Abstract
Although the low temperature is a critical growth constraint on plants, the physiological mechanism remains unclear, especially in mangrove plants. Hence, the morphological characteristics of five mangrove plants (Bruguiera gymnorrhiza, Rhizophora stylosa, Aegiceras corniculatum, Avicennia marina, and Kandelia obovata) were compared under chilling stress. The contents of hydrogen peroxide (H2O2), malondialdehyde (MDA), and proline were tested. Activities of reactive oxygen species (ROS)-scavenging enzyme [superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)] were also measured after chilling stress. It was concluded that K. obovata can well tolerate chilling stress, and B. gymnorrhiza suffered the most severe chilling damage. Leaf-morphology observation exhibited that K. obovata and A. corniculatum can sustain chilling stress, while B. gymnorrhiza wilted and A. marina turned brown. The content of H2O2 increased at first and subsequently decreased in all plants. MDA increased instantaneously in B. gymnorrhiza and R. stylosa but changed slowly in K. obovata and A. corniculatum. The high content of proline accumulated in B. gymnorrhiza and K. obovata. The activities of the SOD, POD, and CAT increased at first and then decreased in all mangrove species. The antioxidants maintained high activity in K. obovata while decreasing earliest in A. marina exposed to the long-term chilling stress. Principal component analysis (PCA) indicated that high antioxidant enzyme activities play key roles in chilling tolerance for mangrove plants. The longer-term chilling tolerance of K. obovata may be related to the high antioxidant enzyme activities and proline accumulation. Lower H2O2 and MDA contents strengthen the anti-chilling ability of A. corniculatum. Further investigation on the molecular mechanisms will facilitate the understanding of the anti-chilling ability of mangrove plants.
Highlights
Mangrove forest distributes in the intertidal coastal areas of the tropics and subtropics, which possesses four high characteristics, namely, high productivity, high return rate, high decomposition rate, and high resistance as one of the unique marine ecosystems (Wang, 2019), and plays a pivotal role in the global climate change due to its special ecological characteristics in the world (Wang and Gu, 2021)
In A. marina and R. stylosa, the color of the leaves had turned brown from part of the leaf veins and gradually developed to the entire leaf, and the browning area was larger than 50% on the 15th day
This study suggested that chilling stress affected leaf morphology, antioxidant enzymes, lipid peroxidation, hydrogen peroxide, and proline content, and the tested mangrove plants responded in different ways
Summary
Mangrove forest distributes in the intertidal coastal areas of the tropics and subtropics, which possesses four high characteristics, namely, high productivity, high return rate, high decomposition rate, and high resistance as one of the unique marine ecosystems (Wang, 2019), and plays a pivotal role in the global climate change due to its special ecological characteristics in the world (Wang and Gu, 2021). Since 1950, it has been observed in a number of climate changes and extreme weather events associated with low or high temperatures (Pachauri et al, 2014). Temperature is one of the key abiotic factors, which can affect the growth and development of mangrove ecosystems (Hatfield and Prueger, 2015). Chilling stress (0–12◦C) of plants results from low temperature (Allen and Ort, 2001). It has been observed that chilling stress can affect the leaf morphology of plants. Most studies that focused on maize, rice, and other plants confirmed that cold temperature exposure reduced leaf expansion and growth, resulting in browning, wilting, and chlorosis (Boese and Huner, 1990; Yoshida et al, 1996). Low temperature can result in sudden leaf loss, branch and stem reductions, and even mortality of various plants including mangrove plants (Peng et al, 2013, 2015; Fei et al, 2015; Lovelock et al, 2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
