The effect of autumn N supply on the architecture of young peach (Prunus persica L.) trees

Abstract

Irrigation and fertilisation were recently considered as useful tools to control tree shape, and reduce pruning costs. The role of the N reserves, which determined spring growth, was considered to be essential. We intended therefore to evaluate its effects on peach tree architecture. Four levels of N fertilisation were applied on 1-year-old trees, from the end of shoot growth to leaf fall. In subsequent spring, each bud fell into one of the ten classes of positions previously defined within the crown. Its development was followed weekly from burst to June. Fertilisation promoted growth until a threshold level, since no differences were evidenced between the three highest N treatments. Fall N did not affect burst but the further transformation of the buds into rosettes, proleptic or ramificated axes. Crown base was little affected. Fall N increased the number of proleptic axes on most median and upper positions. Axes lengthening and thickening were limited on the median positions, promoted at crown top. The variations concerned the mean internodes lengths, not the number of phytomers per axis. Sylleptic ramification was limited to the crown outer parts, and decreased with fall N. Treatment did neither affect the fruit dry weights, nor the ratio between the number of leaves and the number of fruits. Fruit number was proportioned to vegetative growth by blossoming and fruit set. We conclude that a moderate autumn fertilisation improved orchard productivity, but favoured vegetative growth in the crown outer parts. Additional pruning may therefore be required to control tree shape.

Autumnal nitrogen nutrition affects the C and N storage and architecture of young peach trees

“…Nitrogen fertilisation is a regular practice in orchards that affects tree development (Lobit et al 2001;Jordan et al 2009). The effects vary with the time of application (Amponsah et al 2004) and are not evenly distributed within the tree, thus altering tree shape, the root to shoot ratio and the balance between vegetative growth and fruit production (Cheng et al 2002;Jordan et al 2009).…”

C depletion and tree dieback in young peach trees: a possible consequence of N shortage?

“…To our knowledge, bud burst in spring has never been investigated in terms of its relationship with N availability. However, low N storage is known to affect shoot development by (i) decreasing the proportion of rosettes that are transformed into elongated axes (Lobit et al 2001;Grelet et al 2003;Jordan et al 2009), but not the number of developing buds set by a specific peach variety (Perezgonzalez 1993), and (ii) delaying spring development (Jordan et al 2014).…”

“…The latter thus maintained a significant level of starch in spring which penalised spring N uptake and delayed shoot growth (Jordan et al 2009(Jordan et al , 2012. This could probably be explained by the constitution of "safety reserves" under stress conditions (Silpi et al 2007) which become inaccessible unless the onset of a dramatic event compromises tree survival (Vargas et al 2009).…”

“…This study focused in particular on the fate of these deprived trees. Indeed, those trees died within 3 months after bud burst and had therefore been excluded from two previous studies analysing the effects of a nonzero but limited autumn N supply on tree architecture (Jordan et al 2009), gross growth and nutrient status (Jordan et al 2012). Our aim here was therefore to document the link between N deprivation in autumn, C depletion and tree dieback in spring.…”

Flower bud differentiation and development in fruiting and non-fruiting shoots in relation to fruit set in apricot (Prunus armeniaca L.)

“…Differences in size among flowers with different capability to set fruit have been reported in apricot (Rodrigo and Herrero 2002a;Rodrigo et al 2009) and other fruit tree species regardless of the different factors causing these differences, such as nitrogen summer applications (Williams 1965, Jordan et al 2009), previous crop load (Buszard and Schwabe 1995), stresses during floral initiation (Lamp et al 2001) or warm pre-blossom temperatures (Rodrigo and Herrero 2002a). Likewise, the age of the tree and wood (Robbie and Atkinson 1994) and the orientation of branches where flower buds are located (Robbie et al 1993;Almeras et al 2002) have been also related to a different reproductive success.…”