Water, a necessary component of cell protoplasm, plays an essential role in supporting life on Earth; nevertheless, extreme changes in climatic conditions limit water availability, causing numerous issues, such as the current water-scarce regimes in many regions of the biome. This review aims to collect data from various published studies in the literature to understand and critically analyze plants’ morphological, growth, yield, and physio-biochemical responses to drought stress and their potential to modulate and nullify the damaging effects of drought stress via activating natural physiological and biochemical mechanisms. In addition, the review described current breakthroughs in understanding how plant hormones influence drought stress responses and phytohormonal interaction through signaling under water stress regimes. The information for this review was systematically gathered from different global search engines and the scientific literature databases Science Direct, including Google Scholar, Web of Science, related studies, published books, and articles. Drought stress is a significant obstacle to meeting food demand for the world’s constantly growing population. Plants cope with stress regimes through changes to cellular osmotic potential, water potential, and activation of natural defense systems in the form of antioxidant enzymes and accumulation of osmolytes including proteins, proline, glycine betaine, phenolic compounds, and soluble sugars. Phytohormones modulate developmental processes and signaling networks, which aid in acclimating plants to biotic and abiotic challenges and, consequently, their survival. Significant progress has been made for jasmonates, salicylic acid, and ethylene in identifying important components and understanding their roles in plant responses to abiotic stress. Other plant hormones, such as abscisic acid, auxin, gibberellic acid, brassinosteroids, and peptide hormones, have been linked to plant defense signaling pathways in various ways.

Soil contamination with toxic heavy metals [such as lead (Pb)] is becoming a serious global problem due to the rapid development of the social economy. However, accumulation of Pb in plant parts is very toxic for plant growth and decreases crop yield and productivity. In the present study, we have investigated the different concentrations of Pb in the soil i.e., [0 (no Pb), 50, and 100 mg kg^–1] to study plant growth and biomass, photosynthetic pigments and gas exchange characteristics, oxidative stress indicators and the response of various antioxidants (enzymatic and non-enzymatic), nutritional status of the plant, organic acid exudation pattern and also Pb accumulation in the roots and shoots of the plants of two varieties of tomato (Solanum lycopersicumL.) i.e., Roma and Cchuas, grown under different levels of synergic acid [no spray (NS), water spray (WS), 0.3-0.5°μM]. Results from the present study showed that the increasing levels of Pb in the soil decreased non-significantly (P< 0.05) shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, chlorophyll-a, chlorophyll-b, total chlorophyll, carotenoid content, net photosynthesis, stomatal conductance, transpiration rate, soluble sugar, reducing sugar, non-reducing sugar contents, calcium (Ca²⁺), magnesium (Mg²⁺), iron (Fe²⁺), and phosphorus (P) contents in the roots and shoots of the plants. However, Pb toxicity also induced oxidative stress in the roots and shoots of the plants by increasing malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and electrolyte leakage (EL) which also induced increased the compounds of various enzymatic and non-enzymatic antioxidants and also organic acids exudation pattern in the roots such as fumaric acid, acetic acid, citric acid, formic acid, malic acid, oxalic acid contents and increased the concentration of Pb in different parts of the plants. Results also show that the Cchuas showed better growth and development compared to Roma, under the same levels of Pb in the soil. The alleviation of Pb toxicity was induced by the application of synergic acid, and results showed that the application of synergic acid increased plant growth and biomass and also increased the gas exchange characteristics and antioxidant capacity in the roots and shoots of the plants. Research findings, therefore, suggested that synergic acid application can ameliorate Pb toxicity inS. lycopersicumvarieties and result in improved plant growth and composition under metal stress as depicted by balanced exudation of organic acids.

