Arbuscular mycorrhizal symbiosis ameliorates the optimum quantum yield of photosystem II and reduces non-photochemical quenching in rice plants subjected to salt stress

We investigated the influence of Salvia fruticosa colonization by the arbuscular mycorrhizal fungi (AMF) Rhizophagus irregularis on photosynthetic function by using chlorophyll fluorescence imaging analysis to evaluate the light energy use in photosystem II (PSII) of inoculated and non-inoculated plants. We observed that inoculated plants used significantly higher absorbed energy in photochemistry (ΦPSII) than non-inoculated and exhibited significant lower excess excitation energy (EXC). However, the increased ΦPSII in inoculated plants did not result in a reduced non-regulated energy loss in PSII (ΦNO), suggesting the same singlet oxygen (1O2) formation between inoculated and non-inoculated plants. The increased ΦPSII in inoculated plants was due to an increased efficiency of open PSII centers to utilize the absorbed light (Fv’/Fm’) due to a decreased non-photochemical quenching (NPQ) since there was no difference in the fraction of open reaction centers (qp). The decreased NPQ in inoculated plants resulted in an increased electron-transport rate (ETR) compared to non-inoculated. Yet, inoculated plants exhibited a higher efficiency of the water-splitting complex on the donor side of PSII as revealed by the increased Fv/Fo ratio. A spatial heterogeneity between the leaf tip and the leaf base for the parameters ΦPSII and ΦNPQ was observed in both inoculated and non-inoculated plants, reflecting different developmental zones. Overall, our findings suggest that the increased ETR of inoculated S. fruticosa contributes to increased photosynthetic performance, providing growth advantages to inoculated plants by increasing their aboveground biomass, mainly by increasing leaf biomass.

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Arbuscular mycorrhizal symbiosis influences strigolactone production under salinity and alleviates salt stress in lettuce plants

Journal of Plant Physiology ◽

10.1016/j.jplph.2012.08.020 ◽

2013 ◽

Vol 170 (1) ◽

pp. 47-55 ◽

Cited By ~ 167

Author(s):

Ricardo Aroca ◽

Juan Manuel Ruiz-Lozano ◽

Ángel María Zamarreño ◽

José Antonio Paz ◽

José María García-Mina ◽

...

Keyword(s):

Salt Stress ◽

Arbuscular Mycorrhizal ◽

Arbuscular Mycorrhizal Symbiosis ◽

Mycorrhizal Symbiosis

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Categorization of the water status of rice inoculated with arbuscular mycorrhizae and with water deficit

Agronomía Mesoamericana ◽

10.15517/am.v32i2.42066 ◽

2021 ◽

pp. 339-355

Author(s):

Michel Ruiz Sánchez ◽

Juan Adriano Cabrera Rodríguez ◽

José M. Del'Anico Rodríguez ◽

Yaumara Muñoz Hernández ◽

Ricardo Aroca Álvarez ◽

...

Keyword(s):

Water Stress ◽

Water Deficit ◽

Mycorrhizal Fungi ◽

Water Status ◽

Light Stress ◽

Arbuscular Mycorrhizal ◽

Arbuscular Mycorrhizal Symbiosis ◽

Control Treatment ◽

Mycorrhizal Symbiosis ◽

Rice Plants

Introduction. The water deficit negatively affects rice plants and limits their productivity. Arbuscular mycorrhizal symbiosis has been shown to improve rice productivity in drought conditions. Objective. To propose a new categorization for the state of water stress of rice plants inoculated (AM) or not with arbuscular mycorrhizal fungi (nonAM) and exposed to water deficit (D) during the vegetative phase. Materials and methods. The experiment was carried out under controlled greenhouse conditions during the years 2009 and 2010 at the Zaidín Experimental Station, Granada, Spain. The rice transplantation was carried out fourteen days after germination to pots with a 5 cm water sheet and at 30, 40, or 50 days after transplantation (DAT) they were subjected to water deficit during a period of 15 days, at which time the water sheet was restored. The control treatment was maintained throughout the cycle under flood conditions (ww). Evaluations were performed at 45, 55, 65 DAT and after recovery at 122 DAT. The harvest was carried out at 147 DAT. Results. The reduction in water supply demonstrated water stress in the plants, manifested by the decrease in the water potential of the leaves. Arbuscular mycorrhizal symbiosis always favored the water status of the plant. Four categories of water status of plants were proposed taking into account water potentials and agricultural yield: no stress (≥-0.67 MPa); light stress (<-0.67 to -1.20 MPa); moderate stress (<-1.20 to -1.60 MPa), and severe stress (<-1.60 MPa). Conclusion. The categorization of stress due to the water deficit is a tool of high scientific value for the specific case of rice, since this plant has the capacity to adapt to tolerate the presence of a sheet of water throughout its biological cycle and is highly susceptible to water deficit.

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Changes in Photo-Protective Energy Dissipation of Photosystem II in Response to Beneficial Bacteria Consortium in Durum Wheat under Drought and Salinity Stresses

Applied Sciences ◽

10.3390/app10155031 ◽

2020 ◽

Vol 10 (15) ◽

pp. 5031 ◽

Cited By ~ 1

Author(s):

Mohammad Yaghoubi Khanghahi ◽

Sabrina Strafella ◽

Carmine Crecchio

Keyword(s):

Chlorophyll Fluorescence ◽

Energy Dissipation ◽

Quantum Yield ◽

Photosystem Ii ◽

Excitation Energy ◽

Durum Wheat ◽

Photochemical Quenching ◽

Plant Growth Promoting Bacteria ◽

Psii Photochemistry ◽

Non Photochemical Quenching

The present research aimed at evaluating the harmless dissipation of excess excitation energy by durum wheat (Triticum durum Desf.) leaves in response to the application of a bacterial consortium consisting of four plant growth-promoting bacteria (PGPB). Three pot experiments were carried out under non-stress, drought (at 40% field capacity), and salinity (150 mM NaCl) conditions. The results showed that drought and salinity affected photo-protective energy dissipation of photosystem II (PSII) increasing the rate of non-photochemical chlorophyll fluorescence quenching (NPQ (non-photochemical quenching) and qCN (complete non-photochemical quenching)), as well as decreasing the total quenching of chlorophyll fluorescence (qTQ), total quenching of variable chlorophyll fluorescence (qTV) and the ratio of the quantum yield of actual PSII photochemistry, in light-adapted state to the quantum yield of the constitutive non-regulatory NPQ (PQ rate). Our results also indicated that the PGPB inoculants can mitigate the adverse impacts of stresses on leaves, especially the saline one, in comparison with the non-fertilized (control) treatment, by increasing the fraction of light absorbed by the PSII antenna, PQ ratio, qTQ, and qTV. In the light of findings, our beneficial bacterial strains showed the potential in reducing reliance on traditional chemical fertilizers, in particular in saline soil, by improving the grain yield and regulating the amount of excitation energy.

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