A proven photocatalyst, titanium dioxide in the form of nano-anatase, is capable of undergoing electron transfer reactions under light. In previous studies, we had proven that nano-anatase could absorb ultraviolet light (UV-B) and convert light energy to stable chemistry energy finally via electron transport in spinach chloroplasts. The mechanisms by which nano-anatase promotes antioxidant stress in spinach chloroplasts under UV-B radiation are still not clearly understood. In the present paper, we investigate the effects of nano-anatase on the antioxidant stress in spinach chloroplasts under UV-B radiation. The results showed that nano-anatase treatment could significantly decrease accumulation of superoxide radicals O2.-, hydrogen peroxide (H2O2), and malonyldialdehyde (MDA) content, and increase activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and elevate evolution oxygen rate in spinach chloroplasts under UV-B radiation. Together, nano-anatase could decrease the oxidative stress to spinach chloroplast caused by UV-B radiation.

Purpose The purpose of this study is to investigate the relationship between board diversity measured as relation-oriented, task-oriented and board overall diversity and firm’s investment efficiency. Design/methodology/approach This study estimates four dimensions of board diversity, including age, gender, tenure and education. The four dimensions are further categorized in relation-oriented diversity (i.e. age and gender), task-oriented diversity (i.e. tenure and education) and overall board diversity (relation and task oriented). Panel data analysis is used to examine the board diversity–investment efficiency relationship in Chinese listed firms during the years 2003–2018. The findings of the study are robust to a battery of econometric techniques. Findings This study finds relation-oriented, task-oriented and overall diversity of a board curb investment inefficiency by discouraging sub-optimal investment (over- or under-investment). In other words, board diversity improves firms’ investment efficiency. Practical implications The results suggest that board diversity plays a significant role in corporate decisions. The findings illustrate that board diversity disciplines the management, reduces agency conflicts and thereby improves corporate governance, resulting in higher investment efficiency. Originality/value This study has two important contributions. First, this study extends the prior literature of investment efficiency by considering socio-psychological dimension of the board diversity by constructing relation- and task-oriented diversity. Second, contrary to earlier studies on board diversity, this study takes four facets of board diversity, i.e. age, gender, education and tenure that improve corporate governance mechanism.

Alamethicin (AMT) is a linear antimicrobial peptide isolated from fungi Trichoderma viride. To date, the mode of action of AMT in plant cells remains unknown. Our experimental results indicate that AMT causes leaf lesion attributed to its multiple effects on PSII. AMT decreases the O2 evolution rate of PSII. Based on chlorophyll fluorescence data, similar to the classical herbicide diuron, AMT interrupts PSII electron transfer beyond QA at the acceptor side, leading to the inactivation of the PSII reaction centers. Additionally, AMT decreases chlorophyll content and destroys the architecture of PSII pigment assemblies. However, AMT does not affect the oxygen-evolving complex at the donor side of PSII. Thus, it is concluded that AMT is a natural photosynthetic inhibitor with several action sites in PSII.Additional key words: bioherbicide; chlorophyll a fluorescence; leaf lesion; natural product. transport rate; FV/FM -maximum quantum yield of PSII photochemistry; OEC -oxygen-evolving complex; qP -photochemistry quenching coefficient; RCs -reaction centers; ROSreactive oxygen species; TAP -Tris-acetate-phosphate; TR0 -trapping flux.

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