No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
... Many authors have tried to explain the improvement in flower induction through an increase in carbohydrate levels in the tree canopy above the girdle (Chun-Yao et al., 2003;Goren et al., 2004). But Lavee (1989) reported that in many fruit trees carbohydrates are not the limiting factor in flower induction and a specific role for carbohydrates in the induction of flowering has not unequivocally been demonstrated (Goren et al., 2004). Also, it should be kept in mind that improving flower induction can only be achieved through scoring or girdling during the pre-initiation phase, therefore relatively early in the new growing season. ...
... According to Bangerth (2005) the partitioning into vegetative and reproductive meristems is transmitted by correlative signals that finally inhibit or stimulate flower induction. The most widely recognised inhibitory signal is gibberellins (GA's) originating from seeds and/or shoot tips (Bangerth et al., 1986;El-Mahdy, 1988;Lavee, 1989;Li et al., 1995;Bubán, 1996;Prang et al., 1997). It is, however, not clear whether this signal actually reaches the meristem and inhibits floral induction, as labelled GA's applied to seed cavities in fruit less than 0.2% moved into the bourse shoot (Bangerth, 2005). ...
... In general though, correlative developmental processes are not regulated by one hormonal signal (Bangerth, 2005). It has been shown by numerous authors that cytokinins (CK's) have a stimulative effect on flower induction (Greene, 1989;Lavee, 1989;Skogerbø, 1990;Bubán, 1996Bubán, , 2000Ito et al., 2000). The origin of the CK signal is not clear and mature leaves and/or roots are likely sources, although it cannot be excluded that meristems synthesise CK's themselves (Bangerth, 2005). ...
Even though the practice of girdling or scoring pear trees goes back more than 2000 years, many questions still remain about the physiological reasons for the observed responses. The phenological stage at which the technique is used and the intensity of application (scoring, cincturing, girdling or notching) determines the type of response that is obtained. Amongst the most well known responses are a decrease in shoot growth, an increase in fruit set, an increase in return bloom and an increase in fruit size. A number of hypotheses have been presented, either leaning towards a change in carbohydrate levels or with more emphasis placed on endogenous hormone levels resulting in the response to the treatment. Most of these however, do not distinguish between the different techniques (e.g., girdling vs. scoring), time of application of the technique or whether trees are evergreen or deciduous.
... Accurate yield predictions are of value to the producer and the market but of greater importance is the production of fruit of consistently good quality. The initial trigger for the start of an alternating (biennial) cycle may be an external factor such as frost, lack of pollination and drought which may eliminate one year's crop (Jonkers, 1979;Lavee, 1989;Monselise & Goldschmidt, 1981;Monselise & Goldscmidt, 1982). Once this cycle has started it usually amplifies annually and is self-perpetuating. ...
... b) An "on" year with a large amount of flowers and limited fruit drop and thus a large crop set. Lavee (1989) suggested that the signal for low or high fruit set is probably hormonal, diffusing from the fruits and leaves and is a signal for, and a result of, the level of flower and bud differentiation and fruit set. Two probable mechanisms for the control of flowering and fruit set were referred to by Bower et al., (1990), namely energy reserves and endogenous plant growth regulators. ...
Studies were conducted during 1992 on avocado trees with a five year individual record of regular alternate (biennial) bearing. Photosynthesis measurements did not reflect significant differences in the "on" and "off" trees but very significant differences were found in the starch content of root, phloem, and xylem samples. Sugar values (sucrose, glucose and fructose) in the same material did not show significant differences between "on" and "off" trees but chlorophyll determinations revealed a shift in the chlorophyll a to b ratio. The "off" trees had a very much higher mean starch content than the "on" trees in May and July. It can be concluded that carbohydrates play a central role in alternate bearing and is a probable mechanism in perpetuating the cycle.
... Physiologically, biennial bearing in olive is thought to be due to the inhibition of floral bud induction and differentiation by growth substances that are produced and excreted by the developing seeds (Lavee 1989(Lavee , 2006Baktir et al. 2004). In addition, the metabolic effort required by a heavily yielding tree that is furnishing oil production during the late season might come at the expense of resources available for the subsequent reproductive process (Monselise and Goldschmidt 1982;Cuevas et al. 1994;Troncoso et al. 2010). ...
... Attempts to interrupt the reproductive cycle of olive trees at early stages of floral development (Lavee 1989;Fernandez-Escobar et al. 1992) or during bloom ) have been either too risky or inefficient in lessening alternate bearing. On the other hand, chemical fruit thinning, which was first examined decades ago (Hartmann 1952;Lavee and Spiegel 1958;Lavee and Spiegel-Roy 1967), is quite commonly practiced, mainly to obtain large fruits in table olives (Martin et al. 1980;Krueger et al. 2004). ...
Biennial bearing is a major horticultural and economic drawback of olive (Olea europaea L.) cultivation, which particularly affects the olive oil industry under intensive production systems. The number of fruits per tree in an on-year is a primary determinant of the biennial cycle. While fruit thinning using NAA shortly after full bloom is commonly practiced to increase fruit size in table olives, the extent of its influence on biennial bearing is unknown. In the present study, the ability of that common naphthaleneacetic acid (NAA) treatment (100mg/L, 10 days after full bloom) to alleviate biennial bearing in two oil olive cultivars, Picual and Barnea, was poor, although significant influence on the number of fruit was evident solely in Barnea. Picual seemed less susceptible than Barnea to biennial bearing. Consequently, the effect of a broad range of NAA concentrations (0-320mg/L, 10 days after full bloom) on various yield parameters was investigated during a biennial cycle of Barnea trees. There was a gradual proportional decline in the on-year number of fruits from ∼50000 to 10000/tree in response to increasing NAA concentrations. The number of return fruits in the off-year was reciprocal to the on-year fruit load, but remained relatively small, below 15000/tree. The dynamic relationship between fruit load and fruit size in both on- and off-years was a significant compensation factor in fruit and oil yields. In both cultivars, an on-year fruit load smaller than 20000/tree is likely to provide consistent yearly oil yields ranging from 10 to 12kg/tree. The results demonstrate the possibility of using NAA post-bloom spraying to balance biennial bearing in oil olives.
... Em primeiro lugar, o fruto possui um mecanismo de controle que influencia sobre a indução floral das gemas (FERNÁNDEZ-ESCOBAR et al., 1992). A carga de frutos induz a produção de ácido clorogênico por parte das folhas, o que inibe a indução reprodutiva das gemas (LAVEE, 1988;RYAN et al., 2003). Em segundo lugar, o crescimento dos órgãos vegetativos e reprodutivos ocorre ao mesmo tempo, esta sobreposição fenológica é responsável pela existência de uma grande competição entre ambos os órgãos pelos fotoassimilados. ...
