Salinity Duration Differently Modulates Physiological Parameters and Metabolites Profile in Roots of Two Contrasting Barley Genotypes

Abstract

Hordeum maritimum With. is a wild salt tolerant cereal present in the saline depressions of the Eastern Tunisia, where it significantly contributes to the annual biomass production. In a previous study on shoot tissues it was shown that this species withstands with high salinity at the seedling stage restricting the sodium entry into shoot and modulating over time the leaf synthesis of organic osmolytes for osmotic adjustment. However, the tolerance strategy mechanisms of this plant at root level have not yet been investigated. The current research aimed at elucidating the morphological, physiological and biochemical changes occurring at root level in H. maritimum and in the salt sensitive cultivar Hordeum vulgare L. cv. Lamsi during five-weeks extended salinity (200 mM NaCl), salt removal after two weeks of salinity and non-salt control. H. maritimum since the first phases of salinity was able to compartmentalize higher amounts of sodium in the roots compared to the other cultivar, avoiding transferring it to shoot and impairing photosynthetic metabolism. This allowed the roots of wild plants to receive recent photosynthates from leaves, gaining from them energy and carbon skeletons to compartmentalize toxic ions in the vacuoles, synthesize and accumulate organic osmolytes, control ion and water homeostasis and re-establish the ability of root to grow. H. vulgare was also able to accumulate compatible osmolytes but only in the first weeks of salinity, while soon after the roots stopped up taking potassium and growing. In the last week of salinity stress, the wild species further increased the root to shoot ratio to enhance the root retention of toxic ions and consequently delaying the damages both to shoot and root. This delay of few weeks in showing the symptoms of stress may be pivotal for enabling the survival of the wild species when soil salinity is transient and not permanent.

Growth and Element Uptake by Salt-Sensitive Crops under Combined NaCl and Cd Stresses

“…For instance, K/Na ratio in nonstressed muskmelon plants was higher by 1-2 orders of magnitude (in leaves, peel and fruit pulp) in comparison with 60 mM NaCl-stressed plants [21]. Recently, [7] reported inhibited biomass production simultaneously with a strong decrease in K/Na ratio in cultivated and wild barley species exposed to NaCl salinity. [39] noticed significantly decreased Ca/Na ratio with increasing NaCl concentration in lucerne tissues.…”

“…Consequently, important environmental resources, notably quality lands and waters, have become increasingly limiting for food production over recent decades due to excessive salinization [4] and/or metal contamination [5,6]. Globally,~20% of irrigated agroecosystems provide~33% of food supply, but are frequently salt-affected, mostly with excessive Na and Cl ions [3,7]. Horticultural glycophytes are particularly vulnerable to excessive salinity, whereby salt stress limits plant growth and reduces crop yield and quality [2,8,9].…”

“…Horticultural glycophytes are particularly vulnerable to excessive salinity, whereby salt stress limits plant growth and reduces crop yield and quality [2,8,9]. Depending on stress severity and duration, as well as crop, genotype and developmental stage, salt stress disturbs (i) water relations, i.e., osmotic potential [2,10], (ii) ion/mineral homeostasis [11] and (iii) a wide range of metabolic (e.g., hormonal, enzymatic, antioxidant) processes, causing secondary stresses [7].…”

Salinity tolerance evaluation of barley germplasm for marginal soil utilization

“…126/OWB, indicating that these varieties have the ability to restrict the negative effect of salinity to their germination and tillering (tiller number production). According to Dell'Aversana et al (2021) the salinity tolerance of some barley genotypes is attributed to their ability to compartmentalize high amounts of sodium in the roots and restricting the sodium entry into shoot at the seedling growth stage. Also, the fact that most of these varieties are registered varieties has relevant for breeders because they could easily access to these seeds.…”

Ascophyllum nodosum Based Extracts Counteract Salinity Stress in Tomato by Remodeling Leaf Nitrogen Metabolism

“…This dual osmotic and ionic stress can reduce cell expansion, inhibit tissue growth, and cause nutritional imbalances and oxidative stress. All of these factors can strongly decrease plant growth, development and survival [ 37 , 38 ]. Plants try to cope with salt stress by triggering specific strategies to increase cellular osmotic control, restoring cellular and water homeostasis in order to minimize stress damage and reactivate growth [ 39 , 40 ].…”