Sugars and organic acids in ripe ‘Charleston Gray’ and ‘Jubilee’ watermelons [Citrullus lanatus (Thunb.) Matsum & Nakai] were measured at harvest and after 14 or 19 days of storage at 0°, 7°, 16°, 23°, or 27°C. Soluble solids content (SSC), sucrose, fructose, and glucose concentrations mostly did not change during storage at 0°, but all generally were reduced at the higher temperatures. ‘Charleston Gray’ contained about 3% to 4% sucrose, 2% to 3% fructose, and 1.0% to 1.5% glucose. Fructose was the major sugar in ‘Jubilee’, followed by sucrose and glucose. Malic acid was the major organic acid in both cultivars. Temperature of storage had little effect on malic acid concentration. The concentration of citric acid decreased during storage at 23° or 27°, but not consistently at low temperatures.
Reducing sugar (glucose and fructose) and sucrose are the major free sugars (total sugars) in the carrot root. Striking genetic variation exists for the reducing sugar/total sugar ratio (percentage of reducing sugar). Inbred carrot lines with high and low percentages of reducing sugar were used as parents in establishing various F1, F2, F3 and backcross populations to study the inheritance of root sugars. It was determined that a single major gene regulates the reducing sugar to sucrose balance in carrot roots with dominance for high percentage of reducing sugar. We propose that this gene be designated Reducing sugar, symbolized Rs. This relationship is of interest since sugars in the carrot root are a major storage carbohydrate and a primary component of carrot flavor.
Potato tubers (Solanum tuberosum `Russet Burbank') were stored at 1 °C in air for 28 days and then transferred to 10 °C in either air or 2.53 kPa O2. During cold storage there was an increase in sucrose, glucose, and fructose. The activities of extractable sucrose phosphate synthase (SPS) and invertase increased by 2.2- and 7.7-fold, respectively, during 28 days at 1 °C. The activity of sucrose synthase (SS) remained constant at 1 °C and was similar to that found in tubers kept continuously at 10 °C. With the transfer of tubers from 1 to 10 °C, there was an initial sharp rise in respiration which peaked at ≈7 days, followed by a gradual decline. Sucrose declined rapidly during reconditioning, while glucose and fructose declined more slowly. With the transfer of tubers from 1 to 10 °C, the activity of SS increased sharply after 7 days at 10 °C, to be followed by a decline to the levels found in control tubers. The activities of both extractable SPS and invertase decreased during reconditioning, reaching the values of the control tubers within ≈15 days. Low O2 inhibited the decrease in sugars and suppressed the rise in SS activity, but it did not alter the decrease in SPS and invertase. Western blot analysis showed that the amount of SPS protein remained unchanged at 1 and 10 °C. These results indicate that the activity of SPS is regulated by factors other than the amount of its protein. The activities of the above three enzymes showed no changes in tubers kept at 10 °C continuously. In control tubers SPS showed the highest activity, followed by SS and invertase.
evaluated for many years in horticultural crops. However, research in recent years focused on using PGRs to improve fruit quality parameters, such as soluble sugars, fruit color, and phytonutrients ( Buran et al., 2012 ; Gonzalez et al., 2012 ; Gu et al
synthesis, carbohydrate metabolism, and cell division ( Hacisalihoglu et al., 2003 ). Apple production has been increasing worldwide but fruit quality is a limiting factor in achieving the economic potential of apple crops. Sugar is an important index for
al., 2008 ; Goudeau et al., 2008 ; Rodrigo and Zacarias, 2007 ). Regulation of color break is not fully understood, but the process can be stimulated by low temperatures ( Erickson, 1968 ) and by rising levels of peel sugars ( Goldschmidt and Koch
fall-transplanted sugar maple and northern red oak ( Quercus rubra L.) began root regeneration earlier and regenerated more roots in the first season after transplant than mid-fall- and spring-transplanted treatments ( Harris et al., 2002 ), whereas
amounts of soluble sugars appear during winter depending on temperature ( Zapata et al., 2004 ). Soluble sugars consist primarily of sucrose, glucose, and fructose; however, oligosaccharides raffinose and stachyose are also present in winter ( Jones et al
, there has been interest in using materials that lure or attract western flower thrips to increase the efficacy of insecticide spray applications (attract-and-kill strategy). It has been proposed by greenhouse producers that adding sugar to a stomach
) have suggested that total sugar content and sugar in the basal, middle, and apical sections of fresh-cut bamboo shoots initially decreased and then changed variably thereafter in different sections of the shoots during storage at 4 °C for 16 d. Kozukue