Chilling-induced oxidative stress and antioxidant responses in mume (Prunus mume) fruit during low temperature storage

Mume (Prunus mume Sieb. et Zucc.) fruit are harvested and consumed at the mature green stage and have a short storage life at ambient temperature. While cold temperature extends their storage life, improper refrigeration causes severe chilling injury (CI), with fruit suffering more severe CI at of 5–6 °C than at 1 °C. The objective of this research was to determine the involvement of reactive oxygen species (ROS) and antioxidant systems in fruit under chilling stress. ‘Nankou’ fruit were stored at 1 °C or 6 °C for 15 days. Hydrogen peroxide, a preventive ROS, decreased at a slower rate at 6 °C than 1 °C during storage. Malondialdehyde (MDA), an indicator of lipid peroxidation caused by ROS, increased during storage and the contents were higher in fruit stored at 6 °C than at 1 °C. On the other hand, fruit stored at 6 °C had a lower total antioxidant capacity (TAC) and lower activities of antioxidant-related enzymes including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) than at 1 °C. These results indicate that the fruit at 6 °C had more oxidative stress; thus the fruit had more severe CI symptoms than at 1 °C.     

The relationship between chilling injury and membrane damage in lemon basil (Ocimum × citriodourum) leaves

Leaves of lemon basil (Ocimum × citriodourum) were stored in sealed polyethylene bags at 4 °C and 12 °C. At 4 °C, leaf browning, the visible symptom of chilling injury, occurred earlier and was more severe in mature leaves than in young leaves. No positive correlation was found, when comparing young and mature leaves stored at 4 °C, between browning and either substrate levels (free phenolics) or the activities of peroxidase or catechol oxidase, which might catalyse these reactions. The levels of saturated and unsaturated fatty acids differed only slightly and were not correlated with chilling injury. Compared to young leaves, mature ones showed higher lipoxygenase activity throughout the period of low temperature storage. This might indicate more degradation of membrane unsaturated fatty acids. In addition, mature leaves exhibited lower catalase activity than young ones. This suggests lower protection against membrane oxidation in mature leaves. The data thus suggest a correlation between lipoxygenase activity, antioxidant defense, and chilling injury.     

Modified atmosphere packaging alleviates chilling injury in cucumbers

Cucumbers (Cucumis sativus L.) packaged in perforated or sealed 31.75 μm (1.25 mil) low density polyethylene (LDPE) bags were found to have less severe chilling injury than nonwrapped fruit in storage at 5 °C and 90–95% relative humidity. The onset of chilling injury was also delayed by the LDPE packaging compared to the nonpackaged control. The concentrations of CO₂ increased to 3% while O₂ levels decreased to 16% in the sealed bags. Fruit in the sealed bags had the least decay. The O₂ and CO₂ concentrations inside the perforated bags changed very little from the ambient atmosphere. However, there was a marked difference in the weight loss between nonwrapped cucumbers and fruit from perforated or sealed bags. The weight loss of nonwrapped fruit reached 9% in 18 days while perforated and sealed samples lost less than 1% during the same period. Chilling stress induced increases in putrescine levels in all treatments but the sealed fruit had the highest levels of putrescine. Sealed fruit and perforated fruit also had higher content of spermidine than non-wrapped fruit. These high levels of polyamines may have contributed to the increase of chilling tolerance in fruit from perforated and sealed packages.     

Expression of expansin genes during postharvest lignification and softening of ‘Luoyangqing’ and ‘Baisha’ loquat fruit under different storage conditions

Four expansin cDNA fragments, EjEXPA1, EjEXPA2, EjEXPA3 and EjEXPA4, were isolated and characterized from loquat (Eriobotrya japonica Lindl.) fruit. EjEXPA1 mRNA accumulated consistently with the increase in fruit firmness in 0 °C storage of ‘Luoyangqing’ (LYQ) fruit, where chilling injury with increased fruit firmness due to lignification was observed. EjEXPA1 mRNA levels were lower in fruit that underwent low temperature conditioning (LTC, 6 d at 5 °C then 4 d at 0 °C), and in 1-methylcyclopropene (1-MCP) treated fruit, in both cases where chilling injury was alleviated. Fruit of the ‘Baisha’ (BS) cultivar soften after harvest rather than increase in firmness, and high expression levels of EjEXPA1 and EjEXPA4 accompanied the softening of BS fruit stored at 20 °C; such mRNA accumulation was much lower when fruit were stored at 0 °C, where softening was significantly inhibited by the low temperature. Very low expression of EjEXPA2 and EjEXPA3 was observed during storage of both LYQ and BS fruit under the different storage conditions. Our results showed that of the four genes characterized, EjEXPA1 might be associated with chilling-induced lignification while both EjEXPA1 and EjEXPA4 were closely related to softening of loquat fruit during the postharvest period.     

