共查询到18条相似文献,搜索用时 312 毫秒
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甘宁黄土高原地区重要水土保持植物共生固氮资源及特性研究 总被引:6,自引:0,他引:6
甘肃省黄土高原区不同生态条件下栽培和野生豆科植物根瘤菌资源及共生固氮特性的调查结果表明 ,从 112份 2 4属 5 3种根瘤样品中分离获得 87株根瘤菌。它们与豆科植物共生结瘤 6 3 .5 %为有效根瘤。不同种根瘤固氮活性差异较大 ,一般比较低 ,小于 1μmol/(g·h)占 35 %。大于 10 μmol/(g·h)仅占6 %。根据研究结果对这些豆科植物在水土保持中的作用及意义进行了讨论。 相似文献
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甘肃省白龙江流域豆科植物根瘤菌共生固氮研究 总被引:2,自引:0,他引:2
对甘肃省白龙江流域甘南、陇南的大部分地区豆科植物——根瘤菌资源进行了调查 ,共采集 2 1属45种豆科植物 6 9份根瘤样品。从 6 9份样品中获 6 3株根瘤菌 ,对其中 44株根瘤以 13种寄主进行了回接试验 ,31株结瘤 ,结瘤率 70 .5 %。该区根瘤一般带有粉红色 ,形态比较规则。乙炔还原活力测定结果表明 ,88.5 %为有效根瘤。不同种根瘤固氮活性相差不大 ,但高于甘肃省其它地区。对豆科植物在蓄水保土 ,改良土壤状况中的地位进行了讨论。 相似文献
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豆科植物和根瘤菌在生态环境中的地位和作用 总被引:8,自引:0,他引:8
随着我国人口的增加和城市化进程的加快,人类对土地资源的需求不断增加,土地使用的透支趋势明显;另一方面大量使用农用化学物质,对生态环境的胁迫增大。豆科植物在根系中因其可与根瘤菌共生形成特殊结构---根瘤,具有生物固氮作用而受到广泛关注。种植豆科植物,利用豆科植物和根瘤菌形成的共生固氮体系可以减少氮肥的投入,增加土壤的有机质含量,改善土壤生态环境,是一种天然的利于生态环境的农业生产方式。本文介绍了豆科植物和根瘤菌的一些重要特征,论述了豆科植物与根瘤菌共生的关系,表明发展豆科植物对于生态环境的修复、维持土地的生产力以及节能减排方面的重要作用,以期为改善生态环境提供一些可参考的方法和依据。 相似文献
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根瘤菌结瘤基因的表达调控研究概况 总被引:5,自引:0,他引:5
根瘤菌结瘤基因的表达调控在根瘤菌与植物的共生结瘤过程中起着十分重要的作用。随着研究的深入,发现根瘤菌的结瘤过程不仅与根瘤菌结瘤基因表达调控有关,而且与寄主植物的信号分子如黄酮类物质有关。根瘤菌结瘤基因的表达调控有一个复杂的过程,本文将简要地介绍这方面的研究成果。 相似文献
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许多细菌均能产生一类叫做自体诱导物的信号分子,用于感知自身密度的变化,从而调控其生理行为,这种现象称为群体感应[1]。越来越多的研究表明,在根瘤菌中普遍存在着群体感应调控系统[2],并且它可能在根瘤菌与豆科植物共生结瘤固氮过程中起着重要作用。目前,在豌豆根瘤菌中共发现有4种群体感应系统(rai,rhi,cin和tra),其中cin系统位于上游,起总调控作用,tra系统控制着质粒的转移,rhi系统与结瘤数量有关,rai系统的功能还不清楚,它们共同组成了一个复杂的群体感应调控系统[3]。在苜蓿中华根瘤菌中,也发现群体感应系统与根瘤菌的生长和结瘤效率有关[4]。对中慢生型华癸根瘤菌和天山根瘤菌的研究 相似文献
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活性氧(reactive oxygen species,ROS)是一类具有高反应活性的氧衍生物,包括超氧阴离子(·O2—)、羟自由基(·OH)、过氧羟自由基(·HO2)以及过氧化氢(H2O2)等。植物在进行有氧代谢或遭遇生物与非生物胁迫时会产生ROS,它不仅仅是有氧代谢的有毒副产物,同时能作为信号分子调节体内代谢过程,对抗外界环境。豆科植物形成根瘤时同样会产生ROS,这种ROS的变化区别于病原体入侵,而是作为一种信号物质参与结瘤过程。结瘤因子(nod factor,NF)诱导下ROS的产生参与了浸染线形成时细胞壁的重建、植物基质糖蛋白(matrix glycoprotein,MGP)的交联和肌动蛋白微丝的成核和延长过程。细胞质膜NADPH氧化酶(respiratory burst oxidase homologue,RBOHs)是共生过程中ROS产生的主要途径,Rboh基因的过表达会促进根瘤菌浸染和根瘤形成,同时根瘤中的共生微粒体数量增加,固氮效率提高,而表达受抑制后会减少ROS的产生,同时下调结瘤相关基因RIPs、NIN、ENOD2的表达,抑制固氮酶活性。此外,ROS时空上的变化与Ca2+相关联,协同调控根系结瘤。ROS的产生是植物与微生物早期的识别信号,通过认识ROS在早期结瘤过程中的作用有助于我们进一步理解共生关系建立的特异性。本文就ROS在早期结瘤过程中的产生及其发挥的作用做了综述,指出ROS通过直接或间接作用诱导结瘤基因的表达,是豆科植物根瘤形成以及功能固氮的重要信号分子。 相似文献
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根瘤菌与豆科植物共生可以固定大量的氮。根瘤菌剂接种豆科作物是一项普遍推广应用、有效的农业技术。但由于大量土著根瘤菌的存在,产生竞争障碍,降低了接种菌剂的占瘤率。大多数的土著根瘤菌对春雷霉素敏感,因此接种抗春雷霉素的高效结瘤固氮根瘤菌,并用春雷霉素处理种子,可抑制土著根瘤菌,提高接种菌剂的占瘤率,从而达到高结瘤、高固氮和提高产量的目的。本文将探讨诱变对根瘤菌抗春雷霉素突变的作用,并对获得的抗性突变株的生物固氮特性进行分析。 相似文献
