Sprout Inhibition Research Articles

Studies on sprout inhibition of onions by gamma irradiation—I. influence of time interval between harvest and irradiation, radiation dose and environmental conditions on sprouting

Sprout inhibition of onions by gamma irradiation was found to be influenced by the physiological state of the bulbs at the time of irradiation, radiation dose and the storage temperature after irradiation. Sprouting was minimal during storage at ambient temperature (26 to 32°C) while exposure to low temperature (4 to 20°C) or widely fluctuating diurnal temperature (20°C min to 30°C max) accelerated it. Six to nine Krad inhibited sprouting during storage under the above conditions only if the bulbs were irradiated within a fortnight of harvest when they were in the dormant state. Twenty-five Krad caused a transient stimulation of sprouting regardless of the time of irradiation while 6 to 12 Krad only stimulated sprouting when the time interval between harvest and irradiation exceeded three weeks. Irradiation at all dose levels caused discoloration of the growth centre, the extent of which was minimal in bulbs exposed to low doses soon after harvest and in those stored at ambient temperature.

The effect of senescence, handling, sprouting and chemical sprout suppression upon the respiratory quotient of stored potato tubers

Sugar accumulation occurred in senescent tubers at 20°C even in the absence of wilting and particularly if sprout growth was prevented chemically or the sprouts removed. Without sprout growth the considerable sweetening was not accompanied by greatly increased respiration, as occurred in sprouting tubers. Senescent sweetened tubers without sprouts had a variable respiratory quotient, tending on average to be rather high, but this could have resulted from the damage caused by desprouting or chemical suppression. A high (c. 1.3–1.4) respiratory quotient in undamaged sweetened tubers cannot be excluded, however, as it could be masked by the high respiration of the sprouts with a presumed quotient of 1.0. Handling led to variable respiratory quotients, an effect which could last for several weeks.

Studies on potato sprout suppressants. 2. Effect of tecnazene on subsequent growth of seed potatoes

In a field exercise with tecnazene (2,3,5,6-tetrachloronitrobenzene) treated seed stock (cv. Golden Wonder) a significant yield reduction was recorded with the recommended application rate of 0.1 g/kg and airing before planting. The emergence time of the seed was significantly increased and the size of harvested tubers reduced. In a supplementary exercise with 12 common varieties similar trends were noted and various anomalies in growth observed. The implications of these results are discussed.

Effect of gamma irradiation on the indole acetic acid synthesizing system and its significance in sprout inhibition of potatoes

Gamma irradiation interfered with the synthesis of the IAA synthesizing system and exogenous application of 20 ppm IAA within 6 hr after irradiation, triggered the synthesis of this enzyme. This fact is ascertained by the inhibition with protein synthesis inhibitors such as actinomycin D, puromycin and cyclohexamide, on the recovery of enzyme activity on treatment with IAA. Irradiation accelerated the degradation of the existing enzyme by activating proteolytic activity. IAA in irradiated potatoes is completely depleted and this is associated with the activation of H2O2 dependent IAA oxidase. A 50 per cent decrease in the level of tryptophan, the substrate for IAA synthesis is observed at 24 hr after irradiation.

Título en español.

Se estudiaron los efectos de la radiación gamma en la germinación de la variedad del ñame (D. alata) Florido cultivado en Puerto Rico y en los cambios químicos que tienen lugar en el tubérculo. La radiación con dosis de 7.5 Krad no afectó aprobablemente su composición y prolongó por 4 meses más el período de inactividad del ñame. Se sugiere una dosis de 7.5 Krad como la óptima para inhibir la germinación de los tubérculos del ñame de esta variedad. Esto hace posible que haya disponible ñame de buena calidad fuera de temporada. Las pérdidas en peso fueron relativamente bajas y el sabor del tubérculo muy aceptable.

Studies on potato sprout suppressants. 1. Residual levels of tecnazene in laboratory-treated and in commercial samples of potatoes

A technique for the accurate estimation of 0.01 ppm of tecnazene in potatoes (recovery factor 91.6% ±2.8) has been developed by gas chromatography after a preliminary clean-up treatment on an alumina column. 1 μg of tecnazene per kg fresh weight of potato can be detected by this method with some loss in accuracy. In laboratory samples treated at commercial rates 2 to 8 mg/kg were found in all potato samples analysed. 0.1 to 1.0 mg/kg were detected in peeled and boiled potatoes. The implications of these results are discussed.

Chemical Inhibition of Sprouting of Pruned Lemon Trees1

Abstract Trees of ‘Bearss’ lemon [Gtrus limon (L.) Burm. f] in Florida produce numerous undesirable sprouts on scaffold limbs following severe pruning. Considerable time and expense is involved in removing these by hand. Several formulations containing naphthaleneacetic acid (NAA) singly and in combination with ethyl hydrogen 1-propylphosphonate (EHPP) were applied to determine if these sprouts could be satisfactorily controlled with chemicals. NAA by itself was effective and caused no abnormalities in new growth. The addition of EHPP increased sprout inhibition in some cases, but some leaf loss and distortion occurred.

