Influence of salt stress on inoculated Casuarina glauca seedlings

Abstract

Salinity is a serious threat to agriculture in arid and semi-arid regions including Egypt. There is currently a need to select highly salt-tolerant plants to improve recycling of agricultural drainage waters. Due to the importance of Casuarina in soil reclamation and rehabilitation, our study was carried out to evaluate the survival and growth of inoculated Casuarina glauca in hydroponic N-free medium supplemented with different NaCl concentrations (50, 100, 200, 300, 400 and 500 mM). Salt tolerant Frankia strains CcI156 and CgIM4, isolated from root nodules of Casuarina trees grown in loamy sand soils in Egypt, were used for seedling inoculation. Our results showed that inoculated Casuarina seedlings were able to withstand up to 200 mM NaCl. At higher NaCl concentrations (300 to 500 mM), the seedling died gradually three days after exposure to salt stress. However, at lower NaCl (50 mM) concentration, inoculated C. glauca seedlings showed a higher growth rate and higher percentages of nodulation. Nitrogenase activity and the total nitrogen content of nodulated seedlings were also influenced by elevated NaCl concentrations and recorded a reduction at high concentration (200 mM). Salt stress had a strong effect on biosynthesis of osmoprotectants molecules like L-Proline and carbohydrates, which strongly correlated (r = 0.98 and 0.87, respectively) with increasing salt concentrations.

Differential responses of dwarf cashew clones to salinity are associated to osmotic adjustment mechanisms and enzymatic antioxidative defense

“…Although we observed the salt stress effects on this solute concentration in roots were significantly more evident than shoots, leaves proline accumulation was considerably higher than in roots. It has been suggested that leaves accumulate more proline to maintain chlorophyll level and cell turgor to protect photosynthetic activity under salt stress (Silva-Ortega et al 2008, Huang et al 2013, Mansour et al 2016. This is consistent with our results indicating that proline accumulation was greatest in the leaves of stressed plants.…”

“…Salinity can affect plant in a multivariate way, primarily reaching plant growth due to osmotic and ionic components and mineral defi ciency, and following with several metabolic processes as photosynthesis, protein synthesis and lipid metabolism (Praxedes et al 2010, Silva et al 2015, Mansour et al 2016. The control of the absorption of toxic ions by the roots and their transport and distribution through the plant, as well as the capacity to compartmentalize them in the vacuole, has been considered one of the main mechanisms of tolerance to salt stress (Ashraf & Harris 2004, Liang et al 2018.…”

Comparative Proteomic Analysis of Nodulated and Non-Nodulated Casuarina glauca Sieb. ex Spreng. Grown under Salinity Conditions Using Sequential Window Acquisition of All Theoretical Mass Spectra (SWATH-MS)

“…However, broad, interdisciplinary and integrate research to ascertain the contribution of symbiotic Frankia to the environmental plasticity of actinorhizal species has emerged only recently, mostly focusing on salt stress in Casuarinaceae, particularly in the model species Casuarina glauca Sieb. ex Spreng e.g., Santos et al, Ribeiro et al, Batista-Santos et al, Mansour et al, Ribeiro-Barros et al, Jorge et al, and Ngom et al [2][3][4][5][6][7][8][9]. C. glauca is a tropical tree widely used to prevent desertification and erosion, as well as to rehabilitate poor and degraded soils [1,10].…”

“…C. glauca is a tropical tree widely used to prevent desertification and erosion, as well as to rehabilitate poor and degraded soils [1,10]. Such capacity does not necessarily depend on the symbiosis with Frankia, although some strains may enhance stress tolerance [4][5][6]9,[11][12][13].…”

An update on research on Frankia and actinorhizal plants on the occasion of the 18th meeting of the Frankia-actinorhizal plants symbiosis

“…Besides the global contribution of filaos for the rehabilitation of poor sites in various areas of the world such as China and India (Zhang et al 2016) and of alder for the same purpose in Canada (Callender et al 2016), a major focus is the search for salinity-resistant casuarina lineages . The underlying mechanisms are also being studied (Mansour et al 2016;Selvakesavan et al 2016). As pioneer species, actinorhizal plants are exposed to a wide array of stresses (Ngom et al 2016b) which have been reviewed along with approches to transform Casuarina genetically (Froussart et al 2016).…”