Water and minerals transport in plant occur through the transpiration stream as triggered mainly by the environmental conditions. The transpiration of leaves has been studied in great detail over many years and the roles played by the various leaf structures (cuticle, stomata, lenticels etc) are well understood. Similarly well understood are the influences on foliar transpiration of meteorological variables such as temperature, radiation, vapour pressure deficit and wind, also, how these variables can be differently important to foliar transpiration depending on whether one is considering an isolated leaf or an entire canopy (Jarvis, 1985). In contrast with this, the transpiration of fruits has not been studied to nearly the same extent, neither with regard to skin structures and their associated functional properties nor with regard to the transpiration response of fruit to the various meteorological variables. Most fruit-crop species (including apple, apricot, avocado, kiwifruit, capsicum and tomato), suffer from pre- and post-harvest physiological disorders. Higher incidences of these physiological disorders have many times been reported as being associated with lower concentrations of calcium (Ca) in the fruits (Faust et al. 1968, Tzoutzoukou and Bouranis 1997, Ferguson et al. 2003, Thorpe et al. 2003). Transpiration is the main driving force for the xylem stream (White and Broadley 2003) in which Ca seems to move relatively freely while this ion is also well known to be substantially immobile in the phloem (Buckowak and Wittwer 1957). Along with the observation that fruit are largely phloem fed, calcium’s well know xylem mobility and phloem immobility explain in part why fruit are generally low-Ca organs and also why higher fruit transpiration rates are sometimes associated with increased fruit Ca levels (Cline and Hanson 1992, Tromp and Van Vuure 1993, Montanaro et al 2006 and 2010). It is therefore reasonable to hypothesise that for any particular fruit, the seasonal integral of fruit transpiration rate will predict fruit Ca content at harvest and thus (at least potentially) the incidence of Ca-related physiological disorders. This chapter focuses the mechanisms behind fruit transpiration in some fruit tree species, its seasonal trend and discusses the significance of fruit water loss on mineral composition particularly on Ca accumulation.
Montanaro, G., Dichio, B., & Xiloyannis, C. (2012). Fruit Transpiration: Mechanisms and Significance for Fruit Nutrition and Growth. In Advances in Selected Plant Physiology Aspects. InTech. https://doi.org/10.5772/21411