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Effects of timing of fruit removal during the season on starch content in the leaves, branches, bark and roots of young 'Coratina' trees in the subsequent winter (21 December 2006). Bars indicate ±SE. Different letters indicate significant differences (P < 0.05) between treatments.
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Olive (Olea europaea) has a very high tendency for year-to-year deviation in yield (alternate bearing), which has a negative economic impact on the olive oil industry. Among possible reasons for alternate bearing, depletion of stored carbohydrates (CHO) during the On-year (high yield) has often been mentioned. The objective of the present study was...
Context in source publication
Context 1
... estimates of NSC quantities are based on direct measurements of starch and soluble sugar concentrations carried out in January in the various tree organs, multiplied by the organ biomass. Fruit demand was evaluated using the glucose value method (Penning de Vries et al. 1983), projected on the corresponding fruit and oil yields (Table 1) (Figure 3). The highest concentration, ~100 mg g DW −1 , was recorded in the leaves of trees subjected to the earliest fruit removal (6 June 2006): the later the fruit removal, the lower the starch concentration, with the lowest concentration in the leaves of the control trees (53 mg g DW −1 ). ...
Citations
... Thus, there is normally no fruit on trees during flower induction. The biennial bearing of olives is well known [62][63][64], and its molecular mechanism appears to be the ability of a signal formed by past fruit load to repress the increase in FT-encoding transcripts in leaves during winter [10]. As a result, trees with high fruit load in one year will have very low i values the following year [11] and vice versa. ...
With global warming, mean winter temperatures are predicted to increase. Therefore, understanding how warmer winters will affect the levels of olive flower induction is essential for predicting the future sustainability of olive oil production under different climactic scenarios. Here, we studied the effect of fruit load, forced drought in winter, and different winter temperature regimes on olive flower induction using several cultivars. We show the necessity of studying trees with no previous fruit load as well as provide evidence that soil water content during winter does not significantly affect the expression of an FT-encoding gene in leaves and the subsequent rate of flower induction. We collected yearly flowering data for 5 cultivars for 9 to 11 winters, altogether 48 data sets. Analyzing hourly temperatures from these winters, we made initial attempts to provide an efficient method to calculate accumulated chill units that are then correlated with the level of flower induction in olives. While the new models tested here appear to predict the positive contribution of cold temperatures, they lack in accurately predicting the reduction in cold units caused by warm temperatures occurring during winter.
... For example, other evergreen fruit trees neighboring the experiment, such as olives or avocados, yield 3 months later and require a longer fruit development period. As these crops (mango, olive, avocado) have similar energetic fruit load (approximately 7.5-8.1 ton glucose hectare −1 ; (Bustan et al. 2011;Silber et al. 2013;Léchaudel et al. 2005), the faster ripening of mangos imposes twice as large sinks as compared with olives and avocados. These strong sinks can be associated with the larger increase of g s or K L reported for mangos during fruit maturation ( Fig. 5; Fig. 6; de Azevedo et al. 2003;Lu et al. 2012) or the low water requirements of mangos during fruit removal (Fig. 7). ...
Mango's irrigation is typically applied regardless of the fertigation regime, mostly due to a lack of knowledge regarding the fertigation effect on plants' water uptake. From 2017 to 2020, we investigated the seasonal dynamics of mango's water uptake using flushing lysimeters under five different nitrogen (N) fertigation treatments: 2, 10, or 20 mg L −1 of equal amounts of NH 4 and NO 3 , and two additional 10 mg L −1 treatments of only NH 4 or NO 3. Water uptake scaled with the tree size and atmospheric conditions, while at the same time exhibited considerable within-season variability. The 10 mg L −1 produced the largest canopies, bearing the highest yield and the highest water consumption, with minor differences between the NH 4 / NO 3 treatment. In all treatments, the water use increased through time, along with the tree's growth, from ~ 5 m 3 year −1 tree −1 in 2017 (for all treatments) and up to 9.3 m 3 tree −1 year −1 (for 2 mg L −1) or 16.3 m 3 tree −1 year −1 (for 10 mg L −1) in 2020. Daily water use ranged from 10 L tree −1 in winter, climbing up to 100 L tree −1 during summer in the 10 mg L −1 treatment, with a large dependence on the tree's phenology. Fruit set increased stomatal opening and led to high water use, while harvest led to stomatal closure. The findings show that nutrient availability can change mango's water use through changes in canopy development and reproduction, implying that the fertigation scheme should be considered when planning irrigation. Phenology is also a critical factor when considering the mango's water uptake.