Characterization of symptoms of senescence and chilling injury on inflorescences of Heliconia bihai (L.) cv. Lobster Claw and cv. Halloween

Inadequate temperatures during the shipping and commercialization of cut tropical flowers may accelerate the senescence process and cause chilling injury, leading to symptoms that have not yet been described for Heliconia bihai. The aim of the present study was to evaluate physiological responses in cut inflorescences of H. bihai cv. Lobster Claw (LC) and cv. Halloween (HW) as well as symptoms of senescence and chilling injury. For such, changes in fresh weight, bract color (L*, a* and b*), percentage of absolute integrity (PAI) of cell membranes and leakage of potassium ions (LPI) were determined. The flowering stems were evaluated at five different intervals after harvest (0, 2, 4, 6 and 8 d). A refrigerated treatment (RT) with a temperature of 6.5 °C and 85% relative humidity was compared to a control treatment (CT) at room temperature of 24 °C and 66% relative humidity. Both cultivars stored at 6.5 °C exhibited dryness of bract tissue (symptom of senescence) and dark stains that became brownish and evolved to necrosis (symptom of chilling injury). The visual quality of inflorescences decreased with time in both cultivars maintained without refrigeration. The severity of chilling injury increased with the length of storage time in both cultivars. There was a significant reduction in the fresh weight of inflorescences in both treatments (RT and CT) and both cultivars (LC and HW). Bract color changed in both cultivars at 6.5 °C. There was no change in PAI throughout the evaluation period in the inflorescences stored at room temperature, whereas those stored at 6.5 °C for 6 and 8 d had lower PAI values. The inflorescences in the control treatment underwent no change in LPI values, whereas those stored under refrigeration had increased LPI values after the sixth day of storage. The physiological responses of cut Heliconia flowers were influenced by storage period and temperature, as demonstrated by visual symptoms of chilling injury and senescence.     

Plant oil emulsion modifies internal atmosphere, delays fruit ripening, and inhibits internal browning in Chinese pears

'Laiyang Chili’ and ‘Ya Li’ (Pyrus bertschneideri Reld) pears were treated with 3, 6, and 9% emulsions of commercial or refined (reduced -tocopherol levels) plant (soybean, corn, peanut, linseed, and cottonseed) oils at harvest an stored at 0°C for 6 months. Effects of oil treatments on ethylene production, respiration, fruit firmness, fruit color, soluble solid content (SSC), titratable acids (TA), internal browning (IB), and internal CO₂, O₂, and ethanol were studied. At the same concentration, oil treatments induced similar responses regardless of their sources or their -tocopherol concentrations. In both cultivars, ethylene production and respiration in fruit treated with 9% oils were lower in early storage and higher in late storage than that in the controls. Oils at 6% reduced IB, at 9% inhibited IB completely, and at 3% was not effective after 6 months at 0°C and 7 days at 20°C. Plant oil treatment maintained fruit color, firmness, SSC, and TA in a concentration-dependent manner during storage. In the first 4 months storage, 9% corn oil-treated fruit contained similar partial pressure of CO₂ and O₂ as the controls. After 5 months storage, oil-treated fruit contained higher partial pressure of CO₂ and lower levels of O₂ than the controls. When held at 20°C for 7 days, changes of internal CO₂ and O₂ were slower but partial pressure of CO₂ were higher, and O₂ were lower, in 9% corn oil-treated fruit than in the controls. Internal ethanol was not affected by oil treatment compared with control, either during storage or 7 days at 20°C. No off-flavor was detected in either oil-treated and control fruit by sensory evaluation.     

