Effects of season and postharvest storage on the carotenoid content of Solanum phureja potato tubers

The total carotenoid content was determined of tubers from 38 Solanum phureja lines grown in field plots over 3 years. The results indicated a significant difference between years, but the ranking was similar from year to year and the interaction between season and variety was small. Postharvest storage significantly reduced the carotenoid content of the tubers, and reducing the storage temperature further lowered the carotenoid content. Examination of the individual carotenoids revealed that lutein was the most stable and least likely to be reduced, while the levels of the carotenoids derived from beta-carotene were significantly reduced during storage at either temperature. Exposure of the tubers to either mercury or sodium lights resulted in a significant increase in total carotenoid content, concomitant with elevated chlorophyll. Although both types of radiation produced a broadly similar increase in total carotenoid contents, differential effects on the individual carotenoid profile of the light-induced carotenoids were observed.     

Effect of selenate supplementation on glycoalkaloid content of potato (Solanum tuberosum L.)

Potatoes (Solanum tuberosum L.) supplemented with increasing amounts of sodium selenate were analyzed for glycoalkaloid (GA) content. GAs were extracted with 5% acetic acid from freeze-dried tubers of two potato cultivars, Satu and Sini, harvested 10 weeks after planting as immature. The GAs alpha-solanine and alpha-chaconine were quantified by reverse-phase high-performance liquid chromatography (RP-HPLC) with diode array detection. Two independent experiments were performed. In the first experiment, the total GA concentration +/- standard error of the tubers ranged between 105 +/- 9 and 124 +/- 10 mg kg(-1) fresh weight in Satu and between 194 +/- 26 and 228 +/- 10 mg kg(-1) fresh weight in Sini. The ratio of alpha-solanine to alpha-chaconine was 0.2 in Satu and 0.5-0.6 in Sini. In the second experiment, the total GA concentration +/- standard error was 75 +/- 4 to 96 +/- 11 mg kg(-1) fresh weight, and the ratio of alpha-solanine to alpha-chaconine was 0.3-0.4 in Satu. A high sodium selenate supplementation (0.9 mg of Se kg(-1) quartz sand) slightly decreased the GA content in Satu, but this decrease was not statistically significant. Furthermore, at this addition level the Se concentration increased to a very high level of 20 microg g(-1) dry weight, which cannot be recommended for human consumption. In both experiments, the Se concentration in tubers increased with increasing sodium selenate application levels. Our results show that acceptable application levels of selenate did not have an effect on the GA concentration in immature potato tubers.     

Comparison of fatty acid and polar lipid contents of tubers from two potato species, Solanum tuberosum and Solanum phureja

Total and individual fatty acid contents were determined in raw tubers of four genotypes from each of the two species Solanum phureja and S. tuberosum. The four S. phureja genotypes contained statistically significantly higher concentrations of total fatty acids, with their average value being 37% greater than that for the mean of the four S. tuberosum cultivars. In both species, a total of 17 fatty acids were detected in quantifiable amounts, and in all genotypes the predominant fatty acid was linoleic followed by alpha-linolenic and palmitic acids. Unusually, 15-methyl hexadecanoate was present as a minor acid in both species. Although a number of statistically significant differences in the fatty acid percentage compositions were found between and within the two species, these were generally small. Averaged over all species and genotypes, tuber storage resulted in an initial small but statistically significant increase in total fatty acid content, but prolonged storage resulted in a fall to the initial values detected close to harvest. The same trend was evident for S. phureja alone (for mean values of all genotypes), but for S. tuberosum the total fatty acid content remained constant over the whole storage period. For both species, the contents (both as absolute levels and as percent compositions) of linoleic acid decreased and alpha-linolenic acid increased in tubers over the whole storage period, and possible mechanisms are discussed. Also, the absolute levels of these two acids were greater in S. phureja than in S. tuberosum, and this is discussed in relation to the development of flavor-related compounds during cooking. The polar lipids of one representative of S. tuberosum and of S. phureja were qualitatively similar. There were only minor differences in the polar lipid percentage compositions and in the corresponding fatty acid compositions of the individual polar lipids between the two species, although the absolute levels of the total, and of some individual, polar lipids were higher in S. phureja.     

