- Open Access
Measuring ethylene in postharvest biology research using the laser-based ETD-300 ethylene detector
© The Author(s) 2018
- Received: 31 August 2018
- Accepted: 21 November 2018
- Published: 28 November 2018
Ability to measure ethylene is an important aspect of postharvest management, as knowledge of endogenous ethylene production is used in assessing physiological status, while response of crops to exogenous ethylene informs efforts needed to control unwanted ripening. An ethylene monitoring device with a laser-based photoacoustic detector, ETD-300, was recently developed by Sensor Sense B.V., Nijmegen, The Netherlands. In terms of performance, the ETD-300 is superior to all other current ethylene measurement devices, with a sensitivity of 0.3 nL L−1, a response time of 5 s, and an ability to monitor ethylene in real time. Although the ETD-300 is relatively easy to operate, the performance and correctness of the data obtained depends on the choice of settings, which depends on the application.
This article provides a description of different ways in which the ETD-300 can be used in postharvest research for monitoring ethylene production and ethylene presence in an environment. We provided guidelines on selecting the appropriate method (Continuous Flow, Stop and Flow, and Sample methods), and operational curves for deciding on suitable combination of free volume, flow rates, and period for the different measurement methods.
Using these guidelines and operational curves, ETD-300 users can considerably reduce the measurement effort by limiting trial and error in establishing appropriate methodologies for their application. The guidelines also comment on accurate use of the ETD-300, as using the inappropriate settings could lead to erroneous measurements. Although these methodologies were developed primarily for postharvest application, they can be applied in other plant science research.
- Ethylene production
- Operational curves
- Continuous flow method
- Stop and Flow method
- Residence time
- Time delay
Ethylene is an important gaseous phytohormone involved in the regulation of growth, development, ripening, and senescence of many fruit and vegetables [1, 2]. In postharvest management of crops, exogenous ethylene has been shown to induce changes in a number of ripening-related quality attributes, such as softening [3–7], changes in peel colour [5–7], increase production of aromatic volatiles [6, 8–10], and increase in soluble solids content [6, 11].
Fruit of climacteric nature produce large amounts of ethylene at the onset of ripening, and initiate endogenous ethylene production in response to application of ethylene . Consequently, ethylene production could be used for certain climacteric fruit as an indicator of ripening progression. For example, internal ethylene concentration or production rate is commonly used as a maturity index to determine commercial harvest dates for apples fruit [13–15].
An important consideration in postharvest management of quality is how produce respond to exogenous ethylene, as this helps to determine the need to prevent unwanted ripening and senescence. A survey conducted to determine the level of ethylene in the atmosphere of fruit and vegetable in holding areas, distribution centres, and supermarket retail stores revealed concentrations of between 0.017 and 0.2 μL L−1 . For several decades it was believed that environmental ethylene concentrations > 1 μL L−1 are needed to initiate many of the physiological responses that are influenced by ethylene. This was in part driven by the inability of ethylene sensing equipment, mainly gas chromatography (GC), to measure ethylene concentrations of less than 1 μL L−1. However, recent advancement in ethylene sensing technologies able to measure much lower concentrations have led to discoveries that ethylene in the nL L−1 concentrations are sufficient to influence ripening physiology of certain crops [6, 16–19]. Examples of these recent technologies are the flame ionisation detection (FID) and photoionization detector (PID) for use in GC , electrochemical sensors , and laser-based photoacoustic detection [22–24]. Of all current ethylene-sensing technologies, the laser-based sensors have the highest sensitivity (below nL L−1), fastest response time (seconds), good selectivity and capability of real-time monitoring . Cristescu et al.  reviewed current methods for detecting ethylene in plants and demonstrated that laser based sensors, such as the ETD-300 has a sensitivity of about 1 nL L−1, while GCs which has traditionally been used to detect ethylene in plant sciences has a sensitivity of between 10 and 100 nL L−1. In addition, the ETD-300 has a response time of 5 s, compare to GCs that have response times between 200 and 1000 s, making the ETD-300 suitable for real-time minoring of ethylene. Finally, the ETD-300 has a much higher selectivity than most GCs. The main drawback of the ETD-300 is that it is more expensive than other ethylene detection systems.
