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Effect of Light Intensity and Carbohydrate Reserves on Flowering in Olive



In the article “Effect of Light Intensity and Carbohydrate Reserves on Flowering in Olive” by G.W. Stutte and G.C. Martin ( J. Amer. Soc. Hort. Sci . 111:27–31, Jan. 1986), the following correction should be noted. On p. 28, under Materials and Methods, the sentence “The 80% methanol insoluble materials were suspended in saturated CaSO 4 at pH 12.0 and boiled …” should read “The 80% methanol insoluble materials were suspended in saturated CaOH at pH 12.0 and boiled …”.
5. Baker, A.C . 1939. The basis for treatment of products where
fruit flies are involved as a condition for entry into the United
States. USDA Circ. 551.
6. Buescher, R.W. and G.E. Hobson. 1982. Role of calcium and
chelating agents in regulating the degradation of tomato fruit
tissue by polygalactonase. J. Food Biochem. 6:147-1 60.
7. Chan, H .T ., S. Sanxter, and H .M . Couey. 1985. Electrolyte
leakage and ethylene production induced by chilling injury of
papa ya. HortScience 20:107 0-1 072.
8. Chaplin, G.R. and K.J. Scott. 1980. Association of calcium in
chilling injury susceptibility of stored avocados. H ortScience
9. Cou ey, H.M. and G. Farias. 1979. Control of postharvest decay
of papaya. HortScience 14:719-721.
10. Couey, H.M . 1982. Chilling injury of crops of tropical and sub-
tropical origin. HortScience 17:162-165.
11. Coue y, H.M ., E.S. Linse, and A.N. Nakamura. 1984. Quaran-
tine procedures for Haw aiian papayas using heat and cold treat-
ments. J. Econ. Ent. 77:984—985.
12. Eaks, l.L . 1983. Effects of chilling on respiration and ethylene
production of Hass avocado fruit at 20°C. HortScience 18:235—
13. El-Tomi, A.I., A.B. Abou Azig, A.S. Abdel-Kadar, and F.K.
Abdel-W ahab. 1974. The effect of chilling and non-chilling tem-
peratures on the quality of papaya fruits. Egypt J. Hort. 1:179-
14. Ferguson, I.B. 1984. Calcium in plant senescence and fruit rip-
ening. Plant Cell & Env. 7:477-489.
15. Hardy, D.E. 1949. Studies in Hawaiian fruit flies. Proc. Ento-
mol. Soc. Wash. 51 :18 1-2 05.
16. Hatton, T.T. and R.H. Cubbedge 1982. Conditioning Florida
grapefruit to reduce chilling injury during low-temperature stor-
age. J. Amer. Soc. Hort. Sci. 107:57-60.
17. Jones, W.W. and H. Kubota. 1940. Some chemical and respi-
rational changes in the papaya fruit during ripening and the effects
of cold storage on these changes. Plant Physiol. 15:711-717.
18. Jones, W.W . 1942. Respiration and chemical changes of the
papaya fruit in relation to temperature. Plant Physiol. 17:481
19. Kosiyachinda, S. and P.E. Young. 1976. Chilling sensitivity of
avocado fruit at different stages of the respiratory climacteric. J.
Amer. Soc. Hort. Sci. 1 01:665-667.
20. Larcher, W. and M. Bodner. 1980. Dosisletalitat-Nomogram m
zur charackterisierung der Erkaltungsempfindlich keit tropischer
pfan zen. Angew. Botanik 54:273-278.
21. Lipton, W .J. 1978. Chilling injury of Honey D ew muskmelons:
Symptoms and relation to degree of ripeness at harvest. Hort-
Science 13:45-46.
22. Mason, A.C . and O.C. McBride. 1934. Effect of low tempera-
ture on the Mediterranean fruit fly in infested fruit. J. Econ. Ent.
23. Messenger, P.S. and N.E. Flitters. 1958. Effect o f constant tem-
peratu re enviro nments on the egg stage of three species of Ha-
waiian fruit flies. Ann. Ent. Soc. Amer. 51:1 09- 120.
