Bud development and hydraulics: An innovative way to forecast shoot architecture.
The distal zone of one-year-old apple (Malus domestica) shoots was studied on five cultivars for bud size and composition (number of appendages) and hydraulic conductance before bud burst. Our hypothesis was that bud development was related to hydraulic conductance of the sap pathway to the bud independent of an acrotonic (proximal vs. distal) effect.Bud size and composition, and hydraulic conductance, were highly variable for all cultivars. A positive correlation was demonstrated between both the number of cataphylls and green-leaf primordia and hydraulic conductance. Cultivar and bud size affected the intercept of these relationships more than the slope suggesting similar scaling between these variables but different hydraulic efficiencies. A great proportion of small buds were also characterized by null values of hydraulic conductance.Our study suggests that hydraulically mediated competitions exist between adjacent buds within a same branching zone prefiguring the variability of lateral types in the following growing season. It is hypothesized that this developmental patterning is driven by hydraulic characteristics of the whole-metamer, including the subtending leaf, during bud development.
Lauri
Pierre-Eric
PE
INRA; UMR DAP; Montpellier, France.
Cochard
Hervé
H
New Phytol. 2008;178(4):798-807
18346105
J Exp Bot. 2007;58(13):3537-47
18057035
J Theor Biol. 2001 Oct 21;212(4):481-520
11597182
New Phytol. 1990 Nov;116(3):341-381
33874094
Tree Physiol. 2005 Dec;25(12):1545-52
16137940
New Phytol. 2004 Sep;163(3):533-546
33873738
Am J Bot. 2007 Aug;94(8):1273-81
21636493