S.N. Vemmos

Response of Two Olive Cultivars to Salt Stress and Potassium Supplement

ABSTRACT The effects of saline water containing 0, 50, 100, and 150 mM sodium chloride (NaCl), and 100 mM NaCl + 100 mM potassium (K) on photosynthesis, water relations, and ion and carbohydrate content of olive (Olea europaea L.) cultivars ‘Koroneiki’ and ‘Mastoidis’ were studied on five-year-old trees. Salinity increased sodium (Na+) and chloride (Cl−) in tissues of both cultivars, but more so in ‘Koroneiki’ than in ‘Mastoidis.’ Salt-toxicity symptoms were observed at 100 and 150 mM, but not in plants receiving extra K. In salt-stressed plants, leaf water potential declined, whereas turgor potential remained positive due to a rapid decrease in osmotic potential. Salinity increased mannitol content up to 41.3% in ‘Mastoidis’ and 15.8% in ‘Koroneiki’, but reduced starch content in leaves. Photosynthetic rates fell significantly with increasing salinity in both cultivars, but more so in ‘Koroneiki’ than in ‘Mastoidis’. Potassium supplements reduced the concentration of Na+ and increased the concentrations of K+ in leaves, but decreased photosynthesis.

Net photosynthesis, stomatal conductance, chlorophyll content and specific leaf weight of pistachio trees (cv. Aegenes) as influenced by fruiting

SUMMARYNet photosynthesis (Pn), stomatal conductance (gs) and chlorophyll content (chl) were measured on fruiting and nonfruiting pistachio trees (Pistacia vera cv. Aegenes) in 1991 and 1992. Specific leaf weight (SLW) was also measured in 1992. Measurements were taken at frequent intervals from May to September in 1991 and from April to August in 1992. Pn, gs and chl in fruiting trees were greater than in nonfruiting ones from the begin-ing of measurement until mid-June in both years. From mid-June onwards, Pn and gs started to decrease slightly but were approximately the same in fruiting and nonfruiting trees. Chlorophyll (a/b) was similar for fruiting and nonfruiting trees throughout the period of measurement. Although no significant differences were found in SLW between leaves of fruiting and nonfruiting trees, SLW was higher in fruiting than nonfruiting trees until the end of May, after which this relationship was reversed. The results showed that fruiting affected chl, gs and Pn rates from early in ...

Mineral composition of leaves and flower buds in fruiting and non‐fruiting pistachio trees

Abstract The effect of fruiting on mineral composition of leaves and flower buds in pistachio (Pistachia vera L., cv. Aegenes) was studied in two experimental years (1990 and 1992). Nutrient concentrations were measured in leaves and flower buds on fruiting and non‐fruiting pistachio trees at two week intervals from leaf emergence until the flower bud abscission of fruiting trees was completed. The results showed that the presence of fruit significantly increased the leaf concentrations of magnesium (Mg), calcium (Ca), manganese (Mn), and zinc (Zn) throughout the whole period of measurement and that of nitrogen (N) only until the commencement of seed growth (in June). In contrast, fruit decreased leaf concentrations of potassium (K) (throughout the whole period) and that of N (after the commencement of seed growth and high rates of bud abscission). Phosphorus (P) and iron (Fe) concentrations in leaves were not influenced by fruit. The results for flower buds were similar to those for leaves for the nutrie...

Carbohydrate content of inflorescent buds of defruited and fruiting pistachio (Pistacia vera L) branches in relation to biennial bearing

SummaryChanges in carbohydrate content of inflorescent buds of fruiting and defruited branches of the same tree were measured in 1994 and 1995 in the period before and during bud abscission in pistachio (Pistacia vera L. cv. Aegenes) to investigate its relationship to inflorescent bud abscission. HPLC was used for soluble sugar analysis, while starch was hydrolyzed to glucose enzymatically and the amount of glucose was then determined using the glucose oxidaseperoxidase method. The effect of fruit on leaf net photosynthesis (Pn), chlorophyll a and b (Chl (a+b)) in leaves and specific leaf weight (SLW) was also investigated in 1995. Starch concentration was initially similar in buds of fruiting and defruited branches but became greater in buds of defruited branches from early June 1994 (57 d after full bloom (AFB)) and 20 June 1995 (61 dAFB), resulting in higher starch contents. Glucose and fructose concentrations were similar in flower buds throughout the whole period of measurement; inositol and sucrose ...

