Abstract: Mn deficiency is a common nutritional disorder affecting the growth, yield and fruit quality of citrus plants. Twenty-three-year-old 'Washington Navel' orange (Citrus sinensis L.) trees budded onto sour orange (C. aurantium L.) rootstock and grown in two sites (I and II) of an orchard were used. Based on the leaf Mn concentrations, 20 Mn deficient and 10 non Mn deficient trees were selected on 26 January 2000. The trees were separated in 6 groups; each one consisted of 5 trees with similar Mn status. The mean Mn concentrations in the leaves of the groups 1, 2, 3, 4, 5, and 6 were 8.8, 10.5, 11.2, 13.8, 18.3, and 19.8 mg kg(-1) dry weight (d.w.), respectively. The trees of the groups 1-4 were grown in the site I, while those of the groups 5 and 6 in the site II of the orchard. One tree group in each orchard site (site I: group 3; site II: group 6) was not sprayed with Mn and used as a control, while the trees of the other groups (1, 2, 4 and 5) were sprayed on 06 February 2000 with MnSO4-H2O (800 mg 1(-1) Mn). From 18 February 2000 until 19 January 2001, 11 leaf samplings were conducted to monitor the Mn status of the trees. The concentrations of Mn in the leaves of the groups 3 and 6 (controls) were almost constant and presented no significant differences among the samplings. With regard to the Mn treated trees, at the first post-treatment sampling (18 February 2000), the leaf Mn levels were higher by 16.5-25.1 mg kg(-1) d.w., respectively, in relation to their pre-treatment status. At the last sampling (19 January 2001), the Mn status of the trees was also improved by 4.5-7.5 mg kg(-1) (d.w.), compared to their pre-treatment status. Overall, when the concentration of Mn in the leaves is equal or higher than 14 mg kg(-1) d.w., before the spray Mn treatment, only one application of MnSO4-H2O (800 Mg 1(-1) Mn) on February is sufficient to cover the Mn needs of the trees for a whole year. In other cases (leaf Mn levels equal or lower than 13 mg kg(-1) d.w.), the trees should be re-sprayed on July or August.
Abstract: The effect of salinity on the non-enzymic and enzymic antioxidant activity, shoot proliferation and nutrient accumulation was studied in in vitro cultures of the rootstock CAB-6P (Prunus cerasus L.). Three concentrations (0, 30 and 60 mM) of NaCl or CaCl2 were added to a modified MS medium. Between the two salt treatments used, only the explants treated with CaCl2 presented significant decrease in growth parameters. The concentrations of Na+ and Cl- in the explants treated with NaCl were increased, as NaCl in the culture medium increased. Furthermore, in the explants treated with CaCl2 the concentrations of Ca2+ and Cl- were increased while that of K+ decreased, as CaCl2 concentration increased. The activity of peroxidase in leaves as well as the number of its anionic isoforms was increased under 30 mM CaCl2 as well as 60 mM NaCl or CaCl2. On the contrary, increasing salinity, from 0 to 60 mM CaCl2, resulted in a reduction of the catalase activity in leaves followed by disappearance of the only one catalase isoform that was detected in leaves (60 mM CaCl2). In the stems of the explants treated with NaCl the peroxidase activity was reduced. In the stems and leaves of the explants grown in saline substrate the non-enzymic antioxidant activity was significantly increased. The results suggest that the stems and leaves of CAB-6P explants presented variable antioxidant responses that were depended on the salt form used. The contribution of enzymic and non-enzymic protection mechanisms to the adaptation of CAB-6P explants under salinity stress is discussed.
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.
Abstract: Gardenia (Gardenia jasminoides) plants were grown in black plastic bags containing perlite and sand (1:1). The plants were irrigated with 16 modified half strength Hoagland No2 nutrient solutions containing four Fe concentrations (0, 0.5, 1 and 2 mg L-1) in the form of Fe-EDDHA (Fe 6g 100g-1) in combination with four P concentrations (0, 31, 62 and 124 mg L-1).
Increasing P and Fe concentrations in the nutrient solution significantly increased leaf P and K concentrations. However, leaf Ca concentration was slightly decreased by increasing P concentration in the nutrient solution. No significant effects of P and Fe concentration were found concerning leaf Mg and Mn concentrations. Furthermore, the leaf Zn concentrations in plants treated with 0, 31 and 62 mg L-1 P and 0 mg L-1 Fe were significantly increased. By increasing Fe concentration in the treatments containing 62 and 124 mg L-1 P, leaf Fe concentration was increased.
In gardenia roots, the increase of P and Fe concentration in the nutrient solution led to a general increase of root P concentration. Concerning Ca, it was significantly increased in the roots, when P concentration in the nutrient solution increased. There were no significant effects of P and Fe concentration of solution in Mg concentration of roots. Manganese and Zn concentration in roots was only increased in plants treated with 124 mg L-1 P plus 0 or 0.5 mg L-1 Fe. Finally, not significant differences were recorded in root Fe concentration among the studied treatments. In conclusion, the combined PxFe fertilization in gardenia may solve also other nutritional problems like K, Ca and Zn deficiencies.