oliveira é uma das frutíferas mais antigas utilizadas pelo homem. Seu cultivo remonta a 6.000 anos. É originária de vasta grande área, que abrange desde o Sul do Cáucaso até os planaltos do Irã, Palestina e a zona costeira da Síria, estendendo-se pelo Chipre até o Egito, povoando posteriormente para todos os países que margeiam o Mediterrâneo. O cultivo em sebe representa a grande revolução na cultura do olival, porque permite obter em 10 anos de cultivo a mesma produção acumulada de um olival tradicional de sequeiro em 70 anos. Para os cultivos de superintensivo têm sido propostos inicialmente as variedades de alto rendimento como Arbosana, Arbequina e Koroneiki, que apresentam desenvolvimento limitado (porte médio). Posteriormente, foram lançadas novas variedades de porte baixo mais apropriadas ao cultivo em sebe. São recomendados espaçamentos de 3-4 m x 1,0-1,5 m ao longo das linhas. As árvores prontas para o plantio são pequenas, com cerca de 18 meses, 40-50 cm de altura e um bom sistema radicular. Elas devem ser manejadas com cuidado para mantê-las no tamanho certo para a colheita mecanizada ao longo da linha e para garantir um equilíbrio entre a atividade vegetativa e reprodutiva. A grande vantagem que este sistema apresenta reside no fato das cultivares utilizadas terem uma entrada em produção ultraprecoce, permitindo obter logo elevadas produções entre o 3º e o 5º ano após a plantação. No olival superintensivo, sua colheita mecanizada recorre a máquinas de vindimar cavalgantes automotrizes, possibilitando capacidades de trabalho de 2-3h/h. Também o cultivo em sebe permitir ser podado mecanicamente, visando manter uma copa reduzida. Em razão do exposto, há uma redução significativamente nos custos de produção, pois este sistema em sebe facilmente atinge os 12.000 kg/ha. Vale lembrar que no passado ocorreu a domesticação dessa árvore de porte alto para de porte médio e recentemente para de porte baixo, mas por meio do desenvolvimento de novas cultivares com características de baixo vigor e, ao mesmo tempo, de pouca exigência em frio (fatos parecidos sucederam com a outras espécies vegetais) é possível futuramente ampliar o cultivo em sebe para outras regiões fora de climas subtropical e temperado. Portanto, aquele que decidir cultivar essa cultura de forma superintensiva e conhecê-la em maior profundidade, o livro Tecnologias utilizadas no cultivo em sebe da oliveira (Olea europaea, L.) mecanizada, será de grande interesse e ajuda para o produtor que necessita pôr em prática as várias tecnologias abordadas no mesmo.
... The higher the PPO activity, the longer the existence time of the graft interface between rootstock and scion, which affected the survival of graft healing. [51][52][53]. In our study (Figure 2), the NAA treatment significantly enhanced SOD activities of graft junction during the graft union development (Figure 2A). ...
The plant graft healing process is an intricate development influenced by numerous endogenous and environmental factors. This process involves the histological changes, physiological and biochemical reactions, signal transduction, and hormone exchanges in the grafting junction. Studies have shown that applying exogenous plant growth regulators can effectively promote the graft healing process and improve the quality of grafted plantlets. However, the physiological and molecular mechanism of graft healing formation remains unclear. In our present study, transcriptome changes in the melon and cucurbita genomes were analyzed between control and NAA treatment, and we provided the first view of complex networks to regulate graft healing under exogenous NAA application. The results showed that the exogenous NAA application could accelerate the graft healing process of oriental melon scion grafted onto squash rootstock through histological observation, increase the SOD, POD, PAL, and PPO activities during graft union development and enhance the contents of IAA, GA3, and ZR except for the IL stage. The DEGs were identified in the plant hormone signal-transduction, phenylpropanoid biosynthesis, and phenylalanine metabolism through transcriptome analysis of CK vs. NAA at the IL, CA, and VB stage by KEGG pathway enrichment analysis. Moreover, the exogenous NAA application significantly promoted the expression of genes involved in the hormone signal-transduction pathway, ROS scavenging system, and vascular bundle formation.
... Floral bud and flower differentiation and development are a combination of various physiological and biochemical processes. There are multiple hypotheses of how flowering is affected by hormones; the hormonal balance hypothesis [14,15] , the hormone regulated flower gene expression hypothesis [16] , and the hormone-signal-regulating flower bud differentiation hypothesis [17] . Combining endogenous and exogenous hormone studies with transcriptomic data analyses could potentially produce a better understanding of the role of hormones in flowering. ...
Pecan is the only native north American tree nut. The USA produces approximately 80% of the world’s pecans. Pecan trees have an extended juvenility, 10 years to the first nut crop. With mature bearing they begin alternate bearing; alternating large and small crops. Theoretically, a heavy crop inhibits flower induction in the current year resulting in a low crop the following year. The flowering of perennial trees involves a complex interplay of multiple hormones. The possible molecular mechanisms regulating tree flowering can be revealed by endogenous plant hormone quantification, exogenous hormone application and RNA-sequencing. In this review, we synthesize the investigations of transcriptomic analysis and exogenous hormone treatments on bud break and flowering in fruit/nut trees with a focus on pecan. Knowledge of how hormones regulate flowering suggest they are a potential tool for improving return bloom and mitigating alternate bearing.
... For most plants, the flower induction process is associated with environmental factors, nutrients, protein metabolism and hormones (Koutinas et al., 2010;Zhang et al., 2015;Lorca, 2017). However, for pome fruit, the hormonal balance is believed to be one of the main factors driving flower bud formation (Tromp, 1987;Lavee, 1989;Curry and Greene, 1993;Bubán, 1996;Davenport, 2000;Jackson, 2003). ...
... Swain et al., (1995) concluded that only GA 1 and/or GA 3 are associated with embryo and endosperm and are thus physiologically active in pea whereas GA 20 and GA 29 found in the testa of a seed had biological role. Therefore, the common finding of the previous studies indicated that are the amounts and proportions of PGRs carried by synthesis difference between various organs of the plant and their physiological growth stage (Ulger, 1977;Lavee, 1989;Baktır et al., 2004;Okay et al., 2011). Therefore, in some previous studies reported that tried to take control of abscission with external applications GAs and ABA both on-and off-crop years, but the results are not definitive (Lin et al., 1984;Ferguson and Maranto 1989;Lovat and Ferguson, 2006;Açar et al., 2006). ...
... Since the establishment of the hypothesis of the existence of the flower inducing, hormone-like, molecule called "florigen", suggested by Chailakhan in 1930 [45], efforts have been made to clarify the process and factors related to the formation of flower structures and flowering. The process has been studied in a number of plant species over eight decades [22,23,[46][47][48][49][50][51][52][53][54][55]. However, considering its complexity in terms of genetic, hormonal, and environmental interaction, the process is still not completely understood. ...
Here, we reviewed both endogenous and exogenous factors involved in the processes of flower bud formation and flower development in peach, analyzing how they can be affected by climatic change in temperate zones, explored the expansion of peach to tropical or subtropical zones. The process of flower bud formation in peach differs between low winter chilling and temperate conditions. Although the main steps of flower development are maintained, the timing in which each one occurs is different, and some processes can be altered under low winter chilling conditions, with a great impact on fruit production and crop management. Further studies on flower bud induction and differentiation under warmer conditions are fundamental for addressing the alterations in flower bud development that negatively impact on next season's harvest. In the future, horticulturalists and scientists will face several challenges, mainly how high temperatures affect the expression of the main genes regulating flower formation and how to improve crop management in these conditions.
... Plant hormones are important substances regulating flower bud differentiation. There are many studies on hormones and flower bud differentiation, and scholars have also put forward many hypotheses, such as the hormonal balance hypothesis (Muradoglu et al., 2010;Potchanasin et al., 2009), hormoneregulated flower gene expression hypothesis (Clarke et al., 1992), and hormone-signal-regulating flower bud differentiation hypothesis (Lavee, 1989). In Arabidopsis, GA promotes the termination of vegetative development and inhibits flower formation (Yamaguchi et al., 2014). ...
Pecan [Carya illinoinensis (Wangenh.) K. Koch] is a famous high grade dry fruit, oil tree species and excellent tree species for both timber and fruit. Pecan is a monoecious plant, and the formation and number of female flowers directly determine the pecan yield. In this work, to illuminate the molecular mechanism of floral formation in pecan, scanning electron microscopy was employed to distinguish the developmental stages of female flower. Three flower buds and two flowering stages were collected for high throughput RNA sequencing. 65,680 unigenes were generated with 41, 806 differentially expressed genes annotated. Genes involved in hormone signaling, carbon and nitrogen metabolism showed significant differential expression during the floral developmental process. The MADS-box gene family was analyzed in depth, the six type-I genes were not expressed in the FL2 stage, while most type-II genes were highly expressed in the late flower stages. In order to explore the regulation mechanism of pecan flowering, we selected 299 floral-related genes to construct gene co-expression network. The photoperiod pathway genes LHY, PHYA, ELF3 and the gibberellin metabolic pathway gene DELLA proteins function as key roles in floral pathways. We also identified four hormone metabolic pathway genes correlated (SAUR15, IPT1, IAA29, and ARF2) with CiMADS5, CiMADS8, CiMADS9, CiMADS20, and CiMADS39. Furthermore, the expression patterns of 16 unigenes involved in flower development were validated using quantitative real time PCR. These findings are of great significance for further understanding of the molecular basis for reproductive development in Carya Nutt species.
