			Home About us Contact

Malus Domestica (malus + domestica)

Distribution by Scientific Domains

Life Sciences	60%

Selected Abstracts

POLYPHENOLOXIDASE ACTIVITY OF MINIMALLY PROCESSED ,JONAGORED' APPLES (MALUS DOMESTICA)

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2005
A.M.C.N. ROCHA
ABSTRACT The influence of three chemical dips using ascorbic acid (AA), citric acid (CA) and calcium chloride (CC) on the polyphenoloxidase (PPO) activity and on the total phenolic content of minimally processed (MP) apple (Malus domestica, cv. Jonagored) during cold storage was evaluated and a potential relationship with enzymatic browning was investigated. An ascorbic acid dip (42.6 mM) of 5 min duration was the most efficient chemical treatment in reducing the PPO activity of apple cubes. A 92% inhibition was achieved after 7 days of storage at 4C. All treatments were advantageous in comparison to the control in reducing color changes. Color changes, determined by absorbance at 420 nm (soluble pigments) and lightness (L) (insoluble pigments) of apple cubes treated with ascorbic acid were correlated with total phenolic content. No correlation was observed between PPO activity and tristimulus color parameters, browning index or total phenolic content of AA-treated apple cubes. [source]

Factors influencing the effectiveness of an attracticide formulation against the Oriental fruit moth, Grapholita molesta

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2004
Maya L. Evenden
Abstract An attracticide formulation, LastCallÔOFM, was tested against the Oriental fruit moth Grapholita molesta (Busck) (Lepidoptera: Tortricidae) in replicated small plot field trials in apple, Malus domestica (Borkhausen), orchards in South-eastern Pennsylvania, USA. Attracticide treatments were applied using a calibrated hand pump, and treated plots were compared to similar untreated plots. Male moth activity was monitored using virgin female-baited traps, and the potential for reduction in mating activity was assessed using sentinel virgin females. A comparison of application rates showed that 1500 droplets per ha of the attracticide formulation was as effective as 3000 droplets per ha, and both application rates reduced captures in synthetic pheromone-baited traps for prolonged periods. Droplets placed either at high or low positions within the canopy significantly reduced trap capture and mating with sentinel females. In addition, the only sentinel females that mated in the treated plots were located in the untreated portion of the tree canopy. Mate finding behaviour was equally disrupted by formulations with and without insecticide. Therefore, under the test conditions, the mechanism by which the attracticide formulation worked was by disruption of male orientation, and not by the removal of males due to insecticide poisoning. Two field cage experiments tested the impact of population density on the competitiveness of the attracticide formulation compared to virgin females. A significant proportion of males were captured in female-baited traps at the highest female-to-droplet ratio tested. Equal proportions of males were captured in attracticide-baited traps at male moth densities of 10, 20, 40, and 80 males per cage. These results clarify some of the factors influencing the effectiveness and possible mechanisms of an attracticide management tactic against the Oriental fruit moth. [source]

POLYPHENOLOXIDASE ACTIVITY OF MINIMALLY PROCESSED ,JONAGORED' APPLES (MALUS DOMESTICA)

Linked vs. unlinked markers: multilocus microsatellite haplotype-sharing as a tool to estimate gene flow and introgression

MOLECULAR ECOLOGY, Issue 2 2007
WIM J. M. KOOPMAN
Abstract We have explored the use of multilocus microsatellite haplotypes to study introgression from cultivated (Malus domestica) into wild apple (Malus sylvestris), and to study gene flow among remnant populations of M. sylvestris. A haplotype consisted of alleles at microsatellite loci along one chromosome. As destruction of haplotypes through recombination occurs much faster than loss of alleles due to genetic drift, the lifespan of a multilocus haplotype is much shorter than that of the underlying alleles. When different populations share the same haplotype, this may indicate recent gene flow between populations. Similarly, haplotypes shared between two species would be a strong signal for introgression. As the expected lifespan of a haplotype depends on the strength of the linkage, the length [in centiMorgans (cM)] of the haplotype shared contains information on the number of generations passed. This application of shared haplotypes is distinct from using haplotype-sharing to detect association between markers and a certain trait. We inferred haplotypes for four to eight microsatellite loci on Linkage Group 10 of apple from genotype data using the program phase, and then identified those haplotypes shared between populations and species. Compared with a Bayesian analysis of unlinked microsatellite loci using the program structure, haplotype-sharing detected a partially different set of putative hybrids. Cultivated haplotypes present in M. sylvestris were short (< 1.5 cM), indicating that introgression had taken place many generations ago, except for two Belgian plants that contained a haplotype of 47.1 cM, indicating recent introgression. In the estimation of gene flow, FST based on unlinked loci indicated small (0.032,0.058) but statistically significant differentiation between some populations only. However, various M. sylvestris haplotypes were shared in nearly all pairwise comparisons of populations, and their length indicated recent gene flow. Hence, all Dutch populations should be considered as one conservation unit. The added value of using sharing of multilocus microsatellite haplotypes as a source of population genetic information is discussed. [source]

The effect of fungal metabolites on leaves as detected by chlorophyll fluorescence

NEW PHYTOLOGIST, Issue 2 2001
Anandini Kshirsagar
Summary ,,The effect is reported here of cytochalasin E isolated from the fungus Rosellinia necatrix on photosynthesis in young leaves of Malus domestica (apple). ,,Cytochalasin E was administered via the petiole to excised leaves. The chlorophyll fluorescence emission spectrum and time resolved fluorescence decay were measured up to the point where visible leaf damage was observed. ,,Within 2 h, the ratio of fluorescence emission at 730 nm decreased with respect to the peak at 690 nm. Over 6 h a small blue shift in the 690 nm emission band to 685 nm was seen. The time resolved fluorescence decay showed changes over a similar timescale after administration of cytochalasin E. The control decay could be fitted by two components, ,1, 112 ps, ,2, 402 ps, but after 6 h treatment with cytochalasin E the decay required a further component ,3, 4.25 ns for a good fit. ,,Cytochalasin E has a direct effect on photosynthesis, possibly as a result of impairment of light harvesting. This might partially account for the pathogenicity of the root infecting R. necatrix. Fluorescence techniques may therefore provide an early detection system for the fungus, a necessary prerequisite for development of a control strategy. [source]