Effects of Short-Term Exposure to Diesel Exhaust on the Ecophysiology, Growth, and Fecundity of Soybean (Glycine max (L.) Merr.) and Chicory (Cichorium intybus L.)

Plants growing along roadways are often exposed to vehicle exhaust containing both particulate matter (PM) and various gases that could affect gas exchange and thus plant reproduction. To investigate effects of diesel exhaust exposure on plant ecophysiology, growth, and fecundity, individuals of soybean (Glycine max (L.) Merr.) and chicory (Cichorium intybus L.) were exposed to either exhaust from a diesel generator or ambient air. Exposure occurred daily over a 5-day period (beginning 18 June 2013) using open-top chambers in an agricultural field in southwestern Ohio, United States. Plants were evaluated at 3 times (before, directly after exposure, and following a 5.5-week post-treatment recovery period) for photosynthetic rate (A), stomatal conductance (g), water use efficiency (WUE), stomatal clogging due to PM deposition, and number of nodes. Aboveground biomass, fruit number, mean seed number, and seed mass were measured for soybean after the recovery period. In soybean, A minimally decreased with exposure to diesel exhaust (compared to the control), but an increase in g and a decrease in WUE were detected after the exhaust treatment. Chicory exhibited a relatively low increase in A after the treatment, but there were no clear differences in g or WUE. Growth and fecundity were similar among all soybean plants directly after treatment, but after 5.5 weeks plants exposed to diesel exhaust had increased vegetative biomass while exhibiting no difference in fecundity. These plant species reacted differently to short-term diesel exhaust exposure, suggesting that the impact of diesel exhaust will depend on both the plant species and its physiology

High day and night temperatures impact on cotton yield and quality—current status and future research direction

Abstract Heat waves, and an increased number of warm days and nights, have become more prevalent in major agricultural regions of the world. Although well adapted to semi-arid regions, cotton is vulnerable to high temperatures, particularly during flowering and boll development. To maintain lint yield potential without compromising its quality under high-temperature stress, it is essential to understand the effects of heat stress on various stages of plant growth and development, and associated tolerance mechanisms. Despite ongoing efforts to gather data on the effects of heat stress on cotton growth and development, there remains a critical gap in understanding the distinct influence of high temperatures during the day and night on cotton yield and quality. Also, identifying mechanisms and target traits that induce greater high day and night temperature tolerance is essential for breeding climate-resilient cotton for future uncertain climates. To bridge these knowledge gaps, we embarked on a rigorous and comprehensive review of published literature, delving into the impact of heat stress on cotton yields and the consequential losses in fiber quality. This review encompasses information on the effects of heat stress on growth, physiological, and biochemical responses, fertilization, cotton yield, and quality. Additionally, we discuss management options for minimizing heat stress-induced damage, and the benefits of integrating conventional and genomics-assisted breeding for developing heat-tolerant cotton cultivars. Finally, future research areas that need to be addressed to develop heat-resilient cotton are proposed