GONZALEZ VILLAGRA, JORGE ANDRES
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Diurnal High Temperatures Affect the Physiological Performance and Fruit Quality of Highbush Blueberry (Vaccinium corymbosum L.) cv. Legacy
In this study, the physiological performance and fruit quality responses of the highbush blueberry (Vaccinium corymbosum) cultivar Legacy to high temperatures (HTs) were evaluated in a field experiment. Three-year-old V. corymbosum plants were exposed to two temperature treatments between fruit load set and harvest during the 2022/2023 season: (i) ambient temperature (AT) and (ii) high temperature (HT) (5 °C ± 1 °C above ambient temperature). A chamber covered with transparent polyethylene (100 µm thick) was used to apply the HT treatment. In our study, the diurnal temperature was maintained with a difference of 5.03 °C ± 0.12 °C between the AT and HT treatments. Our findings indicated that HT significantly decreased CO2 assimilation (Pn) by 45% and stomatal conductance (gs) by 35.2% compared to the AT treatment. By contrast, the intercellular CO2 concentration (Ci) showed higher levels (about 6%) in HT plants than in AT plants. Fruit quality analyses revealed that the fruit weight and equatorial diameter decreased by 39% and 13%, respectively, in the HT treatment compared to the AT treatment. By contrast, the firmness and total soluble solids (TSS) were higher in the HT treatment than in the AT treatment. Meanwhile, the titratable acidity showed no changes between temperature treatments. In our study, Pn reduction could be associated with stomatal and non-stomatal limitations under HT treatment. Although these findings improve our understanding of the impact of HTs on fruit growth and quality in V. corymbosum, further biochemical and molecular studies are need. © 2024 Elsevier B.V., All rights reserved.
Physiological and molecular effects of TiO2 nanoparticle application on UV-A radiation stress responses in Solanum lycopersicum L.
Nanoparticles (NPs) of titanium dioxide (TiO2) alter photosynthetic and biochemical parameters in Solanum lycopersicum L., possibly due to their photocatalytic properties given by energy absorption in the UV-A range; however, the joint effects TiO2 NPs and UV-A radiation are not well understood. This work evaluates the combined responses of TiO2 NPs and UV-A radiation at the physiological and molecular levels in S. lycopersicum. In a split growth chamber, the presence (UV-A +) and absence (UV-A ?) of UV-A were combined with 0 (water as a control), and 1000 and 2000 mg L?1 of TiO2 NPs applied at sowing. At the end of exposure (day 30 after sowing), the photosynthetic performance was determined, and biochemical and molecular parameters were evaluated in leaf tissues. Better photochemical performance in UV-A + than UV-A ? in control plants was observed, but these effects decreased in 1000 and 2000 mg TiO2 L?1, similar to net CO2 assimilation. A clear increase in photosynthetic pigment levels was recorded under UV-A + compared to UV-A ? that was positively correlated with photosynthetic parameters. A concomitant increase in total phenols was observed on adding TiO2 in UV-A ? conditions, while a decreasing trend in lipid peroxidation was observed for the same treatments. There was an increase in psbB gene expression under TiO2/UV-A + treatments, and a reduced expression of rbcS and rbcL under UV-A ?. These results suggest that the reduction in photosynthetic performance on applying high doses of TiO2 NPs is probably due to biochemical limitation, while UV-A achieves the same result via the photochemical component. © 2023 Elsevier B.V., All rights reserved.
Salicylic Acid Improves Yield, Fruit Quality, and Post-Harvest Storage in Sweet Cherry (Prunus avium L.) cv. Lapins Subjected to Late-Deficit Irrigation
This study evaluated the effect of salicylic acid (SA) application on yield, fruit quality, and post-harvest storage in Prunus avium subjected to deficit irrigation (DI). A field experiment with six-year-old P. avium cv. Lapins was performed under two water treatments: irrigation at 100% of crop evapotranspiration (ETc) [full irrigation (FI)] and irrigation at 60% ETc from the second fruit phase to harvest time (DI). A single 0.5 mM SA was applied to both water treatments at fruit color change. At harvest time, fruits were collected to determine yield, fruit quality, and quality during post-harvest storage (0, 10, 20, and 30 days). The DI reduced fruit yield (11%), fruit weight (8%), and caliber (6%) and increased firmness (7%) and total soluble solids (TSS) (5%) in P. avium compared with FI plants at harvest time. Our study showed that SA application recovered fruit yield (9%), fruit weight (5%), and caliber (4%), improving TSS in DI plants at day 0. Interestingly, SA application significantly reduced P. avium fruit cracking (78% in FI and 82% in DI). Fruit weight was reduced in all treatments, mainly decreasing by 14% in FI and 13% in DI plants at day 30 of post-harvest storage. Fruit weight did not change during post-harvest storage with SA, except on day 30, where a slight reduction was observed. TSS showed no significant differences during post-harvest storage for all treatments. Therefore, SA could be an interesting tool to mitigate the impact of DI on the yield and fruit quality of P. avium and to reduce fruit cracking and prolong fruit quality during post-harvest storage. © 2024 Elsevier B.V., All rights reserved.