Relationships between the biochemical and spectral traits of leaves and the productivity of apple trees in organic and integrated production systems

Abstract

Three apple varieties were investigated in organic and integrated production systems with the objective to examine the relationships between carbohydrates, endogenous formaldehyde (HCHO) and SPAD value during fruit development. The leaves on the eastern, western and southern sides of the apple trees were investigated four times, at 57, 73, 99 and 120 days after flowering. Concentrations of glucose and fructose in the leaves were lower while the sucrose concentration was higher in organic production than in the integrated system. In the integrated production system the high SPAD value and its more intensive increase during fruit development indicated increased photosynthetic activity in the trees in comparison with organic production. In the organic production system, the increase in SPAD values was correlated with increasing ‘fixed’ HCHO concentrations and decreasing fructose concentrations in the leaves. In integrated production the increase in the SPAD value also resulted in a rise in the concentration of HCHO, while the concentrations of carbohydrates (glucose + fructose) in the leaves decreased gradually. The results indicated that the SPAD value and the endogenous formaldehyde concentration in the leaves measured during the early stage of fruit development can be used to characterize the productivity and suitability of the tree for organic production.

Keywords:

• SPAD value
• endogenous formaldehyde
• carbohydrates
• organic production
• integrated production