Mature sweet cherries have low turgor

verfasst von

Moritz Knoche, Eckhard Grimm, Henrik Jürgen Schlegel

Abstract

The pressure inside a mature sweet cherry (Prunus avium L.) fruit is thought to be an important factor in rain cracking. However, to our knowledge, this pressure has never been quantified directly. The objectives of this study are to quantify: 1) the cell turgor (ψ^cell_P) in fruit using a cell pressure probe (CPP) and a vapor pressure osmometer (VPO); and 2) the tissue pressure in a fruit (ψ^fruit_P) using both a fruit pressure probe (FPP) and a compression-plate technique (CP). The value of YcellP in mesocarp cells of mature sweet cherry fruit averaged 28.1 kPa in 'Samba' and 17.5 kPa in 'Sam' at depths below the fruit surface between 200 and 400 mm. A ψ^cell_P (range 38 to 64 kPa for different cultivars) calculated from the tissue water potential (Ytissue = -2968 to -4035 kPa) and the osmotic potential (ψ^fruit_P) (ψ^fruit_P = -3020 to -4116 kPa) of excised mesocarp discs as determined by VPO was of the same order of magnitude as that by CPP. Similar low ψ^fruit_P values were obtained by FPP (range 8.0 to 11.8 kPa across cultivars). The ψ^fruit_P were consistently lower than the YcellP values measured by CPP or by VPO. The ψ^fruit_P value in the mesocarp increased slightly with increasing depth below the surface. However, ψ^fruit_P was always negligible (e.g., 'Samba' ψ^fruit_P = 10 kPa) compared with either ψ^fruit_P ('Samba' ψ^fruit_P = -2395 kPa) or calculated water potential (ψfruit) ('Samba' ψ^fruit = -2385 kPa). When subjecting intact fruit to CP, linear relationships were obtained between the forces applied and the resulting aplanation areas. The ψ^fruit_P values obtained by CP (range in sweet cherry 18.4 to 36.1 kPa) were somewhat larger than the ψ^fruit_P values obtained by FPP (range in sweet cherry 8.0 to 11.8 kPa). Incubating fruit for up to 7.5 h in deionized water or for up to 96 h in air enclosed above dry silica gel had no measurable effects on ψ^fruit_P. The low ψ^cell_P and the low ψ^fruit_P values are not unique to sweet cherry. Values of the same order of magnitude were obtained also in mature sour cherry (Prunus cerasus L.), european plum (Prunus domestica L.), grape (Vitis vinifera L.), gooseberry (Ribes uva-crispa L.), red currant (Ribes rubrum L.), black currant (Ribes nigrum L.), blueberry (Vaccinium corymbosum L.), and tomato (Solanum lycopersicum L.). Possible explanations for the very low values of ψ^cell_P and ψ^fruit_P are discussed.

Organisationseinheit(en)

Institut für Gartenbauliche Produktionssysteme

Typ

Artikel

Journal

Journal of the American Society for Horticultural Science

Band

139

Seiten

3-12

Anzahl der Seiten

10

ISSN

0003-1062

Publikationsdatum

01.01.2014

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Genetik, Gartenbau

Ziele für nachhaltige Entwicklung

SDG 3 – Gute Gesundheit und Wohlergehen

Elektronische Version(en)

https://doi.org/10.21273/jashs.139.1.3 (Zugang: Offen)