24. Minorsky, P.V. 1985. An heuristic hypothesis of chilling injury
in plants: A role for calcium as a primary physiological transducer
of injury. Plant Cell & Env. 8 :75 -94 .
25. Nazeeb, M. and W.J. Broughton. 1978. Storage conditions and
ripening of papaya Bentong and T aiping. Scientia Hort. 9:265 -
26. Pantastico, E.B ., J. Soule, and W. Grierson. 1968. Chilling in-
jury in tropical and subtropical fruits: II. limes and grapefruit.
Proc. Trop. Reg. Am er. Soc. Hort. Sci. 12:171-183.
27. Scott, K.J. and G.R . Chaplin. 1978. Reduction of chilling injury
of avocados stored in sealed polyethylene bags. Trop. Agr. 55:87—
28. Seo, S., G .J. Farias, and E.J. Harris. 1982. Oriental fruit fly:
ripening of fruit and its effect on the index of infestation of
Hawaiian papayas. J. Econ. Ent. 75:173 -17 8.
29. Somner, N.F. and F.G . Mitchell. 1978. Relation of chilling tem-
peratures to postharvest altemaria rot of papaya fruit. Proc. Trop.
Reg. Amer. Soc. Hort. Sci. 22:40-47.
30. Spalding, D.H. and W.F. Reeder. 1975. Low-oxygen high-car-
bon dioxide controlled atmosphere storage for control of anthrac-
nose and chilling injury of avocados. Phytopathology 65:458-
31. Thompson, A.K. and G.R . Lee. 1971. Factors affecting the stor-
age beh avior of papaya fruit. J. Hort. Sci. 46:511 -516.
32. USDA 1978. Combination hot water dip and fumigation, In:
Plant protection and quarantine treatment. Manual USD A, Ani-
mal and Plant Heath Inspection Service. Plant Protection and
Quarantine Service. Section VI. (Rev.) T102 (5) (ai), p. 9.
33. Wang , C.Y. 1982. Physiological and biochemical response of
plants to chilling stress. HortScience 17:173-186.
34. Wardlaw. C.W., E.R. Leona rd, and R.E.D . Baker 1934. Ob-
servations on the storage of various fruits and vegetables II Pa-
paws, pineapples, grandillas, grapefruit and oranges. Trop Agr.
35. Wardowski, W .F., W. Grierson, and G .J. Edwards. 1973. Chill-
ing injury of stored limes and grapefruit as affected by differ-
entially permeable packaging films. HortScience 8:173-175.
36. Zauberman, G., M. Schiffmann-Nadel, and U. Yanko. 1977.
Susceptibility to chilling injury of three avocado cultivars at var-
ious stages of ripening. HortScience 8:51 1-5 13.
In the article Effect of Light Intensity and Carbohydrate
Reserves on Flowering in Olive by G.W. Stutte and G.C.
Martin (J. Am er. Soc. Hort. Sci. 111:27-31, Jan. 1986), the
following correction should be noted. On p. 28, under Ma-
terials and Methods, the sentence The 80% methanol in-
soluble materials were suspended in saturated C aS04 at pH
12.0 and boiled ... should read The 80% methanol in-
soluble materials were suspended in saturated CaOH at pH
12.0 and boiled . . . .
J. A m er. Soc. Hort. Sci. 111(4 ):639-643. 1986. 643
... In contrast, Stutte and Martin (1986) showed that carbohydrate levels did not limit floral induction of olive (Olea europaea), similar to the observations of Ulger et al. (2004). Ulger et al. (2004) found that N levels during the differentiation period may play a role in bud differentiation in a heavy fruiting year, and the C:N ratio seems to have no effect on induction in olive. ...
... While it is not known with certainty if relative changes in [CH 2 O] (King and Ben-Tal, 2001). While the results above, and the work of Stutte and Martin (1986) indicate that nutrient changes at the apex are not required for floral evocation, it is not known if nutrient changes are involved in the flowering of S. ...
