Fruit load in almond spurs define starch and total soluble carbohydrate concentration and therefore their survival and bloom probabilities in the next season

Fernández, E.; Baird, Graeme; Farias, Daniela da Hora; Oyanedel, Eduardo; Olaeta, José Antonio; Brown, Patrick H.; Zwieniecki, Maciej A.; Tixier, Aude; Saa, Sebastián

doi:10.1016/j.scienta.2018.04.030

Cited by 15 publications

(12 citation statements)

References 42 publications

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“…Twigs' total NSC accumulation prior to dormancy and its drop during bud break (Fig. 5) might reflect the temporal importance of these pools for developing buds, thus potentially linking twig total NSC content to fruit bearing capacity 42 . The higher NSC levels in twigs might be accumulated on low fruit bearing years to sustain higher number of floral buds for the next high fruit bearing year 32,42 .…”

Section: Discussion Nsc Seasonal Trend Synchronism and Spatial Gradiementioning

confidence: 99%

“…5) might reflect the temporal importance of these pools for developing buds, thus potentially linking twig total NSC content to fruit bearing capacity 42 . The higher NSC levels in twigs might be accumulated on low fruit bearing years to sustain higher number of floral buds for the next high fruit bearing year 32,42 . The observations of these spatial gradients of total NSC concentration in pistachio and almond trees during low fruit bearing years and their absence during high fruit bearing years support this hypothesis 40,43 .…”

Section: Discussion Nsc Seasonal Trend Synchronism and Spatial Gradiementioning

confidence: 99%

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Comparison of phenological traits, growth patterns, and seasonal dynamics of non-structural carbohydrate in Mediterranean tree crop species

Tixier

Guzmán‐Delgado

Sperling

et al. 2020

Sci Rep

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Despite non-structural carbohydrate (nSc) importance for tree productivity and resilience, little is known about their seasonal regulations and trade-off with growth and reproduction. We characterize the seasonal dynamics of nSc in relation to the aboveground phenology and temporal growth patterns of three deciduous Mediterranean species: almond (Prunus dulcis (Mill.) D. A. Webb), walnut (Juglans regia L.) and pistachio (Pistacia vera L.). Seasonal dynamics of nSc were synchronous between wood tissues from trunk, branches and twigs. Almond had almost identical levels and patterns of nSc variation in twigs, branches and trunks whereas pistachio and walnut exhibited clear concentration differences among plant parts whereby twigs had the highest and most variable NSC concentration, followed by branches and then trunk. While phenology had a significant influence on NSC seasonal trends, there was no clear trade-off between NSC storage and growth suggesting that both were similarly strong sinks for NSC. A temporal trade-off observed at the seasonal scale was influenced by the phenology of the species. We propose that late senescing species experience C allocation trade-off at the end of the growing season because of c-limiting thermal conditions and priority allocation to storage in order to survive winter. Rising temperatures due to global climate change are associated with significant shifts in tree phenology, while the increase in the frequency and intensity of drought events threatens their survival 1-4. The shifts in temperature combined with drought events not only disturb non-structural carbohydrate (NSC, starch and soluble sugars) accumulation in summer but also their remobilization during winter and spring 5-8. As remobilization of stored NSC allows plants to buffer periods of carbon (C) deficit when supply by photosynthesis is not sufficient to sustain maintenance, growth and defense, they play a key role in tree survival through periods of stress and winter dormancy and allow for resumption of growth in spring 9-15. Hence, the disturbance of evolved seasonal patterns of NSC due to climate change may lead to an overall NSC reserve depletion, leaving trees highly vulnerable to mortality 16. As NSC reserve depletion remains debated, another option is that strong C demand of a storage sink could reduce C supply to growth or reproduction, leading to reduction in productivity of natural populations and agroecosystems with dramatic consequences for ecosystems and food production 17-19. It is therefore critical to understand how perennial plants integrate multiannual, seasonal and short-term NSC regulation in response to short-term stress, seasonal environmental signals and long-term global change in order to fully predict and potentially mitigate impact of climate change. The classical view of storage formation as the accumulation of resources when supply exceeds demand is now supplanted by the understanding of storage as a competing C sink 16,20,21. In fact, a classical model of C allocation presented as a static ...

