The objective of this work was to evaluate the effect of individual seal-packaging using low density polyethylene films and waxing treatments on the storage ability and quality of Bell pepper fruit. The fruits were packaged in two kinds of films, waxed and unwaxed and kept at 10°C and 75% RH for 46 days. Characteristics of the films (Thickness and permeability for O2 and water vapor) were determined. Atmosphere changes (O2 and CO2) inside the packages were followed each 5 days. Fruits were evaluated every 10 days, for changes in color, % chlorophyll, texture, soluble solids, acidity, PH, weight loss, % decay and sensory characteristics. The activity of ADH enzyme was used as an indicator of anaerobiosis. MAP + waxing significantly delayed fruit ripening, reduced the losses of chlorophyll, weight, firmness and % of decay respect to the unwaxed and unwrapped fruits (control) and did not result in any abnormal flavors after 20, 30 and 40 days at 10°C. These quality factors demonstrate that MAP + waxing can be used to prolong the shelf life for up to 20 days without affecting the eating-quality of the fruit.
Constant-pressure manometry, previously designed to study O2 and CO2 gas exchange in small pieces of tissue, cells, and organelles, was adapted to study bulky organs. According to this new procedure, a near-zero-volume Devaux chamber connects a manometer to the internal atmosphere volume (VG) of a plant organ covered by a layer of epoxy, submerged in unstirred water, kept at constant temperature, and kept at the same VG pressure. Equations, based on CO2 and O2 solubility at equilibrium with VG, were used to follow O2 consumption as a function of reduced internal O2 pressure over time [for organs with VG < 0.1 (v/v) and respiratory quotient (RQ) of 0.7 to 1.3] to observe the transition between aerobiosis and anaerobiosis and to measure CO2 evolution during the anaerobic phase. For those measurements, bulky-organ manometry performed consistently in tomato [VG = 6.41% (v/v)], sweetpotato [VG = 8.57% (v/v)], and potato [VG = 0.34% (v/v)]. The results indicate that constant-volume manometry is sufficiently precise to detect differences in respiratory metabolism as a function of intercellular O2 concentration in intact plant organs.
Waterlogging of the soil rapidly and dramatically alters both the physical and biological environment of plant roots. In response to environmental stimuli, physiological events occur within the plant which affect its growth and development. The purpose of this paper is to review certain aspects of the physiological responses of plants to waterlogging with respect to the response mechanisms and the subsequent adaptations in the growth and development of the whole plant. Many important aspects of the subject must be only briefly mentioned here, such as the effects of waterlogging on soil chemistry, nutrient availability and uptake, microbiology, pathology, and senescence. The reader is referred to recent literature for information on these topics (3, 13, 19, 21). The overriding effect of soil flooding is to limit the diffusion of oxygen to the root zone. The focus here, therefore, will be on the responses of plants to root anaerobiosis and some initial, rapid mechanisms of adjustment. Further information on long-term adaptation, especially in woody plants, can be found elsewhere (76).
Glycolysis has been shown to accelerate in many plant species, and the glycolytic pathway was considered to replace the Krebs cycle as the main source of energy when O2 becomes limiting. The increase in glycolytic flux is accompanied by the accumulation of glycolytic end products, including ethanol and lactate. Lactate dehydrogenase (LDH) has been isolated from several plant sources; however, there is very little work reported on LDH induction during anaerobiosis and no information is available on the long-term effect of low O2 atmosphere on lactic fermentation in carrot (Daucus carota L.) roots. To understand the regulation of metabolism of lactic fermentation, carrot root shreds were stored under a continuous flow of 0.5% and 2% O2 (balance N2), or air at 5°C and 15°C. The concentration of lactate and the activity of LDH increased rapidly, reached peaks after 2 days, and then gradually decreased. The maximum increase level of LDH was 2.8-, 2.1-, 2.0-, and 1.6-fold; that of lactate was 5.6-, 3.8-, 2.9-, and 2.6-fold for 0.5% O2 at 15°C and 5°C, and 2% O2 AT 15°C and 5°C, respectively, compared with corresponding air control. These results indicate that the lactic fermentation was more accelerated in 0.5% O2 than 2% O2 atmosphere, and more accelerated at the higher storage temperature than the lower one. However, ethanol accumulation, which was found in the carrots under the same low-O2 atmosphere, was much more than lactate accumulation. Thus, carrot roots possess LDH, which appears under low-O2 atmosphere, but lactic fermentation may be a minor carbon flux compared to ethanolic fermentation.
signaling. PGRs can be thought of as components of large signaling networks that communicate information from one part of a plant to another. By way of four examples including the communication of 1) root anaerobiosis—epinasty, 2) soil moisture status
respiration rates and evolution of AA and ethanol ( Fig. 5A ). This burst of respiration appears to be a homeostatic response to the anaerobiosis that prevailed while the fruit were under N 2 atmosphere. Respiration rates and evolution of AA and ethanol were
atmosphere composition and/or CA establishment protocols. The absence of an effect of CA storage on bitter pit incidence in orchard lots with low bitter pit incidence is consistent with Contreras et al. (2014) and DeEll et al. (2015) . Anaerobiosis before
. 1996 Growth, fruiting and ethylene binding of tomato plants in response to chronic ethylene exposure J. Hort. Sci. 71 65 69 Bradford, K.J. Dilley, D.R. 1978 Effects of root anaerobiosis on ethylene production, epinasty, and growth of tomato plants Plant
., 2001 , 2003 ; Oms-Oliu et al., 2007 , 2008 ), an observation of the European and American markets for fresh-cut melon reveals that most operators do not aim at optimizing gas compositions inside the packages given that anaerobiosis is prevented. The
-flavor development due to anaerobiosis along with discoloration ( Beaudry, 2000 ; Watkins, 2000 ). Furthermore, the increase in temperature itself accelerates the deterioration rate of the packaged produce ( Kader, 2002 ), which in combination with the unfavorable