Morpho-physiological traits of sugar beet exposed to salt stress

摘要

Selection of traits increasing salt (NaCI) tolerance would improve the cultivation of sugar beet [Beta vulgaris L. subsp. vulgaris) in salty soils, by reducing or avoiding the usually linked losses in sugar yield and processing quality. This study analysed some adaptive morpho-physiological mechanisms in genotypes grown under controlled conditions in different salt concentrations. Parents and F1 hybrids obtained from a diallel cross were analysed for: i) mid-parent heterosis of root; ii) root length and its morphological components; and iii) length and dry weight of shoot (leaf + stem). Physiological traits such as: i) antioxidant enzyme activities in leaves; ii) root plasma membrane (pm) H~+-ATPase activity; iii) leaf relative water content; and iv) shoot Na/K ratio, were also investigated. Through principal component analysis (PCA), it was possible to group the single morpho-physiological traits. This permitted discrimination of hybrids in relation to their response to salinity. The hybrid Hy-1 in presence of medium salt concentration performed well in terms of root morphology and enzyme activities, which were linked to the cell growth process. These findings evince a better understanding of the salt tolerance mechanisms in sugar beet and the identification of useful physio-biochemical traits useful for sugar beet breeding.