Assessment of drought tolerance in seedlings of sugar beet (Beta vulgarisL.) cultivars using inorganic and organic solutes accumulation criteria

Abstract

Drought is a major environmental factor limiting the production of crops. Drought tolerance of sugar beet (Beta vulgaris L.) cultivars in terms of growth and inorganic and organic solute accumulation was analyzed in this study. Four-week-old seedlings of three cultivars, "Gantang7", "SD13829" and "ST21916", differing in drought tolerance, were treated with different degrees of drought stress. Plant shoots and roots were harvested at 5 d after stress and subjected to analysis. Drought significantly reduced shoot fresh weight and water content in the three cultivars, though the least reduction was found in "ST21916". Either decrease or no change in sodium (Na + ) and potassium (K + ) concentrations was observed in the three cultivars as an effect of drought, whereas a higher root Na + and a lower root K + concentration was noted in "Gantang7". Root calcium (Ca 2+ ) concentration significantly increased in "Gantang7" exposed to moderate and severe drought. Severe drought also caused a significant increase in the proline level in "SD13829" but not in "Gantang7" and "ST21916". Under drought stress, soluble sugar concentrations significantly increased in both "Gantang7" and "SD13829" whilst remaining unchanged in "ST21916". It is clear that Na + , K + and soluble sugars are major contributors to osmotic adjustment (OA), while Ca 2+ and proline have minor contributions to OA in all three cultivars. According to our comprehensive assessment of drought tolerance, it is shown that "ST21916" is more tolerant to drought than the other two cultivars. Therefore, our results suggest that "ST21916" may be more suitable for planting in arid and semi-arid regions.

Effect of osmotic stress on growth and osmolytes accumulation in sugar beet (Beta vulgaris L.) plants

“…A key osmoprotective function of free proline was emphasized in numerous plants (Verbruggen and Hermans 2008, Szabados and Savouré 2010, Wu et al 2014. In addition to osmotic adjustment, proline has certain regulatory functions, acts as a signal molecule, and protects and stabilizes the structure of membranes and enzymes under environmental stress (Szabados and Savouré 2010).…”

“…reduced by drought stress in 4-week-old sugar beet seedlings, and their growth suffered largely from effect at osmotic stress of -1.0 MPa (Wu et al 2014). These results suggested that twomonth-old sugar beet plants display the drought tolerance to some extent, which can be due to increased ability for maintaining adequate water uptake by lateral root.…”

“…Tissue water content (WC) was calculated according to the method as described by Wu et al (2015). Na + and K + concentrations were determined according to the method as described by Wu et al (2014Wu et al ( , 2015. Na + /K + ratios were calculated according to the method as described by Yue et al (2012).…”

Genetic Diversity and Physiological Performance of Portuguese Wild Beet (Beta vulgaris spp. maritima) from Three Contrasting Habitats

“…Wild beet was already used for sugar beet genetic improvement against pathogens (Panella and Lewellen, 2007). While its potential for improvement against abiotic factors has not yet been exploited, it has been proposed that the ability to accumulate compatible solutes is a breeding goal for abiotic stress tolerance (Bagatta et al, 2008; Ober and Rajabi, 2010; Wu et al, 2014), as well as the ability to accumulate Na + and K + (Abbasi et al, 2015). Europe is one of the most important centers for beet diversity (Maxted et al, 2008), the Iberian Peninsula being considered one center of origin of the Beta complex (OECD, 2001).…”

Physiological responses and effective selection criteria of drought tolerant plants

“…Physiological parameters such as relative water content, chlorophyll content have been used as key indicators of drought stress (Soltys-Kalina ., 2016;Ganji Arjenaki ., 2012;Mafakheri ., 2010;Arunyanark ., 2008). Furthermore, for observing metabolic responses to drought stress, proline and total reducing sugar contents are determined (Wu ., 2014;Naser ., 2010 Screening drought tolerant plants 509…”