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Salt excretory halophytes are the major sources of phytoremediation of salt-affected soils. Cressa cretica is a widely distributed halophyte in hypersaline lands in the Cholistan Desert. Therefore, identification of key physio-anatomical traits related to phytoremediation in differently adapted C. cretica populations was focused on. Four naturally adapted ecotypes of non-succulent halophyte Cressa cretica L. form hyper-arid and saline desert Cholistan. The selected ecotypes were: Derawar Fort (DWF, ECe 20.8 dS m−1) from least saline site, Traway Wala Toba (TWT, ECe 33.2 dS m−1) and Bailah Wala Dahar (BWD, ECe 45.4 dS m−1) ecotypes were from moderately saline sites, and Pati Sir (PAS, ECe 52.4 dS m−1) was collected from the highly saline site. The natural population of this species was collected and carefully brought to the laboratory for different structural and functional traits. As a result of high salinity, Na+, Cl–, K+, and Ca2+ content significantly increased at root and shoot level. At root level, some distinctive modifications such as increased sclerification in vascular bundles, enlarged vascular bundles, metaxylem vessels, phloem region, and storage parenchyma (cortex) are pivotal for water storage under extreme arid and osmotic condition. At the stem level, enhanced sclerification in outer cortex and vascular bundles, stem cellular area, cortical proportion, metaxylem and phloem area, and at the leaf level, very prominent structural adaptations were thicker and smaller leaves with increased density of salt glands and trichomes at surface, few and large stomata, reduced cortical and mesophyll parenchyma, and narrow xylem vessels and phloem area represent their non-succulent nature. The ecotype collected from hypersaline environments was better adapted regarding growth traits, ion uptake and excretion, succulence, and phytoremediation traits. More importantly, structural and functional traits such as root length and biomass, accumulation of toxic ions along with K+ in root and shoot, accumulation of Ca2+ in shoot and Mg2+ in root, excretion of toxic ions were the highest in this ecotype. In conclusion, all these alterations strongly favor water conservation, which certainly contributes to ecotypes survival under salt-induced physiological drought. Naturally adapted salt tolerant plants provide exceptional material for exploring adaptive mechanisms they use to confront high salt concentrations. Cressa cretica is a hypersaline hyperarid desert colonizer, which was previously underexplored. In the present study, we focused on the new insight on relationship among anatomical modifications, salt accumulation and excretion and phytoremediation potential of this rare species. [ABSTRACT FROM AUTHOR]

Using halophytes for phytoremediation is an environmentally friendly technique, now gaining importance all over the world. Fagonia indica Burm. f. (Indian Fagonia) is primarily distributed in salt-affected lands of the Cholistan Desert and surrounding habitats. Four populations with three replications from salt-affected habitats were collected from natural habitats to evaluate structural and functional adaptation for salinity tolerance and phytoremediation of hypersaline habitats. The populations collected from the highest saline sites Pati Sir (PS) and Ladam Sir (LS) had restricted growth habit, increased accumulation of K+ and Ca2+ along Na+ and Cl−, more excretion of Na+ and Cl−, increased cross-sectional area of root and stem, larger exodermal and endodermal cells in roots, and broad metaxylem area. Sclerification in stem was high in population. Specific modifications in leaves were reduced stomatal area and increased adaxial epidermal cell area. Important traits associated with phytoremediation potential of F. indica populations (Pati Sir and Ladam Sir) were deeper roots and taller plants, increased density of salt glands on leaf surface, and high excretion of Na+. Additionally, higher bio-concentration factor, translocation factor, and dilution factor for Na and Cl− in same Ladam Sir and Pati Sir population were identified as key phytoremediation attributes. The plants of F. indica colonizing high salinities (Pati Sir and Ladam Sir) were, therefore, more efficient in phytoremediation of saline soils as these populations accumulated and/or excrete toxic salts. Density of salt glands remarkably increased in the Pati Sir population collected from the highest salinity. This population accumulated and excreted the highest amount of Na+ and Cl−. The dilution factor of Na+ and Cl− ions was also the highest in this population. Anatomical modifications such as root and stem cross-sectional areas, proportion of storage parenchyma, and broad metaxylem vessels were the maximum in Pati Sir population. These modifications indicate not only better salt tolerance of the Pati Sir population but also better in accumulation and excretion of toxic salts. This population can potentially rehabilitate hypersaline uncultivated lands through green reclamation. [ABSTRACT FROM AUTHOR]

The role of ionic excretions and hyper-accumulation of salts through alterations of structural and functional traits in five populations of Suaeda vera Forssk. ex J.F. Gmel., a halophytic salt-indicator species of saline environments, was explored. Differently adapted populations of S. vera exhibited specific structural and functional responses for the survival in hyper-saline conditions. Better growth in population from moderately saline habitat (25–30 dS m−1) was linked to high shoot and root K+ and increased ion selectivity (K+/Na+ and Ca2+/Na+). Increased excretion of Na+ and Cl− with increasing salinity level was a critical mechanism in maintaining ionic balance. Drastic differences were observed for anatomical characteristics in populations inhabiting differentially salt-affected lands. The plants from highly saline sites were characterized by narrow metaxylem vessels, low proportion of cortical parenchyma, and reduced phloem area leading to stunted growth. Contrariwise, root area significantly increased due to high proportion of sclerified xylem tissue, which was associated with easier conduction of solutes and protection of roots from collapsing. Root sclerification particularly at the highest salinity regime was a key factor in the survival of this species in salt-affected compact soils. Leaf anatomical characteristics showed reduction with increasing salinity, but the leaf thickness responded otherwise. This contributed to increased leaf succulence because of high proportion of storage parenchyma in populations colonizing hyper-saline habitats. It was concluded that moderate salinity conditions were more suitable for the growth of S. vera, though some populations of this species were able to tolerate much higher salinity levels. [ABSTRACT FROM AUTHOR]

