Co-application of ACC deaminase-producing rhizobial bacteria and melatonin improves salt tolerance in common bean (Phaseolus vulgaris L.) through ion homeostasis

Publisher Copyright: © 2022, The Author(s).A comprehensive body of scientific evidence indicates that rhizobial bacteria and melatonin enhance salt tolerance of crop plants. The overall goal of this research was to evaluate the ability of Rhizobium leguminoserum bv phaseoli to suppress salinity stress impacts in common bean treated with melatonin. Treatments included bacterial inoculations (inoculated (RI) and non-inoculated (NI)), different salinity levels (non-saline (NS), 4 (S1) and 8 (S2) dS m−1 of NaCl) and priming (dry (PD), melatonin (PM100) and hydro (PH) priming) with six replications in growing media containing sterile sand and perlite (1:1). The results showed that the bacterial strain had the ability to produce indole acetic acid (IAA), ACC deaminase and siderophore. Plants exposed to salinity stress indicated a significant decline in growth, yield, yield components, nitrogen fixation and selective transport (ST), while showed a significant increase in sodium uptake. However, the combination of PM100 and RI treatments by improving growth, photosynthesis rate and nitrogen fixation positively influenced plant performance in saline conditions. The combined treatment declined the negative impacts of salinity by improving the potassium translocation, potassium to sodium ratio in the shoot and root and ST. In conclusion, the combination of melatonin and ACC deaminase producing rhizobium mitigated the negative effects of salinity. This result is attributed to the increased ST and decreased sodium uptake, which significantly reduced the accumulation of sodium ions in shoot.Peer reviewe

Yield and yield components of common bean as influenced by wheat residue and nitrogen rates under water deficit conditions

Incorporation of crop residues into agricultural system has become a worldwide efficient practice for enhancing crop production. The main objectives of this experiment was to investigate the major role of incorporating wheat (Triticum aestivum L.) residues and nitrogen (N) fertilizers rates under different water requirements (WR) on growth, seed yield and yield components of common bean (Phaseolus vulgaris L.). The results showed that seed yield under 80% WR in retained crop residue plots was & SIM;11% higher than WR treatment with no residue incorporation. Seed yield was not significantly different between residue retention and removal treatments in 2016, whereas it was higher (12% and 17%) under residue retained plots compared to removed ones in subsequent years. Seed yields responded to N up to 170 and 225 kg ha(-1) in removed and retained residue treatments, respectively in 2017 and 2018. Annual increment of seed yield in residue retained plots (36%) was 2.11 times higher than the residue removed ones (17%). There was higher soil N content in 50% residue retention with 225 kg N ha(-1) under both water deficit treatments in all years. The highest soil organic carbon (SOC) was achieved with normal irrigation in retained residue plots with 225 kg N ha(-1) in all years. Overall, wheat residue incorporation into the soil and N-supply substantially contributed to counteracting yield declines of common bean under water deficit conditions.& nbsp;(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Peer reviewe

Effect of Salinity Stress on Growth, Yield and Some Physiological Traits of Forage Sorghum Cultivars

In order to evaluate the effect of salinity stress on growth, yield, and some physiological traits of forage sorghum cultivars, an experiment was conducted as split-plot based on a randomized complete block design with four replications at experimental farm of College of Agriculture, Shiraz University at 2014 growing season. Treatments were three levels of saline irrigation water (0.4 as control, 7 and 14 dS/m) and three sorghum cultivars (Pegah, White speedfeed and Red speedfeed) as main plots and subplots, respectively. Results showed that salinity stress decreased plant height and leaf area. Pegah cultivar showed the highest forage dry weight in all salinity treatments. Activity of antioxidant enzymes including superoxide dismutase, peroxidase and catalase significantly increased with increasing salinity levels in Pegah and Red speedfeed cultivars. In salt-stressed Pegah these enzymes activity increased 2.1, 4.5, and 2.8 times, respectively in comparison to control. With increasing salinity levels, shoot sodium/potassium ratio of White speedfeed, Red speedfeed, and Pegah cultivars increased  10.7, 6.8, and 1.7 times, respectively whereas root sodium/potassium ratio of the cultivars increased 9.6, 8.1, and 4.7 times, respectively. It seems that the lower absorption of sodium was the major mechanism of salinity tolerance in Pegah and can be an important criterion to evaluate sorghum salinity toleranc

Improving salt tolerance threshold in common bean cultivars using melatonin priming: a possible mission?