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Swainsona formosa (G.Don) J. Thompson (Sturt’s desert pea) is an Australia native legume which has potential as an ornamental pot plant and is also suitable for hanging baskets and as a cut flower. Accurate identification of the timing and control of growth stages is critically important in making management decisions for floricultural crops. One of the impediments to the commercialisation of S. formosa as a pot plant is its inability to produce flowers under low light conditions. The apical meristems of S. formosa were investigated by stereomicroscopy and scanning electron microscopy to identify flowering time and stages of floral development. Conversion from the vegetative to the reproductive stages began within 40 to 46 days after seed germination for axillary branches and 46 to 52 days for central stems. The order of floral organ initiation within each whorl is unidirectional, except for the petal whorl, which is simultaneous; the flower is organised into five whorls and shows a pentamerous arrangement of sepals and petals, ten stamens in two whorls and a central carpel. This is the first description of the complete floral ontogeny of a member of tribe Galegeae in papilionoid legumes. The effect of high light intensity (800 ± 50 μmol m-2s-1) and low light intensity (150 ± 10 μmol m-2s-1) on the flowering of S. formosa was investigated, with particular emphasis on measuring the changes in sugar concentrations in the transition stages of the shoot apices from the vegetative to the floral, using high-performance liquid chromatography. Plants grown under high light initiated flowers within 45 days from seed germination, while plants grown under low light intensity remained vegetative and produced no flowers during the 60-day experimental period. Trace amounts of glucose (0.52 mg g-1) were detected at the beginning of the transition from the vegetative to floral stage (40 days after germination) in the apices of plants grown under high light intensity conditions; this increased to 2.70 mg g-1 with progressive floral development. No glucose was detected in the shoot apices of plants grown under low light during the experimental period. The timing of changes in sucrose quantity matched the timing of morphological changes, indicating a key role for sucrose in flower development. The changes in the sugar composition of the shoot apices are associated with quantitative VI changes in sugar translocation and changes in enzyme activity related to floral transition. Also, the balance between glucose, fructose and sucrose is important for flowering to occur. Adequate amounts of glucose is required for floral initiation and development in S. formosa. Among many factors, the Carbon:Nitrogen (C:N) ratio is considered to be one of the most important physiological signals that induce flowering of S. formosa. Reduced %N and %C at the early transition stage, and an increased C:N ratio in the shoot apices, could be used as indicators for stage changes. To flower, plants need to maintain an appropriate C:N ratio. The mode of N acquisition (fixation versus assimilation) seems to influence %N accumulation in the shoot apices of low light grown plants. To reach a more precise conclusion on the effects of carbohydrates on flowering of S. formosa, the effects of exogenous sugar applications on the flowering of S. formosa were tested. Several experiments (spraying, brushing, injecting and absorbent cotton on apex), on the application of exogenous sugars, were conducted to identify the correct methodology of application, and the types and concentrations of sugars needed to induce flowering of S. formosa grown under low light intensity conditions. Results confirm that S. formosa requires adequate high light intensity for flower induction and development. All the sugar treatments using exogenous application methods failed to induce the transition to flowering in S. formosa plants grown under low light conditions. The failure to flower depends on many factors, such as the use of ineffective concentrations of sugars along with inappropriate application methods. In vitro flowering was achieved within 4 to 6 weeks by placing shoot apices from high light grown stock plants on Murashige and Skoog medium supplemented with 3.0 to 4.5% sucrose. This could be the result of an interplay of factors, including environmental conditions under which the explant source was grown and the types and concentrations of exogenous sugar used in the culture medium. This is the first report of S. formosa producing flowers in vitro. It is suggested that future work on exogenous application of sugars be expanded by using in vitro techniques. The key stages in the transition of S. formosa plants to flowering is correlated with protein concentrations and patterns. High light intensity caused changes in the concentrations and types of proteins that promoted flower initiation and differentiation. VII These protein changes were absent from the vegetative apices of high light plants and all the apices of plants grown under low light. Further studies on protein morphogenetic markers, as well as their genes and conditions for expression, are among the most promising approaches to the regulation of morphogenetic processes in this and other plants.
