Ppm C2H4 Research Articles

Enhancement of Growth and Flowering of Triteleia laxa by Ethylene

Exposure of dormant corms of Triteleia laxa `Queen Fabiola' to 20 ppm C2H4 for 7 days promoted flowering of small corms and resulted in increased apical meristem size, early sprouting, early flowering, more flowers per Inflorescence, and increased fresh weight of daughter corms and cormels. The respiration rate of the C&treated corms increased to four to five times that of the controls during the 7-day treatment, declined markedly after termination of the C2H4 treatment, but remained higher than that of the controls. The C2H4 effects were associated with increased growth rate and consequently a greater final size of the apical meristem (determined by scanning electron microscopy). Leaves produced by C2H4-treated corms were wider, longer, and weighed more than those of the controls.

Temperature Sensitivity of Avocado Fruit in Relation to C2H4 Treatment

Abstract Avocado fruit (Persea americana Mill. ‘Fuerte’) were stored in air with or without C2H4 treatment (100 ppm) at 6°, 9°, 12°, 14°, 16°, 20°, 24°, 27°, 30°, and 34°C. During the storage period, respiration was measured by an automated continuous gas flow system. Fruit stored in air for more than 20 days at 6° developed chilling injury as indicated by gray discoloration of the mesocarp tissue. At high temperatures (30°, 34°), avocado fruit ripened abnormally, showed considerable surface pitting, and had poor flavor. When fruit were stored with 100 ppm C2H4, tissue discoloration was severe below 12°, which implied that chilling sensitivity of avocado fruit increased with C2H4 treatment. Fruit, whether stored with C2H4 or not, showed breaking points around the same temperature region on an Arrhenius plot, suggesting possible involvement of other mechanisms in addition to phase changes of membrane lipid components.

Ethylene Production by ‘Flamekist’ Nectarines as Influenced by Exposure to Ethylene and Propylene

Abstract ‘Flamekist’ nectarine fruit [Prunus persica (L.) Batsch] picked during the slow-growth phase exhibited reduced C2H4 production in response to 1250 and 12,500 ppm C3H6 while fruit picked during the 2nd rapid-growth phase did not. Ethylene production by mature, preclimacteric nectarines during ripening in air at 20°C was stimulated by prior storage in air at 0° or exposure to 100 ppm C2H4 at 0° or 20°. Storage in air + C2H4 at 0° for longer than 4 days, however, nullified the stimulative effect. Subsequent peak-level C2H4 production was reduced by one-half compared to air-stored fruit. Concentration of 1-aminocyclopropane-1-carboxylic acid (ACC) increased along with C2H4 production rates during ripening. In mature fruit showing reduced C2H4 production, ACC accumulated above the expected level relative to control fruit. The data indicates that the inhibition of C2H4 production by C3H6 in developing nectarine fruit during the slow-growth phase is due to low availability of ACC, while in mature fruit the reduction in C2H4 production results from slowed conversion of ACC to C2H4.

Effects of Carbon Dioxide, Oxygen, and Ethylene Levels of Kentucky Bluegrass Sod1

Abstract Sods of ‘Merton’ Kentucky bluegrass (Poa pratensis L.) were placed in atmospheres containing 0, 9, 18, or 27% CO2; 0, 2, 4, 8, or 16% O2; and 0, 2, 4, or 8 ppm C2H4. Neither CO2 nor C2H4 toxicity nor O2 deficiency caused sod injury in commercial sod toads. Ventilation tubes inserted in commercial sod toads failed to increase gas exchange and heat dissipation beyond a 3-cm distance.

Ripening and Reduced Ethylene Production by Nectarine Fruits following Exposure to Ethylene1

Abstract Treatment of ‘Fairlane’ nectarines [Prunus persica (L). Batsch] with as high as 500 ppm C2H4 during 1 week of storage at 0 or 10°C, or treatment of ‘Flamekist’ nectarines with up to 100 ppm C2H4 for as long as 4 weeks at 0 or 10°, had no effect on the rate of color change or softening during storage or subsequent ripening periods at 20° in air relative to air storage. Treatment of ‘Flamekist’ nectarines with 100 ppm C2H4 for 1 week at 0 or 10°, however, resulted in maximal C2H4 production rates upon transfer to 20° in air that were approximately 60 and 40% less, respectively, than fruits stored in air or treated with 1 or 10 ppm C2H4 during storage.

Effects of Ethylene on Chilling Injury and Subsequent Decay of Conditioned Early ‘Marsh’ Grapefruit during Low-temperature Storage1,2

Abstract Early Florida ‘Marsh’ grapefruit (Citrus paradisi Macf.) can be safely degreened with 5 ppm C2H4 up to 72 hours and then stored for 17 days at 1°C, providing the fruit are conditioned for 7 days at 16° prior to storage.

Influence of ethylene on black spot of potato tubers

Sound, hand harvested, whole potatoes were exposed to continuous flowing atmosphere containing air, air with 3 or 5% CO2, and air with concentrations of 0.5, 1.0, and 10ppm C2H4 for periods of 1 to 11 days at 20°C. At 1-day intervals, potatoes were bruised and black spot development assessed. Development of black spot in potatoes exposed to C2H4 was equal to or less than in potatoes at harvest. The severity remained low during 3-day exposure to 1 ppm C2H4 and after transfer to 4 days in air, then increased. Severity of black spot increased in potatoes exposed to air, with intermediate response from exposure to air with CO2. With an increase in sprouting, differences in black spot among treatments diminished. Less black spot developed in immature than in mature potatoes.

Ethylene-light relationship in the growth of the rice coleoptile

Ethylene stimulated growth of rice coleoptiles in the dark and after an irradiation with red light. The red-light inhibition of rice-coleoptile growth was more pronounced when only endogenously evolved C2H4 was involved than it was under C2H4-free (C2H4 removed) or C2H4-saturated (20 ppm C2H4 added) conditions.

STORAGE QUALITY OF McINTOSH APPLES AS AFFECTED BY REMOVAL OF ETHYLENE FROM THE STORAGE ATMOSPHERE

Preclimacteric McIntosh apples were maintained under low (average 6 ppm) C2H4 and high (average 1,570 ppm) C2H4 levels for 189 days at 3.3 °C. Subsequent analysis of the fruit revealed that the low C2H4 storage condition had maintained approximately 0.9 kg (2 lb.) greater firmness in the fruit than had the high C2H4 condition. This extra firmness persisted for more than a week at room temperature. Acidity levels and soluble solids content were increased slightly by the low C2H4 treatment. Low C2H4 treatment caused both a lower internal C2H4 content of the fruit and a lower level of C2H4 emission by the whole fruit than did storage in high levels of C2H4. The low C2H4 storage conditions reduced the incidence of core browning.