Review of the use of the laser-based ethylene detector ETD-300 in postharvest biology
Type of measurement
Online monitoring of wound-induced ethylene production in fresh-cut endive in response to 1-MCP, AVG and heat shock treatments
Real-time measurement of ethylene production in kiwifruit that were bruised, sliced, pricked, or inoculated with Botrytis cinerea
Investigate the effect of ABA-deficiency in ethylene evolution rate in tomato
Demonstrate inhibition of ethylene production in strawberry fruit using a commercial ethylene scavenger
Ethylene production during ripening of feijoa as influenced by harvest maturity, storage duration, treatment with 1-MCP, or ethylene
Ethylene production of feijoa following pre-harvest application of aminoethoxyvinylglycine
Ethylene production during ripening of ‘Kensington Pride’ mango fruit following treatment with 1-MCP and/or ethylene
Ethylene production during storage of different gooseberry cultivars
Ethylene production of avocado and strawberry during storage following different scheduling of controlled atmosphere
Ethylene production of fresh Piper nigrum berries following treatment with different doses of UV-C
Ethylene diffusion properties of commercial kiwifruit polyliners
Monitoring ethylene concentration in gas mixes when mixing standard ethylene gases and air to generate ethylene of certain desired concentration
Ethylene removal rate by vacuum ultraviolet radiation
While the ETD-300 is relatively easy to use, the performance and efficiency are highly dependent on the choice of settings, which is dependent on what ethylene concentration is to be measured, and the scenario on which the measurement is being utilised (i.e. ethylene production versus environmental monitoring). There is also a learning process to adaptation of the ETD-300 as opposed to Gas Chromatography, as sampling of small volumes (few millilitres) is not possible. The objective of this paper is to provide a guideline on the efficient use of the ETD-300 for measuring ethylene in different systems in postharvest biology research, although the same principles will apply for all plant systems.
Description of the ETD-300
The measurement range of the ETD-300 depends on desired selected sensitivity, with possibility to switch between fine and coarse settings. The former is 100 times more sensitive that the latter, but the linearity between the photoacoustic signal of the laser and ethylene concentration is limited to 0–5 μL L−1. Conversely, when using the coarse settings, linearity extends to 500 μL L−1, allowing for measurements of much larger concentrations. For the purpose of this review, only the fine setting, with a theoretical measurement range of 0–5 μL L−1, will be considered. In many of the authors’ measurements, error can be up to 5 nL L−1, such that only measurements greater than 5 nL L−1 are often considered meaningful. When connected to one or more valve controllers, the ETD-300 can be operated in three modes: Continuous Flow, Stop and Flow, and Samples modes.
Continuous Flow measurement
The Continuous Flow mode measures the steady state ethylene concentration of a sample. There is constant gas refreshment of all samples connected to the valve controller, hence avoiding the risk of CO2 accumulation that can influence plant physiology. The Continuous Flow method is recommended to be used if the sample produces sufficient ethylene. The period can be specified for each sample, and this determines how long the sample will be measured. In addition, the flow can be specified for each sample, and determines the rate at which the gas flows through the sample chamber.
Fruit ethylene production
Ethylene production is a common postharvest physiological measurement that can be obtained using the ETD-300 ethylene analyser. The valve control box controls mass flow rate and allows automatic sampling, making it possible to run several measurements in series (Fig. 1). More valve control boxes can be connected to the ETD-300, extending the possible number of simultaneous measurement channels by units of six with each control box. The baseline signal tends to drift with time, hence it is recommended to conduct a zero measurement before and after each measurement. The baseline value is obtained by measuring the signal from the ethylene-free carrier gas (channel 6, Fig. 1).
The maximum pressure of the carrier gas flowing to the catalyser is 6 atm. The ethylene-free gas from the catalyser is connected to a single input point in the valve control box, and is split internally into the different channels. The sample jar could be any sealed container that does not absorb or emit hydrocarbons. Flow of gas into each sample jar is achieved by positive pressure, controlled by the mass flow controller of valve control box. The mass flow controller in the valve control box measures the actual mass flow rate of the gas to the detector, which could be much lower than the set flow rate if the sample jar or connections are not airtight. Therefore, a good way to ensure sample is airtight is to check if the set flow is the same as the measured flow to the detector.
Time delay between measurements in Continuous Flow mode
The effect of the length of the tubing connecting the sample jars to the valve control boxes and to the ETD-300 detector is often insignificant, as in most cases, the volume of the tubing is negligible when compared to that of the sample jars. For example, using a 2 m long tube with inner diameter of 2.22 mm will result to a tube volume of 7.7 mL, which is less than 2% of a small glass jar of 500 mL. The volume of the scrubbers could also add to overall volume. For example, the tubes the authors use to hold the CO2 and water vapour scrubbers have a volume of 30 mL and 60 mL, respectively. By assuming the scrubbers are packed to a porosity of ~ 15%, the additional volume by the scrubbing system is about 13.5 mL. This means the combined additional volume by the scrubbing system and the tubes is less than 5% of a free volume of 500 mL. Depending on the volume of the sample jar, the user may decide whether to consider this additional volume when applying Eq. (3) to estimate the time delay. If the time delay is too long (> 2 h), the free volume can be reduced by adding fillers into the jars, such as glass marbles. The amount of gas to be flushed is an attentive indicator of time delay (Fig. 2). When running several samples in series, the concept of time delay only applies to the first sample, as there is constant gas refreshment through all samples.
