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  • The effect of different cytokinins on chlorophyll content and morphological features of in vitro Nidularium ’Kertész Jubileum’
    47-51.
    Views:
    224

    During in vitro multiplication of Nidularium ‘Kertész Jubileum’, 20 g/l sucrose, 5 g/l agar, 100 mg/l inositol, and different concentrations of benzyladenine (BA), benzyladenine-riboside (BAR), kinetin (KIN), meta-topolin (mT) were added to the MKC (Knudson, 1946) basal medium. Furthermore, 0.1 mg/l naphthaleneacetic acid was used to every medium. Number of shoots, length of leaves, number and length of roots, chlorophyll (a+b) content were examined and evaluated with Ropstat statistical software. As compared to the other cytokinin, significantly most shoots were obtained in the case of applying BA. Increasing of BA-concentration (as far as 2 mg/l) enhanced shoot number (from 10.92 to 19.26) but 4 mg/l BA resulted only 6.63 shoot. The less efficient cytokinin was KIN, in most cases no more than about 2 shoot was achieved. Regarding the length of leaves, the higher level of BA effected averagely the shorter leaves (from 24,46 to 7.31 mm). KIN effected significantly the longest leaves (43.4-61.29) in inverse proportion to the concentration. The same cytokinin resulted the most (and the longest) roots with the highest rooting percentages, but more KIN decreased the number and length of roots (from 7.95 to 4.4 and from 38.49 to 22.73 mm). There were no definite correlation between cytokinin concentration and chlorophyll (a+b) content, but the highest doses resulted decreasing (except of meta-topolin which leads to the lowest values). Summarizing, BAR effected the highest contents (mostly more than 1400 μg/g), particularly in the case of 1 mg/l (1807.3 μg/g).

  • The role of rejuvenated and adult forms of English oak (Quercus robur) in in vitro cultures
    81-83.
    Views:
    140

    In vitro plant material of clones (Q. robur) NL 100 A (adult) and NL 100 R (rejuvenated) received from Germany (A. Meier-Dinkel, 1995) were used in these experiments. WPM medium was used for the multiplication phase. Plantlets were subcultured monthly. Differences in quality and colour of the adult and rejuvenated cultures induced us to follow and compare the changes of mineral- and chlorophyll content and dry weight during the propagation phase. Mineral and chlorophyll content as well as dry weight were measured weekly on three samples during the subculture period.

    In the case of propagation rates we stated, they were similar around the year, but both clones had a high peak in April. Examining the cation-content, we detected that, the plantlets had a highest quantity of several elements during the 2nd and 3rd week of subculture. The iron content was the highest in the 1st week and after that it decreased continuously. It is supposed, that the content of iron is not enough in the media. The chlorophyll content of the rejuvenated clone was higher than that of the adult one.

    In the rooting experiments it was stated that, after one-week cold treatment the rooting ability was the best.

     

  • The effects of growth regulators in proliferation of Sorbus redliana 'Burokvölgy'
    77-83.
    Views:
    189

    The Hungarian cultivar Sorbus redliana 'Burokvölgy' was proliferated on Murashige and Skoog (MS, 1962) medium with half-strength macroelements and 100 mg/1 meso-inositol, 20 g/1 sucrose, 11 g/1 agar-agar. Different combinations of kinetin (KIN), metatopolin (mT), benzyladenine (BA), benzyladenine-ribosid (BAR) and indolebutiric acid (IBA) were tested, and pH was adjusted to 5.6 every case using KOH. The cultures were incubated at 20-24 °C in 8/16 hours dark/light photoperiod for 50-52 days. The main aim of our research was to find the optimal growth regulator and its optimum concentration. Purthermore, to determine the chlorophyll contents of the in vitro propagated plants' leaves. During the proliferation, the highest number of shoots were observed in the case of using BA + IBA, and on the medium containing 0.75 mg/I BA + 0.05 mg/1 IBA 8.93 shoots were found. The addition of KIN + IBA decreased the number of shoots and increased the sizes of leaves — the widest (11.2 mm) and longest (17.8 mm) leaves were obtained on the medium containing 1.00 mg/I KIN + 0.05 mg/1 IBA. The longest shoots (36.46 mm) were found in the case of applying 0.75 mg/1 BAR + 0.05 mg/I IBA. The BA + KIN + IBA combination resulted the shortest shoots. Sometimes not only shoot regeneration but spontaneous rooting was observed during the multiplication. The highest chlorophyll content (1.569 mg/g total chlorophyll, 1.132 mg/g chlorophyll-a, 0.437 mg/g chlorophyll-b) was obtained in the presence of 1.0 mg/I KIN + 0.05 mg/1 IBA.