... Non-regular (alternate or biennial) bearing phenomena have been studied extensively in the past with a number of reports on fruit plants, including pistachio (Monselise and Goldschmidt 1982;Crane and Nelson 1971;Van der Walt et al. 1993;Nzima et al. 1997aNzima et al. , b, 1999Stevenson et al. 2000;Spann et al. 2008;Vemmos 2010), pecan (Sparks 1975;Gemoets et al. 1976), olive (Goldschmidt and Golomb 1982;Bustan et al. 2011;Mert et al. 2013), apple (Williams and Edgerton 1974) and seedless barberry . Genetic characteristics, environmental conditions, yield, and carbohydrate storage and mobilization are contributing factors in this habit. ...
The main physiological problem of seedless barberry is alternate bearing (non-regular fruiting). Thus, we considered bearing (ON) and non-bearing (OFF) mature trees to check the nutrient content, carbohydrates, their distribution, and resorption. Overall, the highest content of N, P, K and carbohydrates was indicated in OFF-trees. Regarding tissues, the highest content of N, P and carbohydrates was observed in canopy branches. Crop loading significantly influenced N distribution within organs and reduced both above-ground and root parts N, P, K and carbohydrate reserves on fruit removal stage. Bearing trees resorbed only 66, 33, 98 and 16% as much N, P and K, respectively, compared to OFF-year status. Although higher N and total carbohydrate remobilization were observed in non-bearing trees, K movement was low in those trees during September (fruit color change). All resorbed and remobilized nutrients are accumulated in perennial storages observed in OFF-year status compared with ON-bearer, with a higher resorption rate. It is concluded that carbohydrates might be important in supporting new vegetative growth and development and supplying berry weight. However, more studies are recommended to find all aspects influencing growth and development of whole tree parts specifically in ON-year status.
... The sugar accumulation in the leaves and consequent reduction of photosynthesis can be produced by the decrease of sink strength of the plant (Herold 1980, Paul andFoyer 2001) produced, for example, by a low fruit load. Indeed, in Bustan et al. (2011), stored non-structural carbohydrates in olives decreased in summer, under maximum carbohydrate demand for fruit growth and oil production. However, despite the known function of some soluble sugars on osmotic potential (Martínez-Vilalta et al. 2016), they have been rarely used to explain the observed effects of different levels of fruit loads on plant water relations (Dell'Amico et al. 2012, Girón et al. 2015. ...
... The absence of these major sinks , Ryan et al. 2018) impairs the sugars exportation by the phloem. The accumulated soluble sugars perform different functions such as the already mentioned inhibition of photosynthesis (Goldschmidt and Huber 1992), the well-defined role in tree survival (Bustan et al. 2011, Tixier et al. 2018 and also a myriad of functions (metabolic, osmotic balance among different organs, etc.) that requires maintaining relatively high concentrations of soluble sugars at all times (Martínez-Vilalta et al. 2016). Some of these functions of great relevance to cope with water stress are osmoregulation (key to maintaining turgor) and maintenance of vascular integrity (xylem and phloem) (Sala et al. 2012). ...