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Abstract Nitrogen contents, nodule numbers, and nodule dry weights of 6-week-oId Sesbania rostrata plants grown in sand culture with only root nodules, only stem nodules or with both were compared and the root nodules were found to contribute to nitrogen acquisition more significantly than the stem nodules. Similar findings were obtained in 15N2-fixing experiments. An 8-week-old plant with both stem and root nodules fixed 1.50 mg nitrogen in a 12 h light period, while the fixation decreased to 1.15 mg nitrogen after the removal of the stem nodules, suggesting that root nodules played major role in nitrogen fixation. However, acetylene-reducing activities per nodule dry weight were higher in the stem nodules. Under flooding conditions, the aerenchyma tissues contributed to about 40% of N2 transport to root nodules, and 60% was supplied through stem. 相似文献
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Exceptional symbiotic nitrogen fixation with Sesbania has provided high soil fertility for many past centuries of paddy rice production. Unique stem nodulation results in high nitrogenase activity levels of S. rostrata, Brem, during rapid growth in continuously flooded rice fields that greatly disfavor legume root nodulation and this functional development. The objective of this study was to determine plant nutrient interactions that influence contrasting root and aerial stem nodule histology governing effective nitrogenase activity levels and nitrogen fixation. Top growth, nodulation, and nitrogenase activity levels were significantly increased with increased available soil P. Response to K levels and Ca additions resulted only when soil P was adequate in all treatment combinations. However, there was no significant correlation between fresh nodule weight, nitrogenase activity, and nodules plant‐1 for both root nodules and aerial stem nodules. Nodule histology was highly contrastive with nodule type and Rhizobium morphology, cytosol composition, and governing enzyme activity levels. Distinctive nonpleomorphic cocci bacteroids of functional aerial stem nodules have tentative designation as Azorhizobium caulinodans gen. nov. sp. nov. 相似文献
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不同水氮耦合管理下耕层土壤的氮动态 总被引:1,自引:1,他引:0
以中国科学院封丘农业生态试验站水氮耦合长期试验地为研究平台,采集了不同水氮耦合管理下耕层0~10 cm、10 ~ 20 cm和0~20 cm土壤,测定了六种形态的氮(无机氮、有机氮、酸解有机氮、酸解铵态氮、溶解性有机氮和微生物生物量氮)和三种与氮周转密切相关的生物性指标(脲酶活性、蛋白酶活性和硝化势).三因素方差分析结果表明,施氮和耕层深度对六种形态氮均有显著作用,而灌水对这六种形态氮无显著作用.单因素方差分析结果显示施氮明显提高了耕层0 ~ 20 cm土壤无机氮、有机氮、脲酶活性及硝化势,而对土壤酸解有机氮和酸解铵态氮无显著影响;六种形态的氮、蛋白酶活性及硝化势均不受灌水量的影响.不同水氮耦合管理下耕层0 ~ 10 cm土壤六种形态氮、脲酶活性、蛋白酶活性及硝化势几乎均明显地高于10~20 cm土壤.通过对不同水氮耦合管理下耕层土壤氮动态的研究,本研究得出最佳的水氮耦合管理模式是灌水至20 cm土层的田间持水量和每季施氮190 kg hm-2. 相似文献
