characteristic pattern of depletion and accumulation of soluble carbohydrates in storage roots. Detecting deviations from the normal pattern could help to diagnose crop problems, such as unwanted excessive depletion of carbohydrates incited by harvest periods
; Schultheis et al., 2000 ), but skin lignin/suberin content was not determined. Therefore, we hypothesize that foliar application of ethephon enhances skin lignification and/or suberization in storage roots promoting skinning resistance. The objectives of this
sweetpotato storage roots of five cultivars indicated that phenolics comprised up to 0.92% of the fresh weight of this tissue ( Son et al., 1991 ). The cultivars varied in phenolic content, and most of the phenolic component consisted of chlorogenic acid and
significantly affecting the concentrations of ascorbic acid, glutathione, and capsaicinoids ( Pascual et al., 2010 ). Pungency is a major determinant of quality in radish ( Raphanus sativus L.) storage roots. The pungent principle of radish storage roots was
Digital image analysis (DIA) was evaluated for use in assessing size and shape attributes of sweetpotato [Ipomoea batatas (L.) Lam.] storage roots in herbicide studies. Digital image files of U.S. no. 1 storage roots were taken using a digital camera. Image analysis was performed using a publicly available software package. Eight size and shape attributes were measured and subjected to univariate and multivariate procedures. DIA revealed differences for storage root width and roundness attributes. Principal component analysis suggested that storage root length, width, and roundness best described the variability of the storage root sample. The results demonstrate the potential use of DIA in augmenting data from sweetpotato herbicide trials as well as other investigations that require information about storage root size and shape responses.
Tissue properties may strongly influence the occurrence of harvest splitting in carrot (Daucus carota L.) storage roots, a disorder generally assumed to be triggered by a high water status in the storage root. Strain within the root, as well as extensibility of root tissue by using a materials testing instrument was measured. Strain was estimated after incubation of transverse root slices in water. Measurements of the gap that developed as a result of a radial cut into the center of the slice were then used to estimate strain within the root. Extensibility of strips of carrot tissue was measured through two cycles of extension and relaxation, which allowed both elastic and plastic extensibility to be determined. Strain assessment demonstrated that carrot cells have considerable potential to increase in volume when placed in water. In some roots, phloem parenchyma adjacent to the cambium expanded to a greater extent than tissues at the periphery of the root, indicating that rigidity of cells varied across the carrot radius. Tissue extensibility was predominantly elastic, indicating the cells are unlikely to dissipate some of the strain that occurs during periods of rapid water uptake through plastic deformation. However, these measurements of extensibility were related to the properties of cells along the entire 20-mm length of the tissue strip that was used. Because we demonstrated that mechanical properties can vary within a small distance, it is concluded that future studies into the mechanical properties of carrot storage root tissue will rely on empirical strain measurements.
diverse collection of 61 genotypes ( Courtney, 2007 ) and indicates a broad range of potential iron uptake in this present population. Table 1. Half-sibling family mean estimates for iron, zinc, and dry matter in sweetpotato storage roots
Storage roots of `Beauregard' and Centennial' were analyzed for total fatty acid composition and fatty acid composition by lipid class. The glycolipid, monagalactosyldiglycerol, may have been involved in chilling tolerance of `Beauregard' storage roots. This lipid had over 70 percent low-melting point fatty acids, mostly linoleic acid and linolenic acid. No consistent differences in the composition of phospholipids could be related to the chilling responses of the two sweetpotato cultivars.
The presence of a major soluble protein in sweet potato [Ipomoea batatas (L.) Lam.] storage roots was demonstrated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Three research groups have previously isolated a major soluble protein. Results from SDS-PAGE in this study indicate that all three proteins (ipomoein, sporamin, and an unnamed 25-kDa protein) appear to be the same. Ipomoein is suggested as the preferred name for this soluble protein.
The sweetpotato [Ipomoea batatas (L.) Lam] breeding clone TU-82-155 was grown during Spring 1990 and Summer 1991 in standard Tuskegee Univ. (Alabama) growth channels (0.15 × 0.15 × 1.2 m) for 120 days in a greenhouse using a hydroponic (nutrient film) system with a modified half-strength Hoagland nutrient solution. The nutrient solution was changed every 2, 14, or 28 days. Total N, oil, ash, amino acid, vitamin, and mineral concentrations in storage roots generally were higher and dry weight and starch concentration were lower with 2-day solution changes than with those less frequent.