  • Determination of chlorophyll content in case of peach leaf curl disease (Taphrina deformans) with spectral analysis
    49-52.
    Views:
    283

    One of the most important conditions of high quality fruit production is the early detection of hytopathologycal infections. The most dangerous disease of peach (Prunus persica) is the Taphrina deformans, which causes serious damages mainly in the years where the weather condition is cool and wet. In this study, healthy and naturally diseased leaves by peach leaf curl were investigated in the laboratory of University of Debrecen, CAAES, Institute of Water and Environmental Management. Both of hyperspectral measurement and the values of spectrophotometer shown the chlorophyll content of diseased leaves were lower than the healthy samples. Based on the experiments the water status of investigated leaves established the infected leaves contained more water in their tissues.

  • Effect of foliar spraying with algae suspension on leaf and fruit quality parameters of apple varieties
    35-38.
    Views:
    198

    Foliar nutrition experiment was made to investigate the effect of algae products on fruit quality of apples (Malus domestica Borkh.). The study was conducted in 2011 at Siófok inWest-Hungary on cv. ‘Jonagored’ and ‘Idared’grafted on M9 rootstock. In our trial leaf diagnostic and fruit quality measurements were made to study the effectiveness of applied products. Relative leaf chlorophyll content was determined by a portable chlorophyll meter. Fruit weight and shape index were measured. Fruit inner qualifying parameters like titratable acid content and Brix value were also determined. It can be stated that the used products had traceable effect on investigated fruit parameters. Although, leaf N content was not effected by treatments significantly, relative leaf chlorophyll content significantly increased by both treatments. Used products significantly increased the fruit weight and shape index. Applied treatments significantly decreased the pH of pulp. Treatments increased the acid contents (fumaric, citric, malic) of apples and decreased the amount of monosaccharides. It means that the applied treatments pushed out the ratio of acid/sugar.

  • Luminescence variations in cucumber (Cucumis sativus L.) leaves derived from different regeneration systems
    50-52.
    Views:
    151

    Plants obtained from in vitro culture can show increased susceptibility to environmental stress conditions. In the process of their adaptation to natural conditions it requires monitoring of their physiological state. The methods used to check this phenomenon should estimate quickly and exactly the tolerance to suboptimal environmental factors. Such requirements are satisfied by the methods of measuring chlorophyll luminescence in vivo, e.g. fluorescence induction and delayed luminescence. The objects of our studies were cucumber plants regenerated from cultures of callus and embryogenic cell suspension, as well as the plants obtained from seeds. The plants derived from in vitro cultures displayed a poor physiological condition at the early phase of adaptation characterised by higher susceptibility both to stress caused by increased density of the light flux and low temperature (4 °C) in comparison with the plants obtained from seeds.