Effect of storage time and γ-irradiation on the development of di-n-propyl disulfide from onion bulbs

Onion bulbs of unirradiated and irradiated with 4.2 and 8.1 Krad by 60Co gamma rays were stored at 4° and 10°C for five months, and the relationship between the sprouting and the amounts of di-n-propyl disulfide (DPDS) developed from the sliced onions was investigated. The amount of DPDS increased apparently along with the sprouting. The sprout inhibition with the irradiation was appeared to suppress the development of DPDS.

Lagerung von Kartoffeln in kontrollierter Atmosphäre

AbstractStorage of potatoes in controlled atmosphere. The interim results obtained from trials with CA‐storage are reported. Storage atmospheres with low O2 and increased CO2 contents largely inhibit the sprout growth of potatoes kept at a temperature of 9 °C so that chemical sprout suppressants may possibly be dispensable.Storage atmospheres with too high a CO2 content cause an intense rise of the saccharose content and lead to increased decay. With tolerable storage atmospheres these disadvantages can be avoided.The remaining questions shall be answered in further trials which shall also help to bring CA‐storage to perfection for its application in practice.

Sprout Inhibition of Onions by Ionizing Radiation

The dormancy period of onion, Cult. Sapporoki was about one month after harvest. Sensitivity of onion to irradiatian gradually decreased after the dormancy period accompanied by growth of inner bud. At this stage, inhibition of sprouting could not be achieved when the same was irradiated after three months of harvest. Complete suppression of sprouting was observed in onions irradiated with 3 to 7 Krad during the dormancy period.Usually, harvested onions are dried for two weeks before irradiation. Inhibition of sprouting and keeping quality were attained with the dose of 3 to 7 Krad when freshly harvested oaions were irradiated either before or during the drying treatment for storage.Irradiation period could be extended by low temperature storage of onion after harvest. Growth of inner bud suppressed at 3-5°C even after three months of storage and the length of inner bud was similar to that of one month old onion. Thus, sprouting was inhibited by irradiation and apical dominence observed for three months from the harvest date when onions were stored at low temperature.Browning of buds was observed in irradiated onions during storage. This was prevented by low temperature storage and such onions have retained good market quality for one month when transferred from low temperature to ambient temperature.

Sprout Inhibition of Potatoes by Irradiation

Sprout Inhibition of Potatoes by Irradiation

Effect of gamma irradiation on indole acetic acid synthesizing system in potatoes

The sprout inhibition of potato achieved by 10 Krad gamma irradiation can be completely reversed by treatment of the tubers with 20 ppm IAA. Studies on the level of IAA synthesizing system in unirradiated and irradiated potatoes showed that on irradiation the enzyme activity steadily decreased and fell to zero at the end of 5 weeks storage. When irradiated potatoes were soaked with 20 ppm of IAA, the loss in enzyme activity was not discernible but, with tryptophan, there was no protection of enzyme activity. The enzyme was purified 12 fold, from control and from irradiated potatoes immediately after irradiation. The product of the reaction was identified as IAA by co-chromatography with authentic sample. The reaction required pyridoxal phosphate and a keto acid. Among the keto acids, α-ketoglutaric acid and phenylpyruvic acid were the best as substrates. The optimum pH for the reaction was 8, and optimum temperature was 37°. The two enzyme preparations differed in their response to substrates and co-enzymes; the Michaelis constant for tryptophan was 6 × 10 −4 M for the enzyme from control and 4 × 10 −4 M for enzyme from irradiated potatoes. The reaction was inhibited by NH 2OH, INH and EDTA. Inhibition by EDTA was reversed by Mn ++.

Present Status of National Research Project on Food Irradiation

The national research project on food irradiation was started in 1967, and is now making good progress in accordance with the programme laid out for its activities. Sprout inhibition of potatoes and onions was the subject first selected for excution, and considerable study has been undertaken on the effects of irradiation and health hazards. A description is presented of the results obtained with investigations on potato, which is considered to be the most promising subject of such treatment.(1) Large scale irradiation tests on three different varieties of potato indicated that potato sprout could be inhibited for 8 months when irradiated within 3 months of harvest to doses of 7-15 krad.(2) Extensive investigations have been carried to determine the health hazards that would be occasioned by the irradiated potatoes. While the final conclusion is not yet to be reached, the results obtained so far do not indicate the existence of any problems related to health hazards associated with the irradiated potatoes.

