Modeling the influence of temperature and relative humidity on respiration rate of prickly pear cactus cladodes
Juan Carlos Guevara, Elhadi M. Yahia, Randolph M. Beaudry and Luis Cedeño
Postharvest Biology and Technology, Volume 41, Issue 3 , September 2006, Pages 260-265
2006
บทคัดย่อ
Modeling the influence of temperature and relative humidity on respiration rate of prickly pear cactus cladodes
Respiration rate (RO2) of prickly pear cactus cladodes (Opuntia spp.) was measured as a function of four temperature (T) and six relative humidity (RH) combinations for O2 partial pressures between 15 and 0.8 kPa, which were considered to support aerobic respiration. The rate of respiration (RO2) was determined based on O2 depletion of the atmosphere in sealed containers containing 1 kg of cladodes. The O2 partial pressure declined linearly over time and the slopes of the fitted lines were used to calculate the rate of O2 uptake. The rate of O2 consumption increased with increasing temperature and decreased with increasing RH. The respiratory rate at 25 °C was approximately 30–40 times higher than at 5 °C. The respiratory rate at 65% RH was between 30 and 90% greater than at 90% RH, depending on the temperature. Data for ln(RO2) for each RH level were regressed against the inverse of the temperature (K−1) to determine Arrhenius constants and calculate the apparent Ea of respiration for the six RH conditions. The Ea was similar for each RH level, varying between a low of 113 to a high of 131 kJ mol−1. The following equation having an r2 of 0.95 was developed describing respiration as a function of RH and temperature (°C) using only four constants:
Ln(R) = (-0.1985 + 50.96 x (1/273.15+T)) x RH + 67.64 – 18430 x (1/273.15+T)