Gibberellins and Cytokinins Related to Fruit Bud Initiation in Apple

Ramírez, Homero; Benavides, A.; Robledo, Valentín; Alonso, Rodolfo Hernández; Gómez, Jorge

doi:10.17660/actahortic.2004.636.50

Cited by 11 publications

(9 citation statements)

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“…This localized inhibition may depend on a critical ratio of inhibitor and promoter hormones that inhibits the flowering of apical meristems (Pellerin et al, 2012), or may be a result of carbon limitation and/or hormonal inhibition of floral initiation by nearby seeds (Dennis, 2000). Inhibition of floral initiation by endogenous GAs (possibly GA 1 , GA 4 , and iso-GA 7 ) produced by seeds was confirmed in heavily cropped "Fuji" trees (Kittikorn et al, 2010) and "Golden Delicious" (Ramıírez et al, 2004). GAs and jasmonic acid (JA) act antagonistically, with JA detected at high concentrations in apple trees when GA concentrations are low, suggesting its key role in floral initiation (Kittikorn et al, 2010).…”

Section: Introductionmentioning

confidence: 89%

Relationships Among the Rootstock, Crop Load, and Sugar Hormone Signaling of Apple Tree, and Their Effects on Biennial Bearing

Kviklys

Samuolienė

2020

Front. Plant Sci.

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Adjustable crop load primarily involves bud manipulation, and usually switches from vegetative to reproductive buds. While this switch is not fully understood, it is still controlled by the ratio of hormones, which promote or inhibit bud formation. To determine the reasons for biennial bearing, the effect of apple rootstock, scion cultivar, crop load, as well as metabolic changes of endogenous phytohormones [zeatin, jasmonic acid, indole-3 acetic acid (IAA), abscisic acid (ABA), and gibberellins 1, 3, and 7 (GAs)], and soluble sugars (glucose, fructose, and sorbitol) were evaluated, and their connections with return bloom and yield of apple tree buds were analyzed. Cultivars "Ligol" and "Auksis" were tested on five rootstocks contrasting in induced vigor: semi-dwarfing M.26; dwarfing M.9, B.396, and P 67; and super-dwarfing P 22. Crop load levels were adjusted before flowering, leaving 75, 113, and 150 fruits per tree. Principal component analysis (PCA) scatter plot of the metabolic response of phytohormones and sugars indicated that the effect of the semi-dwarfing M.26 rootstock was significantly different from that of the dwarfing M.9 and P 67, as well as the super-dwarfing P 22 rootstocks in both varieties. The most intensive crop load (150 fruits per tree) produced a significantly different response compared to less intensive crop loads (113 and 75) in both varieties. In contrast to soluble sugar accumulation, increased crop load resulted in an increased accumulation of phytohormones, except for ABA. Dwarfing rootstocks M.9, B.396, and P 67, as well as super-dwarf P 22 produced an altered accumulation of promoter phytohormones, while the more vigorous semi-dwarfing M.26 rootstock induced a higher content of glucose and inhibitory phytohormones, by increasing content of IAA, ABA, and GAs. The most significant decrease in return bloom resulted from the highest crop load in "Auksis" grafted on M.9 and P 22 rootstocks. Average difference in flower number between crop loads of 75 and 150 fruits per tree in "Ligol" was 68%, while this difference reached~90% for P 22, and~75% for M.9 and M.26 rootstocks. Return bloom was dependent on the previous year's crop load, cultivar, and rootstock.

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Section: Introductionmentioning

confidence: 89%

Relationships Among the Rootstock, Crop Load, and Sugar Hormone Signaling of Apple Tree, and Their Effects on Biennial Bearing

Kviklys

Samuolienė

2020

Front. Plant Sci.

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“…GA12 has been observed as the transported GA form moving within the plant through the vascular system in Arabidopsis (Regnault et al, 2015). In the apple tree, GA4 has been assumed to move from fruit to SAM (Ramírez et al, 2004). The involvement of GA in FI control was further confirmed by differential expressions of genes involved in the GA biosynthesis pathway (GA20ox and GA2ox) in SAM of apple trees with heavy or low crop loads (Guitton et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Impact of Within-Tree Organ Distances on Floral Induction and Fruit Growth in Apple Tree: Implication of Carbohydrate and Gibberellin Organ Contents

Belhassine¹,

Martinez²,

Bluy³

et al. 2019

Front. Plant Sci.

