Ozone Response of Leaf Physiological and Stomatal Characteristics in Brassica juncea L. at Supraoptimal Temperatures

Abstract

Plants are affected by the features of their surrounding environment, such as climate change and air pollution caused by anthropogenic activities. In particular, agricultural production is highly sensitive to environmental characteristics. Since no environmental factor is independent, the interactive effects of these factors on plants are essential for agricultural production. In this context, the interactive effects of ozone (O3) and supraoptimal temperatures remain unclear. Here, we investigated the physiological and stomatal characteristics of leaf mustard (Brassica juncea L.) in the presence of charcoal-filtered (target concentration, 10 ppb) and elevated (target concentration, 120 ppb) O3 concentrations and/or optimal (22/20 °C day/night) and supraoptimal temperatures (27/25 °C). Regarding physiological characteristics, the maximum rate of electron transport and triose phosphate use significantly decreased in the presence of elevated O3 at a supraoptimal temperature (OT conditions) compared with those in the presence of elevated O3 at an optimal temperature (O conditions). Total chlorophyll content was also significantly affected by supraoptimal temperature and elevated O3. The chlorophyll a/b ratio significantly reduced under OT conditions compared to C condition at 7 days after the beginning of exposure (DAE). Regarding stomatal characteristics, there was no significant difference in stomatal pore area between O and OT conditions, but stomatal density under OT conditions was significantly increased compared with that under O conditions. At 14 DAE, the levels of superoxide (O2-), which is a reactive oxygen species, were significantly increased under OT conditions compared with those under O conditions. Furthermore, leaf weight was significantly reduced under OT conditions compared with that under O conditions. Collectively, these results indicate that temperature is a key driver of the O3 response of B. juncea via changes in leaf physiological and stomatal characteristics.

The Effects Morpho-Anatomical Characters Leaves Tectona grandis and Gmelina arborea as Carbon Dioxide Absorption in Unhas Urban Forest

“…Tectona grandis leaves size was 298.424 cm larger than Gmelina arborea leaves size of 165.726 cm. Chlorophyll contents can also be influenced by leaves size, leaves anatomy, and habitat [30], [51], [52], [53], [54]. Chlorophyll content can be used to measure canopy health [55].…”

Individual and Interactive Effects of Elevated Ozone and Temperature on Plant Responses

“…Increased temperatures above the optimum may decrease the uptake of ozone by reducing stomatal conductance [55,84]. However, due to increased stomatal conductance, moderately elevated temperatures (+5 • C) can enhance ozone uptake [24,85]. Lee et al [24,85] reported that +5 • C above an optimal temperature increased O 3 -induced foliar damage and reduced photosynthesis in chamber experiments with constant humidity.…”

“…However, due to increased stomatal conductance, moderately elevated temperatures (+5 • C) can enhance ozone uptake [24,85]. Lee et al [24,85] reported that +5 • C above an optimal temperature increased O 3 -induced foliar damage and reduced photosynthesis in chamber experiments with constant humidity. Conversely, O 3 accelerated leaf senescence in silver birch (Betula pendula), while a +1.2 • C-temperature increase delayed leaf senescence in field experiments [86].…”

“…Without confounding changes in humidity, the stomatal response to higher ambient temperatures obviously showed increased stomatal opening in relation to O 3 flux [92,93]. Presently, the plant physiological characteristics resulting from the combined effects and interacting mechanisms of elevated O 3 and temperature are debatable [24,85,87,88,94,95].…”

Particulate Matter (PM) Adsorption and Leaf Characteristics of Ornamental Sweet Potato (Ipomoea batatas L.) Cultivars and Two Common Indoor Plants (Hedera helix L. and Epipremnum aureum Lindl. & Andre)

“…Accumulated PM on leaves can reduce photosynthetically active radiation (PAR) by absorbing and scattering light rays [30]. Fine particles can block the stomata, leading to reduced gas exchange and plant growth because stomatal movement is highly linked to primary metabolism [31,32]. Particulate matter stress may induce leaf loss and tissue death, decrease chlorophyll levels, and increase leaf temperature, all of which results in physical and chemical changes caused by PM constituents, such as nitrate, sulfate, organic pollutants, and trace elements [33].…”