Abstract |
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Four Astragalus species have been evaluated for their tolerance and adaptability potential to salt stress. The adaptive components of salt tolerance were assessed on the basis of biomass production and anatomical changes. A. tenuifolius was the most tolerant among the species under study, with increased leaf water content, stable shoot dry weight, stable root thickness, thick epidermis and increased cortical cell area, increased root cortex, thick stele, stable xylem tissue. Also, observed intensive density of thick-walled vessel elements. Moreover, thicker leaves and mesophyll tissue, thick upper epidermis, increased vascular bundle area, intensive density of thick-walled vessel elements and larger stomata with unchanged density were recorded in the leaves of this species with an increase in salinity levels. A. armatus the second tolerant species relied on the maintenance of epidermis and stele thickness and xylem vessel diameter under salinity. Also, root and cortex thickness decreased only at 300 mM NaCl, and increased density of xylem vessels, thicker leaves and mesophyll tissue, thick upper epidermis, increased mesophyll cells size, intensive density of thick-walled vessel elements was observed. In addition, the maintenance of water content and the lower (14.2 %) reduction in biomass production. A. mareoticus appeared to be the most salt sensitive when the decrease in biomass production reached 56.8% with anatomical parameters severely affected. For A. caprinus (salt sensitive species) has shown better adaptation than A. mareoticus relied on increased cortical cell area as well as stable root xylem vessel diameter, also, thick upper epidermis and increased leaf vascular bundle area. |