不同浓度1-MCP处理对采后杨桃果实的保鲜效应

探讨不同浓度1-MCP（0、0.3、0.6和0.9 μL/L）处理对在（15±1）℃、相对湿度90％下贮藏的‘香蜜’甜杨桃果实保鲜效应的影响。结果表明：与对照果实相比,1-MCP处理可延缓杨桃果实细胞膜相对渗透率升高,保持较高的果实硬度、果皮叶绿素和果实可滴定酸含量,减少果实的失重和腐烂;其中0.6 μL/L 1-MCP处理12 h的保鲜效果最好,在（15±1）℃下贮藏20 d时,果实好果率达72％,果实外观仍保持鲜绿色、果实质地较硬、食用时酸甜适口。因此认为,浓度为0.6 μL/L的1-MCP处理12 h可以作为‘香蜜’甜杨桃果实在（15±1）℃、相对湿度90％下贮藏保持其果实品质、延长其贮藏寿命的适宜处理条件。     

A comparison of variability in storage behaviour of seed tubers from true potato seed and clonal tubers

Summary The tuber-to-tuber variability in storage behaviour of seed tubers from true potato seed was compared with that in clonal seed tubers after storage in the dark, in diffused light, or in diffused light with a single desprouting. The variability was estimated by calculating standard deviations of length, number and weight of sprouts, and tuber weight loss. After dark storage, the variability of these variables was greater in seed tubers from true potato seed than in clonal seed tubers. After storage in diffused light with a single desprouting, the variability of number, length and weight of sprouts of seed tubers from true seed was not statistically different from that observed in clonal seed tubers. All storage treatments resulted in a greater variability of tuber weight loss in seed tubers from true potato seed than in clonal tubers.     

The effect of storage conditions on subsequent field performance of potato seed tubers in Tunisia

Summary Seed tubers of four cultivars were grown under similar conditions and harvested simulataneously. They were stored in traditional dark storage, diffused-light storage, or cold storage, and with combinations of these three methods for 150 or 230 days beginning in the hot, dry summer period. The effect of storage conditions on emergence, stem and tuber number, tuber size distribution and yield is discussed. Results suggest an optimal combination of storage method, cultivar choice, and sprout management practices may be achieved to obviate the need for cold storage in warm climates. Emergence and yield were consistently good for the 150-day storage period when traditional storage was followed by diffused-light storage. The sam technology gave promising results for the 230-day period with cultivars Claustar or Désirée when seed was desprouted prior to planting.     

Unsprouted potato tubers treated with gibberellic acid (GA3)

Summary Tubers (still unsprouted after an eight months' storage period) of the late varietyLibertas with slow growth in youth and few stems were treated with gibberellic acid (GA₃) in 1958 and 1959. Two sprayings gave similar results as dipping for 15 minutes. 25 ppm probably had more effect than 12,5 ppm. During both years the treatment resulted in more and longer sprouts and more stems, although the number of stems is usually less than the number of sprouts. Emergence was not accelerated and in both years yields tended to be lower. In 1958 all yields reached a high level, treatment gave a non-significant lower yield, but there was a greater number of tubers especially in the 25–40 mm seed-class. In 1959 the size and the number of tubers were affected by second growth owing to the unusually dry summer with short spells of rainy weather. In this year presprouted tubers emerged 10 days earlier than treated and non treated, unsprouted seed, which for a long period gave the crop a lead in haulm growth and even a permanent lead in tuber yield.