Abstract: Two experiments were conducted in Northern Greece during 2004-2005 with the clingstone peach cv. Andross. From our results, it was concluded that fruit firmness and fruit Ca were increased, while K/Ca and K/Ca+Mg ratios decreased, after soil incorporation of ammonium nitrosulfate plus ammonium nitrate followed by foliar sprays with 0-12-14. Fruit Ca was increased and the K/Ca and (K+Mg)/Ca ratios decreased by gypsum and foliar CaCl2.2H(2)O or Ca-chelate treatments, when ammonium nitrosulfate plus ammonium nitrate were applied. When calcium nitrate was applied, fruit Ca was significantly increased by CaCl2.2H(2)O in comparison to gypsum application, while fruit K/Ca and K+Mg/Ca ratios significantly were decreased by CaCl2.2H(2)O as with 0-12-14 foliar sprays in comparison to control treatments. Also, fruit Ca was higher and the K/Ca and the K+Mg/Ca ratios were lower. when calcium nitrate was added instead of ammonium nitrosulfate plus ammonium nitrate (control treatments - I). For overall values, fruit firmness was significantly and positively correlated with fruit Ca concentration (r=0.436*) and negatively with K/Ca and (K+Mg)/Ca ratios in fruits (r=-0,421* and r=-0,389*, respectively).
Abstract: The objective of this research was to study the effect of the chelated form of the iron salt of ethylenediamine di-o-hydroxyphenylacetic acid (Fe-EDDHA) (6% Fe) on in vitro rooting of the rootstock GF-677. The iron salt of ethylenediamine tetraacetic acid (Fe-EDTA) (12% Fe) of the MS basic medium was replaced by Fe- EDDHA, which was applied in three concentrations: 93.5, 187.0 and 280 mg l(-1) (5.6, 11.2 and 16.8 mg l(-1) Fe, respectively). For each treatment of Fe- EDDHA, the effect of ascorbic acid added in four concentrations ( 0, 0.1, 1.0 and 10 mg l(-1)) was studied. After 4 weeks of culture, the explants growing on the medium with 280 mg l(-1) Fe- EDDHA gave the best rooting results. Regarding ascorbic acid, no clear stimulating effect on rooting was found.
Abstract: black plastic bags containing a sand/perlite ( 1: 1) mixture. The plants were irrigated with Hoagland No2 nutrient solution modified to contain three Fe concentrations (0.5, 1 and 2 mg l(-1)) in the form of Fe-EDDHA and four concentrations of NaCl ( 0, 10, 20 and 40 mM). After three months, severe toxicity symptoms were observed on the older leaves ( chlorosis of tips and margins) mainly of the plants treated with 40 mM NaCl. Salinity had little effect on leaf P, whereas P concentration of roots increased in the treatments containing 20 or 40 mM NaCl plus 0.5 mg l(-1) Fe. Generally, K and Ca concentrations of leaves and roots were not affected by the increase of NaCl concentration in the nutrient solution. In the roots, the lowest Mg concentration was observed in the treatments containing 2 mg l(-1) Fe, whereas in the leaves, no significant differences were recorded. Regarding Mn concentration, it was not affected in the leaves but it increased in the roots of the treatments containing 20 and 40 mM NaCl plus 0.5 mg l(-1) Fe. Finally, Fe concentration was increased in the roots of the plants treated with 0.5 mg l(-1) Fe plus 20 or 40 mM NaCl. Concerning Na concentration, generally, it was increased in the leaves and decreased in the roots of the treatments containing high NaCl plus low or medium Fe concentration.
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 scion's 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.
Abstract: In the present paper, the nutrient concentration of plant organs, when different Fe sources were used in gardenia (Gardenia jasminoides Ellis) plants grown in a hydroponic medium containing 1 mg l–1 Fe, was studied. Three Fe sources were applied, namely sequestrene-138 (6% Fe, Fe-EDDHA), sequestrene-330 (10%Fe, Fe-DTPA) and FeSO4·7H2O. The analytical data indicated that Fe and Zn concentrations in shoots were very low and were independent of the Fe source applied. Furthermore, K concentration of shoots was higher than K concentration of roots. It appears that in roots, the concentrations of Fe and Zn were very high. In roots, the lowest Fe concentration was found in the sequestrene-138-treated plants, whereas the highest one in the plants treated with FeSO4·7H2O.
Abstract: The aim of this research was to study the effect of high boron (B) irrigation water on the appearance of B toxicity symptoms and on the seasonal variation of nutrients in leaves and fruits of two table cultivars of olive (Olea europaea L.).The cultivars ´Chondrolia Chalkidikis` and ´Amfissis` located in the same orchard and irrigated with water having an average B concentration of 3.6 mg l-1 were studied. Leaf samples from the current and the previous year nonbearing shoots were collected at 15 or 30 d intervals for a period of 15 months (24 months for B samples). All the leaf and fruit samples were analysed for N, P, K, Ca, Mg, B, Fe, Mn, and Zn. Inflorescence samples were collected at full bloom, while fruit samples were collected 30, 60, 90 and 120 d after full bloom. Also, samples of irrigation water and soil were collected during the experiment and analysed.The results indicated that olive is a species relatively tolerant to excess soil B and no visual symptoms of B toxicity were observed on leaves. Furthermore, B concentration of leaves was at an adequate level, or slightly above it. The two cultivars followed a similar pattern of the fluctuation of B concentration during summer. The maximum B concentration in leaves was 175 mg kg-1 dry matter in ´Chondrolia Chalkidikis` leaves and about 70 mg kg-1 dry matter in ´Amfissis` leaves. The nutritional status of trees for K, Ca, Mg and Fe was found to be sufficient, while Mn was deficient. Nitrogen and P were at the sufficiency level in ´Chondrolia Chalkidikis`, but at the marginal level in ´Amfissis`. Generally, B concentration of flowers was higher than that in the leaves, for the same sampling time. ´Chondrolia Chalkidikis` presented significantly higher B concentration in fruit than ´Amfissis`, during the harvesting period.