... This phenomenon has been long studied in different crop species such as almond (Milella and Agabbio, 1978), apple (Beattie and Folley, 1978;Monselise and Goldschmidt, 1982;Williams, 1989), avocado (Chandler, 1950;Monselise and Goldschmidt, 1982), Citrus spp. (Goldschmidt and Monselise, 1977;Monselise et al., 1981), mango (Chacko, 1986), olive (Monselise and Goldschmidt, 1982;Stutte and Martin, 1986), pecan (Wetzstein and Sparks, 1986) and pistachio (Crane and Nelson, 1971; Monselise and Goldschmidt, 1982) with the main aim of minimizing the alternation of the cropping cycle. ...
... Depending on the species, different productive patterns can trigger the yield reduction generally observed the year after a very high cropping season: 1) reduced induction and differentiation of reproductive buds (Chan and Chan, 1967;Couranjon, 1989;Monselise and Goldschmidt, 1982;Post and Stam, 1983;Stutte and Martin, 1986); ...
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A simplified model for the prediction of carbon balance was developed to elucidate the seasonal trend of sink-source relationships in bearing and non-bearing pistachio (Pistacia vera L.) branches. Seasonal changes in growth rate of vegetative (leaf and shoot) and reproductive (infructescence) organs were monitored in branches of mature rainfed pistachio trees during the entire growing season (April–September). Simulations from the model were used to gain understanding of the implications of crop load on branch carbon (C) depletion and alternate bearing. Results showed that the pistachio branch was energetically able to sustain up to two infructescences (∼28 fruits) having a slightly positive carbon budget (2.6 g of C) at the end of the season. A branch with 4 infructescences (∼56 fruits) ended the season with a very negative carbon budget (-14.1 g of C) suggesting the implication of resource mobilization during heavy crop load. The simulations with the model allowed the identification of two energetically critical periods for pistachio, both characterized by a decreasing trend of the carbon budget. The first is at the beginning of the season, from leaf out until 35/40 days after full bloom (DAFB), when leaves are still not source of carbon, and the branch energetic need is largely satisfied by the remobilization of carbon from the reserves accumulated the previous year and stored through the winter. The second critical period is at the end of the season for bearing branches, at ∼100 DAFB, when a strong reduction in leaf area due to early leaf senescence and drop coincides with high carbon request for kernel growth. Overall, results demonstrate that the branch carbon budget model is a valid tool to study bearing dynamics in tree species and can help to develop physiologically-based management strategies for achieving increased and more constant productions in pistachio orchard systems.
... Experiments were conducted to determine whether changing nutrient concentrations helped to induce Eichhornia crassipes flowering, and the result demonstrated that very low nutrient concentration conditions induced inflorescence formation [7], which reconfirmed the conclusion of Richards [8]. High soluble sugar content promoted S. tonkinensis flowering [9], while it was the opposite for olive [10]. Starch is one of the nutrients that may be converted into soluble sugar to meet the need for metabolic energy during the process of flower bud differentiation [9]. ...
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Styrax japonicus is a small ornamental tree with medicinal values, although its flowering period is short. To date, information about the morphological and physiological characteristics of the petals during the flowering period is limited. In this study, we observed the structure of the petals at the full flowering stage with a scanning electron microscope and detected the contents of nutrients, minerals, and endogenous hormones and the activities of enzymes at different flowering stages. The results showed that the content of soluble sugar exhibited an ‘increase-decrease’ trend, whereas the contents of soluble protein, nitrogen (N), phosphorus (P), and abscisic acid (ABA) showed a ‘decrease-increase’ pattern. The content of starch descended continuously, but the contents of potassium (K), gibberellic acid (GA3), indoleacetic acid (IAA), and malondialdehyde (MDA) ascended continuously. The activities of peroxidase (POD) and superoxide dismutase (SOD) first rose and then declined during the flowering period. Higher contents of soluble sugar, N, K, and IAA promoted S. japonicus flowering; meanwhile, lower contents of starch, soluble protein, P, and GA3 in addition to the lower activity of SOD might be some of the causes of the short flowering period. This work will serve as the foundation for a scientific technique to utilize the flowers and extend the flowering period in S. japonicus.