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Section: Discussion Nsc Seasonal Trend Synchronism and Spatial Gradiementioning

confidence: 99%

Section: Discussion Nsc Seasonal Trend Synchronism and Spatial Gradiementioning

confidence: 99%

Comparison of phenological traits, growth patterns, and seasonal dynamics of non-structural carbohydrate in Mediterranean tree crop species

Tixier

Guzmán‐Delgado

Sperling

et al. 2020

Sci Rep

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“…Lakso et al (2006) observed fruit abscission even when fruit numbers per tree were low (300), suggesting that in some seasons there may be periods where photosynthesis cannot supply carbon demand from developing organs even when flower density is low, or that the low flower density indicates a weakened physiological state of the tree. Fernandez et al (2018) in almond, reported how fruiting spurs depend on fruitless spurs to withstand the high sink demand on their fruits, suggesting that fruit load in almond spurs define starch and total soluble carbohydrate concentration and therefore their survival and bloom probabilities in the next season.…”

Section: Discussionmentioning

confidence: 99%

“…Since initial fruit number was a highly significant factor in explaining fruit set and final fruit number, it is logical that the previous season crop load also would have explained significant variation in fruit set and final number. A related but different variable is photosynthetic supply the previous season which is affected by crop load (Fernandez et al, 2018), but also by insect damage to the leaves during the previous season (Francesconi et al, 1996). In the study by Francesconi, they showed that the fruit numbers per tree the following year was better correlated than flower numbers to the carbon availability.…”

Section: Discussionmentioning

confidence: 99%

Natural fruitlet abscission as related to apple tree carbon balance estimated with the MaluSim model

Lordan

Reginato

Lakso

et al. 2019

Scientia Horticulturae

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Apple trees produce many more flower clusters than needed for a full crop, but natural early season flower and fruitlet abscission drastically reduce the final fruit number. Natural fruit abscission varies significantly year to year. There have been attempts to try to model apple fruit abscission in the past. However, due to the great complexity of a perennial crop system in a dynamic environment with significant plant manipulations, regulatory processes and controlling environmental variables have been difficult to elucidate. In 1995, a field trial was planted at the New York State Agricultural Experiment Station in Geneva, New York with 3 apple cultivars ('Delicious', 'Gala', and 'McIntosh'). Beginning in 2000 and for 18 years thereafter, we recorded the natural whole-season fruit abscission of untreated trees that received no chemical or hand thinning. We also estimated early season patterns of carbohydrate supply-to-demand each year with a carbon balance model. These data were used to correlate tree carbon balance status and other environmental variables with natural fruit abscission responses. In general terms, natural set, defined as final fruit/flower cluster, of 'Gala' averaged ~1 fruit for each flower cluster (fruit set = 0.9), whereas fewer fruits were set on 'Delicious' and 'McIntosh' (fruit set = 0.7 and 0.6, respectively). Fruit set of 'Gala' was less variable than of 'Delicious' or 'McIntosh', and there was a clear pattern for decreasing fruit set when the number of initial flower clusters per tree increased.Fruit weight was less dependent on fruit number for 'Delicious' and 'McIntosh' than for 'Gala'.Multiple regression models indicated that number of flower clusters per tree and average carbohydrate balance between 0-60 degree days (DD) after bloom and 300-360 DD after bloom were the main significant variables that explained 60-80% of the variability in natural fruit set or final fruit number. For 'Delicious', temperatures of the previous fall also explained a significant amount of variation in final fruit set and final fruit number. For 'Gala', carbon balance from bloom to shortly after petal fall and when fruits were about 18 mm were the two main periods, which were more sensible to carbohydrate deficiency triggering fruit abscission. A later susceptible period was also observed for 'McIntosh', suggesting a larger thinning window for this cultivar.