Influence of incorporated wild Solanum genomes on potato properties in terms of starch nanostructure and glycoalkaloid content

Interspecific somatic hybrids produced by protoplast fusion between two wild Solanum species (S. acaule, acl; S. brevidens, brd) and cultivated potato Solanum tuberosum (tbr) were analyzed in terms of the starch nanometer-range structure and glycoalkaloid (GA) contents. The crystallinity of starch granules, the average size of starch crystallites, and the lamellar distances were obtained from tuber samples using wide-angle and small-angle X-ray scattering methods. These measurements showed that incorporation of wild genomes from either nontuberous (brd) or tuberous (acl) Solanum species caused no significant modifications of the nanostructure of potato starch. In contrast, the GA profiles of the hybrids, which were analyzed by LC-ESI-MS in both tuber and foliage samples, differed considerably from those of cultivated potato. Regardless of the low total tuber GA concentrations (approximately 9 mg/100 g of fresh weight), the somatic hybrids contained GAs not detected in the parental species. A high proportion of spirotype GAs consisting of 5,6-dihydrogenated aglycons, for example, alpha-tomatine and tomatidine bound with solatriose, and chacotriose were found in the hybrids. In conclusion, the foliage of interspecific hybrids contained a higher variation in the structures of GAs than did the tubers.     

LC-MS analysis of solanidane glycoalkaloid diversity among tubers of four wild potato species and three cultivars (Solanum tuberosum)

Secondary metabolites in potato tubers include both phytonutrients and plant defense compounds. The extent these small molecules vary among different potato genotypes is not well characterized. LC-MS analysis of tuber extracts from seven potato genotypes showed that one large source of small molecule variation is the glycoalkaloids. Glycoalkaloids are involved in the resistance of potatoes to pathogens and pests, but they also have implications for human health and nutrition. This study focused on glycoalkaloids with solanidane or solanidane-like aglycones, of which over 50 were tentatively identified, many of which appeared to be novel glycoalkaloids. Results suggested the variety of glycoalkaloids in potatoes is considerably greater than previously thought. Dissecting the role of these many glycoalkaloids in human health or pest and pathogen resistance will be a formidable undertaking.     

Marker-assisted sampling of the cultivated Andean potato Solanum phureja collection using RAPD markers

The potato crop originated in the Andean highlands where numerous farmer's varieties and non-cultivated wild species exist. An Andean potato collection is held in trust at the International Potato Center (CIP) to preserve the biodiversity of this crop and ensure the supply of germplasm for potato improvement worldwide. A core collection representing the biodiversity of the Andean potato germplasm is under construction using morphological, molecular, and geographic data. One of the eight cultivated potato species, Solanum phureja, has been genotyped using the RAPD technique. A protocol suitable for large germplasm collection genotyping has been developed to process numerous samples at reasonable costs. From 106 RAPD primers evaluated, we have selected 12 primers yielding 102 polymorphic markers, which unambiguously discriminated all 128 accessions but 2 that are possible duplicates. The S. phureja germplasm collected throughout the Andean countries appears to have a homogeneous genetic constitution. There was no clear geographic pattern as indicated by cluster analysis of the RAPD data. A sub-group of 20 accessions has been identified on the basis of the marker data and selected to maximize molecular (RAPD) variance and polymorphism. The probability of capturing equal amounts of marker polymorphism in this sub-group of 20 accessions by random sampling is less than 40%. This set accessions represents our first group of accessions that may constitute a core of the S. phureja collection. This tentative core will be challenged for diversity content by alternate markers and agronomic traits. Hence, the methodology for sampling less than 10% of the base collection, proposed for core collections by Brown (1989), can be based on molecular marker data provided cost-efficient fingerprints are developed.     

