Transgenic potato plants expressing oxalate oxidase have increased resistance to oomycete and bacterial pathogens

Summary Potato (cv. Bintje) was transformed with a gene encoding an oxalate oxidase from wheat under the control of the CaMV35S promoter. Transgenic potato plants produced high constitutive levels of H₂O₂ as visualized by 4-chloro-l-naphtol staining. The resistance of these plants was tested againstPhytophthora infestans. An increased level of resistance to the disease was marked by a reduced number of lesions as well as by a decreased number of sporangia formed per lesion. In addition, oxalate oxidase overexpressing plants also exhibited improved resistance toStreptomyces reticuliscabiei, the causal agent of netted scab. Increased expression of oxalate oxidase had no effect on the interaction withErwinia carotovora. These experiments show that overexpression of oxalate oxidase represents a potentially interesting approach for protection of potato to pathogens.     

Effect of haulm treatment and harvest time on incidence of tuber rots of potato (Solanum tuberosum L.) after standard wounding and on frequency of stem lesions caused byPhoma foveata Foister

Summary Various haulm treatments and harvest times differentially influenced the incidence of storage rots in potato tubers (Solanum tuberosum L.) in field experiments in Sweden performed over 4 years. The incidence of gangrene caused byPhoma foveata Foister (Phoma exigua var.foveata (Foister) Boerema) increased in cv. Bellona after spraying haulms with diquat as did the amount of infection caused byFusarium avenaceum (Corda ex. Fr.) Sacc. in all three cultivars (Bintje, Bellona, and Magnum Bonum). The lowestP. foveata infection levels occurred after pulling haulms. Late harvesting increased the frequency ofP. foveata in cvs Bintje and Bellona both at 2 and 4 wks interval between haulm treatment and harvest. Tuber and visible stem infection caused byP. foveata were correlated for cvs Bintje and Bellona, but not for cv. Magnum Bonum. The possible relation between tuber and stem infection is discussed.     

Interactive Effects of Sodium and Potassium on the Growth and Photosynthesis of Spinach and Komatsuna

Abstract

Two cultivars of spinach and one cultivar of komatsuna were sand cultured using a nutrient solution with Na and K in various combinations. The growth (fresh weight of shoot) of spinach cv. Atlas was significantly increased when 1.4 mM KC1 of the 7 m M KO was replaced with 1.4 mM NaCl, although the growth was reduced when more KC1 was replaced with NaCl. In another spinach cv. All Right, however, NaCl substituting for 20% of KC1 showed no significant effects. In komatsuna, Na used in place of K at any ratio reduced the growth. The growth of spinach cv. Atlas was increased by applying 20 mM NaCl, irrespective of K dose (480 - 2400 mg K₂O per 1/2000 a Wagner pot). The growth of spinach cv. All Right was also increased by 20 mM NaCl when K was at a deficient level (480 - 960 mg K20 per pot), but was not when K was at: an excessive level (1920 - 2400 mg K₂O per pot). In komatsuna, 20 mM NaCl reduced the growth. In spinach, Na prevented the decrease of the photosynthetic rate and stomatal conductance caused by K deficiency.     

Increased calcium availability improves potato micropropagation and microtuberization

Summary Liquid scintillation counting (LSC) was used to screen six potato cultivars (Alpha, Bintje, Green Mountain, Kennebec, Russet Burbank, and Shepody) and two wild species(S. microdontum andS. kurtzianum) for ability to take up the tracer⁴⁵Ca²⁺ from treatment solutions containing high (15 mM) or low (5 mM) Ca²⁺ levels. In vitro potato micropropagation, microtuberization, and tissue calcium content, determined by flame atomic absorption spectrophotometry (FAAS), were compared for the six cultivars when Murashige-Skoog basal medium Ca²⁺ level was increased from 3, to 5 or 15 mM. All aspects of growth were improved when medium Ca²⁺ level was 15 mM. Microtuber induction occurred earlier, leading to improved yield (19–31%), and microtuber tissue Ca²⁺ concentration was greater (38–226%). Cv. Bintje was the most efficient genotype at accumulating Ca²⁺ from treatment solutions or growth media containing high or low Ca²⁺ levels. It could be identified as a calcium-packer using either LSC or FAAS screening.     