... The internal factors in plants have been found to be the most ideal molecules for binding to cell receptors in signal transduction required for the initiation of development and physiological events (Burg, 1968;Abeles and Leather, 1971;Adams and Yang, 1979;Galston and Kaur-Sawhney, 1987;Flores et al., 1989;Lavee, 1989;Weinbaum et al., 1994;Kakkar et al., 1998;Vemmos, 1999a;Lovatt and Ferguson, 2002;Ulger et al., 2004;Baninasab et al., 2007;Yamada et al., 2007). Polyamines (PAs), one of these internal factors, are ubiquitous polycationic nitrogenous bases of low molecular weight, which are regarded as multifunctional regulators of physiological processes (Konigshofer, 1989;Kakkar et al., 2000;Kuznetsov et al., 2006). ...
Alternate bearing is a significant economic problem adversely affecting the producers, consumers, and economy of a country. In the present study, we aimed to investigate the physiological role of free polyamines (PAs) in fruit bud abscission of the Uzun pistachio variety, which has a strong alternate bearing tendency. The identification and quantification of PAs, such as putrescine (Put), spermidine (Spd), and spermine (Spm), at different physiological stages and in different organs, were carried out by high-performance liquid chromatography. Putrescine was the major PA in all the organs of pistachio trees. Furthermore, the concentrations of Put and Spd in the leaves and shoots sharply declined and reached the minimal levels during the fruit bud abscission period (June), and then increased during the period of kernel development. The concentration of Put and Spd in the panicles increased gradually until the beginning of kernel growth and then decreased until harvest. The concentration of Spm exhibited a negative correlation between shoots and leaves, especially in the 'On-year' trees. There was a significant decrease in PAs in the leaves during the period of bud abscission in the 'Off-year' trees. In the 'On-year' trees, the concentration of PAs exhibited a negative correlation with the panicles, especially when the concentration of Put and Spd increased during the kernel development period, and then decreased. The concentration of PAs in the panicles of the `On-year? trees was higher than that in the nuts, and it exhibited a negative correlation with that in the nuts. The results suggest that PAs might lead to physiological changes during the growth and development stages of pistachios, and a strong relationship was observed.
... In our research, grafting with different methods differentially increased PAL activity: SG had the highest PAL activity at 3 DAG among the three grafting methods, while TAG had relatively lower PAL activity than the other two grafting methods, potentially helping with graft union formation. PPO and POD are not only protective enzymes in plants but also play an important role in lignin biosynthesis (Lavee, 1989;Ali et al., 2006;Zhao et al., 2013). POD activity levels continued to increase in all plants at 7 DAG with PPO levels having the same changes as PAL levels during graft union healing under TAG. ...
To determine the effect of grafting method (hole insertion grafting, HIG; tongue approach grafting, TAG; and spliced grafting, SG) on graft union formation in cucumber grafted onto bottle gourd rootstock, an anatomical and physiological study was carried out during the healing stage. The results showed that the TAG method resulted in an obviously higher daily growth rate than the other grafting methods 7 days after grafting (DAG), with significantly higher values in the scion than in the rootstock. The isolation layer, callus formation, and vascular connection all occurred at the graft junction when using HIG, TAG, and SG. Vascular bridging first occurred between scion and rootstock using HIG or TAG at 5 DAG; this process was delayed with SG. The activities of superoxide dismutase (SOD), POD (peroxidase), CAT (catalase), PAL (Phenylalanine ammonia-lyase), and PPO (polyphenol oxidase) were significantly enhanced in the graft union during the healing process when different grafting methods were used. Compared with HIG and SG, the POD and CAT activities and total phenolic compounds were higher with TAG at 7 DAG; a reduction in PPO activity and lignin content were also overserved at the graft with TAG at 7 DAG. These results suggest that the association of TAG with a higher growth rate during the healing period is linked with the earlier improvement in vascular bundle connection that may be caused by increased antioxidant activities and lower lignin content at the graft junction. These morphological and physiological differences may provide valuable information for revealing the graft union healing process.
... The extent of bienniality can be influenced by many factors, including tree age (Smith et al., 2004), rootstock (Cantuarias-Avilés et al., 2011), variety (e.g., for mango (Shivashankara and Mathai, 1995)), and extent of pruning (Andersen et al., 1996). Alternate bearing is commonly ascribed to either a growth regulator effect (e.g., high GA 3 levels associated with a heavy crop may inhibit inflorescence primordium (IP) development, and thus reduce yield in the following season), or a carbohydrate competition effect (with a heavy fruit crop competing for resources with IP) (Goldschmidt and Golomb, 1982;Lavee, 1989). In the carbohydrate competition explanation for alternate bearing, storage reserves of carbohydrates are exhausted during the 'on year' of high yield, affecting IP development and thus following season yield (Monselise and Goldschmidt, 1982). ...
Inconsistent yield between seasons for table grape cultivars grown in subtropical climates in Australia presents a challenge to the industry in terms of marketing and economic sustainability. The pattern of this yield inconsistency has not been described. Marketable fruit yields of three cultivars (Red Globe (RG), Menindee Seedless (MS) and Flame Seedless (FS)) were acquired over 14 seasons, and individual vine yields of MS were collected for a four-season period from a vineyard in the Central Highlands of Queensland, Australia. Cultivars FS and RG did not show an alternate bearing pattern. Yields of MS varied up to four-fold in consecutive seasons. An alternate yielding pattern as measured by the indicators of an alternate bearing index (I) and associated probability calculated using a resampling process was evident in 7 (2009-2015) of the 14 monitored seasons. Individual vine yield over the four-season period 2014-2017 was irregular and 90% variation in vine yields was due to the variation in the number of bunches per vine. The seasonal yield variation of MS was partly explained (R 2 = 0.31, P < 0.05) by the mean monthly temperature in October of the year preceding harvest. This result is ascribed to the effect of high temperature during inflorescence initiation and early development which occurs in October in the Central Highlands of Queensland.
... In non-irrigated olive groves the yield may vary between 7-8 tons/ha and a few hundred Kg. The occurrence and development of alternate bearing is potent also in intensive orchards with controlled irrigation, nutrition and training techniques, though the level of fruit production is higher and better controlled (Lavee, 1989). Without specific intervention, the gap between 'off' and 'on' years may vary between 5-30 tons/ha (Lavee, 2007). ...
... Flower bud formation is a complex physiological process carried out by meristems located at places where flower buds are formed over the shoots or spurs [Zhang et al. 2015]. Such a process is regulated by a complex cooperation of different plant hormones [Tromp 1987;Lavee 1989;Curry and Greene 1993]. In perennial plants, GA3 generally directs assimilation substances from apex to rapidly growing shoots [Mutasa-Göttgens and Hedden 2009] and inhibits flowering [Wilkie et al. 2008;Mutasa-Göttgens and Hedden 2009]. ...
Effects of prohexadione-calcium (ProCa, 125 and 250 mgL-1) and ProCa + ammonium sulfate (AMS, 500 mgL-1) treatments on vegetative characteristics (shoot growth, branch diameter, trunk cross-sectional area (TCSA), canopy volume, number of flower per cm 2 , number of fruits per cm 2) and quality parameters (fruit size, flesh firmness, color, titratable acidity and soluble solids content (SSC)) of '0900 Ziraat' sweet cherry were investigated in this study. Solutions were sprayed when the shoots were just 10 cm long in 2014 and 2015. As compared to control, in 2015, TCSA decreased only with ProCa treatments (125 and 250 mgL-1) and canopy volume and shoot length decreased with all treatments. On the other hand, number of flower and fruit per cm 2 significantly increased with all treatments. While there were not significant differences in fruit size, flesh firmness, color, SSC and titratable acidity values were significantly lower in 250 mgL-1 ProCa and 250 mgL-1 ProCa + AMS treatments. It was concluded that ProCa treatments could be used as an efficient tool for suppression of shoot growth and to increase the number of flower and fruits per cm 2 in '0900 Ziraat' sweet cherry cultivar.
