Water Potential, Osmotic Potential, and Cell Turgor in Developing European Plums
2022; American Society for Horticultural Science; Volume: 57; Issue: 12 Linguagem: Inglês
10.21273/hortsci16883-22
ISSN2327-9834
Autores Tópico(s)Postharvest Quality and Shelf Life Management
ResumoNeck shrivel is a fruit disorder of european plum ( Prunus domestica L.). We investigate whether an asymmetrical distribution of osmolytes might explain the observations of a turgid stylar end and a flaccid stem end, in a selection of 17 plum cultivars sourced from two sites. The osmotic potential (Ψ Π ) of the juices expressed from stem or stylar end fruit samples decreased (became more negative) during development. The cell turgor (Ψ P ) slightly increased during development up to 352 ± 42 kPa at 78 days after full bloom (DAFB) in the stem end and up to 331 ± 51 kPa at 92 DAFB in the stylar end, and then decreased. At maturity, Ψ P averaged 22 ± 3 kPa in the stem end and 22 ± 4 kPa in the stylar end. These values are negligibly low compared with the very negative values of Ψ Π in the stylar end (−3188 ± 73 kPa) and stem end (−3060 ± 74 kPa). There was a transient gradient in Ψ Π between stylar end and stem end that almost disappeared by maturity. Marked differences in Ψ Π and its distribution were measured across 17 cultivars. In the majority (14), Ψ Π was more negative at the stylar end than at the stem end. A more negative Ψ Π in the stem was only detected in ‘Aprimira’, ‘Topfive’, and ‘Tophit’. Our results demonstrate that cell Ψ P is very low and is essentially independent of Ψ Π in developing european plums. In most cultivars, Ψ Π in the stylar end is more negative than in the stem end. The absence of an axial gradient in Ψ P and the small differences in Ψ Π between the stem and stylar end make both factors unlikely candidates for explaining neck shrivel.
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