Comparison of the calystegine composition and content of potato sprouts and tubers from Solanum tuberosum Group Phureja and Solanum tuberosum Group Tuberosum

The calystegines detected in tubers from 17 Phureja ( S. tuberosum Group Phureja) lines and five Tuberosum ( S. tuberosum Group Tuberosum) cultivars were identified as the A 3 and B 2 structural types. Their concentration in whole tubers was of a similar order of magnitude in both species, as was the variability in the ratio of B 2 to A 3. On average, calystegine concentrations in the peel were about 13 times that found in the flesh for the five Tuberosum cultivars, and 4 times higher for four Phureja lines. Removal of the peel reduced the calystegine content by an average of over 50% in Tuberosum but by only 30% in Phureja, despite the latter having the greater proportion of peel. The calystegine content of sprouts was also determined for five Tuberosum cultivars and four Phureja lines and was found to include small amounts of four additional types, B 3, B 4, N 1, and X 2, in addition to the more abundant A 3 and B 2. Concentrations in the sprouts of Tuberosum were on average 100 times higher than that in the tuber flesh and 8 times higher than in the peel, whereas for Phureja, the equivalent values were 30 and 7 times higher, respectively. No correlation was found between sprout concentration and either flesh or peel calystegine concentration.     

Effects of genotype,environment, and postharvest storage on the total ascorbate content of potato (Solanum tuberosum) tubers

The total ascorbate content of potato tubers from 33 Solanum tuberosum genotypes grown at three geographically diverse sites in Europe in each of two years was determined immediately postharvest and after approximately 4 months of storage at 4 degrees C. Statistically significant differences in total ascorbate concentration were observed between genotypes both at harvest and after storage. In all genotypes, the levels of ascorbate decreased during storage. These results are discussed in terms of their implications for diet and health as well as in terms of breeding for improved vitamin C content in potatoes.     

Sampling leaves of young potato (Solanum tuberosum) plants for glycoalkaloid analysis

Earlier attempts to measure potato (Solanum tuberosum) leaf glycoalkaloids indicated variability among similar plants, suggesting that a single small sampling of a young plant might not be a reliable measure of composition. It was also suggested that freeze-dried leaf samples might be less variable than fresh ones. In the present work, variability was minimized by comparing single leaves from the same stem position of each plant. Comparisons involving other leaves indicated that the glycoalkaloid content was not constant with respect to either time or position on the stem. In addition, the possible influence of differences in growing conditions at different times suggests that repeated plantings should include a known variety as a control to which other plants are compared. Variability was reduced by calculating glycoalkaloid concentrations on a dry weight rather than fresh weight basis. The method of drying the samples, however, had no influence on the variability of data. These considerations should be generally applicable to the sampling of replicate leaves of any plant for analysis of any components.     

Foliar application of selenite and selenate to potato (Solanum tuberosum): effect of a ligand agent on selenium content of tubers

The effect of a foliar spray of selenium on potatoes was investigated for 2 years. Amounts of 0, 50, and 150 g of Se ha(-)(1) were applied both as sodium selenate and as sodium selenite in water, either pure or with the addition of 0.15% of soluble leonardite as a source of humic acids (pH 7). Tuber selenium concentration increased with the application levels, both with sodium selenate and with sodium selenite, when only aqueous solutions were used. When humic acids were added, the tuber selenium level rose more markedly after the application of sodium selenate as compared to the case of the aqueous solutions; however, in the case of sodium selenite, the level showed a large increase only after the application of 50 g of Se ha(-)(1). Kinetics showed that humic acids raised the selenate availability, but no differences were found in the distribution of selenium in the tuber fractions. Foliar application of selenium with humic acids was proven to be a good way to increase the selenium content of potatoes, but the assimilation process of selenium was simpler with selenate than with selenite.     

Radical scavenging capacity and antimutagenic properties of purified proteins from Solanum betaceum fruits and Solanum tuberosum tubers

In this study, antioxidant activities in free-radical-mediated oxidative systems and the genotoxic/antigenotoxic effects of two proteins with molecular mass around 17 kDa, purified from Solanum betaceum fruits (cyphomine) and Solanum tuberosum tubers (solamarine), were investigated. Both proteins inhibited uric acid formation with IC(50) values between 55 and 60 μg/mL, and both proteins were able to reduce oxidative damage by scavenging hydroxyl radicals and superoxide anion in a dose-dependent manner. Furthermore, the DPPH? reduction assay showed SC(50) values of 55-73 μg/mL. Cyphomine and solamarine were able to retain their antioxidant activity after heat treatment at 80 °C for 15 min. Allium cepa and Salmonella /microsome assays showed no genotoxic and mutagenic effects. Solamarine showed an antimutagenic effect against a direct mutagen (4-nitro-o-phenylenediamine). Consequently, the present study showed that the investigated proteins are promising ingredients for the development of functional foods with a beneficial impact on human health and an important source for the production of bioactive peptides.     

