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Biotic factors and interactions among organisms
Published in Stephen R. Gliessman, V. Ernesto Méndez, Victor M. Izzo, Eric W. Engles, Andrew Gerlicz, Agroecology, 2023
Stephen R. Gliessman, V. Ernesto Méndez, Victor M. Izzo, Eric W. Engles, Andrew Gerlicz
Another important example of a mutualism is the relationship between legumes (plants in the Fabaceae family) and Rhizobium bacteria. The bacteria enter the root tissue of a legume plant, causing the tissue to form nodules in which the bacteria live and reproduce (Figure 7.6). The nodules, formed from root tissue, represent an addition interference on the part of the legume plant. The legume also provides the bacteria with sugars. The bacteria’s addition interference comes in the form of fixed (useable) nitrogen, which the bacteria produce from atmospheric nitrogen. The legume would be greatly handicapped in its growth without the fixed nitrogen provided by the bacteria, and the bacteria require the root nodules for optimal growth and reproduction. The fixing of nitrogen by Rhizobia is one the most important means by which nitrogen is moved from the vast atmospheric reservoir into soil and biomass.
Algae: Role in Environment Safety
Published in Ali Pourhashemi, Sankar Chandra Deka, A. K. Haghi, Research Methods and Applications in Chemical and Biological Engineering, 2019
Rajeev Singh, Hema Joshi, Anamika Singh
Azobacter, Azospirillium, blue–green algae, Azolla, micorrhizae, and sinorhizobium are used to benefit the crop production. Azobactor, blue green algae, Rhizobium, and Azospirillium are capable for the nitrogen fixation. Rhizobium bacteria are used to increase the nitrogen fixation capacity in leguminous plants. Blue green algae like Nostoc, Tolypothrix, and Aulosira helps in atmospheric nitrogen fixation and hence enrich the soil fertility. In the millets, sorghum, sugarcane, maize, and wheat field, Azospirillium is used. Cyanobacteria or Blue green algae are a group of microorganism, which plays an important role in the maintenance and buildup of soil fertility as they can fix atmospheric nitrogen. They help to improve the soil’s aeration and water holding capacity. They also add biomass after their decomposition. Azolla is an aquatic fern, found in symbiotic association with Blue green algae. They are found in small and shallow water bodies as well as in rice fields. Biofertilizers are environment friendly and they do not damage the environment like chemical fertilizer does. They are cheap and can be used by farmers easily. They help in the improvement of soil fertility with time. Microorganisms help in the conversion of complex organic material into simple one. So, plant can easily take up the nutrients. They increase the phosphorus content of soil. They help in increasing the crop yield.
Associative Nitrogen-Fixing Bacteria in the Rhizosphere of Rice
Published in Yoshikatsu Murooka, Tadayuki Imanaka, Recombinant Microbes for Industrial and Agricultural Applications, 2020
In contrast, the amount of atmospheric nitrogen fixed biologically on the earth is estimated to be 180 million tons per year [2]. One-half of that is performed in the agricultural field. The importance of rhizobia, which make root nodules on leguminous plants, is well known, and the amount of N2 fixed by them is about 80 million tons. Rhizobia have been used in agriculture without any artificial inoculation, by the process of green manure using leguminous plants such as Chinese milk vetch. Nowadays, efficient strains of rhizobia are sometimes used to inoculate leguminous crops such as soybean. But, they cannot be used with main nonleguminous crop plants, such as rice and wheat.
Ex situ bioremediation of diesel fuel-contaminated soil in two different climates
Published in International Journal of Phytoremediation, 2023
Tjaša Cenčič Predikaka, Tinkara Mastnak, Marta Svoljšak Jerman, Matjaž Finšgar
In this study, the LUs were first seeded with Trifolium repens (zero state). This plant species was chosen for its ability to fixate nitrogen via a symbiotic relationship with Rhizobium species, which is also a common agricultural practice in natural soil fertilization. Fabaceae species are known for their ability to enhance the remediation of hydrocarbon contaminants, to improve soil nutrient and oxygen status, and to increase the bioavailability of contaminants (Tischer and Hübner 2002). Wang and Oyaizu studied the remediation potential of four plant species to evaluate their impact on the remediation of dibenzofuran-contaminated soils (Yanxu and Oyaizu 2009). Their findings revealed that the white clover Trifolium repens was the most promising plant species for this purpose. Trifolium repens is also widespread in the sub-Mediterranean (Location 1) and temperate continental climates in the sub-Pannonian region (Location 2). The vegetation growing on both LUs was used as a natural fertilizer after the turn overs, thus adding nutrients to the polluted soil.
Insights in nodule-inhabiting plant growth promoting bacteria and their ability to stimulate Vicia faba growth
Published in Egyptian Journal of Basic and Applied Sciences, 2022
Amr M. Mowafy, Mona S. Agha, Samia A. Haroun, Mohamed A. Abbas, Mohamed Elbalkini
Symbiotic nitrogen fixation, which is positioned as a major part of biological nitrogen fixation, is an important alternative source of chemical nitrogen fertilizers not only for leguminous but also for non-leguminous plants. The interaction between legumes and rhizobia leads to root nodule organogenesis, an organ that is produced in response to bacterial nod factors and plant developmental signals leading to the formation of a plant stem cell niche [1]. Recently, rhizobia have been shown to improve the nutrition of non-leguminous crops, such as barley, wheat and canola [2]. It has been established that the legume nodule is exclusively inhabited by the rhizobium. Meanwhile, in 2001, this concept has changed dramatically when non-rhizobial strains were regarded for their ability to nodulate legumes, such as Methylobacterium and Burkholderia that have been isolated from Crotalaria [3] and Mimosa [4], respectively. In addition to nodule-inducing bacteria, several bacterial strains have been isolated from nodules as co-inhabitants with rhizobium, such as Klebsiella, Pseudomonas [5], Bacillus [6] and Streptomyces [7]. Interestingly, a review titled ‘the nodule microbiome: N2-fixing rhizobia do not live alone’ has been published in 2017 to conclude that some of these non-rhizobial bacteria might be nitrogen fixer or participate in nodule genesis and the others, more striking, might neither participate in nodulation nor fix nitrogen [8].
Isolation of endophytic bacteria from the medicinal, forestal and ornamental tree Handroanthus impetiginosus
Published in Environmental Technology, 2022
Mauro Enrique Yarte, María Inés Gismondi, Berta Elizabet Llorente, Ezequiel Enrique Larraburu
The genus Rhizobium is widely known for the symbiotic association it establishes with leguminous plants. This interaction is characterized as being very specific and promoting the formation of root nodules. However, it is possible to find strains of Rhizobium spp. colonizing the rhizosphere or living as endophytes within tissues of non-legume plants [32]. In these cases, no nodule formation is observed but there may be promotion of plant growth through atmospheric nitrogen fixation, phytohormone production, and through other indirect mechanisms. Rhizobium spp. have been isolated also from woody non-legume plants. Indeed, Doty et al. [33] and García-Fraile et al. [34] isolated Rhizobium spp. from stems of Populus deltoides and Populus alba, respectively. In our work, we isolated two strains belonging to this genus from roots of pink lapacho. However, they were only able to fix nitrogen under the conditions tested.