Effect of Seed Inoculation on Alfalfa Tolerance to Water Deficit Stress

Abstract

Water deficit is one of the most important environmental stresses that adversely affect crop growth and production and mycorrhizal fungi and symbiotic bacteria have important role in resistance to drought stress. The effect of biofertilizers on alfalfa stress tolerance was studied at the greenhouse condition. Treatments comprised three water-deficit stresses (35%, 55% and 75% of field capacity) and four seeds inoculations (Glomus mosseae, Sinorhizobium meliloti, G. mosseae + S. meliloti and non-inoculated). Water-deficit stress decrease cell membrane stability (39%), total Chl (24.05%), carotenoid (35.55%), quantum yield (50.64%) and forage yield (28.20%), while increased the proline and soluble sugars content (68.55 and 46.53% respectively) and osmotic potential (45.84%). The inoculation of seeds increased the capability of the plants in counteracting the stress, so that the production of compatible solutes was increased and the photosynthetic indices, proline, osmotic potential, membrane stability and forage yield were improved by seed inoculation. Mycorrhiza improved photosynthetic indexes and proline, but bacteria had more efficacy on membrane stability and forage yield. However, double inoculation due to the synergistic effect of mycorrhiza and Sinorhizobium, had the greatest effect than Solitary inoculation. Our results suggest that biofertilized alfalfa plants were better adapted than non-biofertilized ones to cope with water deficit.

Arbuscular Mycorrhizal Symbiosis Alleviates Drought Stress Imposed on Wheat Plants (Triticum Aestivum L.)

“…Chlorophyll status is a key index for evaluating plant photosynthetic efficiency and environmental stress. Augé (2001), Gemma et al (1997) and Azooz and Youssef (2010) are in agreement with the results of other proved the differences of chlorophyll a, chlorophyll b and chlorophyll a + b concentrations were significant between AM and non-AM maize plants under drought stress conditions (Zafari et al, 2017). They suggest that drought stress interferes less with chlorophyll synthesis and/or more with chlorophyll breakdown (Evelin et al, 2009) or protects pigments against (Kyriazopouls et al, 2014) oxidative damage generated by drought (Shinde and Thakur, 2015).…”

Do plant-growth promoting bacteria contribute to greater persistence of tropical pastures in water deficit? - A review

“…When exposed to WD, plants have an immediate response by reducing their osmotic potential inside the cells (Zafari et al, 2017) and their roots' water potential. This happens in order to keep a positive water balance, ensuring water absorption from the soil or a decrease in transpiration (Guimarães et al, 2011).…”

“…In plants under stress, there is the inhibition of leaf elongation (Farooq et al, 2009), a decrease in the emission of new tissues (Borrell et al, 2000a) and a reduction of cell division and growth (Anjum et al, 2011) due to a loss of turgidity of the wall cell (Kaushal e Wani, 2016), and a reduction of tillering, compromising the structure of the canopy, not to mention the acceleration of leaf senescence (Inman-Bamber, 2004). That contributes to a smaller leaf area, with direct impact on light interception (Zafari et al, 2017), degradation of photosynthetic pigments (Streit et al, 2005) and a decrease in photosynthesis efficiency (Zafari et al, 2017).…”