Rootstock Effects on Water Relations of Young Almond Trees (cv. Soleta) When Subjected to Water Stress and Rehydration

Abstract

Rootstocks with size controlling potential are being used in newly planted intensive almond orchards. Due to increased water scarcity, characterizing the response of these rootstocks to water deficit is required. The current work aims to assess whether the rootstock can improve their drought tolerance. We investigated the morphological and physiological response of P. dulcis “Soleta” either self-rooted or grafted on Rootpac-20 rootstock. Plant responses were evaluated during a water stress period (withholding irrigation for 20 days) and subsequent recovery in potted plants under greenhouse conditions. Self-rooted plants had a higher capacity to control vigour than plants grafted onto Rootpac-20, both under full irrigation and no irrigation conditions. Stressed plants exhibited severe dehydration, as indicated by lower leaf water potential and relative water content. Removing irrigation reduced stomatal conductance in grafted and self-rooted plants by a similar extent, suggesting an efficient stomatal control, while the reduction in the net photosynthesis rate was more marked in grafted plants compared to non-grafted plants. Self-rooted plants under water stress increased their root to shoot ratio and water use efficiency, which are positive aspects for growth and survival of these plants.

Examining physiological, water relations, and hydraulic vulnerability traits to determine anisohydric and isohydric behavior in almond (Prunus dulcis) cultivars: Implications for selecting agronomic cultivars under changing climate

“…Furthermore, our results regarding Soleta cultivar are in agreement with Álvarez et al (2020) who indicated that this cultivar displayed physiological responses linked to drought tolerance when growing with its original root system (self-rooted). This result was, however, diminished when plants were grafted onto the dwarfing rootstock Rootpac-20.…”

Reviewing the Adverse Climate Change Impacts and Adaptation Measures on Almond Trees (Prunus dulcis)

“…Planting almond cultivars on drought-tolerant rootstocks (grafting) to reduce the negative consequences of water scarcity [110]. Moreover, rootstocks may also confer resistance to different biotic and abiotic stresses in the soil [111]. Several studies have been conducted to evaluate the potential of rootstock to mitigate climate change impacts [111][112][113].…”

Responses of physiological and morphological characteristics in Thai pummelo cultivars (Citrus maxima (Burm.) Merr.) under drought stress condition

“…TNC is an important parameter under drought stress that indicates the C balance in plants between photosynthetic carbon assimilation and metabolic carbon demand (Chapin et al, 1990). The percentage reduction in the roots was higher than in the shoots, which differed from Alvarez et al (2020), who reported that drought stress significantly decreased shoot growth, including leaf area, number of leaves, plant height and trunk diameter in almond rootstock but had little effect on root growth. Disparities in these results may have been caused by the different seedling types, as it appeared that almond grafted on rootstock adapted well under drought stress compared to air layered pummelo seedlings.…”