There are a number of practical ways to take into account the effect of the time delay during measurements. One way will be to set the first sample of the sequence to be a dummy sample that is programmed to run for the duration of the time delay. Alternatively, the first few samples could be repeated at the end of the sequence.
Selecting flow rate when using the Continuous Flow mode
When using the ETD-300 detector in the Continuous Flow mode, the concentration of ethylene in the gas reaching the detector is proportional to the ethylene production of the sample, and inversely proportion to the selected flow rate. This means for low ethylene producing samples a low flow rate should be selected, so that the ETD-300 detector can detect the concentration of ethylene produced by the sample. Contrarily, for a high ethylene-producing sample, a high flow rate should be used, such that the concentration of ethylene from the sample is not more than the maximum ethylene concentration that the detector can read. Beyond this concentration, the linearity of the photo-acoustic signal and ethylene concentration is not ascertained.
Examples of expected range of ethylene production for some fruits
Ethylene production (μL kg−1 h−1)
For a number of climacteric fruit (e.g. kiwifruit, apple, avocado, peach, pear, and passion fruit) there is a log increase in ethylene production between the pre-climacteric and climacteric. Therefore, a change in measurement settings may be required when assessing fruit at different ripening stages. If no information is available about possible range of ethylene production for a sample, the highest flow rate of 5 L h−1 should be used, as this has the fastest response time, providing quick measurements for screening of right settings. Generally, 5 L h−1 is only suited for measurements of high ethylene production, as the noise to measurement ratio becomes less significant. For low ethylene producing fruits like unripe kiwifruit, mango, strawberry, the minimum flow rate of 1 L h−1 should be used.
As the ethylene production is proportional to the mass of fruit, increasing the amount of fruit is an option for increasing the ethylene production making it possible to measure samples that would have been otherwise undetectable. A point of consideration is that increasing the mass of fruit will ultimately require using sample jars of larger volume, thereby increasing the time delay (Fig. 3a) and introducing the risk of breaking the assumption of constant ethylene production. Another disadvantage of increasing mass of sample by measuring several fruit is that it takes away the true biological variance, and individual assessment of fruit can be important for ethylene production due to the log scale changes that occur during ripening. A single fruit may be producing over 100 times the ethylene of its neighbours, significantly skewing the average of the population.
Ethylene concentration in a local environment
Studies that investigate the effect of ethylene on plant response involve exposing plant material to different concentrations of ethylene (e.g. [3, 4, 7, 17, 18]). A common way to obtain different concentrations of ethylene gas is to mix ethylene standard gases with air by controlling the flow rates of the respective gases and sampling to verify if the desired ethylene concentration is achieved [17, 18, 63]. For mixes with low ethylene concentrations (< 5 μL L−1), the ETD-300 is suitable for checking the ethylene concentration in the mixed gas. To do this, the setup described in Fig. 7 can be used, with the pump connected to the sampling point of the mixed gas. The pump may not be necessary if there is gas flow at the sampling point, as the flow will provide the required positive pressure.
Sometimes it may be desirable to monitor ethylene concentration of a remote environment, such as in refrigerated containers or open market places. In this case, airtight sampling bags could be used to collect the gas sample from the remote environment and taken to location where the ETD-300 is installed. If the volume of the sample is much larger than the volume of the tubing system of the ETD-300, the ethylene concentration can be measured using the setup in Fig. 7, with the pump connected to the sampling bag. For small volumes (< 20 mL), the Samples method should be used (“Samples measurement” section).
Ethylene gas transport properties
Knowledge of gas permeability is an important design parameters when selecting films for packaging fruit, as this will influence the ethylene equilibrium within the package environment . In addition, ethylene diffusion in fruit tissue may in part explain differences in response by different fruit. A common way to measure gas diffusion properties of a material is to use a system with two chambers separated by the sample whose diffusion properties is being measured [65–67]. A known concentration of the gas of interest is flushed through one of the chambers, while the concentration of the gas in the other chamber is continuously monitored. The ability of the ETD-300 to measure real time ethylene, and both control and measure flow rate, makes it suitable for measuring ethylene diffusion properties. Moreover, the low detection limit of the ETD-300 means small increases in ethylene in the measurement chamber could be accurately measured.