Effects of shoot girdling on bud abscission, carbohydrate and nutrient concentrations in pistachio (Pistacia vera L.)

Summary The effects of shoot girdling and fruit removal on bud abscission, and of shoot girdling on nutrient and carbohydrate concentrations in leaves, inflorescent buds and current wood of pistachio shoots were investigated. Girdling individual shoots at the base of the current year’s shoot (girdle I), thus separating inflorescent buds at the terminus of the current year’s shoot from the developing fruits, reduced inflorescent bud abscission by 62–66% compared to untreated controls. In contrast, girdling at the base of 1 year-old shoots (girdle II) or fruit removal treatments reduced bud abscission by 20% and 16%, respectively, in 1994; but had no effect on bud abscission in 1995. Girdle I significantly decreased N concentrations in leaves and Ca, Mg and Mn concentrations in all parts. In contrast, concentrations of P and K in inflorescent buds were significantly higher in girdled shoots. Girdle I increased the dry weight of inflorescent buds and non-structural carbohydrate concentrations in inflorescent buds and current year’s wood. Current wood and leaves on girdled shoots had higher starch accumulation, but leaves had lower fructose concentrations than control leaves. Inflorescent buds on girdled shoots had higher concentrations of starch and sugars, especially sucrose. The possibility that a reduction in sucrose movement from leaves to inflorescent buds inhibits bud growth and triggers inflorescent bud abscission is discussed.

Characterisation of genetic relationships in pansy (Viola wittrockiana) inbred lines using morphological traits and RAPD markers

Summary In this study, genetic relationships between eighteen inbred lines of pansy (Viola wittrockiana) were estimated on the basis of morphological characters and RAPD data. Thirty-one morphological characters were analysed with an unweighted pair-group method using an arithmetic average (UPGMA). For RAPD analysis, twenty-one 10-mer random primers were selected and 127 polymorphic bands, ranging from 0.2 kbp to 2.0 kbp, were obtained. UPGMA cluster analysis using Nei and Li’s distance coefficient, and parsimony analysis using Wagner method, were then performed. In addition, principal component analysis (PCA) was carried out based on the RAPD data. Inbred lines 1 and 14 were isolated in all analyses, and inbred lines 15, 16 and 17 formed a monophyletic group in the RAPD cluster analyses. Inbred lines 6 and 7, and inbred lines 10 and 11 also showed close relationships. However, incongruences existed between these cluster analyses, and the relationships between some inbred lines require further investigation. The results of cluster analyses indicated that flower colour patterns were not suitable for the classification of inbred lines of pansy.

Respiration rate and ethylene production in inflorescence buds of pistachio in relation to alternate bearing

Abstract Respiration rate and ethylene production were measured in inflorescence buds and the surrounding tissue on fruiting and non-fruiting trees of pistachio ( Pistacia vera cultivar ‘Aegenes’). The buds from fruiting trees had higher respiration rates than non-fruiting ones, before and during the abscission period. In contrast, the ethylene production in buds was not significantly different between fruiting and non-fruiting trees. The results indicate that in inflorescence buds, an increased respiration preceded their abscission, and that endogenous ethylene production is not related to bud abscission in pistachio.