Salicylic acid alleviates chilling injury in anthurium (Anthurium andraeanum L.) flowers

We tested if salicylic acid (SA) can alleviate chilling injury in anthurium flowers (Anthurium andraeanum). Cut flowers of five cultivars, individually placed in water, were held at 4 °C and 12 °C. Symptoms of chilling injury (CI) were found in the flowers stored at 4 °C. These symptoms included desiccation of the spadix (the compound floral stalk) and a colour change of the spathe (the large floral bract) to pink and then to brown. The time to the CI symptoms depended on the cultivar. CI symptoms were accompanied by an increase in electrolyte leakage, by loss of fresh weight, and by an increase in catalase (CAT) and superoxide dismutase (SOD) activity. SA at 2.0 mM in water was applied as a 15 min dip. It delayed the CI symptoms, as well as the loss of fresh weight, the increase in electrolyte leakage, and the increase CAT and SOD activity. The data suggest that CI in this system is related to an increase in the concentrations of active oxygen species.     

荫蔽锻炼对大豆苗期光合特性的影响

荫蔽是影响间套作大豆产量进一步提高的限制因素。为探究荫蔽锻炼对大豆叶片光合、荧光特性的影响,本研究采用盆栽试验,分别用远红光LED灯(λ=730nm)、30%透光率遮阳网模拟荫蔽信号和荫蔽胁迫,分锻炼(S1)–恢复(S2)–胁迫(S3)3个阶段,以全过程自然光照为对照(LLLL),设荫蔽信号锻炼(LFLS)、荫蔽胁迫锻炼(LSLS)、不锻炼(LLLS) 3个处理,分析其S3阶段遭受荫蔽胁迫时叶片光合色素含量、光合参数以及叶绿素荧光参数的响应特征。结果表明, LFLS和LSLS较LLLS老叶和成熟叶叶绿素a、叶绿素b、类胡萝卜素含量以及叶绿素总含量显著增加,老叶和新叶叶绿素a/b显著下降。除LSLS成熟叶外,各叶位净光合速率、气孔导度均较未锻炼处理显著增加,老叶和成熟叶锻炼与未锻炼处理胞间二氧化碳浓度差异不显著。与对照相比,无论锻炼与否,后期荫蔽使Fo、qp、NPQ、ΦPSII、ETR降低,而F_v/F_m和F_v'/F_m'则升高,其中,S1阶段的锻炼处理较未锻炼处理Fo下降的幅度更小;老叶qp较对照降低幅度依次为LFLSLLLSLSLS,成熟叶为LSLSLFLSLLLS,新叶为LSLSLFLSLLLS;ΦPSII、ETR均较对照降低但处理间差异不显著; LLLS、LFLS、LSLS新叶中F_v'/F_m'则分别比对照增加6.51%、8.79%和12.05%(P0.05),锻炼后增加幅度更大。由此可见,通过荫蔽锻炼,大豆能通过光合特征的可塑性来适应光环境并表现出更强的荫蔽耐受能力。     

Application of low intensity light pulses to delay postharvest senescence of Ocimum basilicum leaves

Fresh basil (Ocimum basilicum L.) is a highly perishable leafy green vegetable with a storage life of 4–5 d at room temperature. Exposure of basil leaves to temperatures below 12 °C during storage results in chilling injury; therefore, refrigeration cannot be used to extend postharvest life of basil. Typically, leafy vegetables are stored in darkness or extremely low irradiance. Darkness is known to induce senescence, and the initial phase of senescence is reversible by exposure to light. In this work, we studied the effects of low-intensity white light pulses at room temperature on postharvest senescence of basil leaves. Daily exposure for 2 h to 30–37 μmol m⁻² s⁻¹ of light was effective to delay postharvest senescence of basil leaves. Chlorophyll and protein levels decreased, ammonium accumulated and leaves developed visual symptoms of deterioration (darkening) during storage in darkness. Light pulses reduced the intensity of these senescence symptoms. The photosynthesis light compensation point of basil leaves was 50 μmol m⁻² s⁻¹ i.e., higher than the intensity used in this study, and the effect of treatment with red light was the same as with white light, while far red light was ineffective. Light pulses exerted a local effect on chlorophyll loss, but the effect on protein degradation was systemic (i.e., spreading beyond the illuminated parts of the leaf blade). The results of this study indicate that daily treatment for 2 h with low intensity light (30–37 μmol m⁻² s⁻¹ every day) during storage at 20 °C is an effective treatment to delay postharvest senescence of basil leaves. The delay of postharvest senescence by low intensity light pulses seems to be mediated by phytochromes, and it is systemic for protein, and partially systemic for chlorophyll degradation.     