... The amount of light intercepted, together with water and mineral elements absorbed by the roots, is, in fact, one of the main factors determining the productivity of a plant [29]. Numerous scientific investigations have been carried out to study the effect of increasing planting density on olive production [9,[30][31][32][33]. ...
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The objective of fully mechanizing olive harvesting has been pursued since the 1970s to cope with labor shortages and increasing production costs. Only in the last twenty years, after adopting super-intensive planting systems and developing appropriate straddle machines, a solution seems to have been found. The spread of super-intensive plantings, however, raises serious environmental and social concerns, mainly because of the small number of cultivars that are currently used (basically 2), compared to over 100 cultivars today cultivated on a large scale across the world. Olive growing, indeed, insists on over 11 million hectares. Despite its being located mostly in the Mediterranean countries, the numerous olive growing districts are characterized by deep differences in climate and soil and in the frequency and nature of environmental stress. To date, the olive has coped with biotic and abiotic stress thanks to the great cultivar diversity. Pending that new technologies supporting plant breeding will provide a wider number of cultivars suitable for super-intensive systems, in the short term, new growing models must be developed. New olive orchards will need to exploit cultivars currently present in various olive-growing areas and favor increasing productions that are environmentally, socially, and economically sustainable. As in fruit growing, we should focus on “pedestrian olive orchards”, based on trees with small canopies and whose top can be easily reached by people from the ground and by machines (from the side of the top) that can carry out, in a targeted way, pesticide treatments, pruning and harvesting.
... 70 days after bloom in the Off state, pistachio trees began to accumulate soluble sugars and starch in the flower bud, leaf, fruit and shoot, and there was a negative correlation between the sucrose of the bud, leaf and root with glucose of the fruit, indicating the role of carbohydrates in the alternate bearing (Baninasab and Rahemi 2006). Different levels of carbohydrates and minerals have also been reported in the leaves of (Erel et al. 2008;Stutte and Martin 1986). Also, in the study by Pillay et al. (2005) on date palm, reducing the boron element to less than 3.5 mg/ kg fresh plant weight and increasing the ratio of potassium to boron to more than 2500 ppm during Khalal of Off season, the index of plant direction toward alternate bearing is reported. ...
Full-text available
The carbohydrate evaluation of organs (fruit, leaflet and root) at important physiological stages (three peaks of fruit abscis-sion, harvest and before flower induction) on 60 'Mazafati' date palm (Phoenix dactylifera L.) trees in five groves with a history of alternate bearing disorder showed that leaflet starch content before flower induction was the best physiological marker for early detection of this disorder based on both the biennial bearing index (BBI) and fruit bunch number. The differences in carbohydrate between organs in different loading trees were not due to differences in the chlorophyll pigments and photosynthesis rate and were the affect of different loadings on source-sink regulation. The 2-year leaf spray of trehalose disaccharide before flower induction stage on Off trees by activating oxidative stress, increasing leaf hydrogen peroxide index, indicated that these loading differences were due to changes in the allocation of carbohydrate types between organs at this stage. The changing carbohydrate allocation pattern in favor of increasing the leaflet starch compared to other two organs before flower induction by trehalose treatment while increasing flower induction in the Off trees, increasing the bunch number , resulted in controlling the alternate bearing to improve annual production indices and preserving the physicochemical properties of the fruit consistent with the non-alternate bearing trees.
... The same effect has not been apparent in perennial horticultural trees. In most cases with fruit trees, shading of the whole tree, or part of the tree, has resulted in a decrease in flower bud formation [6,[17][18][19][20][21]. This is indicative of the significance of photosynthetic assimilates in the floral transition in these species, and the evidence in this study is in agreement. ...