离体条件下评价二倍体马铃薯(Solanum phureja ×S. stenotomum)耐盐性

为评价马铃薯耐盐性,筛选耐盐种质资源,本研究以164份二倍体马铃薯杂种后代及其亲本为试验材料,进行NaCl胁迫处理,测量盐胁迫和对照条件下杂交后代和亲本的芽长、芽鲜重、芽干重、根长、根鲜重和根干重6个形态指标,然后运用隶属函数分析和聚类分析方法进行综合评价及分类。结果表明,以亲本为对照,比较综合评价D值,筛选出26个耐盐无性系和10个盐敏感无性系;利用6个形态指标和D值分别聚类分析,166个无性系均被分为4个耐盐性不同的类群,表明可以分别利用6个形态指标和D值进行聚类,筛选出在同一类群中共同包含的无性系,提高耐盐评价的精确性;后代无性系根长相对值平均值较高(62.5),且聚类分析后,第一类群和第二类群的根长相对值的差异较小,说明根长不是理想的形态筛选指标,可以考虑用主根数替代根长,作为耐盐筛选的形态指标之一。本研究结果为快速评价大量马铃薯种质资源的耐盐性和马铃薯耐盐育种提供了理论依据和材料基础。     

Impact of crop production system on the content of macronutrients in potato tubers

ABSTRACT

The content of macronutrients in potato tubers arouses interest because of their substantial consumption in the world and significant role in elements' budget in human diet. The research objective has been to evaluate the content of macronutrients in tubers of potatoes grown in different systems of crop production in Poland. In 2012–2014, an experiment was conducted to test potato cultivation in three-crop production systems: conventional, integrated and organic. In each of the six-field crop rotation systems, there were five potato cultivars classified into different earliness groups. The following macronutrients in dry mass of potato tubers were determined: N, P, K, Ca, Mg, Na, S and Cl, and the various ratios between them were calculated. The research carried out proved that potatoes production systems affect the chemical composition of tubers, which is additionally modified by whether condition and genetic features of cultivars. Potato tubers from organic farming contained by about 20% less N than tubers from conventional or integrated systems. Potato tubers from organic production system displayed lower content of Ca and Na in comparison with the conventional and integrated systems. The least of P and S were detected in tubers of the potatoes grown conventionally.     

Nitrates content in table potato tubers under the influence of herbicides and biostimulants

The objective of the study was to determine the effect of herbicides and biostimulants on the potato tuber content of nitrates. The experimental material consisted of tubers harvested in a field experiment which examined the following factors: three medium early potato cultivars (Bartek, Gawin, Honorata) and five methods of herbicide and biostimulant application (Harrier 295 ZC (linuron?+?chlomazon), Sencor 70 WG (metribuzin), growth regulator Kelpak SL (algae extract from Ecklonia maxima ? auxins and gibberellins), growth regulator Asahi SL (sodium para-nitrophenol, sodium ortho-nitrophenol, sodium 5-nitroguaiacol) and a control unit where weeds were mechanically controlled). The tuber content of nitrates was determined in fresh matter with an ion-selective nitrate electrode and silver–silver chloride reference electrode. Herbicides and biostimulants increased the potato tuber content of nitrates compared with control tubers. However, they did not pose a threat to consumer health. Tubers of plants sprayed with the herbicide Sencor 70 WG (metribuzin) and the biostimulant Asahi SL (sodium para-nitrophenol, sodium ortho-nitrophenol, sodium 5-nitroguaiacol) contained the most nitrates whose accumulation was also affected by cultivars and weather conditions in the study years.     

