Physiological and structural modifications in snail medic (Medicago scutellataL.) plants exposed to salinity

Abstract

Seeds of snail medic (Medicago scutellata L.) were assessed for their response to salt at the germination and seedling stages. NaCl at concentrations 86 and 170 mM decreased the final germination percentage. Embryonic axis length, water content and dry weight of embryonic axis and cotyledons were also reduced by salt treatment. Furthermore, 28-d-old plants were grown hydroponically with different NaCl concentrations (0, 86 and 170 mM). After 7 days of treatment, growth, water content and development of the different organs of M. scutellata plant were affected especially at the highest NaCl concentration (170 mM). However, NaCl did not affect root length and the number of stem shoots but reduced stem length and total leaf area. Salt treatment increased markedly the concentration of Na + in leaf and root tissues while reduced that of K + only in root and stem tissues. Lipid peroxidation revealed the damage of the membranes of roots and leaves. Moreover, showed a more intense suberization and lignification at the cambial zone of roots of M. scutellata, were observed under the effect of NaCl.

Mechanism of salt-inhibited early seed germination analysed by transcriptomic sequencing

“…Salinity has long been considered a major and wide-ranging factor that affects seed germination and early seedlings (Darwin, 1856). The high Na + concentrations not only suppress seed imbibition and embryo growth (Daszkowska-Golec, 2011; Khajeh-Hosseini et al ., 2003; Rajjou et al , 2012; Radhakrishnan and Baek, 2017; Attia et al ., 2018) but also leads to inhibition of cell survival, growth and division (Zehra et al ., 2012). Salt tolerance in plants has been linked to a large number of factors, for example NHX1, localized to the tonoplast and SOS1 (SALT OVERLY SENSITIVE 1) localized to the plasma membrane, two key regulators to maintain low cytoplasmic Na + concentration in plant cells (Zhu, 2002; Deinlein et al ., 2014); endogenous ABA contents, which rapidly decline upon imbibition during the early phase of germination (Preston et al ., 2009); Ca 2+ influx, which regulates seed germination under salt stress by modulating Na + accumulation through the SOS pathway (Cheng et al , 2018); and the balance between ROS (reactive oxygen species) generation and ROS scavenging in plant cells (Das et al ., 2015).…”