Changes of Respiration Rate, Ethylene Evolution, and Abscisic Acid Content in Developing Inflorescence and Young Fruit of Olive (Olea europaea L. cv. Konservolia)

Abstract. Simultaneous measurements of respiration, ethylene production, and abscisic acid (ABA) concentrations, as well as the growth parameters length, fresh weight (FW), and dry weight (DW) of olive (Olea europaea L. cv. Konservolia) inflorescence were carried out at short intervals (3–7 days) during the period from bud burst until the 3rd week after full bloom (AFB), when young fruit reached 8 mm in length. The axis of inflorescence elongated remarkably during the 3rd week after bud burst (ABB), massive bract shedding occurred during the 4th week ABB, full bloom (FB) was observed 7 weeks ABB, and massive floral organ abscission 1 week AFB. The results showed a continuous increase in inflorescence FW and DW from bud burst until 4 days before FB. Respiration rate, ethylene production, and levels of ABA were relatively high during the first 3 weeks ABB. After this period, respiration and ethylene followed a similar pattern of changes, inversely to that of ABA concentration. An accumulation of inflorescence ABA 6 and 4 days before FB was associated with the minimum values of respiration and ethylene production on the same dates. The sharp decrease in the ABA concentration during FB and 3 days later was followed by a high rise in ethylene and an increase in respiration rate, which both rose further 1 week AFB. The results suggest a possible correlation of ABA with the early stage of floral abscission, whereas ethylene production seems to be correlated with the terminal separatory activity in olive inflorescence abscission processes.

Carbohydrate changes in flowers, leaves, shoots and spurs of ‘Cox’s Orange Pippin’ apple during flowering and fruit setting periods

SummaryChanges of carbohydrate concentrations in different parts of the flower and the surrounding tissues (leaves, spurs and shoots) were measured in apple (Malus pumila) in 1987 and 1988, during the periods of flowering and fruit setting, to investigate their importance for fruit setting. HPLC was used for soluble sugar and sorbitol analysis. Starch was hydrolysed to glucose enzymatically and glucose concentration was determined colorometrically to estimate starch concentrations. Soluble sugars plus sorbitol (the soluble pool) increased rapidly in all parts of the flower from bud burst until full bloom. In contrast, in the same period, starch concentrations decreased rapidly and reached about zero at full bloom in the storage organs (shoots and spurs), indicating starch conversion to sugars and their movement to the growing flowers. Sorbitol was the most abundant carbohydrate in all apple tissue measured, with the exception of sepals, in which glucose concentration was the highest from full bloom onward...

The Possible Role of Polyamines to the Recalcitrance of “Kalamata” Olive Leafy Cuttings to Root

The objective of this study was to investigate the role of endogenous polyamines (PAs) (the sum of free plus soluble conjugate plus insoluble bound) on rooting potential of leafy cuttings of an easy, that is,“Arbequina” and a difficult-to-root olive cultivar, that is, “Kalamata”. Subsamples of cuttings were taken for PAs analysis before planting in the mist system and during the early phases of rhizogenesis (EPR). “Arbequina” exhibited higher initial free and total PA content than “Kalamata”. Spermidine (Spd) was the predominant PA observed in both cultivars. A low content of free putrescine (Put) and Spd was found in both cultivars, whereas spermine (Spm) was occasionally detected. “Arbequina” as well as “Kalamata” exhibited the highest free Put and free Spd in summer and Put was the predominant PA among the free PAs. “Arbequina” exhibited the highest individual and total PAs in spring, followed by those in summer and autumn. In contrast, “Kalamata” had the maximum PAs in summer and the lowest in autumn. Changes in the endogenous content of individual and total PAs during the EPR were also observed. Treatment of “Kalamata” cuttings in autumn with both indole-3-butyric acid (IBA) and Put increased rooting compared to IBA alone. Among the PAs administered, Put was the most effective, whereas Spd and Spm failed to promote rooting. PAs, especially in their free form, seem to be involved in the rooting process of olive cuttings; Put application enhanced the rooting response of the difficult-to-root “Kalamata” olive cultivar.