Stop and Flow measurement
The Stop and Flow method of measurement can be used either for samples that produce very low amounts of ethylene, or for small samples collected remotely from the equipment in a sealed vessel. In the Stop and Flow mode, the complete volume of gas in the free space of the sample is measured, producing a peak from which the amount of ethylene can be calculated from the area under the peak. The main disadvantage of this method when measuring ethylene production is that CO2 or other volatiles can accumulate to levels that may affect physiological processes. As with the Continuous Flow mode, the period and the flow rate for each sample can be specified. The period determines how long the sample will be measured, while the flow rates determine the rate at which gas flows from the sample to the detector. It is important to flush the system by running ethylene-free gas before the start of measurement, as this ensures the system does not contain any residual ethylene from previous samples, and that the peak starts from the true baseline.
Fruit ethylene production
If ethylene production of a sample is less than 10 nL h−1, the concentration of ethylene reaching the detector during measurement in the Continuous Flow mode at a flow rate of 1 L h−1 could be just above the lower measurement limit of 5 nL L−1 (Fig. 5). In such situations, it would be more accurate to measure ethylene production using the Stop and Flow method. The setup in Fig. 1 is used to measure ethylene production of a sample. The output generated is an ethylene concentration peak, from which the total amount of ethylene is obtained as the area under the curve (nL). The ethylene production (nL h−1 kg−1) is obtained by dividing the amount of ethylene by the residence time and the mass of the sample.
Residence time when using the Stop and Flow mode
For ethylene production measurement, the samples are confined in sealed jars, allowing accumulation of ethylene produced by the plant material. A practical consideration is the length of time to allow for ethylene accumulation. If this is too long, CO2 may accumulate to concentrations that will affect the product physiology, negating the assumption of constant physiology. If too short, the plant material would not produce enough ethylene that is detectable by the ETD-300.
Before using the Stop and Flow mode of the ETD-300 detector to measure ethylene production of a plant material, the researcher should first consult the literature to know what values of ethylene production is expected for the given sample. When this is known, Eq. (7) could be used to estimate the minimum residence time. Operational curves of the minimum residence time to allow for accumulation of 5 nL L−1 ethylene when measuring produce in a closed system as a function of free volume and ethylene production is shown in Fig. 9. Using expected range of ethylene production of a single fruit for different fruit categories (Table 2), suggested residence time for measuring single fruit in closed system with different free volume is also shown on Fig. 9. Measurement of samples with ethylene production less than 20 nL h−1 requires over 7 days, if the free volume is more than 200 mL. Using more fruit will increase ethylene production, while decreasing the free volume, thereby reducing the time required to produce a detectable amount of ethylene. For example, if ethylene production of ripe strawberries is measured using five fruit (~ 60 mL) in a 500 mL jar, the minimum residence time in the closed system will be less 1 h. The ethylene production of similar low ethylene producing fruit and non-climacteric fruit, such as citrus, could be measured using a combination of increasing mass of sample and using longer residence time. Because samples with ethylene production of more than 20 nL h−1 can easily be measured with the Continuous Flow method (Fig. 5), the Stop and Flow method has a narrow practical working range (unshaded area in Fig. 9). This narrow range is mainly for samples with small volumes (10–200 mL), which is a rare case when measuring fruit as most fruit will only fit into at least 500 mL jars, and hence may explain why the ETD-300 is rarely used in the Stop and Flow mode during measurement of ethylene production in postharvest biology. With the exception of Anastasiadi et al. , all the references discussed in the introduction used the ETD-300 in the Continuous Flow mode.
CO2 production rate is highly dependent on ripening stage, and on environmental conditions (temperature, and gas composition), such that the most practical way to ensure CO2 is kept below critical level for samples needing relatively long residence time is to have a septum on the jar for periodic sampling of small gas for CO2 measurements. Alternatively, CO2 scrubbers could be placed inside the closed system to limit accumulation.
Selecting flow rate during Stop and Flow measurement
Effect of cuvette volume on ETD-300 performance when using the Stop and Flow mode
Selecting period during Stop and Flow measurements
The Sample method measures the ethylene concentration of a sample by comparing to reference samples. Both the Continuous Flow and the Stop and Flow methods are useful when it is desirable to measure the ethylene production over time, while the Samples mode of measurement is used when samples need to be analysed only once. For example, measuring the ethylene concentration of a gas sample collected remotely, or measuring ethylene production of produce after storage. The equipment configuration and measurement output are similar to the Stop and Flow mode, with the main difference being that the Samples mode compares the reference samples (standards) with other samples. This implies the flow and the gas volume of all samples measured in series need to be identical. The ethylene concentration of the reference samples has to be provided, and is used to generate a calibration line between the peak area and the concentration.
