Survival tactics of an endangered species Withania coagulans (Stocks) Dunal to arid environments.

Withania coagulans is a valuable medicinal plant with high demand, but its wild growth and local usage pose a threat to its natural habitat. This study aims to understand the plant's growth, anatomy, and physiology in different environmental conditions to aid in conservation and re-vegetation efforts. Fifteen differently adapted populations of Withania coagulans were collected from diverse ecological regions, viz., (i) along the roadside, (ii) hilly areas, (iii) barren land, and (iv) wasteland to unravel the adaptive mechanisms that are responsible for their ecological success across heterogenic environments of Punjab, Pakistan. The roadside populations had high values of photosynthetic pigments, total soluble proteins, root endodermis thickness, stem and leaf cortical thickness, and its cell area. The populations growing in hilly areas showed better growth performance such as vigorous growth and biomass production. Additionally, there was enhanced accumulation of organic osmolytes (glycine betaine and proline), chlorophyll content (chl a/b), and enlarged epidermal cells, cortical cells, vascular bundles, metaxylem vessels, and phloem region in roots. In case of stem area, epidermal thickness, cortical thickness, vascular bundle, and pith area showed improved growth. However, the barren land population showed significant increase in carotenoid contents, vascular bundle area, and metaxylem area in roots, and xylem vessels and phloem area in stems and leaves. The wasteland population surpassed the rest of the populations in having greater root dry weight, higher shoot ionic contents, increased root area, thick cortical, and vascular bundle area in roots. Likewise, cortical thickness and its cell area, and pith area in stems, whereas large vascular bundles, phloem region, and high stomatal density were recorded in leaves. Subsequently, natural populations showed the utmost behavior related to tissue organization and physiology in response to varied environmental conditions that would increase the distribution and survival of species.

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.

Ameliorative Effects of Exogenous Potassium Nitrate on Antioxidant Defense System and Mineral Nutrient Uptake in Radish (Raphanus sativus L.) under Salinity Stress.

Soil salinization has become a major issue around the world in recent years, as it is one of the consequences of climate change as sea levels rise. It is crucial to lessen the severe consequences of soil salinization on plants. A pot experiment was conducted to regulate the physiological and biochemical mechanisms in order to evaluate the ameliorative effects of potassium nitrate (KNO3) on Raphanus sativus L. genotypes under salt stress. The results from the present study illustrated that the salinity stress induced a significant decrease in shoot length, root length, shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, number of leaves per plant, leaf area chlorophyll-a, chlorophyll-b, total chlorophyll, carotenoid, net photosynthesis, stomatal conductance, and transpiration rate by 43, 67, 41, 21, 34, 28, 74, 91, 50, 41, 24, 34, 14, 26, and 67%, respectively, in a 40 day radish while decreased by 34, 61, 49, 19, 31, 27, 70, 81, 41, 16, 31, 11, 21, and 62%, respectively, in Mino radish. Furthermore, MDA, H2O2 initiation, and EL (%) of two varieties (40 day radish and Mino radish) of R. sativus increased significantly (P < 0.05) by 86, 26, and 72%, respectively, in the roots and also increased by 76, 106, and 38% in the leaves in a 40 day radish, compared to the untreated plants. The results also elucidated that the contents of phenolic, flavonoids, ascorbic acid, and anthocyanin in the two varieties (40 day radish and Mino radish) of R. sativus increased with the exogenous application of KNO3 by 41, 43, 24, and 37%, respectively, in the 40 day radish grown under the controlled treatments. Results indicated that implementing KNO3 exogenously in the soil increased the activities of antioxidants like SOD, CAT, POD, and APX by 64, 24, 36, and 84% in the roots and also increased by 21, 12, 23, and 60% in the leaves of 40 day radish while also increased by 42, 13, 18, and 60% in the roots and also increased by 13, 14, 16, and 41% in the leaves in Mino radish, respectively, in comparison to those plants grown without KNO3. We found that KNO3 substantially improved plant growth by lowering the levels of oxidative stress biomarkers, thereby further stimulating the antioxidant potential system, which led to an improved nutritional profile of both R. sativus L. genotypes under normal and stressed conditions. The current study would offer a deep theoretical foundation for clarifying the physiological and biochemical mechanisms by which the KNO3 improves salt tolerance in R. sativus L. genotypes.