Salinity is extremely hazardous to agriculture worldwide and its expanding constantly. Soil of almost 100 countries facing salinity problem including Pakistan. Cyperus laevigatus also act as salinity indicator species is a naturally adapted halophyte dispersed in subtropical regions of world. Six populations of C. laevigatus were collected from different saline habitats to evaluate adaptations regarding anatomical and physiological characteristics. C. laevigatus is perfectly adapted to harsh environmental conditions like dry barren soils, saline lakes, hyper-saline wetlands and salt marshes. Ecological success of this species is due to plasticity in physiological and anatomical characteristics to adapt variable environmental conditions. C. laevigatus is a halophyte, exhibited increased biomass production in moderately saline habitat. Higher uptake of K+ occurs to compensate the uptake of Na+ ion contents, a striking feature of salt-tolerant and halophytic species. Accumulation of osmoprotectants like proline, free amino acids, soluble sugar and protein contribute significantly to osmotic adjustment. Stem thickness enhanced as salinity level of habitat increased to store water in parenchymatous tissues under physiological drought. Intensive sclerification in root cortex provide mechanical strength to plant as well as prevent the radial leakage of water. Well-developed aerenchyma, increased vascular bundle area, broader vessels, small and dense stomata are critical to cope with environmental hazards. Population of Jahlar lake showing maximum biomass production indicate that this species grows better in moderate salinities. Therefore, this species will prove very useful for revegetation of salt affected rangeland and prairies by direct growth of such halophytic ecotypes.

Pakistan faces challenges in both food and energy security. Indeed, extensive literature suggests that food and energy security are interdependent. While acknowledging that food security is still a primary concern for Pakistan, energy security is also a major issue. It is crucial to develop sustainable energy sources for energy production. Among sustainable sources, biomass is a promising source that can be effectively used for environmentally friendly energy production. This article addresses the energy issues and potential solutions using crop residues, non-edible energy crops, and animal and municipal solid wastes in Pakistan. The current research challenges, relevant industries, opportunities, and the future share of energy production derived from renewable and sustainable sources are emphasized with a focus on the potential of biomass energy. This article shows that Pakistan has considerable potential to develop bioenergy crops on marginal lands without compromising food security, with considerable greenhouse gas (GHG) benefits. Pakistan has vast biomass resources, including crop residues, animal waste, municipal solid waste, and forest residues, which collectively produce 230 billion tons of biomass annually. There are about 72 million bovines (cows and buffaloes), 81 million tons per year of crop biomass, and about 785 million birds in poultry farms across the country. Land that is currently non-productive could be used for energy crops, and this has the potential to produce 2500–3000 MW of energy. The utilization of waste cooking oil and fats is the most economically feasible option for obtaining biodiesel due to its easy and almost free availability in Pakistan. Systematic management is needed to collect this huge quantity of waste cooking oil and efficiently convert it to biodiesel. Similarly, molasses may be a promising source for bioethanol production. Furthermore, this study suggests that Pakistan’s energy policies need to be amended to ensure that the energy supply meets the demand. In the future, massive energy projects on biomass-based bioenergy need to be implemented in Pakistan. To achieve its bioenergy potential, Pakistan needs to develop incentive-based bioenergy technologies. Moreover, this objective can only be achieved in the country by initiating R&D projects to promote advanced biomass conversion technologies, such as biogas plants and combustion systems.

The supply of nutrients and proximate matter is insufficient to fulfil the dietary needs of the quickly expanding human population. Green leafy vegetables can prove economical sources of minerals, vitamins and fibers to overcome nutritional deficiencies. Five leafy vegetables (Brassica juncea, Spinacia oleracea, Trigonella foenum-graecum, Chenopodium album and Lactuca sativa) were collected from a horticulture garden and vegetable market for the evaluation of their proximate matter and nutritional composition. Their contents of proximate (moisture, ash, fats, fibers, carbohydrates and protein), minerals (Ca²⁺, K⁺ and P⁺) and anti-nutrients were examined using standard protocols. The contents of fats (0.43 mg g⁻¹f.w.) in S. oleracea; fibers (0.8 mg g⁻¹f.w.) in S. olerace; carbohydrates (0.89 mg g⁻¹f.w.); in B. juncea, proteins (0.91 mg g⁻¹f.w.) in L. sativa; and vitamin A (1.18 mg g⁻¹f.w.) in C. album from the horticulture garden were high enough to meet the daily dietary requirements of adults. Tannins were higher in species collected from the market, which is toxic for human health. It is concluded that vegetables of horticulture garden grown in suitable environmental conditions possess better nutritional composition as compared to vegetables purchased from markets. However, a large-scale research is needed for the analysis of vitamins, minerals, antioxidants, anti-nutrients and heavy metals in leafy vegetables. Further research on ethnomedicinal attributes of leafy vegetables is recommended.