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Age-dependent physiological responses of Corchorus olitorius to aqueous extracts of Murraya koenigii and Tithonia rotundifolia
61-66.Views:50Sustainable crop production increasingly utilizes allelopathic plants as sources of bioactive compounds, yet their bimodal inhibitory–stimulatory effects and oxidative mechanisms require further elucidation. This study investigated the concentration-, tissue-, and stage-dependent effects of aqueous shoot extracts from Murraya koenigii and Tithonia rotundifolia on the germination, growth, and oxidative defense of Corchorus olitorius. Seed emergence and elongation of radicles and plumules were monitored in the laboratory using 50% and 100% aqueous extracts, while potted seedlings were treated separately with 100% extracts. Laboratory bioassays demonstrated a dose-dependent response: a 50% M. koenigii extract transiently increased germination by 4%, while higher concentrations of both species inhibited germination by 7–25%. Juvenile growth inhibition was tissue-specific, with 100% M. koenigii primarily suppressing plumule elongation and 100% T. rotundifolia significantly reducing radicle growth. Conversely, pot experiments using 100% extract concentrations of both plants significantly enhanced vegetative growth, physiological traits, and biochemical constituents, including protein and ascorbic acid. These extracts bolstered the antioxidant defense system—increasing superoxide dismutase, catalase, and peroxidase activities—while markedly reducing malondialdehyde levels. These findings provide evidence of allelopathic hormesis, where initial inhibitory effects transition into growth stimulation and oxidative stress mitigation during later developmental stages. The results suggest that M. koenigii and T. rotundifolia shoot extracts serve as effective eco-friendly biostimulants that improve crop performance by modulating antioxidant responses.
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Impact of boron foliar fertilization on annual fluctuation of B in sweet cherry leaves and fruit quality
27-30.Views:1017The goal of the study was to examine response of sweet cherries (Prunus avium L.) to boron (B) fertilization. The experiment was conducted during 2005-2007 in West Hungary on mature cv. `Germersdorfi 3' grafted on Prunus mahaleb rootstock.
Sweet cherry trees planted on a calcareous chernozem soil. Trees were foliar-fertilized with B. Foliar B sprays were performed: (1) in the spring, at the stage of white bud, beginning of flowering (B1), and (2) repeated 5 weeks after full bloom (B2). In each of spring spray treatments, B was applied at a rate of 0.15 kg ha-I. Trees untreated with B served as a control.
The results showed that B fertilization had effect on B concentration in leaf tissues, mostly after ripening. B was present significantly higher amount in leaf in treated samples after ripening.
Mean fruit weight was slightly increased by B fertilization. Fruit sensitivity to cracking was not influenced by B fertilization. Nevertheless, from our data it can be conclude that the sensitivity of fruit to cracking is improved when the fruit is riper, the fruit density and fruit weight are higher. The soluble solids varied between 15.0 and 15.9% according to the treatments. Our results for the monosaccharides investigated varied between 5.1 and 7.2 as glucose and fructose as well. Galactose and sucrose was detected very small amount in the unprocessed cherries. Applied B treatments increased sugar contents but decreased organic acid contents in sweet cherry fruits.
It is concluded that under conditions of this experiment, B fertilization can be recommended in sweet cherry culture to improve fruit quality and their appearance.
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Salt tolerance of sweet pepper seedlings
62-66.Views:357Laboratory germination tests have been made with three white fruit pepper varieties and with one spice pepper in filter paper rolls wetted with KCl solutions of different concentration. Parallel tests have been conducted with the other species (lettuce, tomato, kohlrabi) to compare the salt tolerance of paprika with that of other vegetable crops.
In greenhouse, the action of KCl has been investigated with transplants raised in soil mixture, in rockwool and with seedlings transplanted from rockwool into soil mixture. Like the trials in the laboratory, the experiments in soil mixture have been made with other plant species, too.
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Spore dispersal, diurnal pattern and viability of Monilinia spp. conidia and the relationship with weather components in an organic apple orchard
17-19.Views:628In a two-year Hungarian study, spore dispersal diurnal periodicity and viability of Monilinia spp. and their relation to weather components were determined in an organic apple orchard. Conidia of Monilinia spp. were first trapped in late May in both years. Low number of conidia were trapped until end-June. Thereafter, number of conidia continuously increased until harvest. Conidia in a 24-h period showed diurnal periodicity pattern, with th highest concentration in the afternoon hours. Spore viability with FDA staining showed that viability of
conidia ranged from 45 to 70% with showing lower viability in the dry than in the wet days in both years. Temperature and relative humidity correlated positively with mean hourly conidia numbers in both years. Mean hourly rainfall was negatively but poorly correlated with conidiacatches in both years. Results were compared and discussed with previous observations. -
Fire blight (Erwinia amylovora) susceptibility of old Hungarian apple cultivars
35-38.Views:381The aim of the Hungarian apple breeding program started in the Department of Fruit Science was to find resistant apple cultivars against major diseases (scab, powdery mildew, fire blight). The outbreak of fire blight (Erwinia amylovora) in 1996 motivated us to search new resistant sources principally from old traditional apple cultivars. First of all, cultivars have been gathered since 1997 from Carpathia (Visk) and evaluated between 2001 and 2003. In this recent study evaluation of resistance of old Hungarian genotypes to fire blight collected from the English National Fruit Collection (Brogdale, Faversham) is presented.
13 old Hungarian apple cultivars in 2002, and 38 genotypes in 2005 have been evaluated. We used `Idared' and 'Jonathan M41' as susceptible controls and 'Liberty' and 'Remo' as resistant ones. Shoots of two-year-old potted plants were inoculated with a mixture of virulent E. amylovora isolates (Ea2, Ea60, Ea67) at a concentration of 5 x 108 cells/ml. Resistance of apple cultivars was evaluated weekly, four times after inoculation by disease severity of symptoms. Numbers of bacterial colonies in 1 cm length shoot were determined in the fourth week after infection.
8 cultivars in 2002 and 9 cultivars in 2005 displayed notable resistance to fire blight based on one-year data. Based on the coincident data of both years, out of the cultivars collected also from Carpathia ‘Pónyik', and `Sikulai' were found to be resistant and gene sources additional old Hungarian valuable apple genotypes could be selected: `Szabadkai szercsika' and `Tordai piros !davit'. The cultivar `Szemes alma' originated from Visk has proved to be recurrently resistant.
The number of bacterial cells in shoots of the investigated cultivars correlated with the severity of symptoms. With this method, which was introduced by us earlier, we can screen cultivars displaying weak visible symptoms, which cannot be proposed as a source of resistance because of their latent infection.
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In vitro shoot multiplication of apple: comparative response of three rootstocks to cytokinines and auxin
36-39.Views:554Shoot multiplication responses of rootstocks cvs. M.26, MM.106 and JTE-H to different concentration of BA, BAR and IBA in eight various combinations were tested on MS-medium. The effect of hormones depended on genotype, type of cytokinin and interaction of cytokinin and auxin. Shoot multiplication was significantly enhanced with the use of BAR as cytokinin. High multiplication rate could be achieved in cvs. M.26, MM.106 and JTE-H: 7.7, 6.9 and 9.9 shoots per explant, respectively.
