Sucrose accumulation and osmotic potentials in sugar beet at increasing levels of potassium nutrition

Abstract

In a pot experiment sugar beet Beta vulgaris L. ssp. vulgaris, cv. Kawetina, was grown on alluvial soil (21 mg exchangeable K 100 g−1) containing 0 (K1), 20 (K2), 40 (K3) and 60mg fertiliser K 100 g−1 soil (K4). The plants were sown on 15 March 1983 and harvested on 23 June, 14 July and 30 August 1983. At final harvest root dry weight/plant had reached 269 g in K1 and between 304 and 310 g in K2‐K4. Sucrose values were 15% (K1) and 17.3–17.7% of root fresh weight (K2‐K4) respectively. The osmotic potential of the storage root decreased with increasing K nutrition and time. At final harvest ψ, was between −1.83 (K1) and −2.26 MPa (K4), 75–79% thereof being contributed by sucrose. Sucrose concentrations in press sap increased from 340–400 mM on 23 June to 475 (K1) and 540–570 mM (K2‐K4) at the end of August. In the same period K concentrations declined from 40–100 to 10–35 mM K+. The sucrose, K and Mg concentrations measured in the press sap were lower than those calculated from sucrose, K, Mg and moisture content of the storage root. This indicates that press sap from thawed storage root tissue is not fully representative. Betaine, analysed only at final harvest, significantly increased with increasing K concentrations in the storage root (r=0.83) and a significant linear regression was found between betaine and sucrose accumulation (r=0.57). This is consistent with the role of betaine as a cytosolic osmoticum for sugar beet storage tissue. Other solutes in the cytosol may also contribute to osmoregulation as sucrose accumulates in the vacuoles.

Probing the Mechanical Properties of Hybrid Inorganic–Organic Frameworks: A Computational and Experimental Study

“…During beet growth, non‐sucrose vacuolar osmotica such as potassium and sodium are progressively replaced by sucrose 35. This is emphasized by the negative correlation between the concentrations of sucrose and the measured inorganic ions.…”

“…Betaine is a cytosolic osmoticum that has been detected in several plant species, reaching especially high concentrations in sugar beet 37. Beringer et al 35 measured a significant correlation between sucrose and betaine concentrations in sugar beet grown under controlled conditions. They concluded that increasing sucrose concentration in the vacuoles gives rise to higher non‐sucrose solute concentration in the cytosol to balance the osmotic potential within the cell.…”

Influence of long-term drought stress on osmolyte accumulation in sugar beet (Beta vulgaris L.) plants

“…It was observed in our experiment in the case of sucrose in all leaves of sugar beet plants that was also demonstrated but to a lesser extent in beet mature leaves by Mäck and Hoffman (2006). Beringer et al (1986) and Kenter and Hoffman (2005) showed that there was a strong positive correlation between concentrations of sucrose and glycine betaine in sugar beet storage roots. As a response to a low precipitation the concentration of both solutes in the tap-roots of sugar beet plants was increased but by different magnitude, only 5% for sucrose and 57% for betaine as compared with wellwatered plants (Mäck and Hoffman 2006).…”

Glycine betaine mediated disease resistance against Sclerospora graminicola in Pearl Millet

“…Glycine betaine (GB) N,N,N-trimethyl-glycine is an amino acid derivative naturally synthesized and accumulated in response to variety of abiotic stress conditions by numerous organisms including bacteria, cyanobacteria, algae, fungi, animals and in plant families [1]. Highest amount of GB is present in storage roots of sugar beet in epicotyl and hypocotyl tissues [2]. GB is one of the most studied compatible compound for abiotic stress tolerance due to its versatile function.…”