Measuring ethylene concentration of a small volume
The error in measured ethylene concentration when using the Stop and Flow method to measure samples with small free volumes can be circumvented by using the Samples method, as this uses the concentration of reference samples to estimate the concentration of the samples. This incorporates the error associated with the sampling method (free volume, flow rate, change in pressure due to injection of the gas into the cuvette) into the measurements. It is important that the reference cuvettes are prepared and measured in the same way as the sample, i.e. the cuvette volume, volume of sample gas injected, measurement flow rate and period.
Another situation where it may be desirable to measure small volumes is monitoring ethylene concentration of an environment remote to the ETD-300 equipment (e.g. during transport). In this case, using airtight containers, small volumes of gas sample can be collected from the remote environment, and later measured using the Samples method. Even when large volumes of gas are collected, a small subsample can be analysed in smaller cuvettes, as described in the previous paragraph.
SGG designed the study, collected the data and drafted the manuscript. AJ, JT, SN and ARE contributed to the design of the experiments and data interpretation. AJ and ARE critically reviewed the manuscript, while SN provided supervision of the data collection. All authors read and approved the final manuscript.
The Massey AgriTech Partnership is grateful to Zespri® International Ltd. for their continuous research funding over the last decade. Most of our experience in using the ETD-300 has been achieved through projects funded by Zespri® International Ltd.
The authors declare that they have no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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- Saltveit ME. Effect of ethylene on quality of fresh fruits and vegetables. Postharvest Biol Technol. 1999;15:279–92.View ArticleGoogle Scholar
- Abeles FB, Morgan PW, Saltveit ME. Ethylene in plant biology. Cambridge: Academic Press; 1992.Google Scholar
- Hershkovitz V, Friedman H, Goldschmidt EE, Pesis E. Ethylene regulation of avocado ripening differs between seeded and seedless fruit. Postharvest Biol Technol. 2010;56:138–46.View ArticleGoogle Scholar
- Hertog MLATM, Jeffery PB, Gwanpua SG, Lallu N, East A. A mechanistic model to describe the effects of time, temperature and exogenous ethylene levels on softening of kiwifruit. Postharvest Biol Technol. 2016;121:143–50.View ArticleGoogle Scholar
- Murayama H, Arikawa M, Sasaki Y, Dal Cin V, Mitsuhashi W, Toyomasu T. Effect of ethylene treatment on expression of polyuronide-modifying genes and solubilization of polyuronides during ripening in two peach cultivars having different softening characteristics. Postharvest Biol Technol. 2009;52:196–201.View ArticleGoogle Scholar
- Johnston JW, Gunaseelan K, Pidakala P, Wang M, Schaffer RJ. Co-ordination of early and late ripening events in apples is regulated through differential sensitivities to ethylene. J Exp Bot. 2009;60:2689–99.View ArticleGoogle Scholar
- Gwanpua SG, Qian Z, East AR. Modelling ethylene regulated changes in ‘Hass’ avocado quality. Postharvest Biol Technol. 2018;136:12–22.View ArticleGoogle Scholar
- Sdiri S, Rambla JL, Besada C, Granell A, Salvador A. Changes in the volatile profile of citrus fruit submitted to postharvest degreening treatment. Postharvest Biol Technol. 2017;133:48–56.View ArticleGoogle Scholar
- Yang X, Song J, Du L, Forney C, Campbell-Palmer L, Fillmore S, et al. Ethylene and 1-MCP regulate major volatile biosynthetic pathways in apple fruit. Food Chem. 2016;194:325–36.View ArticleGoogle Scholar
- Chidley HG, Kulkarni RS, Pujari KH, Giri AP, Gupta VS. Spatial and temporal changes in the volatile profile of Alphonso mango upon exogenous ethylene treatment. Food Chem. 2013;136:585–94.View ArticleGoogle Scholar