... There is an extensive body of literature related to alternate bearing of olive, showing that some of the produced signals are intercepted by leaves in response to environmental conditions to create chemical changes. Phenolic and flavonoid compounds are involved in the arrest of flower bud formation during the physiological initiation periods (Lavee 1989;Akillioglu 1995;Ryan et al. 2002Ryan et al. , 2003. ...
Barberry ( Berberis vulgaris L.) fruit is an important source of anthocyanins and is used for consumption and in medicine. However, fruit production of barberry is not regular. Two experiments in four locations were conducted on this plant to explore if it is alternate bearer and also to investigate carbohydrates and phenolics contents in leaves and shoots during growth season. Evaluation of barberry shrubs in three different location showed strong alternate bearing. The value of leaf number to berry number ratio was small. A correlation was found between tree age and alternate bearing index (ABI), because elder shrubs exhibited more ABI. Total carbohydrates and phenolics contents in vegetative organs showed an increase during the fruit setting stage, except for the carbohydrates in shoots. The highest value of carbohydrates was observed 10 days after leaf appearance and then decrease. ON bearing shrubs showed the highest value of total carbohydrates content in leaves during fruit setting stage, after which it decreased. However, OFF bearing shrubs indicated a reducing trend in this variable. In both bearing statuses (ON and OFF trees), total carbohydrates decreased with season progression. It is concluded that this plant is strongly alternate bearer and this characteristic may be related to carbohydrates and phenolics changes in leaf and shoot organs.
... In general, higher levels of phenolic compounds were measured during the dormant season. Also, the central role of chlorogenic acid in alternation has been identiied, exhibiting 3-4 times greater concentration in fruit-bearing years once compared to the non-fruit-bearing period [55][56][57]. The chlorogenic acid concentration in old season leaves exhibited dramatically variations between seasons [58]. ...
Olive oil includes high amounts of phenols and polyphenols. Through health beneits
to humans, the antioxidant role of polyphenols that contain more than two phenolic
hydroxyl groups has been well proven. Of those polyphenols, oleuropein, hydroxytyrosol,
catechin, chlorogenic acids, hesperidin, nobiletin, and isolavones are major compounds.
Along with the present study, (1) the uses and biological roles of polyphenols have not been limited to their physiological roles to human health; their physiological roles for plant and aromatic values for plant are also evaluated; (2) possible roles of major components in response to environmental stressors are discussed; (3) bibliometric analysis of studies concerned with polyphenols in olive fruit oil has been done to evaluate the research trends concerned with polyphenol in olive fruit oil, considering the main theme of the studies. The study is concluded with highlights, limitation, and future outlooks.
... Environmental conditions play an important role in growth and productivity of olives kinds as productivity varies according to environmental and climate conditions (Lavee, 1989). Studies concerning environmental conditions influenced olive trees behavior (Lavee, 2007), especially its bearing habit, yield and fruit quality are still of need for further studies. ...
The present study aims to evaluate the physiochemical properties of Manzanillo olive fruits and olive oil extracted from it. The olive trees were treated by growth regulators (1-Naphthaleneacetic acid (NAA) and (Gibberellic acid (GA3) which was applied, 10 days after fruit set as foliar application on the trees as follows: NAA 75 ppm, GA3 75 + NAA 50 ppm and GA3 75 + NAA 75 ppm. Olive fruit samples were analyzed for its moisture, oil, protein, ash, fiber and carbohydrate content. Olive oil extracted from each olive fruits samples treated by growth regulators was also analyzed for its physical and chemical properties, oxidative stability and fatty acid profile. The effect of ambient temperature for 24 months storage on some physical and chemical properties of olive oil extracted was also evaluated and compare with sample without any treatments (control sample). The obtained results showed significant differences between Manzanillo olive fruits treated with growth regulators and control samples in moisture and oil content. Also, the oil extracted from Manzanillo olive fruits treated by (NAA) and (GA3) were found to be lower in stability and ability for storage, comparing to control sample, However, treatments of olive fruit with growth regulators led to decreasing in physiochemical properties and storage stability compared with control sample which was found of high quality, more stable and distinctive in total phenols and oxidative stability.
... Applying that criterion, it was possible to: (a) avoid the appearance of many undesired phenotypes in the segregating progeny, and (b) increase the chance of finding plants with enhanced phenotypes directly in the segregating progeny, and (c) use them as ortet for clonal selection of new genotypes for variety registration. This strategy has been used in several olive breeding programs and some new clones have been selected (Lavee 1989;Bellini et al. 2008). The success of the biparental cross-breeding program will depend on the hereditability of the traits to be improved. ...
Olive breeding aims to the adoption of a fast-track breeding methodology to rapidly identify and select ortets within the available gene pool or in progenies from planned mating design for the development of new varieties that meet the current objectives of the olive industry. Basic information is needed on the breeding objectives, the genetic basis of the desired traits, the selection criteria to be adopted, and the genetic diversity available for trait enhancement and new varieties needed by the current and future olive farmers. The available genetic diversity is not yet well organized according to the gene pool concept that greatly facilitates the choice of breeding materials and breeding procedure to adopt. In addition, despite recent significant efforts, the progress of knowledge on single-locus traits and QTLs is still limited, placing the efficiency of olive breeding at a crossroad. To overcome this important limiting factor, the current selection activities could be merged with the biotechnological advancements to formulate a faster trait-enhancement procedure based on cloning and genotyping of immature embryos from planned mating designs. Developments in DNA sequencing will now allow a cost-efficient increase of genomic resources for driving the rapid acquisition of information on genes for important economical and agronomical olive traits. The in vitro germination of immature zygotic embryos, zygotic embryo cloning, and application of modern genomic resources will set the stage for an accelerated olive breeding procedure.
... In apple, flower induction occurs early in the season, about 5-10 weeks after full bloom, and is controlled by a complex physiological process (Zhang et al., 2015). This process might be regulated by a complex network of different plant hormones (Curry and Greene 1993;Lavee 1989;Tromp 1987). In perennial trees, GAs generally inhibits flowering (Wilkie et al., 2008;Mutasa-Göttgens and Hedden, 2009), presumably by diverting assimilates from the apex to the rapidly growing shoot (Mutasa-Göttgens and Hedden, 2009). ...
Different studies describing Prohexadione calcium (P-Ca) as an efficient tool to reduce shoot growth have been extensively reported, but these studies are usually performed in typical temperate climate regions. However, a complete analysis of the effects of P-Ca in pear trees in regions of warm-winter climates has not been performed. Therefore, the objective of this study was to evaluate the effect of different rates of P-Ca on vegetative growth, production and fruit quality of ‘Le Conte’ pear trees, in warm-winter climate conditions. The experiment was conducted during the 2013/2014 and 2014/2015 seasons, in a six year old ‘Le Conte’ pear orchard, trained to a central-leader system, with spacing of 1.5 × 4.8 m, grafted onto Pyrus calleryana. Different P-Ca rates were applied (100, 200, 300, 400 mg L
−1 in different biological stages: first in early spring (shoots ∼2.5 and 5 cm long) for all treatments and the others when shoot growth resumed (GR), but only for some treatments. Variables for vegetative growth, yield components and fruit quality at harvest and post-harvest were evaluated. Shoot length was measured on 10 one-year-old shoots evenly selected and tagged at the time of the first application and, then, at biweekly intervals until the end of the season. The use of P-Ca was effective to control vegetative growth in both seasons, at different rates. At ∼90 days after full bloom (DAFB), P-Ca treated shoots had a pronounced second flush of growth, requiring an additional application of P-Ca in both seasons. In the 2013/2014 season, the only time of P-Ca reapplication was at 93 DAFB for the rates of 100 and 200 mg L−1 , which was enough to check shoot growth throughout the season, but in the 2014/2015 season, three shoot growth flushes were observed according to P-Ca rate, requiring additional P-Ca applications. Unlike the first season, P-Ca reapplication was efficient to reduce shoot length relative to trees treated once with P-Ca. In both seasons, fruit set, number of fruits per tree, yield, average fruit weight, fruit diameter, estimated yield, return bloom, and return yield were not affected by P-Ca applications. P-Ca applications did not alter the qualitative attributes of the fruits of ‘Le Conte’ pear trees at harvest and when they were stored for a period of 30 days of regular air cold storage (RACS) + 3 days of ripening period (RP) in both seasons. These results implicate P-Ca as a potential tool to manage vigor of ‘Le Conte’ pear trees in warm-winter conditions, given its efficiency to control vegetative growth without negatively affecting yield components.
