Citrus rootstocks are a relevant tree part that contributes to crops adapting to biotic and abiotic conditions, it becoming a key factor to face the current era of climate change. Although the emphasis of most studies on rootstocks has been placed on the yield and optimization of the citrus fruit grown in different environments, other studies have paid attention to the effect of rootstock on fruit quality. Hence, the quality of citrus fruit is becoming increasingly more relevant as consumers demand high internal and external qualities to eat citrus fruit fresh. To better understand how rootstock influences citrus fruit quality, the literature that focuses on physico-chemical parameters, nutritional compounds and physiological disorders has been revised. This review points out the influence that the external aspects surrounding plants has on fruit quality, such as the rootstock/scion interaction, the water uptake capacity of roots, the modification of the photosynthetic rate or availability of nutrient minerals.

Calcium (Ca) plays a vital role as a macronutrient in the growth and development of plants. In order of decreasing solubility, Ca can be found in vegetal tissues as soluble Ca (Fraction I), bound Ca (mainly pectates, Fraction II), inorganic insoluble Ca (mainly phosphates and carbonates, Fraction III) and organic insoluble Ca or oxalate (Fraction IV). To explore the impact of Ca fertilizer application on plant growth and its allocation among different fractions, young citrus trees were fed over a complete vegetative cycle with a ⁴⁴Ca labeled fertilizer (T1-Ca), while control plants (T2) received no Ca fertilizer. The results showed that plants receiving Ca exhibited significantly greater biomass. ⁴⁴Ca derived from the fertilizer was localized mainly in sink organs (new flush leaves–twigs and fibrous roots). The primary fraction responsible for total Ca partitioning was Fraction II, followed by Fraction III or IV. Citrus plants, commonly found in calcareous soils, demonstrated improved growth with calcium treatments, indicating a positive link between calcium supplementation and enhanced development. The calcium supplied through the fertilizer (⁴⁴Ca) was predominantly concentrated in sink organs (mainly in Ca-pectate fraction), including new flush leaves and twigs above ground, as well as fibrous roots below ground.

The aim of this study was to establish DRIS (Diagnosis and Recommendation Integrated System) norms and Nutritional Optimal Ranges (NOR) for ‘Rojo Brillante’ Protected Designation of Origin (PDO) ‘Ribera del Xúquer’. The database contained 800 leaf samples collected in different crop phenological stages [after flowering (AF), fruit enlargement (FE), fruit colouring (FC), and harvesting HV)]. DRIS norms (78) were established for macronutrients: N, P, K, Ca, Mg and S; micronutrients B, Cu, Fe, Mn, and Zn and salinity elements: Na and Cl. The Nutrient Balance Index (NBI; the absolute value of the sum of the DRIS indices) was used to determine the optimal sampling period. Fruit enlargement was the period during which persimmon trees were more nutritionally balanced regardless of sprout origin (vegetative or floral) and irrigation type (drip or flood) in orchards