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Zusammenfassung Von der sp?ten SorteLibertas, die in ihrer Jugend ein langsames Wachstum zeigt und wenig Stengel entwickelt, wurden ungekeimte Knollen (nach 8-monatiger Lagerung) in den Jahren 1958 und 1959 mit Gibberellins?ure (GA₃) behandelt. Eine zweimalige Spritzung ergab zumindest ?hnliche Ergebnisse wie das Eintauchen w?hrend 15 Minuten. 25 ppm hat wahrscheinlich eine bessere Wirkung, wie 12,5 ppm. In beiden Jahren ergab die Behandlung mehr und l?ngere Keime sowie mehr Stengel, obzwar die Anzahl der Stengel gew?hnlich nicht so hoch ist, wie die Anzahl der Keime. Es zeigte sich keine Beschleunigung des Auflaufens, jedoch eine Tendenz für einen geringeren Ertrag in beiden Jahren. In 1958 waren alle Ertr?ge hoch und die Behandlung ergab eine nicht signifikante Ertragsverminderung, jedoch eine gr?ssere Knollenzahl (insbesondere in der Saat-Gr?ssenklasse, 25–40 mm). In 1959 war die Gr?sse und die Anzahl der Knollen infolge des ungew?hnlich trockenen Sommers mit kurzen Regenperioden durch Mehrwüchsigkeit beeintr?chtigt. In diesem Jahr sind die vorgekeimten Knollen um 10 Tage früher aufgelaufen, was den Pflanzen im Vergleich zu den behandelten und nicht behandelten ungekeimten Pflanzgut einen l?ngeren Vorsprung im Krautwuchs und einen dauerhaften Vorsprung in der Knollenbildung gab.

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Résumé Des tubercules non germés (après stockage pendant huit mois) de la variété tardiveLibertas, à lente croissance de début et à petit nombre de tiges, ont été traités à l'acide gibberellique (GA₃) en 1958 et en 1959. Deux pulvérisations donnaient des résultats au moins égaux à ceux d'une immersion de 15 minutes. La concentration de 25 millionièmes est probablement plus efficace que celle de 12,5 millionièmes. L'une et l'autre année, les tubercules traités avaient des germes plus nombreux et plus longs et un plus grand nombre de tiges, bien que le nombre de tiges ne soit généralement pas aussi grand que le nombre de germes. La levée ne fut pas accélérée et il se manifesta une tendance de diminution du rendement. En 1958, toutes les récoltes furent bonnes, le traitement entra?nant une diminution non significante de la récolte mais faisant augmenter le nombre de tubercules (particulièrement dans la catégorie de semenceaux de 25–40 mm). En 1959, la grosseur et le nombre des tubercules furent influencés par croissance secondaire (excroissance) par suite de l'été exceptionnellement sec avec de courtes périodes de pluie. Cette année-là, les tubercules prégermés levèrent 10 jours plus t?t que les plants non prégermés, traités et non traités, de sorte que le développement du feuillage fut supérieur pendant une longue période et que celui des tubercules fut supérieur jusqu'à la récolte.

     

Nutritional value of potato tubers from field grown plants treated with deltamethrin

Summary Tubers showed changes in their nutritional value caused by the treatment of the plants with the insecticide deltamethrin. The level of starch was increased in comparison with control tubers; but the amylose percentage was not affected. In contrast, the total protein content decreased in tubers from treated plants, whereas free amino acids level and ascorbic acid content increased. The results showed that the changes in the tubers caused by the treatment of potato plants with deltamethrin did not adversely affect the nutritional value of the progeny tubers.     

Effects of ethylene and 1-methylcyclopropene on potato tuber sprout control and fry color

The study examined the efficacy of 1-methylcyclopropene (1-MCP), an anti-ethylene compound, as a preventative treatment for ethylene-induced fry color darkening in potato (Solanum tuberosum L.) tubers, without reducing the effectiveness of ethylene as a tuber sprouting control agent. The experiment was conducted for two years with ‘Shepody’ and ‘Russet Burbank.’ Tubers of each cultivar from four separate growers received one of the following treatments: Air (control), Air + 1-MCP (1 (μL.L^-1 for 48 h), isopropyl N (3-chlorophenyl) carbamate (chloropropham; CIPC; 1% a.i. [v/v]); continuous ethylene (4 μL.L^-1) in air; continuous ethylene pre-treated with 1-MCP once; continuous ethylene pre-treated with 1-MCP and repeated monthly; and continuous ethylene pre-treated with 1-MCP and repeated bi-monthly. Treatment started after suberization and cooling to 9 C, and samples were evaluated at 3-wk (year 1) or 4-wk (years 2 and 3) intervals thereafter until April (Shepody) or June (Russet Burbank). Sprout growth (sprout fresh weight per tuber), fry color (Agtron reflectance units), tuber weight loss, incidence of disease infection and internal disorders were evaluated. Weight loss, tuber infection, and the occurrence of disorders were not affected by any of the treatments. Sprout growth was controlled by the continuous ethylene supply in both cultivars, and single or multiple additions of 1-MCP to the ethylene treatment did not affect the ethylene control of sprouting. As expected, ethylene treatment alone enhanced fry color darkening in both cultivars. In Russet Burbank tubers, fry color was not darkened in any of the ethylene + 1-MCP (once, monthly, or bimonthly) treatments. In Shepody, fry color was not darkened in the ethylene + 1-MCP monthly or bimonthly treatments, but started darkening 4 wk after exposure in the single ethylene + 1-MCP treatment. It is concluded that 1-MCP can be used to control fry color darkening induced by ethylene without blocking ethylene control of tuber sprouting. However, the number of 1-MCP applications required may vary with the cultivar, e.g., one application was sufficient in Russet Burbank but not in Shepody.     