The effect of chloride fertilization on blackspot susceptibility and other quality characteristics and on yield of potato

Summary Trials were carried out in two years on a sandy loam and on a heavy clay soil with two cultivars to examine the potential of chloride fertilization as a tool to reduce blackspot susceptibility of potatoes and to investigate other effects on yield and quality. Blackspot susceptibility was significantly reduced in cv. Marijke, but not in cv. Bintje as a result of increasing doses of applied chloride from 0 to 400 kg ha1. Dry matter concentration, assessed as under-water weight, was reduced by chloride in both cultivars at the two locations. Fry colour of French fries was improved by chloride. Applying 400 kg ha⁻¹ Cl⁻ to both soil types decreased net tuber yield >35 mm of cv. Bintje but not of cv. Marijke. Chloride caused slower emergence, retarded crop development and less stems per plant on the sandy loam soil but not on the heavy clay soil.     

Effect of applying nitrogen fertilizer to a potato seed crop on the susceptibility of the daughter plants toErwinia carotovora subsp.atroseptica

Summary Seed potatoes of cvs Record and Bintje were grown with 30, 80 or 130 kg N/ha. In the subsequent growing season the seed tubers, which were inoculated or not with two concentrations ofErwinia carotovora subsp.atroseptica (Eca), were subjected to the same fertilization treatment. The incidence of blackleg and the level of seed tuber decay increased from the uninoculated treatment to the higher inoculum level, but the degree varied considerably from one year to another. Cv. Bintje was more susceptible to blackleg and yield loss caused by Eca than cv. Record. In 1990, when disease incidence was high, the proportion of blackleg stems increased with increasing doses of nitrogen fertilizer which had been applied to the seed crop, but was not significantly affected in 1988 and 1992. Seed tuber decay was retarded by the lowest nitrogen dose. The yield of the subsequent crop was not affected by the nitrogen dose applied to the seed crop.     

Production of phytoalexins, glycoalkaloids and phenolics in leaves and tubers of potato cultivars with different degrees of field resistance after infection withPhytophthora infestans

Summary The kinetics of accumulation of phytoalexins, glycoalkaloids and phenolics was studied in two potato cultivars differing in their degrees of field resistance when infected withPhytophthora infestans. Tuber slices and leaves of cvs Pampeana INTA (high degree of field resistance, free of R genes) and Bintje (susceptible) were infected with race C (complex race 1, 3, 5, 7, 11) ofPhytophthora infestans. Phytoalexins and phenolics accumulated in tuber and leaf tissues which had been inoculated. The levels of these compounds in the susceptible cv. Bintje were relatively low and similar to those found before inoculation. Leaves of cv. Pampeana INTA had a very high glycoalkaloid content, suggesting that glycoalkaloids may play a role in protection of leaves against the fungus. However, we could find no correlation between resistance and glycoalkaloid content of tubers. Our results suggest a major role of phytoalexins, phenolics and glycoalkaloids in the complex mechanisms of field resistance.     

Phosphorus reduces salinity stress in micropropated potato

The present study was conducted to determine whether varying the sodium chloride (NaCl) concentrations in Murashige and Skoog (MS) basal medium could affect radiophosphorus (³²P) uptake, and whether high NaCl stress was moderated by the availability of inorganic phosphorus (Pi) to micropropagated potato (Solanum tuberosum L. cv. Russet Burbank). The kinetics of³²P uptake in micropropagated potato plantlets was studied over a 48-hr interval in MS medium containing 1.25 mM Pi and varying concentrations of NaCl (0 to 120 mM). The³²P activity of the top-most trifoliate leaf increased considerably with time, but decreased significantly as medium NaCl concentrations increased. The³²P activity of the root tips at 48 hr was greater, but translocation of Pi into leaves was less, as medium NaCl concentration increased. As medium Pi concentration was increased from 0 to 2.5 mM, in the presence of 120 mM NaCl,³²P activity decreased in root tips but translocation into the topmost leaves occurred more efficiently.     