     

  • Obtention of new ornamental leaf variants of giant reed (Arundo donax L.) originated from somatic embryogenesis and their photosynthetic parameters
    18-24.
    Views:
    406

    Giant reed (Arundo donax L.) is a perennial rhizomatous herbaceous plant, it has been widespread all over the world by human activities. It is a 2-8 meter high, polyploid, sterile species (not produce viable seeds), it can be propagated only by vegetative methods (rhizomes, stem cuttings, in vitro biotechnological methods). It has considered promising dedicated energy crop thanks to high biomass production (20-40 dry tons per hectare depending on microclimate), adaptability of different kind of soils and environment and low energy input required for its cultivation. It has been utilized for energetic purposes, biogas/bioethanol production, cellulose/paper production and ornamental purposes. The objectives of the present study were to determine morphological properties of new ornamental giant reed leaf variants originated from somatic embryogenesis and to evaluate their photosynthetic pigment content and photosynthetic activities. The most typical changes was the appearance of different colour (white, yellow, light green) longitudinal stripes on leaves (also on petiole and on leaf blade). It was significant differences (p<0.05) between green and leaf variants in case of photosynthetic pigments content and photosynthetic activity (Fv/Fm value). There was no detectable chlorophyll a or b content in the white bands of leaves and albino shoots. Total chlorophyll content of the white striped leaf variety was more than twice than the light green leaves. Photosynthetic activity and content of photosynthetic pigments also confirm and determine the morphological characteristics and growth habit of leaf variants.

  • Improving the postproduction quality of Rose cut flowers
    109-114.
    Views:
    117

    In order to improve the post production quality of cut flowers of Rosa hybrida L. cv. Baroness, the effect of 8-hydroxyquinoline sulfate (8-HQS), silver thiosulfate (STS) and 1-methylcyclopropene ( I-MCP) were investigated. 8-HQS was used at 200 and 400 ppm with or without sucrose at 50 g LI. STS was used at 0.2, and 0.4 mM with or without sucrose at 50 g 1-I. l-MCP was used at 0.3, 0.5 and 0.7 g in-3 for 6h.

    The postproduction quality was improved as a result of using any chemical treatment comparing with untreated control. All the treatments of 8-HQS increased the vase life and minimized the percentage of weight loss of rose cut flowers compared to the control. The vase life was lorger when 8-HQS was combined with sucrose. The best treatment of 8-HQS was 400 ppm 8-HQS + 50 g 1-1 sucrose. STS treatment led to prolong the vase life and minimized the percentage of weight loss compared to the control. In addition, the effect was better when sucrose was added to STS. The treatment of STS at 0.4 mM + 50 g 1-1 sucrose was the best one. l -MCP treatment prolonged the vase life and lowered the percentage of weight loss at any level compared with untreated control. The best treatment in this concern was l -MCP at 0.5 g m-3 for 6h. The chlorophyll content (chl.a and chid)) of the leaves for the best treatment of each chemical was higher than the control. The treatment of STS at 0.4 mM + 50 g 1-1 sucrose gave the best results in this respect.

  • The effect of 5-aminolevulinic-acid (ALA) on the development of Saintpaulia ionantha
    33-36.
    Views:
    229

    In recent work the effect of 5-aminolevulinic-acid (ALA) agent (commercial name Pentakeep-V) was examined on the chlorophyll content, growth and development of Saintpaulia ionantha. The newly re-rooted potted plants were irrigated or sprayed with 0.3‰ or 0.5‰ Pentakeep-V solution, and plus 30% long lasting fertilizer was added to half of the all treatments. Control plants were sprayed with tap water. Best result were obtained on the field of flowering. All the treatments promoted chlorophyll-content in the leaves especially spraying with 0.3‰concentration. Plants treated with Pentakeep-V in both concentrations and independently from the spraying or irrigation flowered more than two weeks earlier than control and those that got plus 30% fertilizer. Besides in the case of some treatments the diameter of leaf rosette, the number and surface size of leaves grew comparing to the control. The longlasting fertilizer had positive effect on the fresh weight but none of treatments had effect on the dry weight.