Comparative effects of cut and treated seed tubers vs untreated whole seed tubers on seed decay, Rhizoctonia stem canker, growth, and yield of Russet Burbank Potatoes

Whole seed tubers have been reported to have performance advantages over seed tubers that have been cut, even if the cut tuber pieces are treated with a fungicide dust. For this study, whole seed tubers were compared to cut seedpieces and to cut seedpieces treated with four different commercial fungicide dusts for five consecutive seasons. A new field generation 3 Russet Burbank seed lot was used for each of the five years of this study. Both whole tubers and cut seedpieces were inoculated withFusarium spp., and the seedpieces were then treated with a fungicide dust. Inoculated and uninoculated untreated controls were also included. Emergence,Fusarium seed decay,Rhizoctonia stem canker, stem numbers, and vigor, as well as yield and grade data were obtained.Rhizoctonia stem canker in stems grown from whole seed tubers was significantly higher than in stems from seedpieces receiving fungicide treatment in several of the study years. Predicting whole seed tuber performance is difficult because performance varies more from year to year than performance of cut and treated seedpieces. Yield performance of whole seed tubers was not significantly better than cut and fungicide-treated seedpieces in any experimental year, and yield of large (over 280 g) tubers was significantly less than that recorded for two of the treatments when data from all five years were combined. This study demonstrated that untreated whole seed did not outperform cut and treated seedpieces for vigor, stem numbers, disease ratings, or yield in small plot comparisons for five consecutive seasons.     

Some aspects of total losses during storage and reconditioning of potato tubers

Summary Total losses during storage and reconditioning of several Polish varieties and strains in comparison with the American varietyKennebec are discussed. Several varieties or strains show such high losses that they are not acceptable for processing after storage. Susceptibility to loss is an attribute which must be taken into account when assessing varieties.     

Development during storage of spraing symptoms in potato tubers infected with tobacco rattle virus

Summary In trials with potato tubers infected with tobacco rattle virus (TRV), symptoms of spraing in cvs Bellona, King Edward, Maris Bard, Matilda, Sv 82146 and Sv 82149 increased during storage when the tubers were cut. Storage of intact tubers at a constant temperature of 9°C or at fluctuating temperatures (2 weeks at 18°C, 2 weeks at 9°C and 2 weeks at 18°C) did not increase the frequency of symptoms.     

The relationship between respiration and chip color during long-term storage of potato tubers

Processing potatoes, both sprout inhibited and untreated, were evaluated for respiration rate and chip color during storage under commercial conditions (12 C, approximately 95% relative humidity, in darkness) following three growing seasons. While absolute respiration rates varied depending upon growing season and treatment, all cultivars and treatments studied during the 1995, 1996, and 1997 storage seasons showed similar respiration profiles. The initial stage following curing and sprout inhibition treatment (if applied) showed essentially constant respiration rates for a period of time varying from two to 15 weeks, depending upon growing season, treatment and cultivar. This was followed by a stage that showed a linear increase in respiration rates. In some cases the respiration rates eventually stabilized, or decreased. There was an apparent correlation between respiration trends and chip color changes in most cases, though the statistical significance varied between cultivars and seasons. Qualitative analysis of the data showed that the point at which respiration rates began to increase coincided with the onset of the decline in chip color quality. These trends suggest that measurement of tuber respiration may provide a non-destructive andin situ method to predict changes in processing quality of stored potato tubers.     