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In plants, organs are inter-dependent for growth and development. Here, we aimed to investigate the distance at which interaction between organs operates and the relative contribution of within-tree variation in carbohydrate and hormonal contents on floral induction and fruit growth, in a fruit tree case study. Manipulations of leaf and fruit numbers were performed in two years on “Golden delicious” apple trees, at the shoot or branch scale or one side of Y-shape trees. For each treatment, floral induction proportion and mean fruit weight were recorded. Gibberellins content in shoot apical meristems, photosynthesis, and non-structural carbohydrate concentrations in organs were measured. Floral induction was promoted by leaf presence and fruit absence but was not associated with non-structural content in meristems. This suggests a combined action of promoting and inhibiting signals originating from leaves and fruit, and involving gibberellins. Nevertheless, these signals act at short distance only since leaf or fruit presence at long distances had no effect on floral induction. Conversely, fruit growth was affected by leaf presence even at long distances when sink demands were imbalanced within the tree, suggesting long distance transport of carbohydrates. We thus clarified the inter-dependence and distance effect among organs, therefore their degree of autonomy that appeared dependent on the process considered, floral induction or fruit growth.

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“…Moreover, GA4 has been shown to target key flowering genes in SAM, in Arabidopsis (Eriksson et al, 2006). In apple tree, GA4 and GA1 may inhibit FI (Ramírez et al, 2001; Ramírez et al, 2004). In the present study, the inactive GA9 preceding GA4 in the non-hydroxylating pathway accumulated in OFF trees, and in non-fruiting branches and side of Y-shape trees (supplementary material Figure S5).…”

Section: Discussionmentioning

confidence: 99%

“…GA12 has been observed as the transported GA form moving within the plant through the vascular system in Arabidopsis (Regnault et al , 2015). In the apple tree, GA4 has been assumed to move from fruit to SAM in apple tree (Ramírez et al , 2004). The involvement of GA in FI control was further confirmed by differential expressions of genes involved in the GA biosynthesis pathway (GA20ox and GA2ox) in SAM of apple trees with heavy or low crop loads (Guitton et al , 2016).…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the co-involvement of carbohydrate and hormones in FI control appears as an assumption to further investigate. It implies the involvement of several processes: photosynthesis by leaves, transport from leaves to sinks, including SAM, but also the presence of GA in SAM likely the active forms GA4 and GA1 (Ramírez et al, 2004). Moreover, leaves may have a dual role in FI control since, in addition to be source of carbohydrates, they are also producing FLOWERING LOCUS T (FT) protein, which is transported to the SAM to activate floral induction in many species, including fruit species (Hanke et al , 2007).…”

Section: Introductionmentioning

confidence: 99%

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Impact of within-tree organ distances on floral induction and fruit growth in apple tree: implication of carbon and gibberellin organ contents

Belhassine

Martinez

Bluy

et al. 2019

Preprint

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In plants, organs are inter-dependent for growth and development. Here, we aimed to investigate the distance at which interaction between organs operates and the relative contribution of within-tree variation in carbohydrate and hormonal contents on floral induction and fruit growth, in a fruit tree case study. Manipulations of leaf and fruit numbers were performed in two years on ‘Golden delicious’ apple trees, at the shoot or branch scale or one side of Y-shape trees. For each treatment, floral induction proportion and mean fruit weight were recorded. Gibberellins content in shoot apical meristems, photosynthesis, and non-structural carbohydrate concentrations in organs were measured. Floral induction was promoted by leaf presence and fruit absence but was not associated with non-structural content in meristems. This suggests a combined action of promoting and inhibiting signals originating from leaves and fruit, and involving gibberellins. Nevertheless, these signals act at short distance only since leaf or fruit presence at long distances had no effect on floral induction. Conversely, fruit growth was affected by leaf presence even at long distances when sink demands were imbalanced within the tree, suggesting long distance transport of carbohydrates. We thus clarified the inter-dependence and distance effect among organs, therefore their degree of autonomy that appeared dependent on the process considered, floral induction or fruit growth.

show abstract

Gibberellins and Cytokinins Related to Fruit Bud Initiation in Apple

Cited by 11 publications

References 0 publications

Relationships Among the Rootstock, Crop Load, and Sugar Hormone Signaling of Apple Tree, and Their Effects on Biennial Bearing

Relationships Among the Rootstock, Crop Load, and Sugar Hormone Signaling of Apple Tree, and Their Effects on Biennial Bearing

Impact of Within-Tree Organ Distances on Floral Induction and Fruit Growth in Apple Tree: Implication of Carbohydrate and Gibberellin Organ Contents

Impact of within-tree organ distances on floral induction and fruit growth in apple tree: implication of carbon and gibberellin organ contents

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