Abstract
Huai Zi (HZ) is a new purple mutant of green pepper (PI 631133) that is obtained from the United States Department of Agriculture. The net photosynthetic rate (P N), chlorophyll fluorescence parameters, antioxidant substances, antioxidant enzymes, photosystem 1 (PS1) and PS2 activities were studied through methyl viologen (MV) treatment. The results showed that the P N, actual photochemical efficiency of PS2 (ΦPS2), photochemical quenching coefficient (qP), PS1 and PS2 activities in HZ were lower than those in green pepper. HZ had a stronger ability to eliminate reactive oxygen species(O2 •−) and accumulated less malondialdehyde (MDA) (a membrane lipid peroxidation product) than did green pepper, and had a higher content of antioxidants and antioxidant enzyme activity. This suggests that the lower light energy absorption and higher thermal dissipation and antioxidant activity of HZ contributed to a more stable PS2 photosynthetic capacity, which resulted in photooxidation tolerance. Hence, our study strongly suggests that pepper hybrids can achieve a modest ratio of chlorophyll and anthocyanin content, high P N and resistance to photooxidation, improving yield and resistance to adverse environments.
Highlights
Plants might experience photooxidation under natural conditions [1,2,3], directly limiting photosynthetic productivity [4,5] and resulting in decreased yields
The primary site of photooxidation may be located in the PS2 reaction centre, and related to the rapid turnover of the D1 protein under radiation stress, which leads to its depletion and the loss of PS2 activity [21,22,23,24,25]
We found that Fv/Fm and WPS2 of PS2 significantly decreased in pepper under photooxidation treatment, indicating that the primary conversion efficiency of light energy and potential activity of PS2 were inhibited, directly affecting the photosynthetic electron transport and CO2 assimilation
Summary
Plants might experience photooxidation under natural conditions [1,2,3], directly limiting photosynthetic productivity [4,5] and resulting in decreased yields. The photosynthetic organs have developed photoprotective mechanisms to minimize potential damage caused by light. These mechanisms include the reduction of the direct absorption of light energy by changes in the blade angle, chloroplast movements and waxy layer thickness, protection through state transitions, cyclic electron transport, D1 protein turnover, antioxidant molecules and enzyme systems, and consumption of heat energy through non-radiative dissipation [6]. The first defence mechanism consists of the physiological characteristics that confer long-term protection, while the second line of defense is the immediate photoinhibition responses that provide effective protection in the short term. Studying the physiological basis of tolerance to high irradiance is an important strategy for obtaining stable, high yielding varieties
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.