Management of silver scurf (Helminthosporium solani) with fungicide seed treatments and storage practices

Thiabendazole insensitive strains ofHelminthosporium solani, the causal agent of silver scurf, make controlling the disease with seed treatment difficult. Potato tuber seed treatments and environmental storage management practices were investigated as means to minimize silver scurf. Fungicide seed treatments were evaluated for control ofH. solani; disease was evaluated during the growing season, at harvest, and after 5 months of storage. Silver scurf was observed on progeny tubers eleven weeks after planting. Fungicides that reduced silver scurf incidence and severity on the seed resulted in reduced incidence and severity of the disease in the progeny tubers at harvest and significantly lower disease ratings after storage. Only small increases in disease incidence (0-8%) were seen after storage. Thiophanate-methyl with mancozeb, Captan with mancozeb, and fludioxonil were among the most effective in reducing the incidence and severity of silver scurf on seed and in progeny tubers (Incidence on progeny tubers at harvest for these three treatments were 3%, 9%, and 8% respectively). Thiophanatemethyl alone was not effective for control of silver scurf (48% incidence compared to 43% incidence for the untreated control). Environmental conditions in storage affected disease development. Reduced humidity (85%) during the curing period (0–3 weeks after harvest) significantly reduced (11%) the surface area of tubers infected with silver scurf. Free moisture on the tuber surfaces during storage significantly increased (15%) tuber surface area infection.H. solani was shown to survive in soil and on some potato storage building materials for up to 9 months. The silver scurf disease of potatoes can be suppressed using effective seed treatment and storage management.     

Sprout development and processing quality changes in potato tubers stored under ethylene: 1. Effects of ethylene concentration

Ethylene effectively inhibits sprouting of potatoes (Solanum tuberosum L.) during storage, but it often darkens fry color. The objective of the work described here was to determine if altering the concentration of ethylene applied would reduce the darkening while retaining adequate sprout inhibition. Trials were conducted over three consecutive years (1991–1992, 1992–1993, and 1993–1994). Tubers of cv Russet Burbank (ca 150–300 g) were stored at 9 C for 25 wk in closed chambers in a refrigerated room under continuous exposure to 0.4, 4, 40, or 400 µL L^?1 ethylene gas delivered with the ventilation airstream (ca 0.5 air exchanges per h, for 6 h each day). Untreated control and chlorpropham-treated (CIPC) check tubers were stored under the same conditions but without ethylene supplementation. Sprout number, length, and biomass, fry color, loss of tuber mass, disease, and dry matter content were evaluated at 5-wk intervals. Dose-dependent effects (400>40>4>0.4 µL L^?1) of ethylene on sprout growth and fry color were observed. The 400, 40, and 4 µL L^?1 ethylene treatments inhibited sprout growth as effectively as CIPC, whereas in 0.4 µL L^?1 ethylene sprouting was midway between CIPC and the untreated control. Sprout mass and maximum sprout length in all ethylene treatments were significantly lower (P<0.05) than in the untreated control. Compared with the initial value (57.3 Agtron reflectance units [ARu]), after 5 wk of storage fry color was up to 5 ARu darker in the ethylene treatments, but recovered steadily at the subsequent evaluation dates. At 25 wk of storage the fry color of tubers from the 40 and 4 µL L^?1 ethylene treatments were, however, still darker than tubers stored with CIPC. Inhibition of sprout growth was slightly more effective in the 400 and 40 µL L^?1 ethylene treatments than in 4 µL L^?1, although there were no significant differences (P<0.01) in fry color between these treatments. In comparison with the other ethylene treatments, fry color in 0.4 µL L^?1 ethylene was lighter, but inhibition of sprout growth was significantly (P<0.05) poorer. There were no differences in tuber disease incidence or dry matter content between the treatments. At 25 wk, the untreated tubers had ca 50% greater loss of tuber mass than any other treatment, attributable to their heavy sprouting. Loss of tuber mass in the ethylene treatments was not significantly different (P<0.001) from that in the CIPC treatment.     

Respiration studies on Russet Burbank potato tubers: Effects of storage temperature and chemical treatments

Tubers of Russet Burbank potatoes were stored at 36 F (2.2 C), 42 F (5.6 C), 45 F (7.2 C), 48 F (8:9 C), and 70 F (21.1 C) and respiration rates determined. Chemical treatments 4 with growth regulators were made and respiration rates determined on intact tubers. Tubers stored 42 F (5.6 C) and 45 F (7.2 C) generally respired less and at a more uniform rate than tubers stored at other temperatures. The respiration rate of CIPC and BA (20 ppm) treated tubers was less than the untreated tubers.     