... Also, several studies (Gucci, 2003 andGucci et al., 2007) indicate that regulated deficit irrigation in olive may be suitable to improve physiological balances with a limited input supply. In addition, environmental condition play an important role in growth and productivity of olive cultivars as productivity vary according to climatic condition and environment (Lavee, 1989). Moreover , Luna, (2000), stated that this positive response to increased water supply was essentially due to vegetative growth. ...
A field experiment was conducted during two successive seasons (2014 and 2015) in a private orchard farm, located at the 64 km on the Cairo-Alexandria Desert Road, to study the effect of different irrigation levels, irrigation methods and olive cultivars on plant growth and yield of olive trees(Olea europara, L.). Treatments were: a-three irrigation levels: 4384 m 3 /feddan(100%), 3740 m 3 /feddans (85%) and 3089 m 3 /feddan (70%); b-two drip irrigation methods: on-line surface irrigation and in-line sub surface irrigation and c-two olive cultivars, Picual and Manzanillo. The experiment was designed in a split-split plot with three replicates. Estimated irrigation water was calculated, using FAO method, in order to compare between applied and estimated irrigation regime. Data revealed that using 3740m 3 /fed irrigation level gave the highest growth and yield compared with other treatments. The Estimated irrigation water was close to applied treatment 3740 m 3 /fed. In-line (surface irrigation) method recorded the highest yield and oil during the two successive seasons. The oil content in fruit increased with water decrease. The Picual cultivar showed the highest oil content while, Manzanillo cultivar gave the highest yield. The interaction between the three tested factors show that the 3740m 3 /fed treatment with the In-line surface irrigation combined with Manzanillo cultivar was the best combined treatment. The highest WUE was found in 3089 m 3 / fed. with subsurface irrigation combined with Manzanillo cultivar.
... If well managed, olive trees can keep fruiting for over a century (Zinger 1985;Zohary et al. 2012). Olive orchards produce a large crop one year and small crops in alternate years (Lavee 1989(Lavee , 2007. Olive is mainly a wind-pollinated species and therefore it releases large amounts of pollen to the atmosphere in the spring (March-May) to compensate for the low pollination efficiency that characterizes wind-pollinated trees. ...
For millennia the olive was an important cultivated tree in the southern Levant, as evidenced by numerous archaeological finds and Holocene pollen assemblages. However, the impact of abandonment and rehabilitation of olive orchards (a recurrent historical process) on the fossil pollen record has not been studied. We documented quantitative differences in the olive pollen signature in a well-managed traditional olive orchard, an abandoned orchard, and an orchard rehabilitated after decades of abandonment, establishing the biological basis for understanding the olive pollen signature. The results indicate a strong decline in flowering and pollen production for decades following the cessation of cultivation and a rapid increase following rehabilitation. This strong response suggests that the fossil pollen curves are a reliable marker for determining the extent of olive oil production in ancient times. In terms of agricultural/economic efficiency, rehabilitation of an orchard takes much less time than establishing a new orchard. This could have been one of the reasons why the same sites were reoccupied during peaks of settlement activity in antiquity. The recent field results are compared to fossil pollen data from the Sea of Galilee during the Bronze and Iron Ages.
... This habit causes severe loss for olive grower's income expressed in disturbances in yearly income of the orchard and poor fruit quality (Goldschmidt, 2005). Environmental conditions play an important role in growth and productivity of olives kinds as productivity varies according to environmental and climate conditions (Lavee, 1989). Studies concerning environmental conditions influenced olive trees behavior (Lavee, 2007), especially its bearing habit, yield and fruit quality are still of need for further studies. ...
The objective of this work was study that the effect using one treatment of (Girdling at first week of January and Kaolin sprayed at rate 5% mid December) and chemical (Calcium carbonate, sprayed at rate 5% mid December, Naphthalene acetic acid at 100ppm mid December and Boric acid (17.50%) at 300ppm in first week of March) on oil yield, quality indices, minor components and fatty acids composition of olive Picual cv. during seasons 2012-2013. Yield/tree, fruit weight, seed weight, flesh weight, flesh/fruit weight, flesh/stone, moisture and oil contents (%) were determined. Quality indices (acid value, peroxide value, absorbance at K 232 nm, K 270 nm and ∆k, value), sensory evaluation, total polyphenol, tocopherol, bitter index at K 225 , pigments content, oxidative stability and Fatty acid composition were determined. Results indicated that the treated tree (Picual cv.) by Girdling, Boric acid, Naphthalene acetic acid and Kaolin gave a higher content in oil percentage/tree. Also, same the treatments gave best values in quality indices, total polyphenol, tocopherol and oxidative stability compared with untreated and treated samples with calcium carbonate. On the other hand, the treated trees by Girdling, Boric acid, Naphthalene acetic acid and Kaolin surpassed on untreated and treated samples with calcium carbonate in oleic acid levels. Generally, can be used (Girdling, Boric acid, Naphthalene acetic acid and Kaolin) to increase the productivity of olive trees Picual cv. and also improve the quality attributes of the oil extracted. Also these treatments increased the oleic acid more than untreated sample. To overcome the phenomenon of bearing, this is characterized by olive. Increasing the productivity of trees and increased oil content in fruits. Also improve the quality properties of oil extracted; oil contains high levels from total polyphenol and tocopherols. It also led to use some of the material (nature of the chemical) under study to improve the ratio of oleic acid, a major unsaturated fatty acid in the olive oil.
... Many experiments confirmed the direct involvement of different growth regulators in promoting or inhibiting flower bud induction and differentiation. However, all these studies were related to the effect of a single regulator or its quantitative changes before, during or after flower bud induction (Lavee, 1989). On contrary to plant growth regulators, Ulger et al. (2004) suggested that carbohydrates and mineral nutrients might not have a direct effect to induce flower initiation. ...
For a normal development of temperate zone fruit trees, a very complex phase of their lifecycle
called dormancy is regulated by environmental conditions during autumn-winter
season. This phase allows those species to survive under adverse environmental conditions,
and one of the most important factors which induce and release dormancy stage is
temperature. It was adopted a terminology suggested by Lang et al. (1987) for the different
stages of dormancy: para-, endo-, and ecodormancy.
From the end of the 19th century, cultivation of temperate zone fruit crops were set up in
areas warmer than those traditionally cultivated. As the cultivars grown were those used
traditionally, the chilling requirements were not adequately fulfilled. These difficulties led
to identification and study problems of growing temperate zone fruit crops in warm areas,
which was approached in two different ways. On the one hand, traditional cultivars were
selected and bred to obtain new cultivars with commercial quality and low chilling
requirement, which is a heritable character. On the other hand, new cultural practices, such
as applications of rest-breaking agents, were developed to avoid or reduce the negative
consequences of an insufficient chilling accumulation. The most useful option for temperate
zone fruit crops in warm areas has frequently been a combination of low-chill cultivars and
the adoption of cultural practices to break or avoid dormancy. Although different species of
the Rosaceae family have been bred for low-chill cultivars, the furthest advances have been
made in peaches and apples.