  • Prolonging the vase life of cut Carnation 'GIOKO' by using different chemicals
    65-68.
    Views:
    175

    Cut flowers of Dianthus caryophyllus L. cv. GIOKO were treated with different concentrations of sucrose and in combination with 1­methylcyclopropene (1-MCP) to compare the effect of these treatments with floral preservative (`Spring') on the longevity of flowers. Distilled water was used for preparing all solutions. The control flowers were held in distilled water. Clorox at 2 mL- I was added to all treatments containing sucrose and it was also applied as a separate treatment. The vase life of cut carnations was significantly prolonged due to the use of chemical treatments, as compared to the untreated control. The longest vase life (18.33 days) was obtained by using 1-MCP 0.5 g m-3 for 6 h treatment. All concentrations of sucrose had a positive effect on flower diameter. The best treatment in this respect was 1 -MCP with 30 gL-I sucrose. 1-MCP treatment significantly increased the chlorophyll content, as compared to the control or the "Spring" treatment. The highest values in this respect were obtained by 1 -MCP treatment alone or with the lowest level of sucrose. The effect of these treatments on the pH of solutions is discussed.

  • 1-MCP and STS as ethylene inhibitors for prolonging the vase life of carnation and rose cut flowers
    101-107.
    Views:
    209

    The effect of STS and 1-MCP on the postharvest quality of carnation and rose cut flowers was studied. Cut flowers of Dianthus c..aryophyllus L. cv. Asso and Rosa hybritia cv. Baroness were treated with silver thiosulfate (STS) at 0.4 mM with sucrose at 50 g 1-t and 1-methylcyclopropene ( I -MCP) at 0.5 g m-3 for 611.

    Pretreatment with STS and 1-MCP significantly extended the vase life and minimized the % loss of initial weight of carnation and rose cut flowers comparing to the untreated control. The two chemicals applied inhibited the chlorophyll degradation and carbohydrate loss and hence, significantly improved the postharvest quality of carnation and rose cut flowers comparing to the control. Ethylene production by cut flowers was inhibited as a result of using these chemicals. In general, there were no differences between STS and (-MCP but the later does not have the heavy metal implications of STS treatment, and hence, using 1-MCP pretreatment for extending the vase life of carnation and rose cut flowers was recommended.

  • Sunburn assessment: A critical appraisal of methods and techniques for characterizing the damage to apple fruit
    7-14.
    Views:
    300

    Many methods and techniques have been introduced for measuring alterations in the fruit and in its surrounding environment related to sunburn incidence. The research objectives, fruit materials and the environment to be evaluated dictate the methods to follow. These procedures are either non-destructive and involve techniques that allow us to track the course of sunburn development and related environmental parameters, or destructive and involve the removal of fruit from the tree for field/laboratory measurements. Techniques employed can be used for pre-symptomatic monitoring (before symptoms become visible) or characterizing the symptoms already present. The principles behind the measurements and their usefulness for sunburn assessments are discussed and critically evaluated in this review paper. Descriptions and evaluations of the methods and techniques were made in the following groups: 1. Thermal measurements; 2. Visual assessments; 3. Fruit quality measurements; 4. Measurements of physiological and biochemical alterations; and 5. Practical evaluation of sunburn damage. Thermal measurements involve methods tracking the ambient temperature and fruit surface temperature, and their relation to sunburn formation. Visual assessments cover all measuring techniques (skin color, chlorophyll fluorescence, radiation reflection, electron microscopy) that are able to detect changes on/in the fruit skin related to sunburn formation. Fruit quality measurements are used to point out differences in qualities (soluble solids, firmness, titratable acidity, and water content) between unaffected and sunburned areas of the fruit. The measurements of physiological and biochemical alterations (gas exchange, pigment analysis, enzyme activity, gene expression) give us a better insight to the mechanism of sunburn formation. Practical evaluations involve many procedures that are used by scientists to characterize the susceptibility of cultivars, evaluate protection technology, etc. For this purpose, the following methods are in use: expressing the percentage of the total fruit surface area affected by sunburn or the percentage of the total number of fruits damaged on the tree, or even a scale based on the severity of the symptoms occurred. All assessing methods and techniques described here have their pros and cons as well as their specific applicability, therefore any of these cannot be favored to use exclusively for assessing sunburn incidence. The combination of these techniques will be the best choice to meet a given research objective perfectly.

