Heat-Induced Damage in Potato (Solanum tuberosum) Tubers:  Membrane Stability, Tissue Viability, and Accumulation of Glycoalkaloids

Abstract

Effects of heat on cell membrane permeability, metabolic activity, and glycoalkaloid content were studied in stored potato tubers. Heat-induced alteration of cell membrane permeability was estimated by ion leakage and tissue viability by the (trichlorophenyl)tetrazolium chloride (TTC) reduction test. Solanidine, α-solanine, and α-chaconine contents were determined colorimetrically. Atlantic (a heat-susceptible cultivar) accumulated 74% more total glycoalkaloids (TGA) after 4 h at 35 °C than after 4 h at 22 °C. LT7 (a heat-resistant cultivar) showed a 50% reduction in TGA content after the same treatment. Ion leakage was similar for both cultivars after 90 min at 35 °C, but for the remainder of the incubation period (4 h), it was 15−20% greater in Atlantic than in LT7. At 35 °C, LT7 showed one-third the TTC reduction activity shown by Atlantic. Calcium treatment reduced ion leakage, while it resulted in higher TTC reduction activity in Atlantic than in LT7. Incubation in a solution of glycoalkaloids caused a 50% decrease in TTC reduction activity in Atlantic but did not affect LT7. Damage was aggravated at elevated temperatures, especially in Atlantic. Possible roles of calcium in protection against glycoalkaloid damage are discussed. Keywords: Potato (Solanum); glycoalkaloids; membranes; heat; calcium

Proline induces heat tolerance in chickpea (Cicer arietinum L.) plants by protecting vital enzymes of carbon and antioxidative metabolism

“…The respiration may get affected at supra-optimal temperatures due to direct inhibitory effects of heat stress on enzymes (Salvucci and Crafts-Brandner 2004). The decrease in viability of leaf tissue at 45/40°C in our case is in agreement with the observations on wheat (Wang and Nguyen 1989) and potato (Coria et al 1998) plants exposed to heat stress. Our observations on decrease in leaf water content are in concurrence with the findings on wheat (Sairam et al 2000), turfgrass (Jiang and Huang 2001) and Kentucky bluegrass (Liu et al 2008) plants subjected to heat stress.…”

“…The stress injury was recorded in terms of increase in electrolyte leakage (EL), decrease in tissue viability, chlorophyll and leaf water status. The elevation of temperature resulted in increase in EL indicating membrane injury, which is reported to be a direct consequence of high temperature (Coria et al 1998). The EL has been reported as a useful indicator of heat stress injury to plants in some earlier studies (Liu and Huang 2000;Gulen and Eris 2004) and our findings in this context match with the similar ones reported in heat-stressed strawberry (Gulen and Eris 2004) and rice (Sohn and Back 2007) plants.…”

Metabolomic analysis of wild and transgenic Nicotiana langsdorffii plants exposed to abiotic stresses: unraveling metabolic responses

“…The difference in glykoalkaloid content between control and HS samples was significant at a p value <0.05. δ-Solamarine and δ-solamarine deoxyhexose showed the highest increases in WTHS and RolCHS samples, with a ratio of 8 and 6, respectively, while solamargine presented the highest increase in GRHS samples, being 9 times higher than in controls. The increases in the concentrations of glykoalkaloids in plants exposed to HS agreed with the study by Coria et al [31], which showed that high α-solanidine content in potato tubers could be related to exposure to high temperature (immersion in hot water at 35°C for 4 h). Other studies, moreover, reported enhanced total glykoalkaloid levels in potato tubers after exposure to heat/drought [32,33].…”

I. Heat stress in Triticum: kinetics of Ca and Mg accumulation

“…Nevertheless, as increasing levels of this nutrient were not coupled to the maintenance of the selectivity of membrane permeability (Fig. 3), this pattern disagrees with the findings of Cooke et al (1986) and Coria et al (1998) that suggested different interspecific metabolisms for Ca in sugar beet and potato. During the life wheat genotypes cycle, Mg uptake was not significantly depressed by Ca and, therefore, an antagonistic interaction between these nutrients accumulations in the shoots could not be found (Table 1, 3).…”