Yield and Quality Response of Two Potato Cultivars to Nitrogen Fertilization

Potatoes require high nitrogen (N) fertilizer rates because of their poor N efficiency. Better understanding of N dynamic in potato crops could improve N efficiency and thus enhance crop profitability and reduce N losses. A similar field experiment was conducted in Switzerland in 3 years, from 2009 to 2011, to investigate the yield and quality response to N fertilization of two commercial potato cultivars with different tuber qualities, Bintje and Laura. Five doses of ammonium nitrate were tested: 0, 80, 120, 160 and 200 kg N ha^?1. Aboveground and belowground biomass evolution, total yield, starch concentration and tuber sizes were measured annually. In 2011, the total N uptake and the soil mineral N content were also measured during the growing season and at harvest.The study showed that N fertilization had a positive effect on yield and the percentage of large tubers (>?70 mm) and a negative effect on starch concentration. Both cultivars presented the same potential yield, although cv. Laura’s yield was more affected by N fertilization deficiency and more responsive to the late N fertilizer application. At harvest, both cultivars had a similar N uptake efficiency and N utilization efficiency. However, they differed with respect to N uptake dynamics. Nitrogen uptake was slower for cv. Laura than for cv. Bintje due to a longer period required for the development of the belowground biomass. The results provide useful recommendations for improvement of N fertilization practices (e.g. rate and time of application) of these two cultivars in Swiss conditions.     

香蕉对低pH和铝毒胁迫的响应

香蕉是世界重要的热带亚热带水果,在热带经济的发展中占有重要的地位.我国是世界香蕉重要生产国之一,总产量仅次于印度,位居世界第二.低pH和铝毒是香蕉生产中面临的重要限制因子,严重影响香蕉的产量和品质.明确低pH和铝毒胁迫对香蕉生长和养分吸收的影响,为调控酸性土壤提供重要的理论依据.本研究分别在盆栽和水培条件下开展试验,盆...     

Salinity stress and sodium-potassium interactions in micropropagated potatoes

Summary Increased potassium (K) fertilization of saline soils has been implicated in alleviating salt stress in plants. We examined whether varying K concentrations in Murashige & Skoog (MS: 1962) basal medium could affect salt (NaCl) stress in micropropagated potatoes. Plantlets of cvs Sierra and Russet Burbank were evaluated after 1 month of growth in a medium containing 0. 40, or 80 mM NaCl and 6,20, or 30 mMK. The medium K was adjusted using KNO₃ while total nitrogen was kept constant using NH₄NO₃. Growth parameters were less affected in Sierra than Russet Burbank, and roots were less affected than shoots, as the medium salinity increased. Tissue Na levels were greater when the medium K was 6 mM compared with 20 mM MS control. The medium K concentration 50% greater than MS control did not promote growth and did not limit tissue Na levels. While this should be confirmed by field assessment, our results suggest that while K deficiency promotes salt damage, its addition beyond the usual fertilizer recommendations is not beneficial in alleviating salinity stress.     

Essai de conservation des pommes de terre en atmosphère contrôlée

Résumé Un essai a été effectué avec les 5 principales variété de consommation et de garde cultivées en Suisse. L'air ambiant se composait de 2% d'oxygène et un taux de CO₂ variant de 1–12%. Les températures ont été fixées à 8 et 10°C et l'humidité relative à 85–90%. La variété Bintje a présenté la meilleure aptitude à ce genre de conservation et Eba la plus médiocre. Pour les deux années suivantes, les essais ont été limités à la variété Bintje. L'oxygène variait de 2 à 15% et le CO₂ a été maintenu constant à 6%. Les pertes par deshydratation ont atteint l à 3% et celles causées par la pourriture 2 à 12% après 120 à 178 jours de conservation en atmosphère contr?lée. La qualité organoleptique des tubercules s'est dégradée en raison d'une accumulation très forte des sucres, en particulier le saccharose. Ce type de conservation semblerait également favoriser certains parasites fongiques. Un effet inhibiteur de la germination a été observé.

