The effects of 1-MCP in cyclodextrin-based nanosponges to improve the vase life of Dianthus caryophyllus cut flowers

The present research investigated the effects of a non-volatile formulation of 1-methylcyclopropene (1-MCP) embedded in different cyclodextrin (CD)-based nanosponges (NSs) to extend the postharvest longevity of an ethylene-sensitive carnation cultivar. Cut flowers of Dianthus caryophyllus L. ‘Idra di Muraglia’ were treated with α- and β-CD-based nanosponge-1-MCP complexes (α- and β-NS complexes) in tap water to achieve two different concentrations of active ingredient (0.25 and 0.5 μL L^?1). Treated flowers were compared to cut stems exposed to equivalent concentrations of volatile 1-MCP as well as a tap water control with or without pure α- and β-NS. Identical nanoporous compounds were applied by perfusion to yield a total of 15 treatments. Twenty-four hours after the treatments were applied, the cut flowers were exposed to exogenous ethylene (1 ± 0.2 μL L^?1) for 24 h. The postharvest carnation flower and leaf quality in addition to ethylene production levels were determined daily (beginning 24 h after treatment). None of the α-NS complex applications statistically improved the vase life of cut flowers; however, β-NS complexes were effective in preventing senescence, reducing ethylene production (measured at nearly nil after 11 d), and maintaining original petal color longer. These results were particularly strong at the lowest concentration (0.25 μL L^?1) of β-NS complex. Overall, this method promoted cut flower longevity (loss of ornamental value after 14.7 d; complete damage at day 18.5) better than the commercial 1-MCP gaseous application method.     

Effects of ethylene, pollination, and ethylene inhibitor treatments on flower senescence of gentians

Flower senescence of the potted gentian (Gentiana scabra) ‘Shinbisei’ was investigated in relation to ethylene sensitivity and production. ‘Shinbisei’ flowers were used for all experiments except for those with inflorescences. Exposure to ethylene at 0.5 μL L⁻¹ or higher concentrations for 24 h markedly accelerated flower senescence, indicating that G. scabra flowers are highly sensitive to ethylene. Treatment with 0.2 or 0.5 mM silver thiosulfate complex (STS) and 2 μL L⁻¹ 1-methylcyclopropene (1-MCP), ethylene action inhibitors, and 50 mM α-aminoisobutyric acid, an inhibitor of 1-aminocyclopropane-1-carboxylate (ACC) oxidase, did not delay flower senescence. However, treatment with 1 mM l-α-(2-aminoethoxyvinyl) glycine, an inhibitor of ACC synthase, slightly delayed flower senescence. Pollination significantly accelerated petal senescence of G. scabra flowers. Ethylene production of petals, gynoecium, and stamens in unpollinated flowers slightly increased during senescence. Pollination significantly increased ethylene production of petals, gynoecium and stamens 1 day after pollination. To clarify whether 1-MCP delays senescence of cut gentian inflorescences, cut G. scabra ‘Yuki-hotaru’, G. scabra × Gentiana triflora ‘Aoi-kaze’, and G. triflora ‘Koharu’ inflorescences with various stages of flowers, including buds with colored petals, were treated with 2 μL L⁻¹ 1-MCP for 24 h. 1-MCP treatment delayed flower wilting of cut inflorescences of ‘Aoi-kaze’ and ‘Yuki-hotaru’ more than that of ‘Koharu’, suggesting that there is species variation in the effect of 1-MCP in delaying flower senescence of cut gentian inflorescences.     

Use of 1-methylcylopropene in cyclodextrin-based nanosponges to control grey mould caused by Botrytis cinerea on Dianthus caryophyllus cut flowers

Botrytis cinerea is one of the pathogens resulting in the heaviest commercial losses in ornamental cut flowers, and the severity of grey mould disease partly depends on the presence of ethylene in the storage environment. The efficacy of a β-cyclodextrin-based nanosponge 1:8 (CD-NS) - 1-methylcyclopropene (1-MCP) complex was evaluated as a novel control agent in protecting carnation (Dianthus caryophyllus L. ‘Idra di Muraglia’) cut flowers against B. cinerea infection. Two concentrations of this non-volatile 1-MCP formulation (CD-NS complex, 0.25 and 0.5 μL L⁻¹, a.i.) were compared with commercial gaseous 1-MCP (0.25 μL L⁻¹, a.i.), and an inoculated control. A non-inoculated control was also used to assess the natural infection level. Eleven days after inoculation, the development of grey mould on carnation was significantly reduced (59.9% of flower surface) in cut stems treated with the CD-NS complex at low dosage, compared to the high dosage of the CD-NS complex (91.5%), the commercial gaseous 1-MCP formulation (76.2%) and the inoculated control (100.0%). Endogenous ethylene production was associated with symptom development. Results showed a reduced ethylene production in 1-MCP treated flowers (0.25 μL L⁻¹, a.i., both suspended and gaseous formulation). The CD-NS complex could therefore be an effective alternative to conventional chemicals to protect ornamental cut flowers.     