Soil salinity is increasing overtime in agricultural soils as well as in natural ecosystems particularly in arid and semi-arid regions due to low rainfall and high temperature. In this study, eighteen sites in Punjab from the Cholistan to Thal deserts, and Potohar Platues were selected to investigate the effect of soil salinity with increasing soil depths on soil physicochemical properties and nutrient availability. Soil texture of these soils varied from loamy sand and sandy loam of saline hyper-arid habitats to clay loam of saline semi-arid habitats. Soil saturation percentage, moisture contents, and soil organic matter generally decreased with increasing soil depth. Topsoil ECe ranged from 58 dS m-1 in Kallar Kahar (KKr) to 31 dS m-1 in Noorpur Thal NpT) habitat while for deep soil (25 cm depth), ECe ranged from 50 dS m-1 in KKr to 21 dS m-1 of Khanewall (Knw) habitat. Soil Na+ and Mg2+ contents increased with increasing ECe levels of different habitats but K+ decreased in most of the cases. Soil Ca2+ decreased both with increasing soil salinity as well as with soil depths except for moderately dry Chak # 87A-Feroza (87A), Chak # 70-Feroza (H70), and Hasilpur (HsP) habitats. Most of the salinity causing cations i.e. Na+, Ca2+, and Mg2+ were concentrated in topsoil thereby causing higher ECe levels in surface soils. In comparison, NO3-, PO43- and NH3 generally reduced with increasing depth and by increasing intensity of salinity. It was concluded that soil salinity severally distorted soil physical properties and affected nutrient distribution particularly those of anions in different soil horizons that explains the growth restrictions imposed by high soil salinities on native vegetation of hyper saline arid regions. [ABSTRACT FROM AUTHOR]

Deserts are generally prone to a number of ecological hazards which act as agents for the development of particularly a very diverse group of grasses, which can resist to salt stress through multiple morpho-anatomical and physio-biochemical mechanisms. Of such grasses, Cymbopogon jwarancusa is found inhabiting different saline patches of the Cholistan desert, so its different populations were selected from five saline habitats [least saline Derawar Fort (DF); moderately saline Trawaywala Toba (TW) and Bailahwala Dahar (BD), and high saline Ladam Sir (LS) and Pati Sir (PS)] and tested for their salt tolerance mechanism. Differentially adapted populations of this grass showed specific modifications in terms of anatomical features, mainly increased sclerification in both external hypodermis and internal endodermis, cortical layers, and increased size of xylem vessels with increase in salinity of the habitat. Increased endodermal thickness may control radial movement of water in roots. The reduction in leaf area is found to be the principal strategy that makes C. jwarancusa promising to attenuate the effects of the reduced availability of water under saline stress. Thick epidermis with dense cuticle and large bulliform cells area can be particularly considered as an important adaptation of this grass against physiological drought. Moreover, increased density of trichomes is found critical for checking undue water loss through the leaf surface and increase in these tissues at high salinity level may indicate that this species has better adapted to saline habitat. [ABSTRACT FROM AUTHOR]

• High drought tolerance related to sclerenchyma in stem and bulliform cell development in leaves. • Drought tolerant ecotypes survival depends on dense pubescence. • No single character can be taken as a yard-stick for adjudging drought tolerance. • More drought tolerant ecotypes provide a base for re-vegetation of extreme desert conditions. Cenchrus ciliaris L. is a perennial palatable grass and is capable of growing in a variety of habitats including extreme desert environment. The present study was conducted to explore the effect of drought stress on morpho-anatomical modifications in the aerial parts of C. ciliaris ecotypes, which were collected from the Cholistan Desert. Seeds of C. ciliaris wre collected from different regions in the Cholistan desert and grown in the Faisalabad conditions. Stress treatment were applied to the ramets that were isolated from mother plants. Three moisture regimes were maintained during the experiment, i.e., 100%, 75% and 50% field capacity. Ecotypes were grouped into four categories i.e., highly tolerant, tolerant, moderately tolerant and sensitive. Highly tolerant ecotypes (E92001 and E92002) showed epidermal thickness in leaves and stem, intensive sclerification in stem, increased vascular bundle number, well developed bulliform, increased metaxylem area and decreased stomatal density on both leaf surfaces. Tolerant ecotypes (E92003 an E92008) showed dense pubescence on their leaves. It is concluded that no definite or precise single character can be taken as a yardstick for adjudging the biomass production in theses desert grass ecotypes. [ABSTRACT FROM AUTHOR]