Changes in ascorbic acid content during growth and short-term storage of potato tubers (Solanum tuberosum L.)

Changes in ascorbic acid levels were followed in apical and basal portions of Russet Burbank and Kennebec tubers during growth and development. Influence of nitrogen fertilization during growth and short-term storage on ascorbic acid level of the tuber was also studied. Changes in ascorbic acid content during growth showed two distinct phases, the first phase being characterized by an increase in ascorbic acid content with growth and development of the tuber, followed by a second phase which showed a decrease in ascorbic acid content with increasing maturity. The shift from the first phase to the second phase occurred earlier for Kennebec than for Russet Burbank. Increased nitrogen fertilization resulted in a delay of this shift from the first to the second phase. The apical portion of the tuber consistently showed higher ascorbic acid content than the basal portion. Kennebec tubers were higher in vitamin C content than tubers of Russet Burbank cultivar. High nitrogen fertilization resulted in less ascorbic acid content during growth. Storage of tubers for four weeks at 5.5°C also resulted in a marked decrease in ascorbic acid content of tubers. Nitrogen fertilizer rate during growth had no influence on the decrease in ascorbic acid content of tubers in storage.     

The effect of the temperature of potato tubers on the incidence of mechanical damage during grading and of gangrene (caused byPhoma exigua) during storage

Summary The amount of mechanical damage evident on potatoes graded by reciprocating square-mesh riddles decreased with increase in tuber temperature prior to grading. In a separate experiment, the extent of rotting by gangrene as a result of artificial infection of the surface of injured tubers was reduced in most cases with increase in tuber temperature at the time of inoculation. The incidence of gangrene in consignments of seed potatoes was reduced by storage at 15 to 17°C for about one week (five to ten days) after grading or after delivery.

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Zusammenfassung Sichtbarer mechanischer Schaden an Knollen, die in einem Raum mit Temperaturen von 6 und 11°C durch Schütteln von Quadratnetzsieben sortiert wurden, wurde mit dem Ansteigen der Knollentemperatur von 0 auf 16°C vor dem Sortieren vermindert. Die Temperatur der Knollen hatte weniger Einfluss auf den Schadenindex, wenn die Knollen bei h?herer Raumtemperatur sortiert wurden (Tabelle 1). Bei Kartoffeln mit verschiedenen Knollentemperaturen, die aus einer bestimmten H?he herunterfielen, gesiebt und angesteckt wurden durch Inokulation der Oberfl?che, nahm das Ausmass des durchPhoma-Knollenf?ule verfaulten Gewebes bei zunehmender Knollentemperatur ab (Tabelle 6). Das Vorkommen vonPhoma-Knollenf?ule in Pflanzkartoffelsendungen von Gutsbetrieben im n?rdlichen Schottland wurde in den meisten F?llen vermindert durch Lagerung bei 15 bis 17°C w?hrend ungef?hr einer Woche (5 bis 10 Tage) nach dem Sortieren oder nach Auslieferung der Sendung (Tabellen 7, 8 und 9).

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Résumé L'augmentation de la température du tubercule de 0 à 16° avant le calibrage réduit les dégats mécaniques visibles aux tubercules calibrés aux températures ambiantes de 6 à 11°C, au moyen de cribles à mouvement alternatif et ⦏ mailles carrées. La température du tubercule a moins d'effet sur l'indice des dommages quand les tubercules sont calibrés à une température ambiante plus élevée (Tableau 1). Chez des tubercules à différentes températures, tombés d'une certaine hauteur, calibrés et infectés par inoculation de la surface, le degré de pourriture des tissus causée par la gangrène diminue avec l'accroissement de la température dans le tubercule (Tableau 6). L'apparition de la gangrène dans les lots de plants de pomme de terre provenant des fermes du Nord de l'Ecosse est diminuée dans la plupart des cas par la conservation à des températures de 15 à 17°C pendant environ une semaine (5 à 10 jours) après calibrage ou après livraison (Tableau 7, 8, 9).