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Summary Sprout inhibiting chemicals must be used when potatoes are stored for more than 3 4 months at 8°C. However, tuber metabolism can be regulated and sprout growth inhibited by controlled atmosphere storage. A 3-year study was carried out at the Federal Agricultural Research Station in Changins. In 1978, 5 main table and industrial cultivars grown in Switzerland were tested. The storage atmosphere contained 2% O₂ and CO₂ concentrations of 1,6 or 12%. The temperature was maintained at 8°C and the relative humidity at 85–90% (Table I). This first experiment showed that the cultivars tested varied widely in their storage characteristics. Losses were greatest with cv. Eba, whereas cv. Bintje appeared to store best (Table 2). In 1979 and 1980 only cv. Bintje grown in different regions was used. Oxygen concentrations were 2,6 or 15% and CO₂ concentration was maintained constant at 6%. Temperatures were 8 or 10°C and relative humidity 85 or 95%. Minimum ventilation was maintained throughout the period. Weight losses were 1 3% and losses due to decay 2 12% after 120 178 days of storage (Table 3). Under these conditions, cooking quality was seriously affected because of the marked build-up of sugars, particularly sucrose (Tables 4 and 5). Tuber flesh tended to be more oxidised after cooking (Table 7). The storage conditions also favoured fungal decay caused byFusarium spp. A satisfactory degree of sprout inhibition was obtained. Tubers treated with a sprout inhibiting chemical and stored under normal conditions had better cooking and industrial utilisation qualities than those stored in controlled atmospheres.

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Zusammenfassung Die Kartoffellagerung w?hrend mehr als 3 bis 4 Monate bei einer Temperatur von 8°C ben?tigt die Anwendung von Keimhemmungsmitteln. Die kontrollierte Atmosph?re wirkt auf den Knollenmetabolismus ein und sollte somit erm?glichen das Keimwachstum zu hemmen. W?hrend 3 Jahren wurde an der Landwirtschaftlichen Forschungsanstalt Changins ein Kartoffelagerungsversuch in kontrollierter Atmosph?re durchgeführt. Im Herbst 1978 wurde der Versuch mit 5 in der Schweiz angebauten Lager- und Speisesorten angelegt. Folgende Lagerungsbedingungen wurden gew?hlt: Sauerstoff (O₂) 2% und Kohlendioxyd (CO₂) je nach Verfahren 1 bis 12%. Die Temperaturen betrugen 8°C und 10°C. Dieser erste Versuch zeigte bedeutende Unterschiede im Lagerverhalten zwischen den einzelnen Sorten, wobei Eba die gr?ssten Verluste aufwies und Bintje die geringsten (Tab. 2). In den Jahren 1979 und 1980 wurde der Versuch mit der Sorte Bintje aus verschiedenen Herkünften durchgeführt. Der Sauerstoffgehalt variierte von 2 bis 15% und der Kohlendioxydgehalt wurde konstant bei 6% gehalten. Die Temperaturen betrugen 8 und 10°C und die relative Luftfeuchtigkeit 85–90%. Die Belüftung wurde kontinuierlich und minimal gehalten. Die Gewichts-und F?ulnisverluste betrugen nach 120 bis 178 Lagerungstagen 1 3%, respektiv 2 12% (Tab. 3). Die Speisequalit?t der Kartoffeln hat sich unter diesen Bedingungen deutlich verschlechtert unter anderem infolge erh?hter Zuckeranreicherung und speziell von Saccharose (Tab. 4 und 5). Es wurde eine erh?hte Tendenz zur Oxydation der Knollen nach dem Kochen beobachtet (Tab. 7). Diese Lagerbedingungen begünstigen einige Pilzf?ulnisse, vor allem verursacht durchFusarium-arten. Es wurde eine befriedigende Keimhemmung w?hrend der Lagerung beobachtet. Mit Keimhemmungsmitteln und in natürlicher Luft gelagerte Knollen zeigten im Vergleich zu denen in kontrollierter Atmosph?re gehaltenen Kartoffeln eine bessere Speise- und Verarbeitungsqualit?t.

     

The Selective Extraction of Glucuronoarabinoxylans from Sorghum Endosperm Cell Walls using Barium and Potassium Hydroxide Solutions

