THE LIGHT CONDITIONS UNDER PROTECTED COLOURED HAILNETS AFFECT LEAF ANATOMY, GROWTH AS WELL AS FRUIT BLUSH DEVELOPMENT IN APPLE

In the light of a range of supposedly positive physiological effects, the purpose of this study was to investigate these environmental effects of coloured hailnets (green-black, red-black, green-white, red-white, grey, black and white hailnets) on light conditions beneath them which may affect leaf anatomy, tree growth and fruit quality in an apple orchard located at Klein-Altendorf near Bonn, Germany; uncovered trees served as control.
Coloured hailnets did not considerably affect the spectrum of transmitted light which implied no changes in R:FR ratio and, consequently, did not influence the phytochrome system.
Coloured hailnets transmitted 72-80% of incoming UV-B and 74-89% of PAR depending on hail net colour and caused surface temperatures to drop by 3-16°C with fruit and by 3.3-3.6°C with leaves.
All this led to impaired fruit red (top) colour development in the order of the PAR and UV-B transmission through particular hailnet.
Leaves without coloured hailnet were thicker with more palisade layers and thicker epidermis.
Reproductive growth (return bloom) and leaf anatomy were impaired by the coloured hailnets without considerable impact on vegetative growth (trunk diameter).

VI International Symposium on Light in Horticulture

A.A. Solomakhin, Y.V. Trunov, M. Blanke

apple, climate change, growth, hail net, irradiance, leaf anatomy

https://doi.org/10.17660/ActaHortic.2011.907.33