S13 - Session O3 - Response of cucumber (Cucumis sativus L., cv. Kiara) plants, grown on own root or grafted onto different rootstocks, to high nutrient solution concentrations

Authors: Elena Topalova *, Andon Vasilev, Valentina Petkova

The aim of the performed model study was to establish whether grafting cucumber plants ( Cucumis sativus L., cv. Kiara) onto different Cucurbitaceae rootstocks ( Lagenaria siceraria (K/LS); Cucurbita moschata / 51-17 (K/CMo-M); Cucurbita maxima x Cucurbita moschata Carnivor F1 (K/CMM-K) could improve their tolerance to high nutrient solution concentrations (NSC). The experiments were carried out in greenhouse during 2013-2015. Grafted and own root grown plants were cultivated hydroponically on inert substrate at 3 NSC [1,8 mS cm -1 (optimal), 3,7 mS cm -1 and 5,5 mS cm -1 ] till full maturity. The response of cucumber plants to higher NSC was monitore d twice in the vegetation period through morphological (root length, plant height, fresh biomass, leaf area, number of leaves, etc.) and physiological (photosynthetic pigments, chlorophyll fluorescence, leaf gas exchange, plant water potential, electrolyte leakage) parameters. The growth of cucumber plants was inhibited at high NSC, but more severe in those, grown at own root. The depression of leaf water potential revealed that both groups of plants experienced water stress, especially those, exposed to highest NSC (5,5 mS cm -1 ). An increased electrolyte lea kage from the leaves was established, being stronger in the own root-grown plants. Leaf gas exchange was diminished, but m а ximal efficiency of PS2 was not changed. Based on the results obtained, it was concluded that the grafting of cucumber plants onto Cucurbitaceae rootstocks has potential to increase their tolerance to NSC, but more research is need to clarify the most suitable rootstocks.