  • Postharvest features of chrysanthemum cut flowers as affected by different chemicals
    127-131.
    Views:
    142

    Cut flowers of Chrysanthemum morifolium RAM cv. Suny Reagan were treated with different concentrations of 8- hydroxyquinoline sulfate (8-HQS), silver thiosulfate (STS) and 1-methylcyclopropene (1-MCP) in order to improve the post production quality. 8-HQS was used at 200 and 400 ppm with or without sucrose at 50 O. STS was used at 0.2, and 0.4 mM with or without sucrose at 50 g/1 1-MCP was used at 0.3, 0.5 and 0.7 g/m3 for 6h.

    All the treatments of 8-HQS prolonged the vase life and minimized the percentage of weight loss of chrysanthemum cut flowers compared to the control. The vase life was larger when sucrose not combined with 8-HQS. The best treatment of 8-1-IQS was 400 ppm 8-HQS without sucrose. STS treatment led to prolong the vase life and minimized the percentage of weight loss comparing to the control. In addition, the effect was better when sucroseas was added to STS. The treatment of STS at 0.4 mM + 50 g/I sucrose was the best one. 1-MCP treatment increased the vase life and lowered the percentage of weight loss at any level comparing with untreated control. The best treatment in this concern was 1-MCP at 0.5 g/m3 for 6h. The chlorophyll content (chl.a and chl.b) of the leaves for the best treatment of each chemical was higher than that of the control. The treatment of 1-MCP at 0.5 g/m3 6h gave the best results in this respect.

  • The effect of Ferbanat L nano-fertilizer on the growing of Petunia x grandiflora ’Musica Blue’
    107-109.
    Views:
    241

    During our experiment, the effect of Ferbanat L concentrations were examined by Petunia x grandiflora ‘Musica Blue’ production. The leaf and shoot length, number of flower buds, diameter of flowers, and the date of appearing the first buds were measured. The solution of Ferbanat L in 0.1 % concentration was the most effective on shoot length (21.7 cm). Remarkable increase was observed by the other treatment groups as well comparing to the control group (5.6 cm), the plants treated with solution of Ferbanat L 0.2% (16.5 cm) and 0.3% (14.4 cm) had significant effect as well. The nano-fertilizer had not positive effect on the other examined parameters as leaf and flower size, number of flower buds or chlorophyll content. The culture period shortened five days.

  • Stress physiology of palm trees II. The effect of heavy metals and high irradiance on the photosynthesis of palm Trachycarpus fortunei
    84-88.
    Views:
    149

    A study was carried out to analyse the individual and combined effects of heavy metal toxicity and high irradiance on the photosynthetic characteristics of young, fully expanded leaves of palm seedling Trachycarpus fortunei under laboratory conditions. Heavy metals were found to inhibit both the light and dark reactions of photosynthesis and the inhibition was more affected in the light than in the dark. Single photoinhibitory conditions caused a 60 % decrease in the electron transport activity after 120 min of light exposure which was completely reversible in the dark. In contrast, the combined effect of high light and heavy metal treatment resulted in a 90 % decrease in the activity, but no reversible recovery in the dark could be detected. This indicated that the simultaneous effect of these two stress factors led to irreversible damages of the photosynthetic machinery and as a consequence caused the general destruction of the plant.

    Abbreviations and symbols: Fo: initial chlorophyll fluorescence; Fm: maximum total fluorescence; Fv: variable fluorescence; AFi: intermediate level of fluorescence induction; PSII: photosystem 2.

