Christos Chatzissavvidis

Seasonal Variation of Nutritional Status of Olive Plants as Affected by Boron Concentration in Nutrient Solution

Abstract Ten-year-old olive plants, (Olea europaea L.) cv. ‘Chondrolia Chalkidikis,’ were cultured under ambient conditions in 50 L plastic pots containing inert sand-perlite medium and irrigated for a period of 18 months with 50% Hoaglands nutrient solutions containing 0, 0.5, and 5.0 mg boron (B) L−1. The highest B concentration in the leaves was observed during the period May–June, and declined afterwards. Potassium (K) concentration in the leaves was the lowest in winter, but reached the maximum during the period June–July. Conversely, calcium (Ca) and magnesium (Mg) concentrations increased during the period June–March of the following year. No differences in phosphorus (P), iron (Fe) and zinc (Zn) concentrations were recorded between the treatments. However, P concentration fluctuated from 0.1% to 0.3% D.M. (dry matter) during the year, showing many minima and maxima. Iron and manganese (Mn) concentrations increased gradually from January of the first year to January of the second year and declined afterwards. The highest Fe concentration was about 200 mg kg−1 (D.M.) while leaf Mn varied between 10–50 mg kg−1 (D.M.). Leaf nitrogen (N) concentration was more or less constant during the experiment. The −B and the +5.0 mg B L−1 treatments reduced significantly the percentage of perfect flowers and affected B concentration of inflorescences, as it was 3–4 times greater with 5.0 mg B L−1 in comparison with the control.

Effects of High Boron Concentration and Scion-Rootstock Combination on Growth and Nutritional Status of Olive Plants

ABSTRACT Own rooted olive plants (Olea europaea L.) of the cvs. ‘Megaritiki’ (M), ‘Chondrolia Chalkidikis’ (C), ‘Amfissis’ (A), ‘Kalamon’, ‘Koroneiki’, ‘Agiou Orous’, and wild olives, as well as the scion x rootstock combinations CxC, MxC, MxM, AxM, CxM, AxA, and CxA were irrigated with a nutrient solution containing 10 mg boron (B)/L for two months. In all the own rooted plants and in the rootstock—scion combinations of the same cultivar stem growth rate was decreased due to high B. The lowest B concentration in leaves and roots was found in ‘Kalamon’ and wild olives, respectively. ‘Megaritiki’ had higher leaf B concentration when grafted on ‘Megaritiki’ or ‘Chondrolia Chalkidikis’ compared to own rooted plants. The same cultivar as own rooted plant had higher root B concentration than as rootstock of the other tested cultivars.

Growth, mineral composition, leaf chlorophyll and water relationships of two cherry varieties under NaCl-induced salinity stress

Abstract Growth, mineral nutrition, leaf chlorophyll and water relationships were studied in cherry plants (cv. ‘Bigarreau Burlat’[BB] and ‘Tragana Edessis’[TE]) grafted on ‘Mazzard’ rootstock and grown in modified Hoagland solutions containing 0, 25 or 50 mmol L−1 NaCl, over a period of 55 days. Elongation of the main shoot of the plants treated with 25 or 50 mmol L−1 NaCl was significantly reduced by approximately 29–36%, irrespective of the cultivar. However, both NaCl treatments caused a greater reduction in the dry weight of leaves and scions stems in BB than in TE plants. Therefore, BB was more sensitive to salinity stress than TE. The reduction of leaf chlorophyll concentration was significant only when BB and TE plants were grown under 50 mmol L−1 NaCl. Osmotic adjustment permitted the maintenance of leaf turgor in TE plants and induced an increase in leaf turgor of BB plants treated with 25 or 50 mmol L−1 NaCl compared with 0 mmol L−1 NaCl. Concerning the nutrient composition of various plant parts, Na concentrations in all plant parts of both cultivars were generally much lower than those of Cl. For both cultivars, leaf Cl concentrations were much higher than the concentrations in stems and roots, especially in the treatments containing NaCl. Finally, the distribution of Na within BB and TE plants treated with NaCl was relatively uniform.