During dormancy, several events occur simultaneously, which modifies water and
carbohydrate dynamics, hormonal balance, among others. Water is important for bud and
plant development, such in solute translocation, enzymatic reactions, and osmotic regulated
events, reason why many studies are focused on its dynamics. Recent studies in water
dynamics during dormancy phase, such as the embolism (loss of hydraulic conductivity) in
xylem of plants and water status (free or bound water) in dormant buds determined by
magnetic resonance (MR) techniques, showed the importance of water on dormancy release
process. And under stressed conditions this importance seems to be strongly accentuated.
... Seasonal yield variations are typically observed in olive plantations (Nuberg & Yunusa, 2003), and a range of possible factors that cause this phenomenon, including irrigation and time of harvest, has been proposed . The degree of alternation, indeed, may be highly dependent upon environmental conditions and agronomic practices (Lavee, 1989). Moriana et al. (2003) calculated yield responses as a function of ET c for biennial yield data. ...
The response of mature olive (Olea europaea L.) trees to both regulated deficit irrigation and fertigation was studied for some consecutive years in sub-humid (Italy) and semi-arid conditions (Spain). All cultivars tested in these experiments were preferentially for table olive consumption (pickling and double-aptitude). Data from these long-term studies on field-grown, mature trees are summarized for assessing common effects of water and nutrient supply on plant behaviour and fruit yield. Seasonal yield variations were observed, and showed that the effect of irrigation treatments was somewhat more gradual in the “on” than in the “off” year. Differences amongst cultivars were always marked. Dry matter accumulation in pulp and pit was positively affected by progressively increasing the amount of water supplied to plants, regardless of years and cultivars. The ratio between pulp and pit fresh weight was negatively affected by irrigation, while fruit size was positively influenced by the gradual increase of irrigation water. Average nitrogen levels in leaves were generally above the deficiency threshold at both experimental plantations. Crop yield was not consistently increased by addition of soil nutrients. The effect of fertigation treatments was relatively uninfluential on oil accumulation in fruits. However, polyphenols in oil samples decreased progressively as the addition of nutrients increased. Critical aspects and strategic decisions in modern olive growing are the selection of cultivar, the supply of water, the option of fertilization, together with other orchard management practices. In this paper we outline various aspects of long-term studies in experimental olive plantations with the aim of highlighting inter-regulatory processes, involving plant growth and crop yield, which must be taken into account when planning future field research and modelling exercises.
... This change starts right after fruit set activating the cinnamic acid pathway to lead to an accumulation of Chlorogenic acid (CHA) which was shown to inhibit fruit bud induction during growth session in the winter. This is probably true also for the inhibited growth period in the summer as the level of CHA is high already at that time (Lavee, 1989). ...
Preliminary research indicates that polyamines (PAs) could be markers of flower induction and differentiation in olive. Monthly determination showed an equal PA content between buds collected from suckers and from vigorous shoots sprouted from primary branches, both having a different degree of juvenility producing only vegetative buds. In contrast, the floral buds of fruiting twigs showed a PA content superior to the previous ones throughout the year except in May and July when they were slightly lower. The greatest difference in PA content between floral and vegetative buds was observed in September and early February with a difference of 3 and 2 fold higher in floral buds than in vegetative ones respectively. However, the composition of the PAs was considerably different. In February, the PA content was almost exclusively represented by conjugated spermidine while in September by conjugated Putrescine, Spermidine and bound Putrescine. These results clearly indicate a correlation between the high content of conjugated spermidine and beginning of bud differentiation, which in areas of Central Italy starts to be noted in February while the high PAs content in September could indicate the floral induction of most buds.
... Soluble sugars are known to be the essential component for the cold resistance of plants; changes in their levels during this process have been well documented in Arabidopsis mutants (Uemura et al., 2003). The increase in soluble sugar content in the cold-acclimated stage, has been proposed to be a part of cold acclimation mechanisms in olive plants (Lavee, 1989;Bartolozzi et al., 1999Bartolozzi et al., , 2001Proietti and Famiani, 2002;Eris et al., 2007), as well as in many other plant species, such as peach cultivars (Burak and Eris, 1992), winter rye leaves (Antikainen and Pihakaski, 1994), and cabbage genotypes (Sasaki et al., 2001). Proline as an amphiphilic osmolyte binds onto hydrophobic surfaces via its The same letters among different temperature drop ranges indicate that there are no significant differences after one-way ANOVA (P < 0.05). ...
Two-year-old seedlings of Michelia maudiae Dunn were grown under optimum light and water conditions for plant stability and then treated by three drop range (12, 16, and 20° ° ° °C) with 12, 24, and 48 h conditions to understand the effect of short-term temperature drop (different temperature drop range and duration) on the cold resistance of plants. The overall average temperature for all treatments was 20° ° ° °C. Superoxide dismutase (SOD) activities, relative electrical conductivity, soluble sugar, proline, and malondialdehyde (MDA) contents of leaves were measured, and different treatments were compared with each other. In different time conditions, the MDA content and the relative electrical conductivity were enhanced with the increased drop range and the greatest changes in the 12 h treatment; SOD activities decreased but were higher than current levels before the cooling; and soluble sugar and proline contents significantly increased in the 48 h treatment but were nonsignificant in other treatments. In different temperature drop range treatments, SOD activities and relative electrical conductivity significantly weakened with the extension of time and the greatest decrease was in the 12 h treatment. Soluble sugar and proline contents continued to increase with the greatest changes in the 48 h treatment while MDA content increased and then decreased in the 12° ° ° °C drop range but increased in the 16 and 20° ° ° °C drop range treatments. Finally, using the Fuzzy mathematics method, the cold resistance of M. maudiae Dunn in different temperature drop was evaluated as 12° ° ° °C temperature reduction > > > > 16° ° ° °C temperature reduction > > > >20 ° ° ° °C temperature reduction. This result indicates that M. maudiae Dunn has a relatively high adaptivity to the 12° ° ° °C (20 to 8° ° ° °C) drop range stress.
... In table olive (Olea europaea L.), heavy crop loads result in small fruit of lesser value, late maturity, poor quality ultimately leading to depressed prices (Martin et al., 1980). Moreover, excessive crop loads and excessive numbers of developing seeds decrease or inhibit fl owerbud formation which can contribute to the biennial production pattern (Dag et al., 2010;Fernandez-Escobar et al., 1992;Lavee, 1989Lavee, , 2007Stutte and Martin, 1986). ...
Olive (Olea europaea L.) shows alternate bearing, with unreliable cropping patterns and inconsistent fruit size and quality every year. In many countries, thinning with naphthaleneacetic acid (NAA) is used to minimise alternate bearing behavior in olives. However, in Italy, growers are reluctant to employ this practice and no detailed knowledge is available for specific cultivars. We evaluated the effects of spraying NAA on various dates on the productive and vegetative characteristics of the main Italian table olive cultivar'Nocellara del Belice'. Trunk cross-sectional area, fruit set, fruit drop, fruit size, pit size, yield per tree, crop density and flesh to pit ratio were analysed. The NAA treatment applied on the earliest of the dates selected increased fruit weight and flesh to pit ratio, by reducing crop density and enhancing the leaf to fruit ratio, without reducing yield. Two distinct negative relationships were found between fruit weight and crop density during "on" and "off" years, but a unique relationship between pit weight vs. crop density in both years, suggested that the pit is the strongest sink. Fruit size and quality of'Nocellara del Belice' can be enhanced by NAA application, thereby increasing economic returns in the "on" year.
... In olive, GA3 was shown to en-hance vegetative growth in young trees; but, it reduced flower bud differentiattion even without a noticeable effect on the vegetative growth. Non-uniform response of the olive tree to GA3 ap-plications was attributed to its lim-ited uptake through the leaves (Lavee, 1989;Lavee and Haskal, 1993). GAs produced in the roots may also promote and maintain juvenility (Lavee and Haskal, 1993). ...