Expression of Stay-Green encoding gene (BoSGR) during postharvest senescence of broccoli

Degreening caused by chlorophyll degradation is the most important feature that determines postharvest loss of quality in broccoli. Chlorophyll molecules are assembled to several thylakoid proteins, from which chlorophylls must be released in order to be catabolized. Stay-Green (SGR), a chloroplast-located protein, specifically interacts with light harvesting complex subunits helping toward their destabilization and to the release of chlorophylls. In this work, a fragment of a gene encoding a SGR from broccoli (BoSGR) was cloned. The expression of BoSGR was analyzed and detected an important increment during postharvest senescence, simultaneously with chlorophyll degradation. In order to analyze the effect of different growth regulators, different groups of broccoli heads were treated with cytokinins, ethylene and 1-MCP. Cytokinins and 1-MCP delayed the increment of BoSGR expression whereas ethylene accelerated the process. In addition, several postharvest treatments that delay degreening in broccoli florets were applied to evaluate their effects on BoSGR expression. Samples treated with modified atmosphere, hot air, UV-C or white lights showed a delay in chlorophyll degradation and degreening. In most cases, the treatments also delayed the increment of BoSGR expression during senescence, reaffirming the relationship between the expression of this gene and chlorophyll degradation.     

Expression of genes encoding xyloglucan endotransglycosylase/hydrolase in ‘Saijo’ persimmon fruit during softening after deastringency treatment

Persimmon (Diospyros kaki Thunb.) fruit undergoes intensive cell wall modification during postharvest fruit softening. Xyloglucan metabolism is important in cell wall disassembly. We cloned cDNAs for two xyloglucan endotransglycosylase/hydrolase genes (DkXTH1 and DkXTH2) from ‘Saijo’ persimmon fruit treated with dry ice to remove astringency. In order to determine the ethylene dependence of XTH gene expression, fruit were exposed to 1-methylcyclopropene (1-MCP), an inhibitor of ethylene action, prior to removal of astringency. Ethylene production increased in mature control and 1-MCP-pretreated fruit after dry-ice treatment, and flesh firmness decreased to the same extent during dry-ice treatment in the control and 1-MCP-pretreated fruit. After dry-ice treatment, control fruit softened completely, but fruit firmness was maintained in 1-MCP-pretreated fruit. Accumulation of DkXTH1 mRNA was induced simultaneously with commencement of ethylene production in mature control fruit. Pretreatment with 1-MCP delayed accumulation of DkXTH1 mRNA. DkXTH2 expression also coincided with fruit softening but was intensified by 1-MCP treatment during the deastringency treatment. These results indicate that fruit softening was related to both DkXTH1 and DkXTH2 expression in ‘Saijo’ persimmons.     

Postharvest characteristics of cut dahlia flowers with a focus on ethylene and effectiveness of 6-benzylaminopurine treatments in extending vase life

With the aim of extending vase life of cut dahlia flowers, we investigated the postharvest characteristics of the flowers. Our focus was on the role of ethylene on senescence and on treatments that have extended vase life of other flowers. Continuous exposure to ethylene at 2 or 10 μL L⁻¹ significantly accelerated petal abscission in cut flowers. Flowers continuously immersed in 1 or 10 μL L⁻¹ 2-chloroethylphosphonic acid (CEPA) solution wilted earlier than those treated with distilled water (DW) or 0.15 g L⁻¹ citric acid. Ethylene production from the ovary and ray petal was relatively high (4.5 and 0.9 nL g⁻¹ fresh weight h⁻¹, respectively) at harvest, but decreased gradually over 5 days. No remarkable increase in ethylene production was observed during senescence. Silver thiosulfate complex (STS), an inhibitor of ethylene action, did not extend the vase life of cut flowers, although a high silver concentration was detected in flower organs. In contrast, pulse treatment with 1-methylcyclopropene (1-MCP) and dip treatment with 6-benzylaminopurine (BA) extended the vase life of florets, and BA was more effective than 1-MCP when the flowers were held in both DW and CEPA. BA spray treatment extended vase life of cut ‘Kokucho,’ ‘Kamakura’ and ‘Michan’ flowers. These results suggest that dahlia flower senescence is partially regulated by ethylene, and BA is more effective in delaying the senescence of cut dahlia flowers than ethylene action inhibitors.     

