Biochemical and photosystem characteristics of wild-type and Chl b-deficient mutant in tree peony (Paeonia suffruticosa)

Abstract

In order to explore the adaptive strategies of tree peony yl1 mutant in response to photooxidative stress, the changes of biochemical parameters, chlorophyll fluorescence, and the modulated 820-nm reflection of yl1 mutant and wildtype plants were compared. We found the activities of superoxide dismutase and catalase, the contents of soluble protein, proline, superoxide radicals, hydrogen peroxide, malondialdehyde, and relative electrical conductivity were significantly higher than those of the wild type. The photochemical efficiency of PSII significantly decreased, while the proportion of heat dissipation of yl1 mutant increased greatly. The donor and acceptor side and electron transfer of PSII were greatly inhibited. Meanwhile, the performance of PSI and coordination of two photosystems decreased markedly in yl1 mutant. The yl1 mutant could reduce the damage caused by photooxidative stress by increasing the activity of antioxidant enzymes, the content of some osmoregulatory substances, and the proportion of heat dissipation.studying the mechanism of photosynthesis, the structure and function of the photosystems, and Chl biosynthesis, and are valuable for cultivating excellent varieties and molecular marker-assisted breeding (Zhang et al. 2020). Leaf-color mutants with yellow leaves, variegated leaves, stripes, and other characteristics have a high ornamental value in landscaping. Among them, a yellow-leaf mutant is a common mutation type. The paulownia (Paulownia fortnnei) mutant with white flowers presented light green leaves at the seedling stage, they turned yellow at the mature stage, and had a certain ornamental value (Ru et al. Highlights• Higher photooxidative damage was reported in tree peony yl1 mutant compared to the wild type. • The function and coordination of two photosystems in yl1 mutant decreased significantly. • The yl1 mutant increased the contents of antioxidants and osmoregulants and heat dissipation capacity in response to photooxidative stress.

Selenite foliar application increased the accumulation of medicinal components in Paeonia ostii by promoting antioxidant capacity, reducing oxidative stress, and improving photosynthetic capacity

“…Relative electrical conductivity and malondialdehyde content: The relative electrical conductivity (REC) was assessed as previously described (Zhang et al 2021). Fresh leaves (0.10 g) were rinsed and cut into thin strips, then mixed with 6 mL of distilled water, and incubated at room temperature for 24 h. The initial electrical conductivity (EC1) was measured with an electrical conductivity meter (DDS-11A, Shanghai, China).…”

“…O2 •content was measured by the method of Zhang et al (2021). Fresh leaf samples (1.0 g) were homogenized in 5 mL of PBS (65 mM, pH 7.8), filtered, and centrifuged for 10 min at 10,000 rpm.…”

“…The 820-nm modulation reflection curve was plotted according to the value of MR/MR0 (MR is the modulation reflection at different time points, and MR0 is the MR value of far-red light irradiated with 0.7 ms) (Strasser et al 2010). The maximum redox activity of PSI (ΔI/I0) and the coordination between PSI and PSII (ФPSI/PSII) were calculated according to the formula: ΔI/I0 = (I0 -Im)/Im, ФPSI/PSII = (ΔI/I0)/ψ0 (Zhang et al 2021). At least ten biological repeats were measured for each treatment.…”

Evaluating the physiological and biochemical responses of different mangrove species to upwelling

“…REC was measured using an electrical conductivity meter (DDB-303A, INESA, China), following (Zhang L. X. et al, 2021) with a slight modification. Leaf samples were washed with distilled water and then placed in tubes with 10 ml of distilled water.…”

Responses of the tree peony (Paeonia suffruticosa, Paeoniaceae) cultivar ‘Yu Hong’ to heat stress revealed by iTRAQ-based quantitative proteomics

“…How serious the plant is affected under certain stress can be accurately reflected by some physiological and biochemical indices. Previous research has shown that plants respond to external stress by enhancing antioxidant enzyme activities, like peroxidase and superoxide dismutase, to remove reactive oxygen species (ROS) from the body and weaken lipid oxidation in the cell membrane [ 10 , 11 ], as well as the synthesizing osmoregulatory substances like proline and soluble protein to maintain the water balance inside and outside the cell [ 12 , 13 ]. Furthermore, the level of malondialdehyde and relative conductivity can be used to characterize the severity of cell damage [ 14 , 15 ].…”