Characterization of chilling injury in Heliotropium arborescens and Lantana camara cuttings

Simulated low-temperature shipment of Heliotropium arborescens and Lantana camara cuttings inflicted chilling injury, which was manifested in increased ion leakage in both species. Morning-harvested cuttings of both Lantana and Heliotropium were more sensitive to chilling temperatures than noon-harvested cuttings. However, this difference was expressed only during the summer in Lantana, but both in the winter and summer in Heliotropium cuttings. These results suggest that the chilling injury that occurs during shipment might be alleviated in both species by avoidance of early morning picking of cuttings.

Chilling injury in Lantana was associated with increases in reactive oxygen species (ROS) levels and ethylene production rate. On the other hand, in Heliotropium cuttings ROS levels were increased and the ethylene production rate was reduced after storage at all simulated shipment temperatures. Our results may indicate that different mechanisms of chilling injury exist in Lantana and Heliotropium.     

小麦脱植基相关基因在春性小麦叶片叶绿素降解过程中的作用分析

小麦叶片的衰老会导致产量的损失,而叶绿素降解是小麦叶片衰老的明显特征,分析小麦叶绿素降解过程中脱植基反应的相关基因叶绿素酶（TaCLH）和脱镁叶绿素水解酶（TaPPH）在春性小麦叶片衰老过程中的作用,为解析小麦叶绿素降解的分子机制提供参考。以10个春性小麦品种为参试材料,对衰老过程中TaCLH和TaPPH的相对表达量进行测定,结合不同品种在开花后不同时期的相对叶绿素含量（SPAD）、功能绿叶面积（GLAD）和叶绿素荧光参数的变化规律,研究叶片衰老过程中TaCLH和TaPPH与SPAD、GLAD和叶绿素荧光参数的相关关系。结果表明,TaPPH的相对表达量与GLAD、SPAD及叶绿素荧光参数[ETR、F_v/F_m、Y(Ⅱ)]等生理指标之间存在极显著负相关关系,与TaCLH相对表达量存在极显著正相关关系,表明TaPPH在春小麦叶绿素降解过程的脱植基反应中起主要作用。     

稻鱼共作对水稻叶绿素荧光特征及产量的影响

为探究稻鱼共作系统对水稻叶绿素含量（SPAD值）、荧光参数及产量的影响,设置9000（M1）、15 000（M2）和21 000尾/hm²（M3）稻田鱼放养密度,以水稻单作为对照（CK）,测定水稻不同生育期叶片SPAD值、叶绿素荧光参数和水稻产量及其构成要素。结果表明,与CK相比,在水稻分蘖期和成熟期,各处理叶片光合系统Ⅱ的最大光化学量子产量（F_v/F_m）和潜在光化学活性（F_v/F_o）均显著提高,且成熟期M1和M2处理的剑叶非光化学猝灭系数q_N和NPQ均显著降低;抽穗期各处理SPAD值均比CK显著提高。与CK相比,各处理结实率均显著提高,实际产量均增加,田鱼产量表现为M2>M3>M1,但无显著差异。相关性分析表明,水稻叶片SPAD值、F_v/F_o、F_v/F_m与有效穗数、结实率和产量呈显著正相关,q_N和NPQ与穗粒数呈显著负相关。综上,稻鱼共作系统提高了光能转化效率,减少了光能热耗散,改善了水稻的光合特性,有利于稳定及提高水稻产量。本试验中稻田鱼15000尾/hm²为适宜的放养密度。     

