The Spatial Distribution of Root System in M9 Rootstock Is Affected by Apple Cultivar and Tree Age

Abstract

The aim of study was to evaluate how different apple cultivars affect root morphology and spatial distribution of rootstock. The experiment was conducted with three different cultivars; ‘Golden delicious’, ‘Gala’ and ‘Starking’ grafted on M9 dwarfing rootstock. Nine and fourteen years old, French vertical axe trained trees were included in the experiment. The trench profile method was chosen to study the morphology of root system and the counted root intersects were divided into three classes; fine roots (<2mm), medium-sized roots (2-5 mm), and coarse roots (>5 mm). To analyze the spatial distribution of root system, the respective cumulative number of fine roots at three successive distances from the base of tree trunk and the cumulative number of fine roots in three successive distances from soil surface were expressed as percentage versus the total fine roots. Significant effects of scion on the total number of fine roots, and as well, on their side and in depth distribution were found. The pattern of root distribution is changing over years, tending to shift the bulk of absorptive roots further from the tank and deeper into the soil. This tendency was more visible to high yielding and late maturity cultivars.

Scions impact biomass allocation and root enzymatic activity of rootstocks in grafted melon and watermelon plants

“…In contrast, Gautier et al (2021) reported only minor effects of specific Vitis scion/ rootstock combinations on root-to-shoot fresh biomass ratios. However, previous studies on compatibility aspects among different Solanaceae (Kawaguchi et al, 2008) and also woody perennials such as apple trees (Thomaj et al, 2019) underlined that carbohydrate concentration and C partitioning between graft components are highly diverse and dependent on specific rootstock-scion combinations.…”

“…However, while many previous studies addressed the effects of different rootstocks on vegetative growth ( Babaj et al., 2014a ; Babaj et al., 2014b ), stress tolerance ( Savvas et al., 2010 ; Rouphael et al., 2018 ), yield ( Balliu et al., 2008 ; Yuan et al., 2016 ), and fruit quality ( Kyriacou et al., 2017 ) of scions, little is still known about possible influences of scions on the architecture and metabolic activity of the rootstocks ( Neumann et al., 2014 ; Gautier et al., 2021 ). Furthermore, while a few published reports, to the best of our knowledge, address the effects of a scion cultivar on the rooting pattern of the rootstock ( Franco et al., 1995 ; Harrison et al., 2016 ; Thomaj et al., 2019 ), potential eco-physiological alterations affecting the nutrient acquisition capacity and efficiency of rootstocks remain poorly understood ( Shu et al., 2017 ). As it becomes more and more clear that scions modify rootstock responses to the environment in a genotype-specific manner ( Gautier et al., 2020 ), the importance of studying grafted plants during rootstock selection becomes evident.…”