Various populations of hemicellulosic material were solubilised from water-unextractable cell wall material (WUS) of sorghum (Sorghum vulgarecv. Fara Fara) by sequential extractions with alkali. Saturated Ba(OH)₂-solutions, followed by distilled water, 1 KOH, 4 KOH and 4 KOH containing 4% (w/v) H₃BO₃ were used to extract primarily glucuronoarabinoxylans (GAX) from sorghum WUS. Cellulose remained in the residue. In total over 90% of all GAX originally present in the WUS were recovered, particularly in the saturated Ba(OH)₂, 1 KOH and 4 KOH extracts. Saturated Ba(OH)₂ was found to be the most selective of the extractants tested for GAX. (1→3), (1→4)-β- -glucans were found predominantly in the fraction obtained by washing with water after the extraction with saturated Ba(OH)₂. All extracted arabinoxylans were highly substituted (arabinose/xylose>1) and contained, besides -arabinose and -xylose, the acidic sugars -glucuronic, 4-O-methyl- -glucuronic and -galacturonic acid. The average molecular weight ranged from 210 000–1 300 000, which corresponds with DPs ofc. 1500 to 9300. The selectivity of the extractant was apparently enhanced by the presence of a bivalent cation.     

利用秸秆和肥料增殖木霉及对玉米茎基腐病的生物防治

以玉米秸秆为基质,筛选对木霉增殖有利的营养物质,对生防制剂的田间应用提供依据。利用Plack-ett-Burman试验设计筛选影响木霉产孢的主要营养物,采用最陡爬坡试验测定3种营养物的最适浓度范围;通过Box-Benhnken试验设计,对3种营养物浓度进行优化;盆栽试验检测木霉在土壤中的存活情况防治玉米茎基腐病。结果表明,筛选对木霉产孢影响较大的3个营养物质(氯化铵、硫酸钾、七水硫酸亚铁),最佳配方为氯化铵0.97 g/L,硫酸钾0.92 g/L,七水硫酸亚铁0.97 g/L,在此配方条件下孢子产量为2.61×10~9个/g。盆栽试验表明,利用木霉结合秸秆还田和肥料施用,可增强其存活能力和降低玉米茎基腐病的发生率和病情指数。     

Effect of different levels of nitrogen and farmyard manure on yield and quality of spinach (Spinacea oleracea L.)

The effect of different levels of nitrogen N₀(0kg/ha), N₁(30 kg/ha), N₂ (60 kg/ha), and N₃ (90 kg/ha) and farmyard manure F₀ (0 tonnes/ha), F₁ (10 tonnes/ha), and F₂ (20 tonnes/ha) on the yield and nutrient composition of spinach and its uptake was investigated on a sandy loam soil. Yield; phosphorus, iron, manganese, zinc, and copper uptakes; and ascorbic acid content increased with the application of both the inorganic nitrogen fertilizer and the farmyard manure, with a maximum at the N₃F₂ level, i.e. at 90 kg N/ha with 20 tonnes FYM/ha. However, the contents of protein, -carotene, and reducing sugars were maximum at the highest dose of nitrogen without the application of farmyard manure.     

Potato growth and yield using nutrient film technique (NFT)

Potato plants, cvs Denali and Norland, were grown in polyvinyl chloride (PVC) trays using a continuous flowing nutrient film technique (NFT) to study tuber yield for NASs Controlled Ecological Life Support Systems (CELSS) program. Nutrient solution pH was controlled automatically using 0.39M (2.5% (v/v) nitric acid (HNO₃), while water and nutrients were replenished manually each day and twice each week, respectively. Plants were spaced either one or two per tray, allotting 0.2 or 0.4 m² per plant. ALl plants were harvested after 112 days. Denali plants yielded 2850 and 2800 g tuber fresh weight from the one- and two-plant trays, respectively, while Norland plants yielded 1800 and 2400 g tuber fresh weight from the one- and two-plant trays. Many tubers of both cultivars showed injury to the periderrn tissue, possibly caused by salt accumulation from the nutrient solution on the surface. Total system water usage throughout the study for all the plants equaled 709 liters (L), or approximately 2 L m^-2 d^-1 (7.2 mmol m^-2d^-l). Total system acid usage throughout the study (for nutrient solution pH control) equaled 6.60 L, or 18.4 ml m^-2 d^-1 (7.2 mmol m^-2d^-l). The results demonstrate that continuous flowing nutrient film technique can be used for tuber production with acceptable yields for the CELSS program.     