Juvenility is referred to the period during which a plant cannot be induced to flowers whereas maturity is occurred if a plant gives flowers. The changes from juvenile to mature characteristics are well known as phase changes phenomenon. Plants are unable to initiate flowers after germination and have to undergo in a juvenile developmental phase. This transition period (phase) is a gradual and continuous process until the flowt- ering occurs. Length of juvenile period in most of woody plants is still considered as a big problem. Indeed, it affects the plant breeding efficiency, plant propagation, and to the selection of new cultivars. Therefore, understanding this phenomenon and guttering different ideas of accelerating growth to get early flowering will have great practical significance.
... (Olea europaea, 1989; Fernandez-Escobar et al., 1992; Lavee & Haskal, 1993 ( . Lavee & Spiegel,;1967; Martin et al., 1980 .( ﺟﺒﯿﺮﻟﯿﮏ اﺳﯿﺪ از اﺳﺘﻔﺎده Fernandez-Escobar et al., 1992; Lavee & Haskel, 1993 . ) Proling & Voyiatzis, 1986; Lavee & Haskal, 1993; Rugini & Pannelli, 1993; Iannotta et al., 1999; Palliotti, 1999 .(Congress, ...
... By 'using the LT50 submodel, days where frost These damages give a reasonable answer to the question why so few pollen grains were found in 1981 and 1988 (Table 11). If the hormonal regulation mechanisms, known to control alternate bearing in apples (Lavee 1989), are applied to the present trees it can explain the biennial tendency observed in the pollen seasons. ...
In order to predict the beginning of the pollen season, a model comprising the Utah phenoclimatography Chill Unit (CU) and ASYMCUR-Growing Degree Hour (GDH) submodels were used to predict the first bloom in Alnus, Ulmus and Betula. The model relates environmental temperatures to rest completion and bud development. As phenologic parameter 14 years of pollen counts were used. The observed dates for the beginning of the pollen seasons were defined from the pollen counts and compared with the model prediction. The CU and GDH submodels were used as:
In this work we present the results obtained in the North-east of Tunisia during the period 2010-2017 relative to the morphological, agronomic and technological study of olive varieties implemented in the National Olive Collection of ‘Oued Souhil’ Nabeul, which includes 42 local and foreign varieties.
The descriptive criteria used in this work for the tree, fruits, pits and leaves are those of International Olive Council (IOC, 1981).
The statistic analysis of data (ANOVA, PCA) allowed the distinction of the most performant varieties which are selected on the basis of the most performant variables like water productivity, olive oil production and their ability to valorize more intensive cultivation systems and their adaptative behavior to water shortage. The Cvs., Chemlali, Chétoui and Galega are among these varieties.
The plant graft healing process is an intricate development influenced by numerous endogenous and environmental factors. This process involves the histological changes, physiological and biochemical reactions, signal transduction, and hormone exchanges in the grafting junction. Studies have shown that applying exogenous plant growth regulators can effectively promote the graft healing process and improve the quality of grafted plantlets. However, the physiological and molecular mechanism of graft healing formation remains unclear. In our present study, transcriptome changes in the melon and cucurbita genomes were analyzed between control and NAA treatment, and we provided the first view of complex networks to regulate graft healing under exogenous NAA application. The results showed that the exogenous NAA application could accelerate the graft healing process of oriental melon scion grafted onto squash rootstock through histological observation, increase the SOD, POD, PAL, and PPO activities during graft union development and enhance the contents of IAA, GA 3 , and ZR except for the IL stage. The DEGs were identified in the plant hormone signal-transduction, phenylpropanoid biosynthesis, and phenylalanine metabolism through transcriptome analysis of CK vs. NAA at the IL, CA, and VB stage by KEGG pathway enrichment analysis. Moreover, the exogenous NAA application significantly promoted the expression of genes involved in the hormone signal-transduction pathway, ROS scavenging system, and vascular bundle formation.
Yearly yield fluctuations are normal in fruit trees. Yield alternation might be induced by environmental stresses, but in many fruit tree species yield alternation is an inherent characteristic, resulting in perpetual biennial cycling. Endogenous cues are thought to be the major players in determining the phenomenon, although the genetic basis, if it exists, is still enigmatic. In most cases, alternate bearing is due to inhibition of floral induction, following a heavy fruit load ON year. Understanding of flowering control in model plants has made great progress during recent decades. Due to conservation of many molecular components of the flowering‐control pathways among higher plants, there has also been considerable progress in the identification of these components and in the understanding of their role in fruit trees. In this review, flowering control by exogenous and endogenous cues in Arabidopsis along with updated findings in fruit trees are summarized. The effect of fruit load on flowering‐control genes is also examined. Along with these fundamental traits, more practical aspects, namely mitigation strategies of alternate bearing, are also reviewed. Recent developments in mitigation practices of six representative fruit trees are also summarized. Finally, some basic questions, including the genetic and epigenetic background of alternate bearing, an evolutionary perspective, and possible common mechanisms among various fruit trees, are thoroughly discussed.
Alternate bearing is a significant economic problem that affects fruit producers, consumers and the economy of a country. Concentrations of cytokinin (CK)-like compounds in different tissues of pistachio trees ( Pistacia vera ‘Uzun’) were measured to elucidate the relationship between endogenous CKs and flower bud abscission (alternate bearing). Identification and quantification of CK-like compounds of the Z, DHZ and iP types from different physiological stages and tissues were performed using high-performance liquid chromatography–electrospray ionisation–tandem mass spectrometry (HPLCESI-MS/MS) techniques. Five to seven different CK-like compounds were detected, respectively. Isopentenyl adenine riboside (iPR) and trans -zeatin- O -glucoside ( t -ZOG) were the main isoprenoid CKs, as the dominant conjugates in all the analysed organs of pistachio trees. The leaves and shoots of ‘On’-year trees had significantly higher CK contents than those of ‘Off’-year trees on all the sampling dates. Interestingly, the relatively high CK activity was recorded before flower bud abscission in the fractions corresponding to iPR and t -ZOG, while this activity dropped considerably during the flower bud abscission period (55 DAFB). Consequently, the strong negative correlation between CK concentration and bud abscission could be the first indication of the role of CK-like compounds in this unique phenomenon in the ‘Uzun’ pistachio cultivar. It was concluded that CKs could have an important role in the alternate bearing in pistachio.
The regulation of auxin (indole-3-acetic acid; IAA) level in plants is a complex mechanism and the concept is not completely understood. There are many lines of evidence suggesting that amino acid conjugates of IAA play a vital role in auxin homeostasis but the involved plant enzymes are still under investigation. In the present study, the alteration in the levels of auxin and its conjugate in the different physiological stages and organs, as well as its role in flower bud abscission in Pistacia vera L., were investigated. The levels of the auxin and its conjugates, such as IAA, indole butyric acid (IBA), IAA-Ala, IAA-Leu, IAA-Asp, and IAA-Glu, were analyzed by Ultra-Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (UPLC/ESI-MS/MS) technique. Among the auxin conjugate IAA was the main conjugate and dominant indole detected in pistachio extract observed in this work. It has also been determined that quite a few organs of ‘Off’ year trees have higher auxin content than ‘On’ year trees. It was observed that the auxin level is low in fruit-bearing trees in both leaves and shoots. It affects fruit yield and fruit bud abscission and plays some role in the alternate bearing. Decreased levels of auxin were observed in most of the organs of 'On’ trees during kernel development resulting in bud abscission. This study shows that auxin conjugates play an important role in IAA metabolism, particularly, in flower bud abscission and fruit kernel development
Environmental factors such as suitable light and thermal conditions are essential for the reproductive development of olive buds. However, the tree and its buds have to be in a suitable responsive physiological state in order to respond. Furthermore sufficient well developed buds from the previous season with a good nutritive balance, capable to differentiate are required on the tree. In the present paper, we are demonstrating the changes in the nutritional state of the tree developing in ON and OFF years affecting the responsiveness of the buds and level of vegetative growth to the environmental conditions. After a heavy crop a nutrient dilution occurred and vegetative growth is inhibited. Thus, a following growing season is required to regain a good nutrient balance for generating vegetative growth with sufficient buds responsive to environmental differentiation stimuli for the initiation of the next ON year.