水稻矮化宽叶突变体osdwl1的生理特性和基因定位

Plant height is one of the important factors affecting rice lodging. The semi-dwarf rice varieties possess high level of lodging resistance, and could reduce yield loss and improve grain quality. Thus, it is very important to study the molecular and physiological mechanism of dwarf formation in rice. In this study, a stable hereditary dwarf and wider-leaf mutant osdwl1 was obtained from ⁶⁰Co γ-radiated indica restore line Zixuan 1, and its morphological and physiological characteristics, cytological observation, genetic analysis and gene mapping were investigated. Under field condition, the mutant osdwl1 exhibited dwarf and wider-leaf after the tillering stage due to shorter length of the parenchyma cells, and its panicle length and all internodes length were significantly shorter compared with wild type plants at mature stage. Paraffin sections and scanning electronic microscopy (SEM) observation revealed that the number of small vascular (SV) bundles and the distance between SVs increased significantly, resulting in wider-leaf blade in osdwl1. Moreover, the number of microhairs on the abaxial and adaxial epidermis were also increased significantly in osdwl1. In addition, starting at the 3-4 leaf seedling stage, yellowing was visible at the upper middle parts of old leaves in osdwl1. Physiological analysis and transmission electron microscopy (TEM) observation indicated that the lamellar structure of chloroplast was distorted and began to collapse in some mesophyll cells, which led to the reduction of total chlorophyll contents, net photosynthetic rate and F_v/F_m ratio of the second and third leaves from top in osdwl1 at the heading stage. Relative to the wild type plants, the soluble protein content, catalase (CAT) and superoxide dismutase (SOD) activities were significantly decreased, which in turn resulting in the accumulation of H₂O₂ and O₂^-, and a steady increase of malondialdehyde (MDA) contents in the mutant leaves. Genetic analysis and gene mapping showed that osdwl1 was controlled by a single recessive nuclear gene, located in a region of 333 kb between SSR marker RM19297 and the InDel marker ID269-2 on the short arm of chromosome 6. The results would further facilitate the cloning and functional analysis of OsDWL1 gene.     

耐性不同辣椒幼苗光合和PSII光化学效率对低温弱光的响应

模拟节能日光温室低温弱光逆境,研究了耐性不同辣椒幼苗光合作用和光化学效率对低温弱光的响应。结果表明,在15℃/5℃(昼/夜)、100μmol•m-2•s-1 PFD条件下处理1~7d后,耐低温弱光的佳木斯辣椒叶片的羧化效率（CE）、气孔导度（Gs）、光合能力及RuBP再生速率的降低幅度均显著地低于冷敏感的陇椒6号。处理1~7d后,佳木斯叶片的PSII最大光化学效率Fv/Fm、实际光化学效率ΦPSⅡ和光化学猝灭系数qP均无显著变化,处理3d后,陇椒6号叶片的Fv/Fm、ΦPSⅡ和qP降低,且随处理时间延长,降低幅度加大。陇椒6号的气孔对低温弱光非常敏感,胁迫1d后,最大气孔导度即降低了66.41%,净光合即检测不出,而佳木斯的只降低了15.02%,处理的前5d能检测到净光合速率。低温弱光处理后,两品种辣椒幼苗叶片的光合色素含量均降低,佳木斯叶片的Chla/Chlb不变,Car/ChlT下降;陇椒6号的Chla/Chlb和Car/ChlT增大。在低温弱光胁迫下,佳木斯叶片的超氧化物歧化酶（SOD）、抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）活性显著高于陇椒6号。处理前期,佳木斯的SOD、APX、GR活性同步提高,陇椒6号的GR活性不能与SOD、APX同步升高。     

光温处理对‘黄金芽’茶生长及叶绿素荧光参数的影响

为选择最适宜于甘肃省文县碧口茶区幼龄‘黄金芽’的光温管理方式,以2年生‘黄金芽’茶苗为试验材料,研究单一棚膜(T1)、单一遮阳网(T2)、棚膜+遮阳网(T3)3种不同的光温管理方式对‘黄金芽’夏梢生长和叶片叶绿素荧光参数的影响,以无棚膜无遮阳网(CK)作为对照。结果表明,遮荫提高了‘黄金芽’叶片的初始荧光(F₀);遮荫显著提高了‘黄金芽’叶片最大荧光产量(Fm);遮荫显著提高了13:00和15:00‘黄金芽’叶片的最大光化学效率(Fv/Fm);T3显著提高了13:00和15:00的‘黄金芽’叶片的光下开放的PSⅡ反应中心的激发能捕获效率(Fv′/Fm′);遮荫显著降低了11:00、13:00和15:00时‘黄金芽’叶片的光化学猝灭系数(qP);T2的非光化学猝灭系数(qN)在15:00时显著低于CK;T1和CK对‘黄金芽’造成13:00和15:00时的光抑制,但未破坏PSⅡ反应中心。甘肃省文县碧口镇‘黄金芽’在三伏天遮荫可以提高其Fv/Fm,同时降低qP;全光照会导致13:00和15:00时‘黄金芽’PSⅡ反应中心失活而出现光抑制,需进行适度遮荫处理。     