Common bean (Phaseolus vulgaris L.) is mostly cultivated on marginal soils where salinity is a key stress. The focus of the present study was to evaluate the efficiency of melatonin priming and hydro priming on germination, growth parameters, antioxidant defense system and tolerance threshold in seven common bean cultivars grown under different levels of salinity stress. The experiments were conducted as a factorial arrangement based on a completely randomized design with six replicates. The results showed that salinity levels decreased radicle and hypocotyl lengths, seedling vigor index, and salinity tolerance threshold under Petri dish conditions. However, melatonin priming alleviated the inhibitory effects of salinity and enhanced salt tolerance threshold of all the cultivars. The highest tolerance thresholds of Dorsa, Almas, Koosha, and Pak cultivars were obtained under 100 µM melatonin treatment, while in Sayad, Shekoofa, and Derakhshan, 20 µM melatonin caused higher thresholds. Results of the greenhouse experiment showed that melatonin priming increased salt tolerance threshold, but it reduced malondialdehyde content and hydrogen peroxide accumulation. It also induced a higher increase in relative shoot dry weight of the cultivar Dorsa than the other cultivars. The cultivars Dorsa and Shekoofa treated with 100 and 20 µM, respectively, maintained a lower MDA content and Na+ concentration and a higher K+/Na+ ratio in shoot and root, N concentration and salt tolerance threshold than the other cultivars under salinity stress. These results suggest that seed priming with melatonin enhances salinity tolerance by stimulating antioxidant activities, alleviating oxidative damage and enhancing plant dry weight. © 2021 Taylor & Francis Group, LLC.12 month embargo; published online: 17 May 2021This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Effects of salt stress and mycorrhiza fungi on morpho-physiological characteristics of sweet corn

In order to investigate the interaction of mycorrhizal fungi and salinity on growth and physiological characteristics of sweet corn, a greenhouse experiment was conducted at College of Agriculture, Shiraz University, in 2014. The experimental design was factorial based on Completely Randomized Design in three replications. Treatments included salinity at four levels (0.4 (control), 4, 7, 10 dS m-1), and the fungi at three levels (no fungi (control), Glomus mosseae, Glomus intraradices). Results indicated that at flowering stage, with increasing salinity levels, leaf chlorophyll a, b and a+b content and carotenoid decreased at a rate of 18.9, 52.4, 33.1, and 34.5 respectively. Application of mycorrhiza under salinity, partially offset the negative impacts and increased tolerance of maize to NaCl by enhancing SOD and CAT activities, chlorophyll contents, carotenoid and K concentrations in leaves, plant height, leaf area, and total dry weight at flowering stage significantly, compared to control. The Na/K ratio at salinity level of 10 dS m-1 in treatments inoculated with GIN and GM fungi decreased by 39.69 and 40.45 percentage, respectively. Increases plant height, leaf area, total dry weight, concentrations of chlorophyll a, b, chlorophyll a+b and carotenoid and K, the activity of antioxidant enzymes compared with the control. Moreover, GIN type fungi had a greater advantage over GM and reduced the negative effects of salinity. Results indicated that application of mycorrhiza alleviated the adverse effect of salinity stress and improve the sweet corn dry weight up to 38 percentage at salinity level of 10 dS m-1

Foliar Application of Melatonin Improves the Salt Tolerance, Ion and Redox Homeostasis and Seed Oil Fatty Acid Profile in Camelina sativa

Salinity affects the yield and quality of oilseed crops. The effects of a single foliar application of solutions with different concentrations (0, 30, 60 or 90 µM) of melatonin (MEL) to camelina (Camelina sativa) plants grown in soil in a greenhouse and irrigated at four salinity levels (0.5, 4, 8 and 16 dS m−1) were assessed. Increasing salinity decreased leaf chlorophyll and photosynthetic rates, decreased K concentrations and increased Na concentrations in roots and shoots, and increased oxidative marker levels and the activity of protective antioxidant enzymes in leaves. Under severe salinity stress, the MEL90 treatment resulted in increases in chlorophyll, gas exchange attributes, leaf antioxidant enzyme activities, and decreases in leaf oxidative markers and Na. Salinity decreased seed yield, with no seeds being produced at salinities above 8 dS m−1. The MEL90 treatment resulted in increases in seed yield and poly- and mono-unsaturated fatty acid contents and decreases in saturated fatty acid contents. The MEL90 treatment was more effective in alleviating salinity effects than those including lower MEL concentrations. The highest concentrations of K and K/Na ratios were observed with the MEL90 treatment under non-stressed conditions. Data suggest that MEL foliar applications could increase salinity stress tolerance in camelina