能力;速效磷较高且弱碱性土壤环境会增加菌株溶解有机磷能力,而中性偏酸及高磷低氮土壤会增强菌株分泌生长素能力。6、根瘤菌株SY12、SY3.1及GDB27固氮能力较强,固氮量均在70mg/pot以上,且此三株菌均源于旱作农区。更多还原

【Abstract】 Pea(Pisum sativum L.) is an important rotation crop in many arid and semi-arid parts of the world, the nitrogen benefits to the following crop are reported. Pea cultivation in arid and semi-arid agricultural regions is of great significance to rehabilitation ecological damage and inhibition soil degradation. At present time, the study on basic research including the investigation, collection and selection of resources for pea Rhizobium is less, which limit the use of pea-Rhizobium resources. In our study, 353 nodules has been collected from 8 different ecological regions in Gansu, Qinghai and Shanxi province, namely Dingxi, Wuwei, Qingyang, Linxia, Lanzhou, Huzhu, Ge’ermu and Zizhou. 364 pure cultivation were obtained by seperation and purification, the ability of stress tolerance, growth-promoting and nitrogen fixation of strains was evaluated after back-inoculation and soil selection of Rhizobium strains. Meanwhile, the the effect of soil factors of different ecological regions on strains was analyzed and discussed. The main results as follows:1. The status of pea root nodule is relevant to the climate conditions of sampling in different ecological regions. The nodules were less in Qingyang and Dingxi, and it was hard to collect nodule in Zizhou. There was a number of nodules in the looser and higher humidity soil in Wuwei, Lanzhou, Ge’ermu, Linxia and Huzhu. The efficiently spherical nodules, about 1cm in diameter, were found in Huzhu, Qinghai province.2. Inoculation with the selection strains had a role in promoting growth of pea. Compared with CK, the shoot dry weight increased by 2.9%-78.5%. The strains GDB27, GLC1 and QGW19 inoculated Yannong No.2 and Luwan, the shoot dry weight increased by over 57% compared to CK. Rhizobium inoculated pea increased soil nitrogen after harvest in Loessial soil and Irrigation-silting soil, NH4+N respectively 25.5 and 17.7 mg/kg, NO3-N 15.7 and 7.9 mg/kg.3. The stress-tolerant ability of pea rhizobia was closely related to their ecological environment. Pea rhizobia from salt and drought stress conditons was able to adapt to the salt and drought stress. The test on salt tolerance of 29 pea rhizobia showed 34.5% of the strains was resistant to 4.5% NaCl concentration medium. QGW19 obtained from Ge’ermu, GWC7.3 and GWWW16 obtained from Wuwei, GQZ5 obtained from Qingyang were better than other strains in stress-tolerant ability; Pea rhizobia with alkaline tolerance from northwestern generally was found, but the acid tolerance was weak, the alkaline tolerance of GWC7.3 was the better, followed by GQZ5, QGW19, GWWW16 and GLC1, the acid tolerance of GLC1 was the best, followed by QGW19 and GDW6; The study found pea rhizobia could be growth in -0.6mPa-0.2mPa of osmotic potential medium, when the osmotic potential was less than -0.6mPa, the growth of rhizobia were significantly inhibited, 48.3% of strains in the osmotic potential -1.0mPa could be growth, the drought tolerance of GDB27 and GQZ5 were found, followed by SY12, GWC7.3, SZ32 and GQC1. Strain GLC1 with the salt-tolerance, acid and alkalinity-tolerance, drought-tolerance was found.4. Phosphate solubilization ability of pea rhizobia were weak, but pea rhizobia were indicated with the good ability of secretetion auxin. QGW19 and GLC1 had a better phosphate solubilization ability than other strains, followed by SY3.1, XC3.1, GWC7.3, GQZ5; 10 strains, including QGW19, SY3.1, SY12, XC3.1, GWC7.3, GWWW16, GDB27, GQW28, GQZ5 and GLC1, were indicated with the good ability of secretetion auxin. QGW19, GLC1 and XC3.1 with both phosphate solubilization and secretetion auxin ability were found.5. The stress-tolerant and growth-promoting ability of pea rhizobia were closely related to the soil factors in seperation regions. The salt-tolerant ability of strains could be relatively increased by higher soil available nitrogen and alkaline soil, the drought-tolerant ability of strains could be relatively increased by higher soil available K content, and the acid-tolerant capacity of strains could be relatively increased by higher soil organic matter content, and the alkaline-tolerant ability of strains was mainly affected by soil pH; The phosphate solubilization ability of pea rhizobia could be relatively enhanced under high soil available P and weak alkaline soil conditions, whereas the ability of secretetion auxin could be relatively broadened under neutral soil pH and high soil P and low soil N conditions.6. The study also found pea Rhizobium with high nitrogen-fixing ability was usually from dry farming areas, such as, SY12、SY3.1 and GDB27 (N fixed 70mg/pot over).更多还原