External authors:

• Ismael Opazo ( Ctr Estudios Avanzados Fruticultura CEAF )
• Luis Villalobos-Gonzalez ( Ctr Estudios Avanzados Fruticultura CEAF )
• Marco Garrido ( Universidad de La Serena )
• Guillermo Toro ( Ctr Estudios Avanzados Fruticultura CEAF )
• Ariel Salvatierra ( Ctr Estudios Avanzados Fruticultura CEAF )
• Mauricio Ortiz ( Ctr Estudios Avanzados Fruticultura CEAF )
• Maria Matamala ( Ctr Estudios Avanzados Fruticultura CEAF )
• Barbara Moreno ( Ctr Estudios Avanzados Fruticultura CEAF )
• Paula Pimentel ( Ctr Estudios Avanzados Fruticultura CEAF )

Abstract:

Background and AimsStone fruit trees (Prunus spp.) are cultivated in semi-arid to temperate climates which are areas prone to water deficit. Rootstocks contribute significantly to the development of more resilient trees; however, their role in determining drought tolerance across different fruit varieties remains poorly understood. This study assessed the influence of rootstocks over drought tolerance in multiple Prunus species and their potential interactions.MethodsExperiments were conducted using 20-L container with two contrasting rootstocks (drought-tolerant and drought-sensitive), grafted with seven different Prunus species. The plants were subjected to a progressive water deficit until the transpiration nearly stopped. Parallel experiments using ungrafted rootstocks in rhizotrons were conducted to monitor root growth over time.ResultsPhysiological and growth parameters were measured in rootstocks and scions. Although rootstocks did not significantly affect leaf water relations, they strongly influenced growth under water deficit across all grafted species. Grafted tree tolerance is related to rootstock tolerance and their interactions with scions. Rhizotron experiments in ungrafted plants evidenced higher root growth in the sensitive rootstock but a shallower distribution, potentially limiting its ability to access deeper soil water.ConclusionThis study demonstrated that rootstocks and their interactions have a broad effect on drought response in grafted Prunus species, influencing both the onset of stress symptoms and tree growth. A candidate factor could be root growth pattern, although specific interactions among rootstocks and scions also play a significant role. Further research is required to elucidate the mechanisms that influence drought tolerance in grafted fruit trees.