The presence of fruits provokes significant modifications in the plant water relations and leaf gas exchange. The underlying processes driving these modifications are still uncertain and likely depend on the water deficit level. Our objective was to explain and track the modification of leaf water relations by the presence of fruits and water deficit. With this aim, net photosynthesis rate (AN), stomatal conductance (gs), leaf osmotic potential (Ψπ), leaf soluble sugars, and daily changes in a variable related to leaf turgor (leaf patch pressure) were measured in olive trees with and without fruits at the same time, under well-watered (WW) and water stress (WS) conditions. Leaf gas exchange was increased by the presence of fruits, this effect being observed mainly in WW trees, likely because under severe water stress, the dominant process is the response of the plant to the water stress and the presence of fruits has less impact on the leaf gas exchange. Ψπ was also higher for WW trees with fruits than for WW trees without fruits. Moreover, leaves from trees without fruits presented higher concentrations of soluble sugars and starch than leaves from trees with fruits for both WW and WS, these differences matching those found in Ψπ. Thus, the sugar accumulation would have had a dual effect because on the one hand, it decreased Ψπ, and on the other hand, it would have downregulated AN, and finally gs in WW trees. Interestingly, the modification of Ψπ by the presence of fruits affected turgor in WW trees, whose change can be identified with leaf turgor sensors. We conclude that the plant water relationships and the leaf gas exchange are modified by the presence of fruits through their effect on the export of sugars from leaves to fruits. The possibility of automatically identifying the onset of sugar demand by the fruit through the use of sensors, in addition to the water stress produced by soil water deficit and atmosphere drought, could be of great help for the fruit orchard management in the future.
... 2 Study area (Catalonia, NE Spain): location, climatological information (MAP, mean annual precipitation, and MAT, mean annual temperature), topographical information (DEM, digital elevation model), and woody crop distribution. Almagro et al. 2010;Aragues et al. 2010;Bustan et al. 2011;Fernández et al. 2011a;Fernández et al. 2011b;Segal et al. 2011;Arnan et al. 2012;Gucci et al. 2012;Larbi et al. 2012;Mezghani et al. 2012;Nardino et al. 2013), measured or personally communicated by other authors. More details about data, measurements and data homogenization can be found in Appendix 3 and in Table B.2 of Appendix 2. To estimate aboveground biomass from trunk basal area, the equation drawn from the experiment performed in 18 young olive orchards published in Villalobos et al. (2006) was used. ...
Carbon sequestration and storage in biomass is one of the most important measures to mitigate climate change. Mediterranean woody crops can sequestrate carbon in the biomass of their permanent structures for decades; however, very few studies have focused on an assessment of biomass and carbon sequestration in these types of crops. This study is the first to estimate above- and belowground biomass carbon stock in Mediterranean woody crops through a bottom-up approach in the NE Iberian Peninsula in 2013. Moreover, this is the first time that an assessment of the annual changes in carbon stock in the study area over a six-year period is presented. For this purpose, eight crop- and site-specific equations relating biomass or biometric variables to crop age were calculated. Most of the data were our own measurements, but unpublished data supplied from other authors as well as data from literature were also considered. Census of Agriculture data was used to scale results from individual data up to the municipality level at the regional scale. Results show that in woody cropland in NE Spain the total biomass carbon stock in 2013 was 5.48 Tg C, with an average value of 16.44 ± 0.18 Mg C ha−1. Between 2013 and 2019, although there was a 2.8% mean annual decrease in the area covered by woody crops, the carbon stock in the biomass of these crops increased annually by 3.8% due to the growth of the remaining woody cropland. This new estimation of carbon stocks may contribute to better understand carbon balances and serve as a baseline to global inventories. It may also serve to assess and manage carbon storage as an ecosystem service provided by Mediterranean woody cropland for mitigating climate change and, in combination with adaptive strategies, for supporting a productive and resilient agro-food system.
... The early and mid-season flushing influence the yield whereas, the late season flushing does not have any contribution towards yield (Kumar et al. maximum growth of fruits. The significance of fruit tree reserves in influencing fruit set and weight has also been reported in olive (Bustan et al. 2011). ...
The present study was carried out in 2017–18 at ICAR-NRC on Litchi, Muzaffarpur to assess the effect of temperature, flowering time and inflorescence length on yield of litchi (Litchi chinensis Sonn.) cv. Shahi. The study revealed that the temperature, flowering stage as well as length of inflorescence were positively correlated with florescence width (0.98) while fruit set was negatively correlated with temperature (-0.863). There was a strong correlation between fruit set and size of the inflorescence. Early-season flowering had higher fruit set (8.56%) as compared to mid (7.58%) and late-season (4.05%) flowering. Fruit set was critically reduced by 50% in late flowering
plants resulting in drastic reduction in the total fruit yield. A strong positive correlation (0.84) was found between inflorescence hickness and fruit weight. Fruit and pulp weight were influenced by stage of flowering, as early flowering exhibited highest fruit weight (24.56 g) compared to mid and late flowering in which fruit weight was reduced by 35.42% and 50%, respectively.
