Photosynthesis and chlorophyll fluorescence of Iranian licorice (Glycyrrhiza glabra l.) accessions under salinity stress

Abstract

While salinity is increasingly becoming a prominent concern in arable farms around the globe, various treatments can be used for the mitigation of salt stress. Here, the effective presence of Azotobacter sp. inoculation (A1) and absence of inoculation (A0) was evaluated on Iranian licorice plants under NaCl stress (0 and 200 mM) (S0 and S1, respectively). In this regard, 16 Iranian licorice (Glycyrrhiza glabra L.) accessions were evaluated for the effects on photosynthesis and chlorophyll fluorescence. Leaf samples were measured for photosynthetic pigments (via a spectrophotometer), stomatal and trichome-related features (via SEM), along with several other morphological and biochemical features. The results revealed an increase in the amount of carotenoids that was caused by bacterial inoculation, which was 28.3% higher than the non-inoculated treatment. Maximum initial fluorescence intensity (F0) (86.7) was observed in the ‘Bardsir’ accession. Meanwhile, the highest variable fluorescence (Fv), maximal fluorescence intensity (Fm), and maximum quantum yield (Fv/Fm) (0.3, 0.4, and 0.8, respectively) were observed in the ‘Eghlid’ accession. Regarding anatomical observations of the leaf structure, salinity reduced stomatal density but increased trichome density. Under the effect of bacterial inoculation, salinity stress was mitigated. With the effect of bacterial inoculation under salinity stress, stomatal length and width increased, compared to the condition of no bacterial inoculation. Minimum malondialdehyde content was observed in ‘Mahabad’ accession (17.8 μmol/g FW). Principle component analysis (PCA) showed that ‘Kashmar’, ‘Sepidan’, ‘Bajgah’, ‘Kermanshah’, and ‘Taft’ accessions were categorized in the same group while being characterized by better performance in the aerial parts of plants. Taken together, the present results generally indicated that selecting the best genotypes, along with exogenous applications of Azotobacter, can improve the outcomes of licorice cultivation for industrial purposes under harsh environments.

Integrated Metabolomics and Transcriptomics Analyses Highlight the Flavonoid Compounds Response to Alkaline Salt Stress in Glycyrrhiza uralensis Leaves

“…The decrease in chlorophyll content in leaves subjected to alkaline salt stress may have been caused by the inhibition of the electron transport chain, destruction of the oxygen-evolving complex, reduction of the electron transferring capability of the donor-sides of PSII, and inactivation of the PSII reaction centers, all of which affect photosynthesis. 33 Consequently chlorophyllase activity is induced, leading to a reduction in chlorophyll content. 34 Metabolomics Analysis of G. uralensis under Alkaline Salt Stress.…”

“…Chlorophyll a and chlorophyll b are the primary components of plant chlorophyll, and their contents and roles also influence plant photosynthesis and energy conversion. The decrease in chlorophyll content in leaves subjected to alkaline salt stress may have been caused by the inhibition of the electron transport chain, destruction of the oxygen-evolving complex, reduction of the electron transferring capability of the donor-sides of PSII, and inactivation of the PSII reaction centers, all of which affect photosynthesis . Consequently chlorophyllase activity is induced, leading to a reduction in chlorophyll content …”

Salinity Stress Influences the Main Biochemical Parameters of Nepeta racemosa Lam.

“…The reported results are variable between species and treatments. For low salt concentrations, Portulaca oleracea L. exhibited an increased concentration of both chlorophyll a and b, while for high salt concentrations, both chlorophyll pigment concentrations decreased [ 40 , 41 ]. Our results presented in Figure 4 indicate a stimulating effect of up to 30% for the salt concentrations used in this study, especially in the case of the Na 2 SO 4 III variant.…”

Adaptation of Glycyrrhiza glabra L. to water deficiency based on carbohydrate and fatty acid quantity and quality

“…Careless overexploitation of wild ecotypes of G. glabra has recently resulted in a rapid reduction of its populations, if not extinction. Because of the plant’s high economic value and the risk of extinction owing to overharvesting, it appears vital to grow and domesticate this valuable species 2 . It has various physiologically-active compounds, including terpenes, flavonoids, polysaccharides, sugars, amino acids, minerals, lipids, and glycosides 3 .…”