Induction of Sensitivity to Gibberellic Acid in Developing Wheat Caryopses: Effect of Rate of Desiccation

1979 ◽  
Vol 6 (2) ◽  
pp. 229 ◽  
Author(s):  
PB Nicholls
Keyword(s):  
Relative Humidity ◽  
Gibberellic Acid ◽  
Incubation Medium ◽  
Amylase Activity ◽  
Dry Out

No change in the total β-amylase activity, attributable to the presence of 10-6 M gibberellic acid (GA3) in the incubation medium, was found in freshly harvested, de-embryonated, immature (11-38 days post-anthesis) caryopses of wheat. Significant amounts of GA3-induced α-amylase activity was found in 26-h incubates of similar caryopses which had been allowed to dry out either in the ear or detached from the ear. After 10 days of storage of detached immature caryopses in air of 99-100% relative humidity, de-embryonated half-caryopses responded to applied GA3 by producing α-amylase. More α-amylase was found in 26-h incubates if detached caryopses dried out slowly, but rapid desiccation led to little or no α-amylase being produced in the presence of GA3. Caryopses taken from ears cultured on 0.4 or 4% sucrose for 10 days did not respond to applied GA3 whereas those from ears cultured on water did respond, although the amount produced in 26-h incubates was not as large as those from slowly dried ears. Development of the ability to respond to GA3 by increasing α-amylase activity depended on the duration of desiccation or isolation from the plant. Changes in metabolism emanating from the interruption to the supply of sucrose to the caryopsis may be involved in the development of the ability of the aleurone to respond to GA3.

scholarly journals Hydroxyproline and proline inhibit α-amylase from isolated barley aleurone layers

2014 ◽  
Vol 52 (3-4) ◽  
pp. 253-263 ◽  
Author(s):  
Craig C. Freudenrich ◽  
William V. Dashek
Keyword(s):  
Carboxylic Acid ◽  
Hordeum Vulgare ◽  
Gibberellic Acid ◽  
Glutamic Acid ◽  
Incubation Medium ◽  
Amylase Activity ◽  
Membered Ring ◽  
Pipecolic Acid ◽  
Enzyme Substrate ◽  
Barley Aleurone

Previously, we reported that 1 mM hydroxyproline appeared to inhibit the gibberellic acid-induced release of α-amylase from isolated <em>Hordeum vulgare</em> L. cv. Himalaya aleurone layers into an incubation medium. Here, we report our attempts to determine the mechanism(s) for this inhibition and whether this inhibition can be caused by other proline analogues. Both 1 mM hydroxyproline and proline inhibited extracellular a-amylase activity without affecting its intracellular activity. This suggested that neither hydroxyproline nor proline impaired the release of a-amylase. Lineweaver-Burk plots revealed that both hydroxyproline and proline uncompetitively inhibited α-amy-lase. Thus, the inhibition is probably an assay artifact resulting from the formation of an enzyme-substrate-hydroxyproline or -proline complex. Because azetidine-2-carboxylic acid, glutamic acid and pipecolic acid did not inhibit extracellular α-amylase activity, the uncompetitive inhibition of a-amylase must be unique to imino aicids as well as their precursors and derivatives which possess a five membered ring.

POSTHARVEST FACTORS ASSOCIATED WITH THE OCCURRENCE OF BREAKDOWN IN SPARTAN APPLE

1975 ◽  
Vol 55 (3) ◽  
pp. 743-747 ◽  
Author(s):  
S. W. PORRITT ◽  
P. D. LIDSTER ◽  
M. MEHERIUK
Keyword(s):  
Relative Humidity ◽  
Gibberellic Acid ◽  
Soluble Solids ◽  
Malus Pumila ◽  
Factors Associated ◽  
Holding Period ◽  
C Storage ◽  
Storage Atmosphere ◽  
Malus Pumila Mill ◽  
Soft Fruit

The incidence of internal breakdown in Spartan apples (Malus pumila Mill.) was significantly reduced by a 3-day holding period at 20 C or 2 wk in hypobaric storage at 0 C prior to 0 C storage. Dipping fruit in solutions of calcium chloride or gibberellic acid prior to storage also reduced the disorder. High relative humidity in the storage atmosphere was associated with soft fruit, low soluble solids, low ethylene production and increased incidence of breakdown.

