Studies on Water Transport through the Sweet Cherry Fruit Surface: XII. Variation in Cuticle Properties among Cultivars (original) (raw)

2012, Journal of the American Society For Horticultural Science

Water uptake through the exocarp of intact sweet cherry [Prunus avium (L.)] fruit was determined gravimetrically in an immersion assay (25 °C). Fruit with sealed pedicel/fruit juncture were incubated in water during the fi rst interval (0 to 0.75 hour) and in 10 mM salt solutions of selected cations during the second (0.75 to 1.5 hours) and third interval (1.5 to 2.25 hours) of an experiment. Rates of water uptake (F) were calculated for fi rst, second and third intervals (F I , F II and F III , respectively) and salt effects indexed by the ratios F II /F I and F III /F I . AgNO 3 (F II /F I = 0.65), NaCl (0.70), BaCl 2 (0.67), CdCl 2 (0.69), CuCl 2 (0.42), HgCl 2 (0.58), and SrCl 2 (0.69), and the salts of trivalent cations AlCl 3 (0.50), EuCl 3 (0.58), and FeCl 3 (0.49), signifi cantly decreased water uptake into mature ʻSamʼ fruit as compared to the water control (0.87). KCl (0.82), NH 4 Cl (0.85), CaCl 2 (0.75), MgCl 2 (0.88), MnCl 2 (0.81), and ZnCl 2 (0.72) had no effect, LiCl (1.00) increased uptake. Similar data were obtained for F III /F I . The effect of FeCl 3 on water uptake was independent of the presence of CaCl 2 , AlCl 3 , or CuCl 2 , as sequential or simultaneous treatment with these salts reduced water uptake to the same extent as with FeCl 3 alone. Increasing FeCl 3 concentration up to 1 mM decreased uptake, higher concentrations had no further effect. FeCl 3 and CaCl 2 to a smaller extent decreased water uptake in developing ʻReginaʼ sweet cherry fruit (55 to 91 days after full bloom). FeCl 3 had no signifi cant effect on water uptake along the pedicel/fruit juncture, but markedly reduced uptake through the exocarp of all cultivars investigated (ʻBurlatʼ, ʻEarly Riversʼ, ʻHedelfi ngerʼ, ʻKnauffsʼ, ʻReginaʼ, ʻSamʼ, ʻSummitʼ, and ʻVanʼ). Effects of CaCl 2 on water uptake were limited to ʻBurlatʼ, ʻEarly Riversʼ, and ʻHedelfi ngerʼ. CaCl 2 and FeCl 3 both decreased fruit cracking, but FeCl 3 was more effective. The mode of action of mineral salts in decreasing water uptake and fruit cracking and their potential for fi eld use are discussed.