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“…Relative to the period 1971-2000, mean winter temperature is expected to keep increasing throughout the 21st century, with a total increment between 1.2 and 3.2 • C projected for the representative concentration pathway (RCP) scenario RCP4.5 (characterized by the expectation of 4.5 W m −2 of additional radiative forcing by 2100 compared to pre-industrial conditions) [2]. Compared crop load has been proposed to decrease the concentration of starch in almond spurs, with negative effects on flower initiation and flowering rate in the following season [32]. After dormancy has been established, buds only resume growth after fulfilling their temperature requirements (CR and HR) [18] during a period when trees do not have mature leaves.…”

Section: Introductionmentioning

confidence: 99%

Mild Water Stress Makes Apple Buds More Likely to Flower and More Responsive to Artificial Forcing— Impacts of an Unusually Warm and Dry Summer in Germany

et al. 2020

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Climate change may result in increasingly frequent extreme events, such as the unusually dry conditions that occurred in Germany during the apple growing season of 2018. To assess the effects of this phenomenon on dormancy release and flowering in apples, we compared irrigated and non-irrigated orchard blocks at Campus Klein-Altendorf. We evaluated bud development, dormancy release and flowering in the following season under orchard and controlled forcing conditions. Results showed that irrigated trees presented longer (39.2%) and thinner shoots compared to non-irrigated trees. In both treatments, apical buds developed a similar number of flower primordia per cyme (4-5), presenting comparable development and starch dynamics during dormancy. Interestingly, buds on non-irrigated shoots exposed to low chill levels responded earlier to forcing conditions than those on irrigated shoots. However, chill requirements (~50 Chill Portions) and bud phenology under field conditions did not differ between treatments. In spring, buds on non-irrigated trees presented a higher bloom probability (0.42) than buds on irrigated trees (0.30). Our findings show that mild water stress during summer influenced vegetative growth during the same season, as well as the response of buds to forcing temperatures and flowering of the following season. The differences between irrigation levels in the phenological responses of shoots under low-chill conditions point to a so-far understudied impact of water supply on chilling requirements, as well as subsequent bud behavior. Accounting for the effects of both the water status during summer and the temperature during the dormant season may be required for accurately predicting future tree phenology in a changing climate.to 1986-2005 and using the scenario RCP4.5, total precipitation during April-September is predicted to change between about −20% (25th percentile of multi-model distribution) and +10% (75th percentile) in central Europe by 2046-2065 [3]. These changes may result in more frequent extreme events, similar to the extraordinary heat and dry weather observed during the apple growing season in June-September of 2018. Such seasons do not only have immediate impacts, but they may also affect orchard performance in the following growth period. In fact, tree development in a given season depends on processes that occurred during the previous year, including the accumulation of reserves and dormancy induction, as well as flower initiation and differentiation [4,5].Apple trees are cultivated in a wide range of climates, including temperate and tropical regions [4]. Accordingly, growing techniques have been adapted to a range of temperature and water regimes. Under drought conditions, where water scarcity limits apple production, regulated deficit irrigation (RDI) allows maintenance of productive orchards [5,6], although this practice may have undesirable implications for fruit maturity, quality, and shelf life [7]. On the other hand, RDI has been proposed as a useful approach to control excessi...

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Fruit load in almond spurs define starch and total soluble carbohydrate concentration and therefore their survival and bloom probabilities in the next season

Cited by 15 publications

References 42 publications

Comparison of phenological traits, growth patterns, and seasonal dynamics of non-structural carbohydrate in Mediterranean tree crop species

Comparison of phenological traits, growth patterns, and seasonal dynamics of non-structural carbohydrate in Mediterranean tree crop species

Natural fruitlet abscission as related to apple tree carbon balance estimated with the MaluSim model

Mild Water Stress Makes Apple Buds More Likely to Flower and More Responsive to Artificial Forcing— Impacts of an Unusually Warm and Dry Summer in Germany

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