Photosynthetic and antioxidant‐related properties in blueberry under low‐ and high‐density covering material

Abstract

Covering material is an important tool to reduce damage from extreme weather events, especially in horticultural species. However, physiological and biochemical responses to covering material are still limited in woody plants. Thus, this study aimed to evaluate covering material effects on photosynthetic and antioxidant performance in blueberry cv. Legacy to high-density polyethylene (HDPE) and low-density polyethylene (LDPE) covering treatments under field conditions during two consecutive seasons. Our results showed that net photosynthesis (P n ) was reduced in LDPE compared to uncovered treatment during the first season. Interestingly, P n increased 10% in HDPE compared to uncovered and LDPE treatments. Stomatal conductance (g s ) was not affected by covering material; meanwhile, the transpiration (E) only showed a 22% increment in LDPE. HDPE exhibited the highest chlorophyll a in the 2018/2019 season compared to the uncovering treatment, as well as chlorophyll b and chlorophyll a/b ratio, but during the 2017/2018 season. A tendency to decrease chlorophyll a level in uncovered plants and LDPE treatment was observed during the 2018/2019 season. Antioxidant activity showed no differences among covering materials. By contrast, phenols increased in LDPE treatment followed by control plants, showing HDPE treatment the lower values during 2018/2019. In conclusion, this study demonstrated that blueberry plants subjected to HDPE treatment showed better P n and chlorophyll levels than uncovered and LDPE treatments, which could be associated with the diffuse transmittance in HDPE, whereas a high E and phenols were observed in LDPE, whereas intrinsic water use efficiency was lower, which is related to high direct transmittance in this covering material during the summer season.

Impact of the Covering Material on Drought Tolerance Responses and Soil Water Content in Two Cultivars of Young Blueberry Plants under Protected Cultivation

“…A recent study in highbush blueberry plants, cv. Legacy, reported that g s was not affected by covering the orchard with polyethylene films of contrasting densities, despite the covering materials exhibiting high percentages of diffused transmittance [37]. The weak and erratic response of gs to covering treatments may explain why Fv/Fm was similarly high (~0.8) in all plants (Figure 9A), indicating an optimum PSII efficiency.…”

Effects of bleeding of Actinidia arguta (Sieb. & Zucc) Planch. ex miq. on its plant growth, physiological characteristics and fruit quality

“…Carotenoids have a strong antioxidant effect, and carotenoids were significantly lower in the bled plants than the control, indicating a reduced antioxidant capacity of plants due to the bleeding treatment [ 55 ]. Further, the chlorophyll a/b of leaves was lower in this treatment than that the control, which demonstrates that the cell membrane of plant leaves is damaged via bleeding and its ion exchange ability is weakened [ 56 , 57 ]. Several studies have shown that the photosynthetic pigment and photosynthase contents influence the photosynthetic rate to a certain extent [ 58 , 59 ], which is the consistent with our result.…”