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The aims of this study were to investigate the sunlight requirements during floral initiation and differentiation for the development of flower buds in ‘Autumn Bright’ nectarine and to explore its source–sink relationship. In early January 2019 (111 days after full bloom), prior to floral initiation and differentiation, 12 new shoots were tagged on 14 trees, with four shoots in each of the low (0–1.2 m), middle (1.2–2.0 m), and high (>2.0 m) canopy heights. Three treatments (bud shading; leaf pluck; bud shading and leaf pluck) were applied to three shoots in each canopy height on the fourth and eighth bud, in addition to a fourth control shoot. Light penetration was measured at the different canopy heights. Buds were assessed in Spring for floral transition, number of floral buds per node, and fruit set. The treatments at the node level had no effect on floral initiation, indicating that sink strength was not promoted by additional light. Light penetration decreased with decreasing canopy height and corresponded with lower floral buds in the low zone. Fruit set was uninfluenced by all treatments. The results of this study emphasised the importance of the availability of photosynthetic assimilates for floral initiation in peach and nectarine trees. Balanced crop load management and summer pruning to enhance canopy sunlight distribution would increase the availability of nutrients for improved floral transition in this cultivar.
... Ces avortements 'par vague' font penser aux alternances d'années à fruit chez les fruitiers (Monselise and GoldschmidtGuitton et al. 2012). En effet, chez ceux-ci, des alternances d'années à fort et à faible rendement sont couramment observées, et il est classiquement rapporté que les années à fort rendements présentent des taux élevés de réserves en TNC, contrairement aux années à faible rendement(Goldschmidt and Golomb 1982;Stutte and Martin 1986;Wilkie et al. 2008). Ces vagues d'avortement ressemblent également aux vagues de fertilité observées sur les hampes florales d'Arabidobsis thaliana en réponse à des carences en carbone déclenchées par une prolongation de 24h de la phase obscure au cours de son développement(Smith and Stitt 2007). ...
Dans le contexte de réchauffement climatique, le maintien des rendements est un enjeu majeur pour la filière viticole. L’augmentation des températures impacte négativement certaines phases clés du développement reproducteur en induisant notamment des phénomènes de coulure ou de pertes précoces d’inflorescence. L’altération du bilan carboné pourrait être un facteur majeur des diminutions de rendements en réponse aux températures élevées et l’évaluation de cette hypothèse permettrait d’ajuster les pratiques pour limiter les effets du réchauffement climatique. Si l’implication du bilan de carbone chez les plantes annuelles semble être à la base des baisses de rendement observées ces dernières années, les choses sont beaucoup moins claires chez des pérennes comme la vigne du fait des très nombreux cofacteurs possible ainsi que de la difficulté à expérimenter dans des conditions totalement contrôlées. Afin de s’affranchir de ces contraintes, notre étude a été réalisée en conditions contrôlées sur la Microvigne, un mutant naturel insensible à l’acide gibbérellique et un nouveau modèle d’étude pour la génétique et la physiologie de la vigne. Ce mutant présente un phénotype nain et une floraison et fructification continues le long de l’axe proleptique. L’approche utilisée dans cette étude a consisté à (i) développer un cadre d’analyse adapté à la Microvigne; (ii) décrire l’impact de l’élévation de la température, sur les développements végétatif et reproducteur de la vigne, et plus particulièrement l’avortement des stades précoces du développement reproducteur; (iii) caractériser les changements du bilan de carbone de la Microvigne induits par la contrainte thermique, et enfin (iv) évaluer l’implication potentielle du bilan de carbone dans les phénomènes d’avortement précoces en réponse au stress thermique. Ce travail a permis de mettre en évidence des phénomènes d’avortement complet d’inflorescences en réponse à l’élévation des températures. Par ailleurs, nous avons pu montrer un rôle du statut carboné dans ce phénomène, soit via les teneurs totales en carbohydrates, soit via l’état global des réserves à l’échelle de la plante. Ce travail montre les potentialités su modèle Microvigne et ouvre de nouvelles perspectives pour l’analyse des effets des contraintes abiotiques sur le développement végétatif et reproducteur de la vigne.
... Ulger et al. (2004) also suggested that the fructose level was higher in the ON year than in the OFF year, glucose was not different in ON and OFF years in'Memecik'olive variety. Moreover, Stutte and Martin (1986) showed that a high level of starch did not have a positive effect on flowering. Combined with the above studies, we think that sucrose may play a major role in the regulation of apple flowering, while others (glucose, fructose, sorbitol and starch) may not be the main impact factors. ...
