No abstract

Continuous light can be used as a tool to understand the diurnal rhythm of plants and it can also be used to increase the plant production. In the present research, we aimed to investigate the photosynthetic performance of V. radiata under continuous light as compared with the plants grown under normal light duration. Chlorophyll a fluorescence transient (OJIP test) technique was used to understand the effect on various stages of photosynthesis and their consequences under continuous light condition. Various Chl a Fluorescence kinetic parameters such as Specific energy fluxes (per Q A -reducing PSII reaction center (RC)) (ABS /RC; TR 0 /RC; ET 0 /RC; DI 0 /RC), phenomenological fluxes, leaf model, (ABS/CSm; TR/CSm; ETo/CSm), Quantum yields and efficiencies (φPo; φEo; Ψo) and Performance index (PI abs ) was extracted and analysed in our investigation. Conclusively, our study has revealed that continuous light alters the photosynthetic performance of V. radiata at a different point but also improve plant productivity.

In the present work, we demonstrated the biosynthesis of silver nanoparticles (AgNPs) by highly stable, economic and eco-friendly method using leaf extract of Terminalia arjuna (T. arjuna) and employing as a catalyst for the degradation of methyl orange (MO), methylene blue (MB), congo red (CR) and 4- nitrophenol (4-NP). The biosynthesis of AgNPs was visually validated through the appearance of reddish-brown color and further confirmed by the UV-spectra at 418 nm. The TEM and FE-SEM studies revealed the spherical shape of particles with size ranged between 10–50 nm. Face centered cubic crystalline nature of AgNPs was proved by XRD analysis. The negative value of zeta potential (−21.7) indicated the stability of AgNPs and elemental composition was confirmed by EDS. FT-IR analysis revealed the functional groups present in the plant extract trigger the biosynthesis of AgNPs. The AgNPs exhibited strong degradation of MO (86.68%), MB (93.60%), CR (92.20%) and 4NP (88.80%) by completing the reduction reaction within 20 min. The reaction kinetics followed the pseudo-first-order and displayed k-values (rate constant) 0.166 min−1, 0.138 min−1, 0.182 min−1 and 0.142 min−1 for MO, MB, CR and 4-NP respectively. This study showed an efficient, feasible and reproducible method for the biosynthesis of eco-friendly, cheap and long-time stable AgNPs and their application as potent catalysts against the degradation of hazardous dyes.

The World Health Organization, which proclaimed the COVID-19 a pandemic in early March 2020, imposed a partial lockdown by the Government of India on 21 March 2020. The aim of this investigation was to measure the change in air pollutants, including particulate matter (PM 2.5 and PM 10 ) and gaseous pollutants (NO 2 , CO and O 3 ) during COVID-19 lockdown (25th March to 14th April 2020) across four major polluted cities in North India. In all region, PM 2.5 , PM 10 , NO 2 and CO were significantly reduced while O 3 has been shown mixed variation with increased in Agra and decreased in all other stations during lockdown. PM 2.5 was reduced by ~20–50% and highly decreased in Noida. PM 10 was most significantly decreased by 49% in Delhi. NO 2 was reduced by ~10–70%, and high reduction was observed in Noida. Likewise, ~10–60% reduction was found in CO and most significantly decreased in Gurugram. However, an increased in O3 was observed in Agra by 98% while significantly reduced in other sites. Compared to the same timeframe in 2018–2019, PM 2.5 and PM 10 values for all sites were reduced by more than 40%.

With the growing awareness for the need of sustainable environment, the importance of synthesizing and the application of green nanoparticles has gained special focus. Among various metal nanoparticles, silver nanoparticles (AgNPs) have gain significant attention. AgNPs are synthesized conventionally by physical and chemical methods using chemicals such as reducing agents, which are hazardous to environment due to their toxic properties, provoking a serious concern to create and develop environment friendly methods. Thus, biological alternatives are emerging to fill gaps, such as green syntheses that use biological molecules taken from plant sources in the form of extracts, which have shown to be superior to chemical and physical approaches. These biological molecules derived from plants are assembled in a highly regulated manner to make them suitable for metal nanoparticle synthesis. The current review outlines the wide plant diversity that may be used to prepare a rapid and single-step procedure with a green path over the traditional ones, as well as their antifungal activity.