Effects of Elevated Ozone on Polka Dot Plant (Hypoestes phyllostachya) with Variegated Leaves

Abstract

In this study, impacts of O on four cultivars ('Rose', 'Pink', 'Blush' and 'White') of the polka dot plant with variegated leaves were investigated for the first time. Ozone fumigation [(120 ± 20 ppb) for 14 days (8 h day, from 8:30 to 16:30)] resulted in visible foliar injuries, decreased contents of pigments (chlorophyll a and b, and carotenoid), the inhibition of photosynthesis, the increase of quantum yield of non-regulated heat dissipation and fluorescence emission (Y(NO)), and the damage of cell membrane. Elevated O increased the content of anthocyanin (Ant). 'White' showed the highest, and 'Rose' the lowest amount of injured leaf area, indicating that the former was the most sensitive, and the latter the most tolerant to O stress. After O exposure, the highest Ant content was found in 'Rose', followed by 'Pink', 'Blush', and 'White'. Levels of Ant were likely responsible for the different sensitivities to O due to their roles in photoprotection.

Responses of growth, photosynthesis and related physiological characteristics in leaves of Acer ginnala Maxim. to increasing air temperature and/or elevated O3

“…Chlorophyll fluorescence parameters were measured with a FMS–2 fluorometer (Hansatech Instruments, Norfolk, UK) following the method of Sui et al (2017): maximum quantum efficiency of photosystem II (PSII) photochemistry ( F v / F m ), actual quantum efficiency of PSII ( Φ PSII ), quenching of photochemical efficiency of PSII ( q P ) and non‐photochemical quenching (NPQ). First, the dark fluorescence yield ( F o ), maximum fluorescence yield ( F m ) and F v / F m were measured after the samples were dark‐adapted for 20 min.…”

“…Electrolyte leakage (EL) of leaves was measured as described in Sui et al (2017). Fresh fully expanded leaves (0.2 g) were cut to uniform size, put in test tubes with 20 ml double distilled water at 25 °C for 24 h, then electrical conductivity (EC 1 ) measured using a digital conductivity meter (DDS − 11A).…”

“…Tropospheric ozone (O 3 ), as a phytotoxic air pollutant, is generated by photochemical reactions of nitrogen oxides (NO x ) and volatile organic compounds (VOC) (Sitch et al 2007; Sui et al 2017; Shang et al 2019). According to monitoring results from 338 cities in China, the mean maximum daily 8‐h O 3 concentration of these cities reached 70.4 ppb in 2018 (China Ecological and Environmental Bulletin 2018, available at http://www.cnemc.cn/, in Chinese), which exceeded the ambient air quality standards for China.…”

“…According to monitoring results from 338 cities in China, the mean maximum daily 8‐h O 3 concentration of these cities reached 70.4 ppb in 2018 (China Ecological and Environmental Bulletin 2018, available at http://www.cnemc.cn/, in Chinese), which exceeded the ambient air quality standards for China. The high O 3 concentrations have caused damage to plants, such as inhibiting growth and thus reducing biomass (Kivimäenpääet al 2017; Pleijel et al 2018; Wang et al 2020) and decreasing photosynthesis rate (Calatayud et al 2011; Yu et al 2018; Xu et al 2019a), which have led to increases in plant reactive oxygen species (ROS) and membrane lipid peroxidation (Kumari et al 2015; Brandão et al 2017; Sui et al 2017).…”