食品照射に関する特定総合研究の現況

The national research project on food irradiation was started in 1967, and is now making good progress in accordance with the programme laid out for its activities. Sprout inhibition of potatoes and onions was the subject first selected for excution, and considerable study has been undertaken on the effects of irradiation and health hazards. A description is presented of the results obtained with investigations on potato, which is considered to be the most promising subject of such treatment.(1) Large scale irradiation tests on three different varieties of potato indicated that potato sprout could be inhibited for 8 months when irradiated within 3 months of harvest to doses of 7-15 krad.(2) Extensive investigations have been carried to determine the health hazards that would be occasioned by the irradiated potatoes. While the final conclusion is not yet to be reached, the results obtained so far do not indicate the existence of any problems related to health hazards associated with the irradiated potatoes.

The treatment of potato tubers with sprout inhibitors

Working with the sprout inhibitors IPC and CIPC we compared 3 treatment methods: (1) a 10 ppm dosage of powder distributed over the tubers, (2) a Swingfog treatment (atomizing a solution in the air duct, dosage up to 20 ppm), (3) a porous cartridge containing the inhibitor placed in the air duct. To obtain good sprout inhibition in connection with accumulated IPC/CIPC residue values below the legal level of 0.5 mg per kg peeled tubers we advise the powder treatment only for relatively long storage (up to May–June); a 10 or 20 ppm Swingfog treatment for short storage (up to January–February) or longer storage respectively. With the cartridge system we obtained promising results; good sprout inhibition and satisfactorily low residue values.

Sprouting tendency of stored potatoes

The rest period of the potato tuber is here defined as the time following the lifting when internal inhibition prevents the tuber from sprouting. The dormant period is the subsequent time when the tuber does not sprout owing to unfavourable external conditions. The sum of the periods denotes the sprouting tendency at the storage temperature used, here 4–5°C. The sprouting tendency varies particularly between varieties but also between years and places of cultivation. The concepts of rest and dormancy are often very practical to use but from a theoretical point of view there may be no reason for separating them. They are two parts of the same physiological process ranging from strong sprout inhibition to vigorous sprout growth. Thus, rest or dormancy does not depend on qualitative but quantitative differences in the endogenous amounts of growth regulating substances.

Pycnidium production by Botryodiplodia theobromae. III. Germination of pycnidiospores

Pycnidiospores of Botryodiplodia theobromae Pat. germinated within 5 h on solid media. The rate and amount of germination in liquid media were lower than on solid media. Near maximum germination occurred over the range 15–42 °C and at 100% relative humidity. Light, which is essential for pycnidium production, had no effect on germination. Five fungicides (Dinocap (Karathane WD), Pano-drench, Bordeaux mixture, Captan, and copper sulphate) commonly applied to fruits, and four potato sprout suppressants (diethylene glycol monobutyl ether, ethylene glycol monobutyl ether, n-amyl and isoamyl alcohol), at concentrations ranging from 0.001% to 2.5%, inhibited germination and germ-tube growth. The potential use of the germination inhibitors as protectants against Botryodiplodia theobromae rot is discussed.

Sprout Inhibition of Potatoes by Ionizing Radiation

Succeeding to the previous report another potato var. Norin-1-go was investigated on the sprout inhibition by irradiation.7 Krad was enough to keep the potato unsprouted for more than eight months after harvest at room temperature. The 5-10mm germed tubers were also suppressed and failed to grow further by 7 Krad.The organoleptic test of crisps made of irradiated potato showed that the crisps produced from untreated sample was better than that of treated one.There was not so much difference between the crisps of irradiated potatoes. The reducing sugar content was much higher in the potato stored at 5°C than stored at room temperature and decreased a little with radiation dose. The crisps made of potato stored at 5°C and the crisps with higher dose were darker. The color of the oil extracted from crisps was not affected by the treatment applied here.

Sprout Inhibition of Potatoes by Ionizing Radiation

Sprout Inhibition of Potatoes by Ionizing Radiation

Gamma Irradiation and Enriched CO2 Atmosphere Storage Effects on the Light‐induced Greening of Potatoes

SUMMARY – Michigan‐grown Kennebec and Sebago potato tubers were exposed to gamma irradiation in the dose range of 0 to 400 Krad and subsequently stored in atmospheres containing 0.03% to 15% CO2. Upon illumination with 3,000 lux for periods up to 20 days while maintaining the atmosphere, all tubers developed some greening. The tubers exposed to 200 and 400 Krad were inhibited from greening to the highest degree but suffered general quality loss. The levels of 10 to 20 Krad, which are suitable for the sprout inhibition of potatoes, did not cause significant inhibition of greening under any of the conditions of this experiment. Storage in enriched CO2 atmospheres inhibited the greening to the extent of 50% at 15% CO2, only upon prolonged illumination (12 days), while irradiation (40 Krad) was only effective after a short period (4 days) of illumination. Irradiation in the O–40 Krad range did not increase the inhibition caused by CO2. The inhibition of potato greening by irradiation was effective through a period of 5 weeks storage in the dark prior to illumination.