     

  • The effect of different biostimulators on morphological and biochemical parameters of micropropagated Hosta ’Gold Drop’
    22-29.
    Views:
    227

    During in vitro multiplication of Hosta ‘Gold Drop’, 20 g l-1 sucrose, 5.5 g l-1 agar and 4 concentrations (0.1-0.8 ml l-1) of Ferbanat L, Kelpak, Pentakeep-V were added to half-strength Murashige and Skoog (MS) basal medium. As compared to the control and other biostimulators, plants with lower peroxidase activity, larger fresh weight, more, longer shoots and roots, larger leaves were developed on medium containing Kelpak. The best concentration was 0.4 ml l-1 for in vitro rooting, shoot formation, plant weight and ex vitro chlorophyll, carotenoid level, peroxidase activity. Pentakeep was the less efficient biostimulator, increasing of its concentration mostly decreased root and shoot values (furthermore, abnormal callus formation was observed, as non-wanted effect), chlorophyll content and sizes (length, width) of leaves, not only during in vitro propagation but also (as after-effect) acclimatization because of the high mortality and weakly developed survivor plants.

  • Effect of 1-MCP and chemicals on the vase life of Rosa hybrida L. cv. 'Bordeaux'
    13-16.
    Views:
    145

    The effect of 1-MCP on rose cultivar 'Bordeaux ' was studied in combination with different preservative solutions. The flowers were treated with 1-MCP for 6 hours at 17 °C and for 18 hours at 4 °C. As for the diameter of flowers the best resu lts was achieved, when applying 20 gL- 1 sucrose + Clorox (2 ml L- 1), as well as preservative "Spring" ( I 0 gL-1) + 1-MCP ( 18 hours). Similar results were measured in the case of Spring + Clorox + 20 gL-1 sucrose with 1-MCP (6 and  18 hours). The longer MCP treatm ent gave better results as compared to the shorter ones, because the flowers were much more open.The condition of flowers was the best in the solution of Clorox + 20 gL-1 sucrose and Spring solution combined with the longer MCP treatment. and Clorox + 20 gL- 1, on the IQ1h day. The longest vase life ( 10,3 day) was observed in the case of Spring application combined with 18 hours of MCP treatment. ln this treatment the vase life was prolonged by 3,3 days. As regards the calculated ornamental values, the following sequence could be established :"Spring" + l-MCP ( 18hrs) 134 points, Clorox + 20 gL-1 sucrose + 1-MCP (l8h) with 129 point, and the third was the Clorox + 20 gL-1 sucrose with 1 19 point.

  • Rhizogenesis in in vitro shoot cultures of passion fruit (Passiflora edulis f. flavicarpa Deg.) is affected by ethylene precursor and by inhibitors
    47-54.
    Views:
    165

    The effects of the ethylene precursor ACC and two inhibitors, AgNO3 and AVG, on root formation were tested in in vitro shoots of passion fruit (Passiflora Midis f.flavicalpa Deg.). The organogenic response was assessed on the basis of percentage of shoot-forming. roots, root number and length. The time course of ethylene production was also monitored. ACC inhibited root formation by delaying root emergence and increasine, callus formation at the basis of the shoots. In addition, ACC caused a marked increase in ethylene production, coupled to leaf chlorosis and senescence with lower rooting frequencies, number and length of roots. IAA supplementation increased ethylene production. Both ethylene inhibitors, AgNO3 and AVG, at appropriate concentrations reduced callus formation at the basis of shoots. AVG increased the number of roots per shoot, but drastically reduced length of differentiated roots. Regarding to leaf pigments, ACC promoted a marked reduction on carotenoids and total chlorophyll, whereas AVG and AgNO3 delayed explant senescence and pigments degradation, not differing from IAA supplemented and non-supplemented control treatments. The results confirm previous reports on the beneficial effects of ethylene inhibitors on in vitro rooting and suggest its reliability to be used as an alternative approach to evaluate sensitivity of Passiflora species to ethylene.

