Air volume measurement of 'Braeburn' apple fruit

• Published in: Journal of experimental botany Vol. 55; no. 399; pp. 1061 - 1069
• Main Authors: Drazeta, L, Lang, A, Hall, A.J, Volz, R.K, Jameson, P.E
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-05-2004; Oxford Publishing Limited (England)
• Subjects: Agronomy. Soil science and plant productions; Air; Air - analysis; Apple; Archimedes’ principle; Biological and medical sciences; Braeburn; cell configuration; Economic plant physiology; Extracellular space; Extracellular Space - chemistry; Fructification, ripening. Postharvest physiology; Fruit - anatomy & histology; Fruits; Fundamental and applied biological sciences. Psychology; Growth and development; Horticulture; intercellular space; internal injury; Malus - anatomy & histology; Parenchyma; Pith; Postharvest technology; Reproducibility of Results; Research Papers: Regulation of Growth, Development and Whole Organism Physiology; Tissue samples; Water balance; Water immersion; Weights and Measures; Archimedes' principle; Apple; Intercellular space; Fruit; Braeburn; Dicotyledones; Angiospermae; Rosaceae; Spermatophyta; Malus domestica; internal injury; cell configuration
• ISSN: 0022-0957; 1460-2431; 1460-2431
• DOI: 10.1093/jxb/erh118

The radial disposition of air in the flesh of fruit of Malus domestica Borkh., cv 'Braeburn' was investigated using a gravimetric technique based on Archimedes' principle. Intercellular air volume was measured by weighing a small tissue sample under water before and after vacuum infiltration to remove the air. In a separate procedure, the volume of the same sample was measured by recording the buoyant upthrust experienced by it when fully immersed in water. The method underestimates tissue air volume due to a slight invasion of the intercellular air spaces around the edges of the sample when it is immersed in water. To correct for this error, an adjustment factor was made based upon an analysis of a series of measurements of air volume in samples of different dimensions. In 'Braeburn' there is a gradient of declining air content from just beneath the skin to the centre of the fruit with a sharp discontinuity at the core line. Cell shape and cell packing were observed in the surface layers of freshly excised and stained flesh samples using a dissecting microscope coupled to a video camera and a PC running proprietary software. Tissue organization changed with distance below the skin. It is speculated that reduced internal gas movement, due to the tightly packed tissue of 'Braeburn' and to the potential diffusion barrier at the core line between the cortex and the pith, may increase susceptibility of the flesh to disorders associated with tissue browning and breakdown.