Influence of storage upon light-induced chlorogenic acid accumulation in potato tubers (Solanum tuberosum L.)

The influence of 2 weeks and 3 months of dark storage upon light-induced chlorogenic acid accumulation within tuber tissue of four potato cultivars and upon 5-, 4-, and 3-caffeoylquinic acid concentrations within cv. King Edward was determined. Storage period significantly affected (P < 0.05) the magnitude of the light-induced chlorogenic acid response with accumulation rates 3-4 times higher in tubers exposed to light after 2 weeks compared with those placed under light after 3 months. Comparison of chlorogenic acid concentrations in controls after 2 and 3 months of dark storage indicated that tuber chlorogenic concentrations decline during prolonged cold store at 5 degrees C. Rates of accumulation in response to light were cultivar-dependent with cv. Fianna the most light-sensitive and cv. Maris Piper relatively light-insensitive. In virtually all cases exposure to sodium and fluorescent light promoted higher rates of accumulation than did exposure to high-pressure mercury light sources. Chlorogenic acid values steadily increased over 15 days of illumination with, in the majority of cases, no indication of cessation. Light exposure increased 5-, 4-, and 3-caffeoylquinic acid accumulation rates in cv. King Edward. Irrespective of storage period and light source, ratios of 5-:4-:3-caffeoylquinic acid were ca. 85:15:0 at day 0 and 52:42:6 by day 15.     

The effect of different production systems on the content of micronutrients and trace elements in potato tubers

The aim of this study was to determine the effect of different production systems (conventional, integrated and organic) on the content of micronutrients and trace elements in the tubers of very early, early and medium-early maturing potato cultivars. Five Polish potato cultivars were grown in three production systems under field conditions. In plant material selected microelements (chemical elements essential for living organisms) were analysed: boron (B), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn) as well as some trace elements (not regarded as essential element for living organisms): chromium (Cr), nickel, (Ni) and lead (Pb). The content of micronutrients and trace elements in potato tubers was modified by production system, genotype and weather conditions during the growing season. Organically grown potatoes had a higher content of B (8.6–8.9?mg kg^?1) and Cu (2.8–3.1?mg?kg^?1), and a lower content of Fe (47.0–47.1?mg?kg^?1), Mn (6.0–6.4?mg?kg^?1) and Zn (11.9–12.2?mg?kg^?1), than potatoes grown in conventional and integrated systems. Potatoes grown in the conventional system had the highest Pb content. Organic cultivation can assure better alimentation of potato tubers with B and Cu, which are important microelements often deficient in the soils. On the contrary, when cultivating potato in conventional system, one should supply this element with fertilisers.     

不同光强下龙葵对镉的吸收积累及生理响应

采用土培方法探讨了不同光强（自然光和50%遮光）和镉（Cd）不同添加量（0、 25、 50、 75和100 mg/kg）复合处理下,龙葵对Cd的吸收累积特征,超氧化物歧化酶（SOD）、 过氧化物酶（POD）、 过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性以及叶绿素、 丙二醛（MDA）、 谷胱甘肽（GSH）和植物螯合肽（PCs）含量等的变化特征。结果表明, 自然光条件下龙葵叶绿素b、 叶绿素a+b以及地上和地下部Cd富集量均显著低于遮光处理; 叶和根的SOD、 POD、 CAT和APX活性在自然光条件下随土壤Cd添加量的增大先升后降,而在遮光处理下则持续升高; 除Cd 25 mg/kg处理时根POD及叶CAT活性在不同光强处理下没有显著差异外,其余Cd添加量处理下SOD、 POD、 CAT和APX活性在自然光条件下均显著高于遮光处理; 自然光条件下龙葵叶和根的MDA含量显著高于遮光处理,而叶和根的GSH含量和叶中PCs含量均显著低于遮光处理。研究结果表明,遮光环境促进了龙葵对Cd的富集,并且减轻了Cd对龙葵的氧化胁迫。     

Effect of seasonal changes on content and profile of soluble carbohydrates in tubers of different varieties of Jerusalem artichoke (Helianthus tuberosus L.)