Determination of chilling and heat requirements of 69 Japanese apricot cultivars

Chilling requirement, together with heat requirement, which has an impact on the climatic distribution of the genotypes of tree species, determines the flowering date. It also played an important role in the protected cultivation of fruit trees. In our study, we estimated chilling requirements for breaking of dormancy and heat requirements for flowering for 2 successive years in 69 Japanese apricot cultivars of Nanjing (China). The chilling requirements of those Japanese apricot cultivars ranged from 24 to 82 chill portions according to the dynamic model, and the heat requirements of those cultivars fluctuated between 691.9 and 2634.7 growing degree hours. The Japanese apricot cultivars were classified into three groups according to their chilling requirements: the low chilling requirement cultivars with less than 50 chill portions, the medium chilling requirement cultivar ranging from 50 to 70 chill portions, and the high chilling requirement cultivars with more than 70 chill portions. In our study, cultivars originated in Guangdong of China generally have a low chilling requirements, and originated in Zhejiang and Jiangsu of China have a high chilling requirements. Cultivars with lower or higher chilling requirement are not suitable for introduction of Nanjing due to their abnormal phenotype. We also observed that the heat requirement of Japanese apricot had no obvious relationship with their origins. The determination of chilling requirements of 69 Japanese apricot cultivars provided some basis for their rationalized introduction and distribution, and was also important in a breeding program. Those results also expanded our understanding of the temperature responses of flower bud in Japanese apricot during the dormancy progress.     

榆林不同树龄胡杨叶片叶绿素荧光特征比较

为研究榆林风沙草滩区不同树龄条件下引种胡杨的叶绿素荧光特性差异,以榆林红石峡沙地植物园的11种引种胡杨为研究材料,分别在其生长期和枯黄期测定叶片叶绿素含量(SPAD)、初始荧光(F₀)、最大荧光(Fm)、最大光化学效率(Fv/Fm)、实际光化学效率(Φ_PSII)、表观光合量子传递速率(ETR)、光化学淬灭系数(qP)和非光化学淬灭系数(NPQ),并对6年生胡杨设置施肥处理（有机肥0、75、150 kg/hm²）,测定其株高、胸径和冠幅等指标。结果表明,不同树龄条件下引种胡杨的叶绿素含量、Fv/Fm、Φ_PSII、ETR、qP和NPQ等参数均呈现显著差异,2年生密胡杨2号的叶绿素含量最高,而2年生、4年生、5年生胡杨的Fv/Fm、Φ_PSII、ETR和qP值高于其他供试材料;施肥处理明显提高了胡杨的株高和冠幅,且以有机肥150 kg/hm²处理下的增长量最大。综上,2年生、4年生、5年生胡杨为适宜榆林风沙草滩区的引种树龄,有机肥150 kg/hm²为最佳施用肥力水平。     

Influence of modified atmosphere packaging on sensory quality of shiitake mushrooms

Shiitake mushrooms (Lentinus edodes) were packaged under air in two macroperforated packages (A—9.0 × 10³ perforations/m², 0.1 mm² surface and B—17 perforations/m², 0.1 mm² surface) and under two gas mixtures (15% and 25% O₂) in polyethylene packages, and stored at 5 °C for 18 d. The sensory quality of the mushrooms was evaluated using a trained assessors panel.

Mushrooms packaged in macroperforated packages A showed the smallest deterioration rate. However, weight loss after 6 d of storage reached 15%, which is unacceptable. Besides, shelf life of shiitake mushrooms in active modified atmosphere was limited by off-odour development. Mushrooms in these packages developed off-odour after 12 d of storage due to the fact that O₂ concentrations fall bellow 5%.

On the other hand, the shelf life of mushrooms packaged in macroperforated packages B was limited by their sensory deterioration, particularly by changes in the colour and uniformity of their gills. In this film, mushrooms could be stored for approximately 10 d with a weight loss lower than 2%.

Results from the present work suggest that during the first 6 d of storage all the evaluated packaging conditions were useful for reducing mushroom deterioration rate.