1-MCP处理对采后青花菜内源激素变化的影响

以青花菜品种"曼陀绿"(Brassica olracea L. var. italica)为试材,研究了1-MCP处理对青花菜采后叶绿素含量、乙烯释放速率和内源玉米素(ZR)、赤霉素(GA)、生长素(IAA)、脱落酸(ABA)含量的影响。结果表明：1-MCP延缓了叶绿素降解,降低了组织对乙烯的敏感性,延缓了GA的分解,推迟了ABA的积累。经1-MCP处理的青花菜ABA/GA和ABA/IAA比值上升缓慢。     

A novel technique using 1-MCP microbubbles for delaying postharvest ripening of banana fruit

This study aimed to investigate the application of microbubble technology for delaying banana ripening. A preparation of 1-MCP designed for use as a form of aqueous micro bubble (MBs) solutions was formulated. Banana fruit were immersed in 500 nL L⁻¹ of aqueous 1-MCP microbubbles (1-MCP-MBs) or fumigated with 500 nL L⁻¹ 1-MCP, then stored at 25 °C for 8 days. 1-MCP-MBs were more effective in delaying postharvest ripening than conventional 1-MCP fumigation. 1-MCP-MBs reduced the respiration rate and ethylene production compared to the control and 1-MCP fumigated fruit. Moreover, 1-MCP-MBs delayed yellowing and maintained firmness of banana fruit during storage. These results indicate that 1-MCP-MBs can be used as an alternative method for delaying the postharvest ripening of banana fruit, and its application for other commodities needs to be further elucidated.     

Effects of auxin and methyl jasmonate on cut rose petal growth through activation of acid invertase

Petal growth associated with flower opening depends on cell expansion caused by water influx. To understand the mechanism of flower opening and to develop a method for improving cut flower quality, we investigated the changes in the amount of soluble carbohydrates and invertase activities in rose (Rosa ‘Meivildo’) petals using attached and cut flowers, and the effects of α-napthylacetic acid (NAA) and methyl jasmonate (MeJA) on cut flowers. Cut rose flowers were harvested at the tight bud stage (TB), or mature bud stage (MB), which is the commercial harvest stage, and 2 days after TB. Cut flowers were immediately treated with deionized water or 1% (w/v) glucose. Fresh weight (FW) and the levels of soluble carbohydrates in petals in cut flowers were lower under postharvest conditions than those of attached flowers during flower opening. Although invertase activities in petals of attached flowers increased drastically during TB and MB, those in the petals harvested at TB did not increase under postharvest conditions. These results suggested that sucrose metabolism, including invertase activity, could be an important factor in cut rose flower opening to a greater extent after harvest. In addition, we tried to control flower opening by affecting invertase activities in petals of cut rose flowers. Cut flowers treated with NAA opened faster and those treated with MeJA opened later than in controls. Levels of soluble carbohydrates and invertase activity in petals were also changed by these treatments. In flowers treated with NAA, activities of both vacuolar and cell wall invertases increased 1 day after treatment and then decreased through to the end of the treatment, although activities in control flowers never increased after harvested. By contrast, cell wall invertase activity in MeJA treated flowers increased 1 day later than with the NAA treatment and remained at a relatively high level until 4 days after treatment compared to the controls. Our results suggest that inducing invertase activity in postharvest conditions may important for the quality of cut roses.     

1-MCP和乙烯脱除剂对嘎啦苹果贮藏生理及品质的影响

以嘎啦苹果为试材,研究1－MCP与乙烯脱除剂不同处理对0℃贮藏180d的果实生理与品质变化的影响。结果表明,1－MCP处理可较持久地抑制果实的乙烯合成,进而抑制果实的呼吸作用,延缓衰老,保持果实品质,其中,1．0μL．L^-1浓度1-MCP处理的嘎啦苹果可贮藏180d,0．5μL·L^-1浓度的1-MCP处理可贮藏150d：乙烯脱除剂处理在贮藏前期对抑制果实乙烯合成、延缓衰老也有较好的作用．其中MA＋2袋乙烯脱除剂处理可贮藏150d,MA＋1袋乙烯脱除剂处理可贮藏120d;对照果实（MA贮藏）衰老较快．0℃条件下仅能贮藏90d。     

1-MCP regulates ethylene biosynthesis and fruit softening during ripening of ‘Tegan Blue’ plum