Germination response to phytochrome depends on specific dormancy states in wild oat (Avena fatua)

1993 ◽  
Vol 71 (11) ◽  
pp. 1528-1532 ◽  
Author(s):  
J. Q. Hou ◽  
G. M. Simpson
Keyword(s):  
Relative Humidity ◽  
Gibberellic Acid ◽  
Red Light ◽  
Avena Fatua ◽  
Mechanical Injury ◽  
Wild Oat ◽  
Dormancy Breaking ◽  
Negative Effects ◽  
Germination Response ◽  
Genetic Origins

Effects of brief red and far-red light on germination of seeds from dormant lines of wild oat (Avena fatua L.) were studied in combination with mechanical injury to the seed coat, application of gibberellin A3, or changes in relative humidity during afterripening. Aberrant germination responses to phytochrome action were observed in the mechanically injured seeds in some of the lines, i.e., brief red light inhibited or delayed germination induced by injury, and immediately following far-red light cancelled the negative effects. Phytochrome action influenced germination of the gibberellin-treated seeds in a normal fashion, although effects of the gibberellic acid and brief red light on germination were not additive. Brief red light inhibited germination of seeds afterripened in zero relative humidity; the same light promoted germination of those in 30 and 60% relative humidity. Germination response to phytochrome in wild oat depends on specific seed dormancy states, illustrated by genetic origins, dormancy-breaking methods and afterripening conditions. Key words: Avena fatua, dormancy, mechanical injury, gibberellin A3, phytochrome, relative humidity.

scholarly journals Botrytis Blossom Blight of Southern Blueberries: Cultivar Susceptibility and Effect of Chemical Treatments

Plant Disease ◽  
1998 ◽  
Vol 82 (8) ◽  
pp. 924-927 ◽  
Author(s):  
Barbara J. Smith
Keyword(s):  
Relative Humidity ◽  
Gibberellic Acid ◽  
Conidial Suspension ◽  
Full Bloom ◽  
Disease Symptoms ◽  
Chemical Treatments ◽  
Severity Scores ◽  
Flower Stage ◽  
Southern Highbush ◽  
Cultivar Susceptibility

The susceptibility of blueberry flowers at each developmental stage was evaluated by inoculating potted blueberry bushes of the rabbiteye cultivars Climax, Premier, and Tifblue, and the southern highbush cultivars Gulfcoast and Cooper, during bloom with a conidial suspension of Botrytis cinerea and incubating in a dew chamber for 2 days at 20°C and 100% relative humidity. Flower stage was rated at the beginning of each study and at 2 and 4 weeks after inoculation. The efficacy of five fungicides (benomyl, captan, cyprodinil, cyprodinil + CGA173506, and propiconazole) and a surfactant for control of Botrytis blossom blight was evaluated by inoculating Climax and Gulfcoast plants 2 days before or 2 days after treatment with each fungicide. The effect of chemicals used during bloom on the severity of Botrytis blossom blight was evaluated by treating Tifblue and Cooper plants with gibberellic acid, surfactant, and fungicide combinations 1 day prior to inoculation. Botrytis disease symptoms were scored 2 and 4 weeks after inoculation on a visual scale of 0 to 7. Flower susceptibility increased as flower stage at inoculation increased. Tifblue flowers at or near full bloom (stages 5 and 6) at the time of inoculation were very susceptible to Botrytis blossom blight. Flowers treated with benomyl, cyprodinil, and cyprodinil + CGA173506 2 days after inoculation had lower Botrytis severity scores than inoculated flowers not treated with fungicides. Flowers treated with gibberellic acid 1 day prior to inoculation had lower Botrytis scores 2 and 4 weeks later than untreated flowers, while flowers treated with a nonionic surfactant received the same Botrytis severity scores as untreated flowers.

scholarly journals Amylase and acid phosphatase activity in potato tubers treated with gibberellic acid and stored at 2°C and 8°C