Most perennial fruit trees have an alternate bearing problem where a heavy fruit load is produced one year (ON year) but few flowers and fruits produced the next year (OFF year), resulting in a significant fluctuation in production. In the present study, comparative transcriptome analysis of terminal buds of apple (Malus domestica Borkh., cv. Nagafu No. 2) trees was conducted during the floral induction period in the ON and OFF years to identify the potential regulatory pathways controlling alternate bearing. A total of 1027 differentially expressed genes (DEGs), most of which were involved in secondary metabolism, sugar metabolism, plant hormone pathways, were identified. The analysis focused on differences in sugar content and hormone levels between the ON and OFF trees. Sucrose content, zeatin-riboside (ZR), and abscisic acid (ABA) levels were lower in ON-year buds than in OFF-year buds. ON buds also had elevated levels of gibberellins (GAs), with a higher expression of GA20 oxidase (GA20ox) and a significant lower level of RGA-like2 (RGL2). Expression analyses also revealed a significantly higher level of SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE genes (MdSPL1, MdSPL6 and MdSPL12) transcripts levels in buds of OFF trees at 45 days after full bloom (DAFB). LEAFY (LFY) expression increased significantly prior to flower induction in OFF buds. These findings provide new information of the role of hormones in alternate bearing, as well as other processes, and provide new insights into the molecular mechanisms regulating alternate bearing in perennial fruit trees.
... Gibberellins (GAs), which are produced in great abundance by the seed during its development, produce an inhibiting effect on the floral induction. Many studies show the involvement of GAs in the control of olive plant flowering and also show that the pit hardening phase has a physiological importance in the floral induction (Stutte and Martin, 1986;Navarro et al., 1990;Rapoport et al., 1990;Feernandez-Escobar et al., 1992;Lavee and Haskal, 1993;Proietti and Tombesi, 1996). Ferguson et al., 1994 reported that phytohormones have a triggering effect on the initiation of vegetative and flower buds on the new shoot growth of olives. ...
... 70 days after bloom in the Off state, pistachio trees began to accumulate soluble sugars and starch in the flower bud, leaf, fruit and shoot, and there was a negative correlation between the sucrose of the bud, leaf and root with glucose of the fruit, indicating the role of carbohydrates in the alternate bearing (Baninasab and Rahemi 2006). Different levels of carbohydrates and minerals have also been reported in the leaves of (Erel et al. 2008;Stutte and Martin 1986). Also, in the study by Pillay et al. (2005) on date palm, reducing the boron element to less than 3.5 mg/ kg fresh plant weight and increasing the ratio of potassium to boron to more than 2500 ppm during Khalal of Off season, the index of plant direction toward alternate bearing is reported. ...
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Bunch wilting, a disorder of date palm (Phoenix dactylifera L.) and caused by climatic factors (low relative humidity along with high temperatures), critically damages its production in Iran. In this study, the effects of 5-aminolevulinic acid (5-ALA) as precursor of chlorophyll and elicitor of antioxidants applied to be involve directly or indirectly in stress tolerance mechanisms, bunch wilting severity, and other physiological aspects on 10–12 years old date palm in two locations. 5-ALA concentrations included 0 (control), 200, 240 and 280 ppm, applied as aqueous solution at biweekly intervals from fruit set until the beginning of fruit Kimri stage on leaves around the fruit bunches (for three times). Results showed that the yield of trees and bunch weight increased; hydrolytic enzymes activities in stalk and fruit decreased and activities of peroxidase, superoxide dismutase, and catalase, important enzymes of the antioxidative system were increased. The plants’ redox state changed as identified by decrease in H2O2 and proline of fruits. Microelement concentrations of leaves were changed at damage stage. Perhaps, due to mild environmental conditions in location A, lower bunch wilting and better physiological conditions of fruits recorded compared to location B. Foliar application of 5-ALA resulted to a coordinated action of the antioxidative system, affecting the defense-related enzymes. The treatment caused biosynthesis of chlorophyll and adjustments in H2O2 and proline compositions in leaf, stalk, and fruit. Bunch wilting was alleviated by 240 ppm 5-ALA, moderating the response of tree load to environmental stress conditions.
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