Roles of alcohol dehydrogenase, lactate dehydrogenase and pyruvate decarboxylase in low-temperature sweetening in tolerant and susceptible varieties of potato (Solanum tuberosum)

Papaya fruits were exposed to a continuous flow of an atmosphere containing less than 0.5% O2 (the balance is N2) for 0 to 5 days at 20°C. Fruits were evaluated every day after exposure to low O2 atmosphere, and simultaneously after 3 days in air at 20°C. During every evaluation period part of the fruits were promptly frozen for the analysis of the activity of the enzymes alcohol dehydrogenase (ADH), pyruvate decarboxylase (PDC), and lactate dehydrogenase (LDH), and pyruvic acid. The rest of the fruits were evaluated for flesh firmness, external and internal appearance, incidence of decay, and presence of off–flavors. Fruits had major decay problems and presented some off–flavors after 3 days in low O2 and 3 days in air at 20°C. The intolerance of the fruit to low O2 is, correlated with an increase, after 3 days, in the activity of ADH and PDC but not with the activity of LDH. On the basis of these results, it is concluded that insecticidal O2 atmosphere can be used as a quarantine insect control treatment in papaya for up to 3 days without the risk of significant fruit injury.

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Responses of Papaya to Short-term Insecticidal Oxygen Atmosphere

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.117.1.96 ◽

1992 ◽

Vol 117 (1) ◽

pp. 96-99 ◽

Cited By ~ 19

Author(s):

Elhadi M. Yahia ◽

Marisela Rivera ◽

Omar Hernandez

Keyword(s):

Lactate Dehydrogenase ◽

Alcohol Dehydrogenase ◽

Continuous Flow ◽

Carica Papaya ◽

Pyruvate Decarboxylase ◽

Oxygen Atmosphere ◽

Insect Control ◽

Control Treatment ◽

Short Term ◽

Off Flavors

Papaya (Carica papaya L., cv. Sunrise) fruits were exposed to a continuous flow of an atmosphere containing <0.4% 02 (the balance being N2) for 0 to 5 days at 20C. Decay was a major problem, and some fruit had developed off-flavors after 3 days in low O2 plus 3 days in air at 20C. The intolerance of the fruit to low O2 correlates with an increase in the activity of pyruvate decarboxylase and lactate dehydrogenase but not with the activity of alcohol dehydrogenase. Insecticidal O2 (< 0.4%) atmospheres can be used as a quarantine insect control treatment in papaya for periods <3 days at 20C without the risk of significant fruit injury.

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Tolerance of Sesbania virgata plants to flooding

Australian Journal of Botany ◽

10.1071/bt09144 ◽

2009 ◽

Vol 57 (8) ◽

pp. 661 ◽

Cited By ~ 25

Author(s):

Ilisandra Zanandrea ◽

José D. Alves ◽

Sidnei Deuner ◽

Patrícia de F. P. Goulart ◽

Paôla de C. Henrique ◽

...

Keyword(s):

Lactate Dehydrogenase ◽

Alcohol Dehydrogenase ◽

Anaerobic Metabolism ◽

Pyruvate Decarboxylase ◽

Soil Surface ◽

Dry Mass ◽

Stress Induction ◽

Whole Plant ◽

Sesbania Virgata ◽

Activity Of Enzymes

Sesbania virgata (Cav.) Pers. is a bush, pioneer and occurs naturally in Brazil. It belongs to the Fabaceae family and it is indicated for recovery of degraded areas because of its rusticity and capacity to tolerate flooding. The present research was carried out to investigate the ability of S. virgata plants to adapt to flooding conditions. Plants containing six expanded leaves were placed in masonry tanks and were subjected to the following conditions: control (well watered), soil-waterlogging (water to the setup level of 1 cm above the soil surface – roots and parts of the stems flooded) and complete submergence (whole plant flooded). The evaluations were conducted on the day of the stress induction and after 7, 14, 21, 28, 35, 42, 49 and 56 days of the treatment. After 15 days of return to normoxic environment, plant survival was assessed. Growth (height, dry mass of shoots and roots), vigour, carbohydrate content and the activity of enzymes involved in anaerobic metabolism (lactate dehydrogenase, pyruvate decarboxylase and alcohol dehydrogenase) were also evaluated. Our results suggested that sesbania plants are tolerant to flooding, because they can survive being submerged for 56 days. The reasons for this tolerance include the accumulation and use of carbohydrates in the leaves and roots, maintenance of growth and the activation of anaerobic metabolism, particularly in steps catalysed by the enzymes pyruvate decarboxylase and alcohol dehydrogenase.

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