- Asiche WO, Mitalo OW, Kasahara Y, Tosa Y, Mworia EG, Owino WO, et al. Comparative transcriptome analysis reveals distinct ethylene-independent regulation of ripening in response to low temperature in kiwifruit. BMC Plant Biol. 2018;18:1–18.View ArticleGoogle Scholar
- McMurchie EJ, McGlasson WB, Eaks IL. Treatment of fruit with propylene gives information about the biogenesis of ethylene. Nature. 1972;237:235–6.View ArticleGoogle Scholar
- Watkins CB, Bowen JH, Walker VJ. Assessment of ethylene production by apple cultivars in relation to commercial harvest dates. N Z J Crop Hortic Sci. 1989;17:327–31.View ArticleGoogle Scholar
- Rudell DR, Mattinson DS, Fellman JK. The progression of ethylene production and respiration in the tissues of ripening ‘Fuji’ apple Fruit. HortScience. 2000;35:1300–3.Google Scholar
- Chu CL. Use of internal ethylene concentration as a maturity index of eleven apple cultivars. Acta Hortic. 1984;157:129–34.Google Scholar
- Wills RBH, Warton MA, Ku VVV. Ethylene levels associated with fruit and vegetables during marketing. Aust J Exp Agric. 2000;40:465–70.View ArticleGoogle Scholar
- Jabbar A, East AR. Quantifying the ethylene induced softening and low temperature breakdown of ‘Hayward’ kiwifruit in storage. Postharvest Biol Technol. 2016;113:87–94.View ArticleGoogle Scholar
- Pranamornkith T, East A, Heyes J. Influence of exogenous ethylene during refrigerated storage on storability and quality of Actinidia chinensis (cv. Hort16A). Postharvest Biol Technol. 2012;64:1–8.View ArticleGoogle Scholar
- Wills RBH, Warton MA, Mussa DMDN, Chew LP. Ripening of climacteric fruits initiated at low ethylene levels. Aust J Exp Agric. 2001;41:89–92.View ArticleGoogle Scholar
- Bassi PK, Spencer MS. Methods for the quantification of ethylene produced by plants. Berlin: Springer; 1989. p. 309–21.Google Scholar
- Esser B, Schnorr JM, Swager TM. Selective detection of ethylene gas using carbon nanotube-based devices: utility in determination of fruit ripeness. Angew Chemie Int Ed WILEY-VCH Verlag. 2012;51:5752–6.View ArticleGoogle Scholar
- Harren FJM, Reuss J, Woltering EJ, Bicanic DD. Photoacoustic measurements of agriculturally interesting gases and detection of C2H4 below the ppb level. Appl Spectrosc Soc Appl Spectrosc. 1990;44:1360–8.View ArticleGoogle Scholar
- Harren FJM, Bijnen FGC, Reuss J, Voesenek LACJ, Blom CWPM. Sensitive intracavity photoacoustic measurements with a CO2 waveguide laser. Appl Phys B Photophys Laser Chem Springer-Verlag. 1990;50:137–44.View ArticleGoogle Scholar
- Harren F, Reuss J. Spectroscopy, photoacoustic. Encycl Appl Phys. 1997;19:413–27.Google Scholar
- Cristescu SM, Mandon J, Arslanov D, De Pessemier J, Hermans C, Harren FJM. Current methods for detecting ethylene in plants. Ann Bot. 2013;111:347–60.View ArticleGoogle Scholar
- Hermans C, Vuylsteke M, Coppens F, Cristescu SM, Harren FJM, Inzé D, et al. Systems analysis of the responses to long-term magnesium deficiency and restoration in Arabidopsis thaliana. New Phytol. 2010;187:132–44.View ArticleGoogle Scholar
- Gallego-Bartolomé J, Arana MV, Vandenbussche F, Žádníková P, Minguet EG, Guardiola V, et al. Hierarchy of hormone action controlling apical hook development in Arabidopsis. Plant J. 2011;67:622–34.View ArticleGoogle Scholar
- Jibran R. Identification of genetic regulators of longevity in dark-held detached Arabidopsis inflorescences. A thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Biology. Massey University; 2014.Google Scholar
- Wilson RL, Kim H, Bakshi A, Binder BM. The ethylene receptors ETHYLENE RESPONSE1 and ETHYLENE RESPONSE2 have contrasting roles in seed germination of Arabidopsis during salt stress. Plant Physiol. 2014;165:1353–66.View ArticleGoogle Scholar
- Salman A, Filgueiras H, Cristescu S, Lopez-Lauri F, Harren F. Sallanon H. Inhibition of wound-induced ethylene does not prevent red discoloration in fresh-cut endive (Cichorium intybus L.). Eur Food Res Technol. 2009;228:651–7.View ArticleGoogle Scholar
- van den Dungen R, Te Lintel Hekkert S, Cristescu SM, Harren FJM. Highly sensitive ethylene detector for on-line measurements on kiwifruits. Acta Hortic. 2011;913:651–6.View ArticleGoogle Scholar
