ISHS Acta Horticulturae 527: International Symposium on Growth and Development of Fruit Crops
TOCOPHEROL AND ITS POTENTIAL FOR IMPROVING FRUIT QUALITY IN APPLE |
| Authors: | G. Noga, M. Schmitz |
| Keywords: | Apple, apple scab, fruit color, Malus domestica, oxidative stress, pigments, Venturia inaequalis |
| Abstract:
Foliar applications of vitamin E (  -tocopherol) were evaluated for reducing oxidative stress in apple leaves and fruit as well as for improving quality of apple fruit. -Tocopherol, when applied under controlled conditions on ‘Jonagold’ leaf discs, significantly reduced oxidative stress induced by the herbicide paraquat.
This was documented by monitoring chlorophyll fluorescence as an index of electron transport activity in the chloroplasts.
Area of paraquat-induced necrotic lesions was diminished by 55 % in leaf discs pretreated with -tocopherol.
In field experiments, treatment of ‘Jonagold’ apple trees with an emulsifiable vitamin E solution (0.1% a.i.) resulted in a 3-fold increase of endogenous -tocopherol content in the leaves and a 6-fold increase in the fruits within 48 h following application.
As a consequence of repeated treatments from mid June until the end of August (2 week interval) at 0.1% a.i., incidence of Venturia inaequalis leaf infection, based on number of lesions per 100 leaves, was reduced to about one third of control trees.
There was no apple scab infection of fruits, neither in the control nor in the vitamin E treatment groups.
At harvest, fruit colour was significantly better in the treatment group with repeated vitamin E application as compared to the control.
A similar effect was obtained when vitamin E was applied at 0.35 % in combination with ethephon at 0.03% three weeks after full bloom.
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