... The compensatory effect of photosynthesis, along with the high turnover of the accumulated pool between the different organs of the tree could explain the maintenance of TNC concentration over the growing season obtained in several studies (Hoch et al. 2003). So, in normal conditions and even under maximum demand for TNC, those could never be depleted, especially if they are quantified at the whole-tree level (Bustan et al. 2011). The depletion could be observed transiently at the organ level (Furze et al. 2019) but the plant organs became autonomous during the growing period and the accumulated fraction of TNC is quickly replenished indicating no C limitation in normal conditions. ...
... The main argument in favor of growth-storage tradeoff and storage regulation is the maintenance or the increase of TNC reserves in periods of high C demand (Silpi et al. 2007;Bustan et al. 2011). We suggest that this could result from the remobilization of the accumulated pool of TNC from other tree organs to support the high demand for C. Measurements are often done using stem or branch samples, but almost never using root samples for the difficulty of sampling. ...
... Some physiological traits are reported to be independent of C budget of trees. For instance, the shift from reproductive to vegetative phase is reported to be independent of TNC reserves in olive trees (Bustan et al. 2011) contradicting thus the growth-storage trade-off theory. ...
Key message
A contribution to understand the eco-physiological significance of the total non-structural carbohydrate reserves through making a distinction between accumulated and stored pools along with their respective roles played in woody plants.
Abstract
Plant assimilates are partitioned to growth, defense, maintenance and reserves. Reserves of total non-structural carbohydrates (TNC) are accumulated when the demand for carbon (C) is lower than C supply. Accumulated TNC are stored if not used for growth and metabolism during the growing period. The assessment of the physiological significance of TNC reserves in trees should distinguish between accumulated and stored pools. Accumulated fraction of TNC is characterized by a rapid turnover rate that buffers temporary negative C balance of trees in an annual cycle, whereas stored fraction is characterized by a slow turnover rate that could buffer demand for TNC throughout all tree life during stressful conditions. The increased need for TNC during acute adverse environmental conditions associated with the slow turnover of stored TNC reserves induces the remobilization of the fraction of TNC initially destined for growth and defense which could be a cause of tree mortality. The observed C “sequestration” could be due to the slow turnover dynamic of stored TNC that could be in turn, an adaptive strategy to survive adverse conditions at long term, especially in areas characterized by poor nutrient availability, repeated disturbance and prolonged drought periods. The storage-growth tradeoff is discussed.
... The low dependence of yield on autumnal NSC reserves can be expected from the fact that multi-year observations of NSC content on walnut tree twigs were relatively unaffected by seasonality compared to the two other studied species 1 . In addition, it is important to note that an impact of NSC reserves on yield is not always detected, for example in Olea europea L. (olive tree) no such impact has been reported 21 . However, such a relationship may be very difficult to detect in small, short term experimental studies due to high temporal and year-to-year variation in NSC content 1,3,9 . ...
Successful yield in orchards is the culmination of a series of events that start with plants entering dormancy with adequate energy reserves (non-structural carbohydrates; NSC). These NSC are responsible for the maintenance of activities during dormancy and extending onto the period of activeness. Using multi-year yield information and monthly NSC content in twigs, we show that high levels of carbohydrate in Prunus dulcis , Pistachio vera , and Juglans regia during the winter months are indeed associated with high yield, while high levels of the NSC in late summer often correlate with low yield. An evaluation of monthly NSC level importance on yield revealed that for P. dulcis high levels in February were a good predictor of yield and that low levels throughout summer were associated with high yield. In P. vera , high levels of NSC in December were best predictors of yield. J. regia exhibited peculiar patterns; while high pre-budbreak reserves were associated with high yields they only played a minor role in explaining crop, the most important months for predicting yields were June and July. Results suggest that NSC levels can serve as good predictors of orchard yield potential and should be monitored to inform orchard management.
... Starch may be utilized as a secondary source when demand exceeds concurrent photoassimilate supply (Bustan et al., 2011). On the other hand, at stage 2, there were no significant variations in bark starch levels after low temperatures. ...