A high content (60-65% of dry mass DM) of water soluble carbohydrates was found in early harvested varieties (Bella and Bianka) and middle early varieties (Topstar and Gigant) harvested 22-25 weeks after plantation. In late varieties (Waldspindel, Violet de Rennes, Rote Zonenkugel) a similar amount was obtained (55-60% of DM) when harvested 29-33 weeks after planting. There was a distinctive impact on maturing process as well as frost period alterations which resulted in conversion of high polymer inulin to low polymer inulin as well as to sucrose. In early/middle early varieties a correlation between sucrose and inulin level (r = - 0.952**) with a linear regression of y = - 1.35x + 62.32 was observed, whereas the dpn of inulin decreased from 12-14 to 6-8. In late cultivars this correlation was not as exact (r = - 0.502**); dpn of inulin decreased from 12-16 to 7-10. This knowledge about carbohydrate profiles for different varieties of Jerusalem artichoke offers the possibility of selecting suitable cultivars and deciding the appropriate harvest time for an optimum processing of tubers for their application as prebiotic and novel food component.     

刺萼龙葵对入侵地土壤可培养真菌多样性影响

为了研究刺萼龙葵入侵的微生物学机制,分别在2008年至2009年7月、8月在刺萼龙葵入侵严重的朝阳地区选择3个样区,即入侵区(Ⅰ)、耕作区(Ⅱ)及土著区(Ⅲ)进行选择性取土及抽样调查,对采集的75份土样经分离、纯化、鉴定的真菌分属30个属,通过对刺萼龙葵入侵区(Ⅰ)土壤真菌的培养,共分离鉴定出了约40种真菌,且分属21个属;其中在刺萼龙葵入侵区(Ⅰ)土壤真菌的各种类群中,以青霉属(Penicillium)、曲霉属(Aspergillus)、毛霉属(Mucor)、根霉属(Rhizopus)、木霉属(Trichoderma)、镰孢菌属(Fusarium)、枝顶孢属(Acremonium)种类较多,为优势类群,其分离频率分别为18.13%、15.20%、8.77%、8.77%、7.60%、5.85%、5.26%。而附球菌属(Epicoccum)、接霉属(Zygorhynchus)、节丛孢属(Arthrobotrys)、弯孢属(Cunularia)菌株数仅为1,为该区稀有类群;通过对入侵区(Ⅰ)、耕作区(Ⅱ)及土著区(Ⅲ)土壤真菌数量比较发现,入侵区(Ⅰ)土壤真菌数量是耕作区(Ⅱ)的1.6倍,而入侵区(Ⅰ)与土著区(Ⅲ)的土壤真菌数量相差不大,比例接近1;根据Jaccard相似性指数原理,入侵区(Ⅰ)、耕作区(Ⅱ)和土著区(Ⅲ)的土壤真菌群落相似性处在中等相似的水平,其土壤真菌群落相似性差异性并不显著。结果表明刺萼龙葵入侵并没有使土壤可培养真菌多样性产生明显的变化。     

Effects of light treatment on isoflavone content of germinated soybean seeds

Our research objective was to increase isoflavone content in the germinated soybean seeds of four different varieties (Pungsannamulkong, Cheongjakong, Aga4, and Aga3) by optimizing light treatments (dark, greenhouse, fluorescent, incandescent, and ultraviolet lamps). The results demonstrated that the highest isoflavone content was produced from the Aga3 variety, which was developed by an interspecific cross between Eunhakong (Glycine max) and KLG10084 (G. soja) at the Plant Genetic Laboratory, Kyunpook National University. Aga3 is known to have one of the highest isoflavone content in the world at present. Our results recommend exposure of 7-day-old Aga3 sprouts to a combined light treatment of greenhouse lamps (12 h per day) and ultraviolet light (40 min per day) for maximum isoflavone production. Aga3 produced high levels of isoflavone because, in part, it contained very high isoflavone levels within the seed as compared with the other varieties. Under stress conditions, Aga3 could produce over 1.90 times more isoflavone than its seed content and 1.53 times more isoflavone than when grown under dark conditions.