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Enhancement of Medicago sativa Plant Growth and Yield after Treatment with Rhizobium spp.

Massadeh Muhannad I., Alkhataibeh Emtethal A., Al-Ghzawi Abdul Latief A., Aukour Fakher

Journal of Ecological Engineering

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2024

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Vol. 25, nr 2

33--43

EN

Rhizobium plays an important role in cultivation of legumes throughout the nitrogen fixation process. In the present study, the growth of alfalfa (Medicago sativa) was studied after treatment with Rhizobium spp. isolated from two different sites in Jordan. The effect of the two isolates (RS1 and RS2) and co-inoculation of the two isolates (RS1+RS2) was tested on alfalfa. Chlorophyll contents, relative water content, leaf area, shoot length, stem diameter and plant biomass (leaf, root and shoot dry weight) were studied under growth chamber conditions (day/night temperatures of 25°C; 16:8 h photoperiod) using different inoculum doses (10 ml, 20 ml and 40 ml). The effect of Rhizobium isolates on alfalfa was compared with rhizosphere plant growth-promoting rhizobacteria (PGPR) collected from the same soil samples. The results indicated that RS1 at high dose (40 ml) and RS2 at any dose significantly enhanced alfalfa growth in all measured parameters compared with control plants (without bacterial inoculation). RS2 was better than RS1 in most measured parameters even at low inoculum dose (10 ml), whereas no significant differences between the two strains were found at high inoculum doses. Co-inoculation of the two isolates was less effective than each isolate alone. On the other hand, the PGPR showed a significant enhancement of alfalfa growth as they enhanced significantly all measured parameters compared to the control plants at all doses.

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Use of Rhizosphere Microorganisms in Plant Production – A Review Study

Paliwoda Dominika, Mikiciuk Grzegorz

Journal of Ecological Engineering

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2020

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Vol. 21, nr 8

292--310

EN

Minimizing or neutralizing the effects of environmental stresses on crop plants, protecting against pests and diseases, and at the same time ensuring optimal plant growth and development are currently the most important tasks faced by growers and plant producers around the world. Nowadays, the goal is to limit the use of chemicals as much as possible to protect the environment and improve the quality of food. The interest in the use of beneficial rhizosphere microorganisms is becoming global, as it can represent an environmentally friendly alternative to chemicalization in the era of threats to crop cultivation in the modern world (climate change, drought, salinity, introduction of plant pests).

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Zastosowanie drobnoustrojów o działaniu synergistycznym w procesie biologicznego wiązania azotu

Waraczewska Z., Niewiadomska A., Kosicka-Dziechciarek D.

Woda-Środowisko-Obszary Wiejskie

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2017

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T. 17, z. 2

157--168

PL

W ostatnich latach wzrosło zainteresowanie optymalizacją i zwiększeniem biologicznego wiązania azotu przez układy symbiotyczne z równoczesną poprawą właściwości chemicznych, biologicznych i fizycznych gleby. Cele te mogą być realizowane w ramach zielonej biotechnologii, w tym przez wykorzystanie mikroorganizmów stymulujących wzrost roślin, tzw. PGPR (ang. Plant Growth Promoting Rhizobacteria), poprzez zastosowanie koinokulacji (jednoczesnego szczepienia) makrosymbiontów (roślin) odpowiednim szczepem z rodziny Rhizobiaceae oraz endofitem o działaniu synergistycznym. Bakterie z grupy PGPR, stosowane do koinokulacji w uprawach roślin bobowatych mogą wpływać na rośliny bezpośrednio m.in. poprzez dostarczanie pokarmu roślinom, a także pośrednio przez indukuję odporności roślin na patogeny i szkodniki. Ponadto endofity mają zdolność wydzielania regulatorów wzrostu, takich jak auksyny, gibereliny czy cytokininy, które mają wpływ na zwiększenie wydajności diazotrofii. Poprzez zastosowanie koinokulacji obserwuje się zwiększenie liczby brodawek, wzmocnienie kolonizacji korzenia przez bakterie z rodziny Rhizobiaceae oraz wzrost poziomu aktywności nitrogenazy. Potencjał PGPR wykorzystywanych w układach symbiotycznych jest szeroko udokumentowany w licznych pracach naukowych, ale nie został dotychczas dostatecznie wykorzystany. Niniejszy przegląd literatury ma na celu przedstawienie i usystematyzowanie dotychczasowej wiedzy dotyczącej wpływu koinokulacji roślin na wydajność procesu biologicznego wiązania azotu.

EN

In recent years, researchers have increasingly focused their interests on searching for products allowing optimisation and enhancement of biological nitrogen fixation with the assistance of symbiotic systems accompanied by a simultaneous improvement of soil chemical, biological and physical properties. “Green biotechnology” confronted these issues indicating possibilities of utilisation of microorganisms stimulating plant growth, the so called Plant Growth Promoting Rhizobacteria (PGPR) employing coinoculation (simultaneous inoculation) of (plant) macrosymbionts with an appropriate strain from the Rhizobiaceae family and an endophytic bacteria characterised by synergistic action. Bacteria from the PGPR group employed for the coinoculation of legume plants affect these plants directly, among others, by supplying nutrients for plants as well as indirectly by inducing plant resistance against patogens and pests. In addition, endophytes are capable of secreting growth regulators such as auxins, gibberellins or cytokinins, which can exert impact on increased diazotroph efficiency. Application of coinoculation results in amplified numbers of nodules, strengthening of root colonisation with bacteria from the Rhizobiaceae family and in increased levels of nitrogenase activity. Potentials of PGPR group employed in symbiotic systems have been documented extensively in numerous scientific publications but until now these capabilities have not been sufficiently utilised. The discussed literature review aims at presenting and systematising our current knowledge regarding influence of plant coinoculation on the optimisation of the biological nitrogen fixation process.

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The application of plant growth promoting rhizobacteria (PGPR) in low input and organic cultivation of graminaceous crops; potential and problems

Cummings S. P.

Environmental Biotechnology

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2009

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Vol. 5, No. 2

43-50

EN

Although the uses of plant growth stimulating bacteria (PGPR) to improve the yield of graminaceous crops have been studied for over seventy years the utility of the technology remains uncertain. Increases in crop yield have often been inconsistent, reflecting a lack of understanding of the mechanisms by which PGPR exert their effects. Because PGPR are able to fix N2, this was initially assumed to boost crops by supplementing soil N. However, it is now clear, that for most free living PGPR, other mechanisms affecting root development, and nutrient uptake can account for the observed increase in crop yields. Here we review the current state of our understanding of PGPR in graminaceous crop cultivation, identifying their potential contribution to more sustainable agricultural practices but also highlighting issues that need to be addressed before this technology can be appropriately assessed as a replacement for inorganic N addition.