Fractional isolation and partial characterization of non-starch polysaccharides and lignin from sago pith

Sago pith non-starch polysaccharides were fractionated into cold water solubles (2.6%), hot water solubles (0.8%), dimethylsulfoxide solubles (0.8%), 5% NaOH soluble hemicelluloses (1.2%), 24% KOH–2% H₃BO₃ soluble hemicelluloses (0.6%), and cellulose (5.3%). Lignin was measured by 5% NaOH extraction (0.6%) and sodium chlorite oxidation (4.2%). Glucose and rhamnose were the major sugars in cold and hot water soluble non-starch polysaccharides. The neutral sugars in dimethylsulfoxide (DMSO) soluble non-starch polysaccharides were found to be enriched in rhamnose, xylose, glucose, and arabinose. Extraction of sago pith with aqueous 5% NaOH produced hemicelluloses, which were enriched in xylose and, to a lesser extent, glucose, arabinose, galactose, and rhamnose-containing polysaccharides, together with 7.4% uronic acids and 3.9% lignin. Further extraction of the delignified pith residue with aqueous 24% KOH and 2% H₃BO₃ removed the residual hemicellulosic fraction, which was enriched in glucose and xylose-containing polysaccharides, together with 5.8% uronic acids and 1.1% associated residual lignin. Six phenolic acids and aldehydes were detected in the mixtures of alkaline nitrobenzene oxidation of 5% NaOH soluble lignin and associated lignin in hemicelluloses and cellulose fractions. The lignin fraction contained a high proportion of non-condensed syringyl units and small amounts of non-condensed guaiacyl units as well as fewer non-condensed p-hydroxyphenyl units.     

Increase in phosphorylase activity during cold-induced sugar accumulation in potato tubers

Summary The accumulation of reducing sugars, sucrose and hexose phosphates in cv. Bintje and genotype KW77-2916 during storage at 2, 4, or 8°C was studied in relation to several catalytic activities. Bintje tubers accumulated sugars during storage at 2 or 4°C, whereas KW77-2916 showed reduced cold-sweetening at 2°C. The increase in glucose 6-phosphate and sucrose occurred concurrently and preceded the increase in reducing sugar concentration. Phosphorylase activity showed a strong interaction with temperature, storage duration and sugar accumulation in both genotypes. Invertase activity increased in Bintje concomitantly with the increase in reducing sugars, but this effect was less obvious in KW77-2916. The activities of other glycolytic and Krebs cycle enzymes showed no obvious correlation with sugar accumulation. It is suggested that the increase in phosphorylase activity acts as a triggering event in the sweetening of potato tubers during cold storage.     

The Role of Active and Passive Water Uptake in Maintaining Leaf Water Status and Photosynthesis in Tomato under Water Deficit

Abstract

Tomato (Lycopersicon esculentum Mill. cv. Know-You 301) shoots were grafted onto the rootstock of the same species or Solanum mammosum and grown in nutrient solution. After the grafted tomato plants developed 4–5 leaves, the uppermost fully expanded leaves were used to determine net photosynthetic rate (P_N) , transpiration rate and leaf water potential (Ψ_L) under control (unstressed) and —0.5 MPa water deficit (mannitol was added to nutrient solution). Both PN and leaf conductance (G_L) were reduced under water deficit. However, tomato plants grafted onto S. mammosum rootstock had higher Ψ_L, P_N and G_L than those grafted onto tomato rootstock under water deficit. This result demonstrates that S. mammosum roots had a greater ability in water uptake under water deficit. Under +0.2 MPa pressure, the root of S. mammosum showed a higher exudation rate than that of tomato. However, the former showed a lower exudation rate than the latter under –0.5 MPa water deficit. It was concluded that the greater ability of water uptake in S. mammosum rootstock under water deficit is related to a lower hydraulic conductivity, which promotes passive, rather than active water uptake.     

Effects of a short period of drought on changes in tuber volume and specific leaf weight. I. Long-term changes

Summary Single-stemmed potato plants, cv. Bintje, were grown on a nutrient solution under controlled conditions. They were exposed to a short drought stress, or remained untreated. Long-term measurements of tuber volume were carried out with a non-destructive volume-meter. Specific leaf weight was monitored with a β-gauge. Tubers from the same plant varied in rate and duration of growth. The relative growth of stressed tubers was 43–54% less than that of the control tubers. The hierarchy of tubers from one stem changed over time in plants that were exposed to the stress. Specific leaf weight declined during the stress period but there was a prompt recovery after the relief from drought. This response was similar to the response of the average rate of volume increase of the tuber.