Interactions between leaf macronutrients, micronutrients and soil properties in pistachio (Pistacia vera L.) orchards

Abstract - The interactions between: (i) leaf dry matter macronutrietns, micronutrients and soil chemical properties, (ii) leaf macro- and micronutrients, (iii) soil macro- and micronutrients and (iv) soil chemical properties, and soil micro- and macronutrients in 50 pistachio orchards were investigated in leaves and soils by means of regression analysis. Most of the soils were deficient in plant-available P, Zn, Mn, Fe, and B, while they were excessively supplied with Cu. Leaf analysis showed that most of the trees were sufficient in K, Mg, Mn and B, but deficient in N, P and Fe, and excessive in Zn and Cu. It was found that almost all the significant elemental interactions occurring in pistachio leaves or soils were synergistic, contributing considerable quantities of available nutrients and, therefore, improving the nutrient status of pistachio trees, and the level of soil fertility. On the other hand, the interactions between K and Mg in leaves, and between soil pH and leaf N or soil Fe, Mn and B, were antagonistic. It is suggested that these results must be taken into account during fertilization of pistachio trees, in order to avoid nutritional disorders and to promote plant growth, productivity and nut quality.

Effect of nitrogen source on olives growing in soils with high boron content

A greenhouse experiment was conducted to study the effects of nitrogen (N) forms (NO3–, 2.6 mmol/L; NH4+, 2.6 mmol/L; NO3–, 1.0 mmol/L plus NH4+, 1.6 mmol/L) and boron (B) (0.025, 0.5 and 1.0 mmol/L) on the growth and mineral composition of olive plants (Olea europaea L.). One-year-old own-rooted plants of the olive cultivars Megaritiki, Chondrolia Chalkidikis, Koroneiki and Kalamon were grown in plastic bags containing inert sand–perlite medium (1 : 1) and were irrigated with a 50% modified Hoagland nutrient solution. The plants treated with NO3– and 1.0 mmol B/L presented higher leaf B than those treated with NH4+ and 1.0 mmol B/L, for all cultivars. The addition of ammonium form fertilisation caused a significant accumulation of B to root tissues when the latter consisted of 0.5 mmol/L. As B was increased in the NO3–-N treatments, the number of leaves and the root dry weight of cv. Megaritiki as well as the plant height of cvv. Koroneiki and Kalamon were reduced. The above results suggest that in olive, addition of NH4+ to high B soils may be more beneficial for growth of olives than addition of NO3–. In most cases N form did not affect total leaf and root N levels. Also, the NH4+-N treatments showed a decline in root phosphorus (P) and an increase in leaf potassium with increased B. The general trend was a decrease of P in leaves with increasing B.

How apple responds to boron excess in acidic and limed soil

Abstract Two year-old apple plants ( Malus domestica cv. Red Chief Delicious) were grown in an acidic and limed soil, and fertilized with B (0, 1, 3 and 5 mg kg -1 soil). Fresh matter weight of plants was positively correlated with the applied B only in acidic soil. The number of nods, plant height, stem diameter, and shoot length were not particularly affected by either B additions or liming. The length of internodes of the plants grown in limed soil showed a positive correlation with the amount of added B, but the opposite effects were observed in the acidic soil. Boron and K concentration in leaves showed a positive correlation with added B in both soils. Leaf N and Fe concentrations were negatively affected by B additions in soils, while leaf Mn and Zn concentrations were also affected by added B and soil pH, reflecting thus their soil mobility. Chlorophyll content in leaves was reduced at high B treatments, only in plants grown in the acidic soil. Our results show that added B even in our high B-content acidic soil did not cause any detrimental effects on apple plants, and that liming seemed to buffer trace metal excesses, characteristic of any acidic soil.

Effect of calcium on the ion status and growth performance of a citrus rootstock grown under NaCl stress

Abstract Two-year-old own-rooted sour orange (Citrus aurantium L.) plants grown in a greenhouse were irrigated for 15 weeks with Hoagland nutrient solutions containing either NaCl (0, 20, 40, 60, 80 or 100 mmol L−1) or a combination of salts NaCl + CaCl2·2H2O (10 + 10 mmol L−1, 20 + 20 mmol L−1, 30 + 30 mmol L−1, 40 + 40 mmol L−1 and 50 + 50 mmol L−1). The effect of the combined treatments on vegetative growth (fresh matter) was similar to the effect of NaCl. Salinity did not affect the leaf water potential, but did significantly increase the water content of the leaves and the shoot : root ratio (fresh matter). Furthermore, the N concentration of the leaves and the Mg concentration of the new stems were reduced, whereas the K concentrations of the leaves increased. Salinity led to a general increase in Na and Cl concentrations in all plant parts. Chloride concentrations were significantly greater than the corresponding Na values in all tissues. Little or no effect of salinity was recorded with regard to the P, Fe, Mn and Zn concentrations. The addition of Ca to the nutrient solution in the form of CaCl2·2H2O decreased the Na and Cl concentrations in the leaves. Thus, the application of CaCl2·2H2O might mitigate the accumulation of these toxic ions caused by NaCl.

