Integration of Physiological and Molecular Traits Would Help to Improve the Insights of Drought Resistance in Highbush Blueberry Cultivars

Abstract

Water deficit or drought is one of the most severe factors limiting plant yield or fruit quality. Thus, water availability for irrigation is decisive for crop success, such as the case of highbush blueberry (Vaccinium corymbosum L.). Therefore, drought stress may compromise blueberry production due to lower fruit weight or fruit yield. Despite this, it is unclear if there is any difference in the response of blueberry cultivars to water deficit, either in terms of physiological and molecular parameters, or in terms of their sensitivity or resistance to drought. In this study, we determined the effect of drought on different physiological parameters in blueberry plants (relative water content (RWC), photochemical efficiency of photosystem II (Fv/Fm), Carbon Isotopic Discrimination, and proline content) in six V. corymbosum cultivars. We also explored molecular responses in terms of gene expression coding for late embryogenesis abundant proteins. Finally, we estimated cultivar water deficit resistance using an integrative model based on physiological results. Upon water deficit conditions, we found reductions in Fv/Fm, RWC, and isotopic discrimination of 13C (Δ13C), while proline content increased significantly for all cultivars. Additionally, we also found differences in the estimated water deficit resistance index. These results indicate differences in water deficit resistance, possibly due to variations in cultivars’ genetic composition.

Analysis of Physiological Status in Response to Water Deficit of Spelt (Triticum aestivum ssp. spelta) Cultivars in Reference to Common Wheat (Triticum aestivum ssp. vulgare)

“…To assess the drought tolerance of the studied cultivars, the resistance index (RI) was calculated based on the equation proposed by Balboa et al (2020) [33]. For this purpose, the plant physiological activity (PPA) in drought-stressed and control plants was estimated, taking into account the following input data: RWC (%), A (unit value), Y (PSII) (unitless) value below 1), Fv/Fm (unitless) value below 1) that have the same weight in the equation.…”

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

“…Stomatal conductance (gs) was measured on three leaves per plant using a steady-state porometer (SC-1, Decagon Instruments, Washington, USA). Photosystem II (PSII) efficiency was assessed at the beginning and at the end of the season using a chlorophyll fluorimeter (Pocket PEA, Hansatech Instruments, England, UK) and determined on the basis of a variable (Fv/Fm), where Fv = [Fm − Fo], and Fm = maximum fluorescence performance [26], by previously darkening the leaves for 20 min [27] and using claps with a measuring area of 4 mm in diameter. Both assessments were performed in the upper third of the canopy on mature, healthy, and sun-exposed leaves without chlorosis or obvious damage, using the same plant on which Ψ s was determined.…”

Response of Winter Wheat (Triticum aestivum L.) to Selected Biostimulants under Drought Conditions

“…Using the results of physiological measurement parameters, an equation using a 0 to 1 scale was developed for all biostimulants, based on which the plant tolerance to drought stress was assessed. The following input data were used in the following equation: A-CO 2 assimilation level, E-transpiration level, Yield-quantum yield of the photochemical reaction in PSII, all weighted equally [26].…”

“…The highest DRI value was observed for plants treated with 'Bacillus velezensis' (0.508%), whereas the lowest value was obtained for plants treated with 'Naturvital ® -Plus' (0.278%) (Table 6). Physiological results were also used to estimate the water deficit resistance in blueberry cultivars using a water deficit resistance index; this allowed for the assessment of the physiological parameters and comparison of the cultivars' reactions under drought [26]. The DRI conversion factor was also successfully used in the earlier studies and indicated the spelled wheat varieties as more tolerant to drought [23].…”