2015 ◽  
Vol 30 (1) ◽  
pp. 95-101 ◽  
Author(s):  
M. Bielińska-Czarnecka ◽  
K. Białek
Keyword(s):  
Acid Phosphatase ◽  
Gibberellic Acid ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Amylase Activity ◽  
Amylolytic Activity ◽  
Potato Tubers ◽  
Two Peaks

Amylase activity was higher in tubers stored at 2°C and mare marked in the soaked ones (both in water and in GA<sub>3</sub>). In the late and difficult-sprouting cv. Uran, sokaing resulted in increased amylolytic activity also at 8°C stored tubers. On the contrary, the acid phosphatase activity was a little higher at 8°C than at 2°C stored tubers. At the former temperature two peaks of activity were marked:, in November–December and February–March.

scholarly journals 588 Moisture Balance in Dry-heat-treated Vegetable Seeds

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 498A-498
Author(s):  
Jung-Myung Lee ◽  
Du-Hyun Kim
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Gibberellic Acid ◽  
Seed Coat ◽  
Vegetable Crops ◽  
Atmospheric Moisture ◽  
Dry Heat ◽  
Heat Treated ◽  
Moisture Balance ◽  
Seedling Characteristics

Dry-heat (DH) treatment has been extensively used for inactivation of some seed-borne virus and Fusarium disease in many vegetable crops, especially in cucurbitaceous vegetables. Strains of tobamovirus (cucumber green mottle mosaic virus; CGMMV) could be successfully inactivated by treating the infected seeds at 75 °C for 72 h. However, DH-treated seeds frequently exhibit slow and poor germination and abnormal seedling characteristics, such as distorted, white streaked, and punctured cotyledons in the seedlings. The moisture content in seed coat and inner cotyledons fell down to below 1% in DH-treated seeds when treated at 75 °C or higher. However, when the seeds were treated at 65 °C, final moisture content in the DH-treated seeds were maintained at about 2.5% to 3.5%. Seeds absorbed moisture above 20% at 100% RH, 9% to 10% at 73% RH, and 4% to 5% at 28% RH, respectively. When the intact and DH-treated seeds were exposed to conditions of varying relative humidity, DH-treated seeds absorbed atmospheric moisture at a much slower rate than the intact seeds in all tested cultivars, and this is thought to be one of the major reasons for slower germination in DH-treated seeds. The inactivation of virus, comparison of respiration of seeds, and endogenous gibberellic acid contents will also be presented.

scholarly journals EFFECTS OF MALTING CONDITIONS TO QUALITY OF GERMINATED RED SORGHUM

2018 ◽  
Vol 55 (5A) ◽  
pp. 49
Author(s):  
Nguyen Tien Cuong
Keyword(s):  
Relative Humidity ◽  
Dry Matter ◽  
Amylase Activity ◽  
Soluble Sugars ◽  
Traditional Foods ◽  
Experimental Conditions ◽  
Dry Matter Loss ◽  
The World ◽  
Sorghum Bicolor L

Sorghum, one of the most popular cereals in the world, can be used directly or in malted and/or fermented form in the preparation of several traditional foods. The aim of this study was to investigate the effects of malting conditions to quality germination of red sorghum in order to select the malted sorghum for beverage production. Twenty malts types originated from red sorghum (Sorghum bicolor L. Moench) were produced under different experimental conditions: steeping (30 °C for 15 - 44 h with and without aeration), germination (30 °C, 98 % relative humidity, 45 - 72 h) and drying or lyophilisation. Dry matter loss, production of sugar, α and β-amylase activities were determined. The obtained results showed the distribution of dry matter loss during malting: steeping (2.2 - 4.0 %), germination (3.7 - 6.5 %), drying (1 %) and degerming (4.3 - 7.5 %). The starch was slightly hydrolysed (2.5 %) for producing soluble sugars: maltose (2.9 - 4.0 %) and glucose (1.7 - 3.6 %). Any organic acids production during the malting was detected. The obtained malted sorghum contained high α-amylase activity but a low level of β-amylase. The highest α- and β-amylase activities were 173.1 U.gms-1 and 3.4 U.gms-1, respectively. These results were obtained for steeping 44 h with aeration, germinated 45 h and lyophilised sorghum. The amylase activities were positively correlated with the water content of grain at the end of steeping.

Sign in / Sign up

Export Citation Format

Share Document