|Authors: ||D. Savvas, G. Ntatsi, N. Moiras, A. Tsakalidis , A. Ropokis, A. Liopa-Tsakalidi|
|Keywords: ||cadmium, chroma, firmness, hue, manganese, nickel, quality, TA, TSSC, zinc|
The aim of the current work was to study the impact of heavy metal contamination in the root zone of cucumber on fruit quality characteristics and examine whether grafting on selected rootstocks could mitigate possible adverse effects.
A greenhouse experiment was carried out in which non-grafted and grafted cucumber plants (Cucumis sativus L. ‘Creta’) were exposed to excessively high external Ni, Cd, Mn, and Zn concentrations (50, 10, 100, and 50 μmol L-1, respectively). The rootstocks used for grafting were ‘Creta’ (self-grafting treatment), ‘Power’, ‘TZ-148’, ‘Ferro’, and ‘Strong Tosa’. The plants were cultivated in bags filled with perlite.
The tested Cd, Mn, and Zn concentrations imposed only few minor effects on cucumber fruit quality.
In particular, Cd increased slightly fruit acidity, Mn increased slightly fruit acidity and decreased slightly fruit length, and Zn decreased slightly ‘Chroma’ in comparison to the control treatment.
However, the exposure of cucumber to an external Ni concentration of 50 μmol L-1 increased appreciably the Hunter color parameters L* (brightness), b* (yellowness), and ‘Chroma’ measured on the external fruit surface, as well as the titratable fruit acidity, and suppressed the fruit firmness, mean fruit weight, and fruit length.
Grafting, led to a slight decrease in fruit acidity, total soluble solids content (TSSC) and fruit length, but increased fruit firmness and fruit diameter, while the mean fruit weight was not influenced.
Nevertheless, the exposure of cucumber to the tested high external Cd and Zn concentrations eliminated the effects of grafting on TSSC and fruit diameter, while the exposure to high external Mn levels also eliminated the impact of grafting on fruit diameter.
Grafting onto ‘Power’, ‘TZ-148’ and ‘Ferro’ reduced slightly b* (yellowness) and ‘Chroma’ in cucumber fruit, but this effect was eliminated by exposure to high external Zn concentration.
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