Apical dominance

The BUD2 mutation affects plant architecture through altering cytokinin and auxin responses in Arabidopsis

“…Although an antagonistic role of auxin and cytokinin in the regulation of apical dominance has been postulated for decades, little is known about the underlying molecular mechanisms. Recent studies have shown that auxin can regulate the expressions of IPT genes and that cytokinin biosynthesis is directly affected by auxin in local shoots [32,33], suggesting that auxin may modulate cytokinin concentration and thus represses AM outgrowth [31,[34][35][36].…”

“…Auxin was first regarded as a direct regulator in this process [14], a notion strengthened thereafter by physiological studies on decapitated shoot apices [15][16][17], and by analyzing auxin biosynthesis, transport and signaling [18][19][20][21][22][23][24][25][26][27][28][29] in plants. However, when radiolabelled auxin was applied to a decapitated stump, the outgrowth of axillary buds was inhibited even though radiolabelled auxin was not found to accumulate in axillary buds, suggesting an indirect suppression effect of auxin on the AM outgrowth [28,30] and the presence of second messengers.Cytokinin has been proposed as a second messenger that mediates the action of auxin in controlling the apical dominance, because it promotes the outgrowth of lateral buds when directly applied to buds [31]. Although an antagonistic role of auxin and cytokinin in the regulation of apical dominance has been postulated for decades, little is known about the underlying molecular mechanisms.…”

“…Although an antagonistic role of auxin and cytokinin in the regulation of apical dominance has been postulated for decades, little is known about the underlying molecular mechanisms. Recent studies have shown that auxin can regulate the expressions of IPT genes and that cytokinin biosynthesis is directly affected by auxin in local shoots [32,33], suggesting that auxin may modulate cytokinin concentration and thus represses AM outgrowth [31,[34][35][36].Recent studies on a series of branching mutants, such as more axillary growth (max) of Arabidopsis [37][38][39][40], ramosus (rms) mutants of pea [41][42][43], decreased apical dominance (dad) mutants of petunia [44,45] and dwarf (d) mutants of rice [46][47][48][49][50][51], have revealed strigolactone as a second messenger of auxin action on the control of AM outgrowth [52,53]. Strigolactones, a group of terpenoid lactones that have been found in root exudates of diverse plant species, are synthesized from carotenoids in roots and transported acropetally or synthesized locally to repress the outgrowth of shoot branches [38,[54][55][56].…”

Effects of Shoot-Bending in Relation to Root Media on Cut-Flower Production in Roses

“…It has been reported that bending of the primary shoot promotes the formation of axillary shoots by breaking apical dominance (Cline, 1991). Zieslin and Halevy (1978) found that in roses bending the stem caused growth of a strong shoot close to the bend and another strong shoot close to the distal end.…”

“…In traditional production, a tall hedgerow canopy assures ample foliage area to capture light. With shoot-bending, it becomes possible to maintain the low canopy height without sacrificing foliage area.It has been reported that bending of the primary shoot promotes the formation of axillary shoots by breaking apical dominance (Cline, 1991). Zieslin and Halevy (1978) found that in roses bending the stem caused growth of a strong shoot close to the bend and another strong shoot close to the distal end.…”