The modern olive industry has been expanding at a steady pace during the past twenty years and relies almost entirely on the total mechanisation of grove management for competitiveness. Consequently, achieving high levels of efficiency is necessary for the profitability of the industry. A broader approach to harvesting efficiency considers it as a ratio between an amount of valuable resource produced (P) and an amount of valuable resources consumed
In this study, the annual protein alterations in bearing and non-bearing olive trees were investigated in the leaves of Ayvalik, Domat, Gemlik and Memecik varieties that display different bearing levels. Quantitative protein analyses were performed on leaf samples of olive trees that are collected at fourteen periods between June 2000 and January 2002. Protein levels of the leaves varied considerably depending on the phenological period of the trees. Although the variation was different for each olive variety, it was established to be between 39.2 mg/ml at maximum and 0.5 mg/ml at minimum. The leaf protein level of all varieties of bearing trees reached a maximum at the full blooming and early fruit development and was at a minimum during the morphological differentiation period. The highest protein level difference between the bearing and non-bearing trees belonged to the Memecik variety, which has the highest bearing alteration. In reverse, this difference was lowest for the Domat variety. This study showed a close correlation between the level of fruit yield on the trees and the quantity of leaf protein. We believe that this correlation can be used to estimate the yield in advance by evaluating the level of the leaf protein in June.
Branch bending has been practiced for decades as an effective means of inducing floral buds in ‘Fuji’ apple in China. Endogenous hormones play an important role in apple flowering. The main purpose of this study is to investigate the hormone concentrations (ABA, ZR, IAA and GA) in spurs, medium and long shoot terminals of ‘Fuji’ and ‘Gala’ apple trees subjected to bending of different angles (70°, 90° or 110°). In both cultivars, the proportion of floral buds and spurs increased, but that of medium and long shoots decreased with increasing bending angles. The ABA and ZR concentrations in shoot terminals increased, but the IAA and GA concentrations decreased as the bending angles increased from 70° to 110°. The ZR concentration increased monotonically in spurs apexes, but in medium and long shoot terminals it increased from a minimum on May 10 to a maximum on June 20 for ‘Fuji’ apple trees or on July 20 for ‘Gala’ apple trees, and then decreased thereafter. It was also observed that the ‘Gala’ apple trees had a higher ABA concentration but a lower IAA concentration in shoot terminals than the ‘Fuji’ apple trees. The ZR concentration in spurs apexes of ‘Gala’ apple trees was higher before July 1, and the GA concentration was higher before June 20, but lower after July 20 than the ‘Fuji’. The (IAA + GA + ZR)/ABA ratio of spurs apexes in ‘Fuji’ apple trees decreased with increasing bending angles during the whole growth season, with a significant difference between those bent at 110° and those bent at 70°. There was no significant difference for the ‘Gala’ apple trees. The (IAA + GA + ZR)/ABA ratio peaked on June 20, and it was higher in ‘Fuji’ than in ‘Gala’ apple trees throughout the study period.
Plants can avoid freezing damage by preventing extracellular ice formation below the equilibrium freezing temperature (supercooling). We used Olea europaea cultivars to assess which traits contribute to avoid ice nucleation at subzero temperatures. Seasonal leaf water relations, non-structural carbohydrates, nitrogen and tissue damage and ice nucleation temperatures in different plant parts were determined in five cultivars growing in the patagonian cold desert. Ice seeding in roots occurred at higher temperatures than in stems and leaves. Leaves of cold acclimated cultivars supercooled down to -13 °C, substantially lower than the minimum air temperatures observed in the study site. During winter, leaf ice nucleation and leaf freezing damage (LT50 ) occurred at similar temperatures, typical of plant tissues that supercool. Higher leaf density and cell wall rigidity were observed during winter, consistent with a substantial acclimation to sub-zero temperatures. Larger supercooling capacity and lower LT50 were observed in cold-acclimated cultivars with higher osmotically active solute content, higher tissue elastic adjustments and lower apoplastic water. Irreversible leaf damage was only observed in laboratory experiments at very low temperatures, but not in the field. A comparative analysis of closely related plants avoids phylogenetic independence bias in a comparative study of adaptations to survive low temperatures.
This article is protected by copyright. All rights reserved.
The effect of gibberellic acid (GA3) spraying on the contents of lignin and auxin, and the activities of correlated enzymes during flower-bud induction was determined in 13-year-old bayberry trees (Myrica rubra Bieb.) in the year of low crop. The results show that the activity of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) in the leaves of the control trees reached the maximum in turns during the period of flower-bud induction, catalyzing the biosynthesis of lignin which was depleted during flower-bud initiation. GA3 spraying during flower-bud induction significantly inhibited the activities of PAL, PPO, POD and IAA-oxidase (IAAo), and increased the level of indole-3-acetic acid (IAA), delaying the biosynthesis of lignin in leaves of the current shoots, as well as inducing the more vigorous growth and inhibiting flower-bud initiation and formation.
Established tissue-culture propagated own-rooted cultivar ‘Golden Delicious’ apple (Malus domestica Borkh.) trees were treated with paclobutrazol at a dosage of 40 mg cm−2 of trunk cross-sectional area (average of 1.48 g per tree) via trunk drench at the end of the fifth growing season. They responded the second season after application. Treatment with the triazole GA biosynthesis inhibitor had more effect on vegetative growth than on flower cluster or fruit number. It reduced terminal shoot length and tended to reduce fruit yield and seasonal net photosynthesis on a leaf area basis. Weight per fruit was not changed but fruit length tended to be slightly reduced whereas russeting index was increased. Promalin (GA4 + 7 + BA) applications to paclobutrazol-treated trees did not alter growth or fruiting. Despite the fact that paclobutrazol inhibited terminal shoot growth, treated trees went into biennial bearing as readily as untreated trees after a heavy fruit load season. Vegetative growth was vigorous the “off year” and terminal shoot growth was no longer inhibited by paclobutrazol. Applications of GA4 + 7 to trees during the “off-year” did not affect vegetative growth that season or fruiting the following season. “On year” yield tended to be reduced from trees that had been treated with paclobutrazol 5 years earlier.
The nutrient element fluctuations of olive tree flowers (Olea europaea L. cv ‘Konservolia') during their development were studied, since this period is a crucial one for the productivity of the tree. The profiles of number and kind of flowers along inflorescence were also recorded at the yellowish petal stage (one week before full bloom) in relation to the nutritional element status of the organ. Inflorescence development in ‘Konservolia’ lasted about eight weeks until full bloom. Changes in DW/FW ratio verified the intense hydration of the organ two weeks before full bloom and the considerable desiccation in parallel to floral organ shedding a week after. The strong positive linear regression among DW‐water soluble proteins, macro‐ and micronutrients during inflorescence development confirmed the role of the organ as a strong sink for these materials. Fluctuations in iron (Fe) and copper (Cu) concentrations and accumulations revealed increased demands for these elements after full bloom, while the observed deep decrease in zinc (Zn) concentration during this period may suggest significant losses by the abscised floral organs. The distributions of nutrient elements along inflorescence axis suggested a polarization among the flowers in lower and upper inflorescence positions. This polarization may be related to the observed distributions of the perfect and staminate flowers along axis. Analysis of the nutritional status of the flowers of the inflorescence base seems to approach satisfactory the overall nutritional status of the inflorescence at the yellowish closed petal stage.
Annual variations in the ambient concentrations of Betula pollen monitored by volumetric sampling at sites in London and also at a site to the South of the city between the years 1961–1990 are analysed in relation to the main meteorological parameters. Attention is focussed on variations in the start and duration of the seasons and on the annual patterns of pollen abundance. Consideration is given also to the variation in the severity of seasons. The paper examines possible rhythms in the annual production of Betula pollen and develops empirical regression models from the analyses of the trends to predict the main characteristics of the seasons.
ResearchGate has not been able to resolve any references for this publication.