The spring low temperature mainly targets developing buds, new leaves, reproductive
organs, which are comprised of soft and fresh tissues, resulting in tremendous economic
losses. Pecan is an economically important nut crop of the United States. This research
was aimed to study the impact of spring freeze on pecan buds/flowers during the spring
season. For this objective, different pecan cultivars were studied under artificial low�temperature conditions provided by freeze chambers as well as after the naturally
occurred spring low-temperature (on April 21, 2021) in the Cimarron Valley Research
Station (97° 02'13" W 35°58'55" N), Perkins, OK. For the freeze chamber experiment,
three pecan cultivar/rootstock combinations i.e., Pawnee/Peruque, Kanza/Giles, and
Maramec/Colby were observed after 10 treatments: 5 temperatures (-6°C, -2°C, 0°C,
2°C, and 4°C) each for 2 durations (4 and 8 hours). For the natural spring low�temperature experiments, 5 cultivar/rootstock combinations i.e., Pawnee/Peruque,
Kanza/Giles, Kanza/Mount, Kanza/Colby, and Maramec/Colby were evaluated. The
visual observation of damage in different pecan cultivar/rootstock combinations showed
the same trend in both chamber and field low temperature for example in both cases
Maramec/Colby showed minimum injury to buds/flowers/new leaves. Further, different
methods such as FDA, H2O2, Baker’s procedure were tested to check the qualities of the
staminate and pistillate flowers after low-temperature treatments. The carbohydrate
content from bark and wood tissues was analyzed in both of the experiments. Significant
differences were observed in sugars and starch content before and after the freeze event
as well as between low-temperature treated samples. In the natural spring event, the bark
sugars were significantly increased after the freeze event. In the case of low-temperature
treatments, it declines in most of the branches. This suggests the role and variation in
carbohydrates utilization and translocation during low-temperature conditions. The
gibberellins content was analyzed using the ELISA kit. Overall, this research provides
information about different aspects related to spring freeze conditions in pecans.
... As carbohydrates are the products of carbon assimilation, only chloroplast-containing organs are able to produce them, as sources, while other plant organs are defined as sinks (Smith et al. 2018). Flowers and fruits are high sinks for assimilates (Bustan et al. 2011) and the plant ability to transfer sugars between its organs was well described in this context (Sha et al. 2020). In woody plants, other common strong sinks are the roots, which use sugars in the short term and accumulate polysaccharides for the long term (Ryan et al. 2018). ...
... Carbohydrate balance was suggested as a possible cause of alternate-bearing, as the low-yield year ('off') allows the plant to gain a reserve pool, which is depleted during the 'on' year. This theory was studied and proven in apples (Malus domestica L.) (Lordan et al. 2019), but refuted in Pistacia vera (pistachios) (Vemmos 2010), Citrus x sinensis (oranges) (Dovis et al. 2014) and Olea europaea (olives) (Bustan et al. 2011). Another suggested factor of alternate bearing is the nutritional status of the plant, which is commonly evaluated by the diagnostic (youngest mature) leaf mineral concentration. ...
Jojoba (Simmondsia chinensis (Link) Schneider) holds high industrial value and an extended cultivation trend. Despite its increased importance, there is a lack of fundamental information about its metabolic reserves and development. Our objective was to characterise metabolite allocation and fluctuations in the carbohydrate and nutrient balance of jojoba plants, as affected by fruit load and the plant's annual cycle. Metabolite profiles were performed for each organ. Soluble carbohydrates (SC) and starch concentrations were surveyed in underground and aboveground organs of high-yield and fruit-removed plants. Simultaneously, nitrogen, potassium and phosphorus were determined in the leaves to evaluate the plant's nutritional status. We found that sucrose and pinitol were the most abundant sugars in all jojoba organs. Each sugar had a 'preferred' organ: glucose was accumulated mainly in the leaves, sucrose and pinitol in woody branches, and fructose in the trunk wood. We found that fruit load significantly influenced the carbohydrate levels in green branches, trunk wood and thin roots. The phenological stage strongly affected the SC-starch balance. Among the examined minerals, only the leaf potassium level was significantly influenced by fruit load. We conclude that jojoba's nutrient and carbohydrate balance is affected by fruit load and the phenological stage, and describe the organ-specific metabolic reserves.