- Nitsch L, Kohlen W, Oplaat C, Charnikhova T, Cristescu S, Michieli P, et al. ABA-deficiency results in reduced plant and fruit size in tomato. J Plant Physiol. 2012;169:878–83.View ArticleGoogle Scholar
- Elmi F, Cools K, Terry LA. The use of It’s Fresh! Ethylene remover technology with e + ® Active as a practical means for preserving postharvest fruit quality. Acta Hortic. 2013;1012:1205–10.View ArticleGoogle Scholar
- Rupavatharam S, East AR, Heyes JA. Re-evaluation of harvest timing in ‘Unique’ feijoa using 1-MCP and exogenous ethylene treatments. Postharvest Biol Technol. 2015;99:152–9.View ArticleGoogle Scholar
- Rupavatharam S, East AR, Heyes JA. Effects of preharvest application of aminoethoxyvinylglycine (AVG) on harvest maturity and storage life of ‘Unique’ feijoa. N Z J Crop Hortic Sci. 2016;44:121–35.View ArticleGoogle Scholar
- Razzaq K, Singh Z, Khan AS, Khan SAKU, Ullah S. Role of 1-MCP in regulating ‘Kensington Pride’ mango fruit softening and ripening. Plant Growth Regul. 2016;78:401–11.View ArticleGoogle Scholar
- Anastasiadi M, Mwangi PM, Ordaz-Ortiz JJ, Redfern SP, Berry M, Simmonds MSJ, et al. Tissue biochemical diversity of 20 gooseberry cultivars and the effect of ethylene supplementation on postharvest life. Postharvest Biol Technol. 2016;117:141–51.View ArticleGoogle Scholar
- Alamar MC, Collings E, Cools K, Terry LA. Impact of controlled atmosphere scheduling on strawberry and imported avocado fruit. Postharvest Biol Technol. 2017;134:76–86.View ArticleGoogle Scholar
- Collings ER, Alamar Gavidia MC, Cools K, Redfern S, Terry LA. Effect of UV-C on the physiology and biochemical profile of fresh Piper nigrum berries. Postharvest Biol Technol. 2018;136:161–5.View ArticleGoogle Scholar
- Samarakoon H. Ethylene flux in postharvest kiwifruit systems. A thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Food Technology. Massey University, New Zealand; 2013.Google Scholar
- Pathak N, Caleb OJ, Rauh C, Mahajan PV. Effect of process variables on ethylene removal by vacuum ultraviolet radiation: application in fresh produce storage. Biosyst Eng. 2017;159:33–45.View ArticleGoogle Scholar
- Gross KC, Wang CY, Saltveit ME, editors. The commercial storage of fruits, vegetables, and florist and nursery stocks, agricultural handbook 66. Washington (D.C.): U.S. Department of Agriculture, Agricultural Research Service; 2016.Google Scholar
- Produce Fact Sheets - UC Postharvest Technology Center - UC Davis. http://postharvest.ucdavis.edu/Commodity_Resources/Fact_Sheets/. Cited 7 Nov 2018.
- Gwanpua SG, Verlinden BE, Hertog MLATM, Van Impe J, Nicolai BM, Geeraerd AH. Towards flexible management of postharvest variation in fruit firmness of three apple cultivars. Postharvest Biol Technol. 2013;85:18–29.View ArticleGoogle Scholar
- Gwanpua SG, Verlinden BE, Hertog MLATM, Bulens I, Van de Poel B, Van Impe J, et al. Kinetic modeling of firmness breakdown in ‘Braeburn’ apples stored under different controlled atmosphere conditions. Postharvest Biol Technol. 2012;67:68–74.View ArticleGoogle Scholar
- Li T, Tan D, Liu Z, Jiang Z, Wei Y, Zhang L, et al. Apple MdACS6 regulates ethylene biosynthesis during fruit development involving ethylene-responsive factor. Plant Cell Physiol. 2015;56:1909–17.View ArticleGoogle Scholar
- Yang X, Song J, Campbell-Palmer L, Walker B, Zhang Z. Allergen related gene expression in apple fruit is differentially controlled by ethylene during ripening. Postharvest Biol Technol. 2012;63:40–9.View ArticleGoogle Scholar
- Feng X, Apelbaum A, Sisler EC, Goren R. Control of ethylene responses in avocado fruit with 1-methylcyclopropene. Postharvest Biol Technol. 2000;20:143–50.View ArticleGoogle Scholar
- Antunes MD, Sfakiotakis E. Ethylene biosynthesis and ripening behaviour of ‘Hayward’ kiwifruit subjected to some controlled atmospheres. Postharvest Biol Technol. 2002;26:167–79.View ArticleGoogle Scholar