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Junichi Yamaguchi 《Soil Science and Plant Nutrition》2013,59(2):367-383
Abstract It is well known that stem nodules are formed on the aerial parts of Aeschynomene spp. and Sesbania rostrata grown in the field (Yatazawa and Yoshida 1979; Dreyfus and Dommergues 1981; Yoshida et al. 1985). We have reported that stem nodules were successfully formed by inoculation of Rhizobium isolates derived from both stem and root nodules of A. indica (Yoshida et al. 1985; Sasakawa et al. 1986). The specific activity of nitrogen fixation in stem nodules is comparable to that of root nodules (Sasakawa et al. 1986; Sasakawa 1990). A red pigment, which suggests the presence of leghemoglobin, was detected in stem nodules as well as in root nodules (Yatazawa and Yoshida 1979; Yatazawa and Susilo 1980; Sasakawa et al. 1986). 相似文献
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Junko Terakado Shinsuke Fujihara Shigeko Goto Ryoko Kuratani Yoshito Suzuki Shigeo Yoshida Tadakatsu Yoneyama 《Soil Science and Plant Nutrition》2005,51(3):389-395
Leguminous plants form nitrogen-fixing root nodules and the number of nodules is controlled by a self-regulating mechanism called autoregulation. However, signaling substances involved in nodule regulation have not been identified. In the present study, we used brassinolide, a most effective molecular species of plant hormone brassinosteroids, and brassinazole, an effective inhibitor of brassinosteroid biosynthesis to determine whether brassinolide played a role in systemic regulation of noduel formation in wild type soybean and its super-nodulating mutant. Foliar application or direct injection of brassinolide into the root base inhibited nodule formation and root development in the super-nodulating mutant (En6500), but not in the parent line (cv. Enrei). The internodes in the plants subjected to foliar application were significantly longer than those in the untreated plants. In contrast, the application of brassinazole on mature leaves or into the culture media resulted in the increase of the nodule number in Enrei. These treatments also inhibited internodal growth in Enrei. The results indicate that brassinosteroids may regulate the nodule number in soybean plants. The function of brassinosteroids for the systemic regulation of nodule formation was examined. 相似文献