Sylleptic Shoot Formation in Young Apple Trees Exposed to Various Soil Temperature and Air Humidity Regimes in Three Successive Periods of the Growing Season

Influence of cultivar and rootstock on early growth and syllepsis in nursery trees of pear (Pyrus communis L., Rosaceae)

“…Studies on pear carried out by other authors showed that branching, i.e., syllepsis was considerably more affected by the cultivar than by the rootstock, though less so than in other fruit species (Jacyna, 1996(Jacyna, , 2004, particularly when the rootstocks had similar vigour, as was the case in this study. Air temperature, soil temperature and relative humidity also play important role in sylleptic branch formation (Tromp, 1996) The influence of rootstock and cultivar/rootstock interactions on syllepsis was not found in this study (Table 1). The effect of rootstock on syllepsis was a function of their effect on scion vigour (Lewko et al, 2007).…”

“…These measures include pinching of seedlings (Wertheim, 1978), removal of immature sub-terminal leaves (Popenoe and Barritt, 1988) or treatment with plant hormones to facilitate the growth (Volz et al, 1994;Henrique et al, 2006). Also, reduction in apical dominance and increase in lateral ramification under nursery production are most commonly achieved through growth enhancement measures (Tromp, 1996). Nevertheless, pear is usually considered as a vigorous species and its branching habit is often naturally erect.…”

“…However, such nursery trees are not produced by conventional growing methods in a nursery, due to the low natural tendency of nursery-grown fruit trees to develop sylleptic shoots during the first year after grafting (Popenoe and Barritt, 1988;Volz et al, 1994;Wertheim and Estabrooks, 1994). In fruit trees, lateral buds of growing shoots usually do not leaf out (Tromp, 1996) and rich nutrition and optimal water supply of nursery soil in early summer bring fruit trees to their optimum enabling lateral buds to grow into "sylleptic shoots" during the first year after bud-grafting. There are striking differences between the cultivars of diverse fruit species (Wertheim, 1978).…”

“…There are striking differences between the cultivars of diverse fruit species (Wertheim, 1978). Also, the differences in the development of sylleptic shoot over the years are due to environmental conditions (Tromp, 1996). Fruit tree architecture is defined by a number of criteria related to primary growth (Lauri et al, 1995).…”

Elevated air humidity modulates bud size and the frequency of bud break in fast-growing deciduous trees: silver birch (Betula pendula Roth.) and hybrid aspen (Populus tremula L. × P. tremuloides Michx.)

“…Crowns are shaped by an interaction between endogenous stimuli, such as apical control, and exogenous factors including light, temperature, nutrient availability, and water supply (Tromp 1996; Barthélémy and Caraglio 2007;Cline et al 2009;Choubane et al 2012;Demotes-Mainard et al 2013).…”