Boron toxicity effects on grafted and non-grafted pepper (Capsicum annuum) plants

Grafting is a vegetative plant propagation technique. In a grafted plant, the upward supply of water and mineral nutrients as well as the downward flow of photosynthesis are modified. In this context, the objectives of this work were to find out whether the grafting of pepper plants (Capsicum annuum L. family Solanaceae) reduces leaf boron concentration of some commercial cultivars under boron toxicity and to examine the effects of grafting and scion-cultivars on the levels of phenols, flavonoids and antioxidant capacity. Ungrafted plants of the cultivars Century, Twingo, Imperial and Arlequin, as well as grafted Twingo, Imperial and Arlequin plants as scions, and Century as rootstock were used. The plants were treated with 5 mg L-1 boron for 7, 14, 21 and 28 days. After 21 and 28 days of treatment, grafting significantly reduced the boron concentration in the leaves of the scion-cultivars while it was increased by 80% in the non-grafted plants. After 21 days of boron treatment, it was found that grafting reduced the concentration of leaf phenol to 60-70% in ungrafted Century plants. In Century x Twingo there was a 33% increase in the flavonoid concentration of leaves after 7 days grafting; while in the Century x Imperial and Century x Arlequin combinations this was decreased by 75-92% compared to non-grafted Century plants. The antioxidant capacity of leaves after 21 days treatment increased in all rootstockscion combinations by 28% as measured by the FRAP and DPPH methods. In conclusion, grafting reduced boron concentration in the leaves of the tested scion-cultivars, as well as having an effect on the phenol and flavonoid concentrations and antioxidant capacity of the leaves.

Responses of trifoliate orange (Poncirus trifoliata (L.) Raf.) to continuously and gradually increasing NaCl concentration

Abstract The effect of continuous or gradual stress due to NaCl on in vitro growth, proline and sugar accumulation and nutrient acquisition of trifoliate orange (Poncirus trifoliata (L.) Raf.) explants was studied. Apical shoot tips obtained from previous subculture were transferred to a Murashige and Skoog nutrient medium for proliferation and were exposed to continuous or gradual salinity stress for 42 days. The salt used to induce salinity was NaCl added in six concentrations: 0, 50, 100, 150, 200 and 300 mM. Gradual salinization was achieved by transferring the explants sequentially every week to the above mentioned NaCl concentrations. Most salt treatments had a negative effect on the growth parameters of explants. Sodium concentration of explants increased in all NaCl treatments compared to control and it was higher in the treatments with gradual exposure to salinity. Potassium concentration was reduced, mostly in the treatments with continuous exposure. Calcium andMg concentrations increased in all saline treatments. In general, the high salinity level in the substrate enhanced the proline and sugar concentrations of the studied explants. In conclusion, salinity had significant impacts on the growth and chemical status of P. trifoliata.

Response of pomegranate cv. wonderful plants tο salinity

Three salts (NaCl; KCl; Na2SO4) were supplied to pomegranate cv. Wonderful plants, in order to investigate their effects on growth, nutrient status, chlorophyll, total carbohydrate content and antioxidant defense system. In general, high salt supply led to a significant decline in total N and K content of plants. Also, all salt treatments decreased Ca and Mg concentration of leaves. Both NaCl and KCl treatments increased leaf Cl concentration by up to 418%. Salt excess resulted in a significant decline of chlorophyll and carbohydrate concentration of leaves and/or roots. Finally, concerning antioxidants, diamine oxidase activity increased in the treatment of 120 mM Na2SO4. In conclusion, salinity impaired mineral nutrition of pomegranate cv. Wonderful. On the other hand, that cultivar presented mechanisms that alleviated the detrimental effects of salinity. Therefore, the studied plants, even under high saline treatments, managed to maintain water content, chlorophyll fluorescence and enzyme activity in normal levels. These results suggest that ,Wonderful, may be cultivated under saline conditions provided that a suitable fertilization program is used.