     

  • Ecological drought resistance and adaptability of apple varieties
    113-122.
    Views:
    288

    For adequate yields in apple plantations, during the long growing period of the fruit primordia, one of the decisive factors is water supply. Indicators of stress are valuable signs for the diagnosis of drought and necessity of watering, i.e. planning the irrigation of plantations. The aim of the present study was to find reliable signs of water stress on apple trees and at the same time conclude on the drought tolerance of different varieties. The plantation of apple varieties grafted on various stocks and cultivated according to different systems (irrigated, non irrigated, integrate and biological) has been examined continuously by leaf analysis. Along the period of growing fruits, measurements were made in the field, then the leaf samples were analysed in the laboratory for composition of pigments, carbohydrates and antioxidants, as well as the histology of the tissues checked. Without irrigation, the mean leaf mass and the relative chlorophyll content (SPAD) of the variety Idared on M4 stocks increases beyond the values of 50 SPAD, whereas on M26 stock and integrated system, it declines. In the collection of varieties, grown according to the „integrated” system, during the development of fruits, ‘Gála’ and ‘Remo’ varieties have been affiliated to the “less susceptible” group regarding drought tolerance because of the leaf morphology, structure and content of SPAD and antioxidants. However, ‘Idared’ and ‘Jonagold’ belong to the “susceptible” group. To the same group are ranged the ‘Akane, Red Rome vanWell, Pink Lady’ varieties. Those varieties reacted to a short period of drought by increased production (content) of carbohydrates. Regarding changes of carbohydrate content ‘Greensleeves’ and ‘Ozark Gold’ varieties belong to the moderately water dependent (requiring) group. In the field, SPAD-tests facilitated the measurement of nutrient-uptake and incorporation, which is proved by the tight correlation between the data of SPAD and the increment of leaf weight (r=0.76–r=0.88), however, this depends on the variety too. SPAD is an indicator of water supply and is related with the density of stomata, cannot used for the selection of water-exigent varieties but for (drought) tolerant ones. In integrated culture, the (drought) susceptible varieties display (water-soluble) hydrophilic and lipophilic antioxidants (ACWand ACL resp.) the quantity of which may have some role in drought tolerance.

  • Hyperspectral data in water stress detection
    15-17.
    Views:
    171

    Remote sensing methods are applied widespread to investigate large land fields. Within these methods the status of certain vegetation can be determined based on the reflectance spectra of the chlorophyll, in order to support agriculture, forestry and the evaluation of soil pollution. The main aims of our study were to determine and validate the reflectance spectra of fruit tree species, in order to facilitate the identification and evaluation of stressed fruit trees in orchards.

  • Studies on the drought responses of apple trees (Malus domestica Borkh.) grafted on different rootstocks
    29-36.
    Views:
    355

    The morphological and chemical changes in the leaves of eight apple varieties grafted on M4, M26 and MM 106 rootstocks were examined during fruit development in non-irrigated plantation. The aim of the experiment was to examine the defensive mechanisms in apple trees under the mild and serious dryness occurring during fruit development. The content of a relative chlorophyll (SPA D value) of the apple leaves on eastern side of the trees was lower than western and southern sides under drought occurring du ring fruit devclop111ent Under sustained drought from first of July to August the SPAD value, the weight of leaves were larger and the stomata density was significantly larger than in the previous periods. There was a close positive significant correlations bet ween SPAD and stoma density both in the group with less sensitive to drought (r=0,8429) and in the large water demanded group (r=0,9209) equally. The rate of increase in SPAD values and the stoma density was slower in the group with drought tolerant, than in the group required good water supply. The varieties being sensitive to water deficite such as Akane. Pink Lady and Red Rome van Well have a l ready responded intensively to short time of drought by the increasing of carbohydrate and antioxidants product ions. At 42 days of sustained drought as soon as the level of carbohydrate in the leaves decreased, the antioxidant s contents of the leaves rised suddenly in the apple varieties with moderate water requirement s as Greensleeves and ldared. Gala apple variety seemed to be able to defend the drought for longer time because there was no change in relatively high level of carbohydrates and antioxidants of their leaves under severe drought during fruit development.