- Hu H, Zhao S, Li P, Shen W. Hydrogen gas prolongs the shelf life of kiwifruit by decreasing ethylene biosynthesis. Postharvest Biol Technol. 2018;135:123–30.View ArticleGoogle Scholar
- Lalel HJD, Singh Z, Tan SC. Aroma volatiles production during fruit ripening of ‘Kensington Pride’ mango. Postharvest Biol Technol. 2003;27:323–36.View ArticleGoogle Scholar
- Shiomi S, Kubo Y, Wamocho LS, Koaze H, Nakamura R, Inaba A. Postharvest ripening and ethylene biosynthesis in purple passion fruit. Postharvest Biol Technol. 1996;8:199–207.View ArticleGoogle Scholar
- Shiomi S, Wamocho LS, Agong SG. Ripening characteristics of purple passion fruit on and off the vine. Postharvest Biol Technol. 1996;7:161–70.View ArticleGoogle Scholar
- Zhou HW, Lurie S, Ben-Arie R, Dong L, Burd S, Weksler A, et al. Intermittent warming of peaches reduces chilling injury by enhancing ethylene production and enzymes mediated by ethylene. J Hortic Sci Biotechnol. 2001;76:620–8.Google Scholar
- Gong D, Cao S, Sheng T, Shao J, Song C, Wo F, et al. Effect of blue light on ethylene biosynthesis, signalling and fruit ripening in postharvest peaches. Sci Hortic. 2015;197:657–64.View ArticleGoogle Scholar
- Saquet AA, Almeida DPF. Ripening physiology and biochemistry of ‘Rocha’ pear as affected by ethylene inhibition. Postharvest Biol Technol. 2017;125:161–7.View ArticleGoogle Scholar
- Chiriboga M-A, Saladié M, Giné Bordonaba J, Recasens I, Garcia-Mas J, Larrigaudière C. Effect of cold storage and 1-MCP treatment on ethylene perception, signalling and synthesis: influence on the development of the evergreen behaviour in ‘Conference’ pears. Postharvest Biol Technol. 2013;86:212–20.View ArticleGoogle Scholar
- Nham NT, Macnish AJ, Zakharov F, Mitcham EJ. ‘Bartlett’ pear fruit (Pyrus communis L.) ripening regulation by low temperatures involves genes associated with jasmonic acid, cold response, and transcription factors. Plant Sci. 2017;260:8–18.View ArticleGoogle Scholar
- Van de Poel B, Vandendriessche T, Hertog MLATM, Nicolai BM, Geeraerd A. Detached ripening of non-climacteric strawberry impairs aroma profile and fruit quality. Postharvest Biol Technol. 2014;95:70–80.View ArticleGoogle Scholar
- Atta-Aly MA, Brecht JK, Huber DJ. Ethylene feedback mechanisms in tomato and strawberry fruit tissues in relation to fruit ripening and climacteric patterns. Postharvest Biol Technol. 2000;20:151–62.View ArticleGoogle Scholar
- Zhang M, Yuan B, Leng P. The role of ABA in triggering ethylene biosynthesis and ripening of tomato fruit. J Exp Bot. 2009;60:1579–88.View ArticleGoogle Scholar
- Van de Poel B, Vandenzavel N, Smet C, Nicolay T, Bulens I, Mellidou I, et al. Tissue specific analysis reveals a differential organization and regulation of both ethylene biosynthesis and E8 during climacteric ripening of tomato. BMC Plant Biol. 2014;14:11.View ArticleGoogle Scholar
- Amoah RS, Landahl S, Terry LA. The timing of exogenous ethylene supplementation differentially affects stored sweetpotato roots. Postharvest Biol Technol. 2016;120:92–102.View ArticleGoogle Scholar
- East AR, Samarakoon HC, Pranamornkith T, Bronlund JE. A review of ethylene permeability of films. Packag Technol Sci. 2015;28:732–40.View ArticleGoogle Scholar
- Ho QT, Verlinden BE, Verboven P, Vandewalle S, Nicolai BM. A permeation-diffusion-reaction model of gas transport in cellular tissue of plant materials. J Exp Bot. 2006;57:4215–24.View ArticleGoogle Scholar
- Turan D, Sängerlaub S, Stramm C, Gunes G. Gas permeabilities of polyurethane films for fresh produce packaging: response of O2 permeability to temperature and relative humidity. Polym Test. 2017;59:237–44.View ArticleGoogle Scholar
- Lammertyn J, Scheerlinck N, Verlinden B, Schotsmans W, Nicolaı̈ BM. Simultaneous determination of oxygen diffusivity and respiration in pear skin and tissue. Postharvest Biol Technol. 2001;23:93–104.View ArticleGoogle Scholar
- Beaudry RM. Effect of O2 and CO2 partial pressure on selected phenomena affecting fruit and vegetable quality. Postharvest Biol Technol. 1999;15:293–303.View ArticleGoogle Scholar