Functional traits for salinity tolerance in differently adapted populations of Fimbristylis complanata (Retz.)

Aridity-driven changes in structural and physiological characteristics of Buffel grass (Cenchrus ciliaris L.) from different ecozones of Punjab Pakistan

Cenchrus ciliaris L. is a perennial grass that can grow in a diverse range of habitats including challenging deserts. The purpose of the study was to investigate the impact of aridity on morpho-anatomical and physiological traits in C. ciliaris populations collected from arid and semi-arid areas of Punjab, Pakistan. The populations growing in extremely arid conditions displayed a range of structural and physiological adaptations. Under extremely dry conditions, root epidermal thickness (90.29 µm), cortical cell area (7677.78 µm2), and metaxylem cell area (11,884.79 µm2) increased while root pith cell area (2681.96 µm2) decreased in tolerant populations. The populations under extremely aridity maximized leaf lamina (184.21 µm) and midrib thickness (316.46 µm). Additionally, highly tolerant populations were characterized by the accumulation of organic osmolytes such as glycinebetaine (132.60 µmol g-1 FW) was increased in QN poulations, proline (118.01 µmol g-1 F.W) was maximum in DF populations, and total amino acids (69.90 mg g-1 FW) under extreme water deficit conditions. In arid conditions, abaxial stomatal density (2630.21 µm) and stomatal area (8 per mm2) were also reduced in DF populations to check water loss through transpiration. These findings suggest that various parameters are crucial for the survival of C. ciliaris in arid environments. The main strategies used by C. ciliaris was intensive sclerification, effective retention of ions, and osmotic adjustment through proline and glycinebetaine under arid conditions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-023-01351-3.

Phytoremediation potential modulated by structural and functional traits in a saline desert halophyte Fagonia indica Burm. f

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.

Alleviation of cadmium toxicity in Zea mays L. through up-regulation of growth, antioxidant defense system and organic osmolytes under calcium supplementation

Calcium (Ca) is a macronutrient and works as a modulator to mitigate oxidative stress induced by heavy metals. In this study, we investigated the role of Ca to ameliorate the Cd toxicity in Zea mays L. by modulating the growth, physio-biochemical traits, and cellular antioxidant defense system. Maize genotype Sahiwal-2002 was grown under a controlled glasshouse environment with a day/night temperature of 24 ± 4°C/14 ± 2°C in a complete randomized design with three replications and two Cd levels as (0 and 150 μM) and six regimes of Ca (0, 0.5, 1, 2.5, 5, and 10 mM). Maize seedlings exposed to Cd at 150 μM concentration showed a notable decrease in growth, biomass, anthocyanins, chlorophylls, and antioxidant enzymes activities. A higher level of Cd (150 μM) also caused an upsurge in oxidative damage observed as higher electrolyte leakage (increased membrane permeability), H2O2 production, and MDA accumulation. Supplementation of Ca notably improved growth traits, photosynthetic pigments, cellular antioxidants (APX, POD, and ascorbic acid), anthocyanins, and levels of osmolytes. The significant improvement in the osmolytes (proteins and amino acids), and enzymatic antioxidative defense system enhanced the membrane stability and mitigated the damaging effects of Cd. The present results concluded that exogenously applied Ca potentially improve growth by regulating antioxidants and enabling maize plants to withstand the Cd toxicity.

Salicornia europaea L. Functional Traits Indicate Its Optimum Growth

Salicornia europaea L. grows in areas periodically flooded by salty or brackish water. It has potential economic value, because it can be used as food, forage, or biofuel, and has potential in pharmaceuticals and cosmetics. Increasing interest in S. europaea is due to its extreme salt tolerance and well growth in marginal saline soils. However, the variation in its functional traits in response to environmental conditions is still poorly studied. There are still questions regarding the optimal level of salinity for different traits. Therefore, we worked to address the question if S. europaea traits from different scales are controlled by salinity level. Based on performed pot experiment, we found that almost all traits are salinity dependent but affected in different ways. We demonstrated that morphological, biomass, and anatomical properties indicate optimum growth between 200 and 400 mM NaCl and growth limitations at 0, 800, and 1000 mM NaCl. Moreover, we found the most affected traits which include photosynthetic pigments and protein content, plant surface area, peroxidase activity, and anatomic traits related to cell shape. Our results significantly expanded the knowledge about S. europaea functional traits variation in response to salinity, which can be important for discovering regulating processes and for possible future agricultural applications.