Drought is one of the major constraints limiting agricultural production worldwide and is expected to increase in the future. Limited water availability causes significant effects to plant growth and physiology. Plants have evolved different traits to mitigate the stress imposed by drought. The presence of plant growth-promoting rhizobacteria (PGPR) could play an important role in improving plant performances and productivity under drought. These beneficial microorganisms colonize the rhizosphere of plants and increase drought tolerance by lowering ethylene formation. In the present study, we demonstrate the potential to improve the growth of velvet bean under water deficit conditions of two different strains of PGPR with ACCd (1-Aminocyclopropane-1-Carboxylate deaminase) activity isolated from rainfed farming system. We compared uninoculated and inoculated plants with PGPR to assess: a) photosynthetic performance and biomass; b) ACC content and ethylene emission from leaves and roots; c) leaf isoprene emission. Our results provided evidence that under drought conditions inoculation with PGPR containing the ACCd enzyme could improve plant growth compared to untreated plants. Ethylene emission from roots and leaves of inoculated velvet bean plants was significantly lower than uninoculated plants. Moreover, isoprene emission increased with drought stress progression and was higher in inoculated plants compared to uninoculated counterparts. These findings clearly illustrate that selected PGPR strains isolated from rainfed areas could be highly effective in promoting plant growth under drought conditions by decreasing ACC and ethylene levels in plants.

Water being an essential component for plant growth and development, its scarcity poses serious threat to crops around the world. Climate changes and global warming are increasing the temperature of earth hence becoming an ultimate cause of water scarcity. It is need of the day to use potential soil amendments that could increase the plants’ resistance under such situations. Biochar and gypsum were used in the present study to improve the water use efficiency and growth of Abelmoschus esculentus L. Moench (Lady’s Finger). A six weeks experiment was conducted under greenhouse conditions. Stress treatments were applied after thirty days of sowing. Plant height, leaf area, photosynthesis, transpiration rate, stomatal conductance and water use efficiency were determined weekly under stressed (60% field capacity) and non-stressed (100% field capacity) conditions. Stomatal conductance and transpiration rate decreased and reached near to zero in stressed plants. Stressed plants also showed resistance to water stress upto five weeks and gradually perished at sixth week. On the other hand, water use efficiency improved in stressed plants containing biochar and gypsum as compared to untreated plants. Biochar alone is a better strategy to promote plant growth and WUE specifically of Abelmoschus esculentus, compared to its application in combination with gypsum.

Soil pollution with heavy metals has become a global issue because of anthropogenic activities causing gradual loss of soil nutrients and fertility, thus, reducing agricultural production. Biochar is recommended as an organic and environment-friendly option to address the issue of nutrient deficiency and heavy metal pollution. The present study was performed with biochar derived from Cannabis sativa to surplus soil nutrient pool and heavy metal immobilization. The characterization through scanning electron microscopy (SEM) revealed that biochar was brittle, porous, alkaline, and labile in nature. The elemental composition of biochar was carbon (75.3%), oxygen (19.2%), calcium (3.9%), potassium (1.5%), and chlorine (0.08%) determined by energy dispersive X-ray spectroscopy. Fourier transform infrared (FTIR) spectroscopy revealed the occurrence of carbonyl group, phenols, and alcohols in biochar derived from Cannabis sativa. The soil was spiked with lead and cadmium salt solution (25 ppm and 250) and incubated for 30 days. It was found that biochar amendments (1% = BC1 and 5% = BC5) significantly (p < 0.05) increased the soil physicochemical properties such as pH, electrical conductivity (EC), oxidizable organic carbon (OC), total organic carbon (TOC), and organic matter (OM). In the case of BC5, OC increased by 189.86%, TOC increased by 189.13%, and OM increased by 188.68%, as compared to the control. Similarly, soil available nitrogen (AN) and soil available phosphorous improved by 233.3% and 101.79%, respectively, compared to control. On the other hand, BC1 showed a significant reduction (p < 0.05) in lead and cadmium concentrations by 45.74% and 56.58%, respectively, in comparison to BC5 and control. In conclusion, we suggest that Cannabis sativa biochar may serve as an effective treatment for enhancing soil fertility and remediation of soil polluted with heavy metals.

In the current state of huge waste production and energy crisis, there is a need to find additional alternate energy resources and options for waste management. The present study was designed to measure the potential of different fruit wastes to serve as substrate for lipid accumulation in oleaginous bacteria. For this purpose, three novel bacterial strains (AF3, KM1 and KM10) isolated from the crude oil samples were systematically compared for their lipid accumulation potential using three types of waste including orange waste (OW), mango waste (MW) and apple waste (AW). Using waste as sole substrate, it was observed that maximum lipid accumulation by each strain was above 20%, which confirms that the bacteria belong to the oleaginous group. However, each bacterial isolate represented differential accumulative capacity with varying organic matter removal efficiency. Maximum lipid accumulation was achieved by KM10 (>25%) with AW as substrate, and KM1 (>24%) with MW as substrate; however, AF3 represented only 21% lipid accumulation using AW as substrate. Similarly, the maximum removal efficiency was recorded for KM10 in AW, followed by OW, where >60% and >50% of volatile solids (VS) removal, respectively, were achieved over the period of 7 days of incubation. This showed that the oleaginous strains also exhibit excellent waste treatment efficiency. The 16s RNA gene sequencing results showed that these KM1 and KM10 strains were Serratia surfactantfaciens and Serratia liquefaciens. In the end, a circular economy model was presented to highlight the significance of the mechanisms, which offers dual benefits over the linear economy model. Overall, the findings of the present study revealed that the novel oleaginous strains not only provide considerable lipid accumulation, but are simultaneously capable of low-cost waste treatment.

Margalla Hills National Park (MHNP) is a declared natural reserve of Pakistan, and Saidpur village is located at its foothills. To sustain livelihood, Saidpur community relies on natural resources and has established an intriguing relationship with the surrounding ecosystem. Human intrusion and related impacts were investigated through self-structured questionnaire from village community to gather information about demography, life practices, natural resource use, and their perception about the environment. Quadrat analysis revealed that the overall plant density was <4 plants/m², whereas ordination biplot has indicated significant reduction in plant cover and sparse distribution of species in areas close to human settlement. Survey results show that more than 50% families rely on forest wood as fuel source. Logistic regression has identified education paucity (odds ratio, OR = 2.6, 95% confidence interval, CI = 1.0–6.7), large family size (OR = 5.0, 95% CI = 1.5–16.6), and fuel type (OR = 3.5, 95% CI = 1.2–9.9) as significant predictors of accelerated forest cutting in MHNP. Male members were mostly illiterate and in favor to promote construction activities which reflects their low concern and casual attitude toward resource conservation. In this study, lack of awareness and peoples’ dependency on natural resources emerged as priority challenges, and hence, we suggest provision of alternate fuel sources, better education and sustained income resources as incentives to bring behavioral change. It is pivotal to involve local community before the adoption of any conservation plan as intervention strategy to protect MHNP ecosystem.