To investigate the effects of postharvest application of 1-MCP on ethylene production and fruit softening, activities of ethylene biosynthesis and fruit softening enzymes were measured during postharvest ripening of plum (Prunus salicina Lindl. cv. Tegan Blue) fruit after being exposed to 1-MCP (0, 0.5, 1.0 or 2.0 μL L⁻¹) at 20 ± 1 °C for 24 h. Following the treatments, fruit were allowed to ripen at ambient temperature (20 ± 1 °C), and ethylene production in fruit, activities of ACS and ACO, ACC content and fruit softening enzymes (PE, EGase, exo-PG and endo-PG) in fruit skin and pulp were recorded at different intervals. Postharvest application of 1-MCP significantly delayed and suppressed the climacteric ethylene production with reduction in the activities of ethylene biosynthesis enzymes (ACS, ACO) and ACC content, and fruit softening enzymes (PE, EGase, exo-PG and endo-PG) in the skin as well as in pulp tissues. The reduction was more pronounced with increased concentrations of 1-MCP. 1-MCP treated fruit showed different rates of fruit softening and activities of ethylene biosynthesis enzymes in the skin and pulp tissues which warrant further investigation on regulation of gene expression related to these enzymes with the inhibitory effect of 1-MCP.     

1-甲基环丙烯不同时间处理对芒果贮藏生理的影响

以"台农"芒果为材料,测定了1-甲基环丙烯(1-MCP)0-18h处理对芒果贮藏期的呼吸强度、乙烯释放量、可溶性固形物、成熟度指数的影响。结果表明:不同时段的1-MCP处理均能降低呼吸强度,推迟呼吸高峰的到来,延缓乙烯释放量增加,推迟可溶性固形物含量上升,有效延缓后熟进程。其中12、18h处理对延缓成熟的效果优于6h处理,二者之间对成熟度的影响差异不明显,建议使用1-MCP处理12h为宜。     

乙烯抑制剂在采后观赏植物中的应用研究进展

乙烯作为植物衰老激素在观赏植物及切花开花衰老过程中起着关键性的调节作用。利用乙烯抑制剂控制乙烯作用就成为延长观赏植物观赏寿命和提高其观赏价值的主要途径和经济有效的方法,是采后观赏植物研究的主要方向之一。在此,综述了近年来在采后观赏植物研究和生产实践中广为应用的几种乙烯抑制剂,并简要说明了其特点和作用原理。     

Diurnal carbohydrate dynamics affect postharvest ethylene responsiveness in portulaca (Portulaca grandiflora ‘Yubi Deep Rose’) unrooted cuttings

Portulaca (Portulaca grandiflora) is an herbaceous ornamental annual plant that is commonly propagated by shoot-tip cuttings and shipped long distances before they are rooted in greenhouses. During transit and rooting, a significant number of leaves usually abscise, which delays or prevents subsequent rooting. We investigated the effect of preharvest diurnal carbohydrate dynamics on postharvest performance of unrooted shoot-tip cuttings of portulaca ‘Yubi Deep Rose’. The production of ethylene was quantified, as well as the efficacy of 1-methylcyclopropene (1-MCP) to improve the postharvest performance. The initial carbohydrate concentrations in cuttings increased with later harvest during the day (8 a.m., 12 p.m., and 4 p.m.). When cuttings were placed into a dark postharvest environment at 20 ± 1 °C for 48 h, cuttings harvested at 8 a.m. had complete leaf abscission, whereas only partial leaf abscission was observed in cuttings harvested at 12 p.m. and 4 p.m. Leaf abscission was negatively correlated with preharvest leaf carbohydrate and stem starch concentrations, but not significantly correlated with postharvest ethylene production during storage. Application of 1-MCP improved the storage quality of cuttings, irrespective of the time of cutting harvest, and did not inhibit the rooting response during subsequent propagation. Collectively, these results indicate that with the increase in preharvest endogenous carbohydrate levels of portulaca cuttings, as the photoperiod progresses, subsequent postharvest ethylene responsiveness decreases, but there is no effect on ethylene synthesis.     

Effect of 1-methylcyclopropene (1-MCP) treatment on sweet basil leaf senescence and ethylene production during shelf-life

The effect of 1-methylcyclopropene (1-MCP) on shelf-life and postharvest quality of sweet basil detached leaves was examined. Treatment with 0.2, 0.4 and 0.6 g m⁻³ 1-MCP for 8 h was conducted at 15 °C in the dark. After the treatment the leaves were packed in polyethylene bags then sealed and stored at 20 °C. All 1-MCP concentrations significantly increased the shelf-life of leaves compared to the untreated control, and leaf weight loss with 1-MCP treatment was minimal. 1-MCP treatment significantly retarded the degradation of chlorophyll and protein content of detached leaves during storage and decreased leaf ethylene production. 1-MCP treatment also significantly retarded the decrease of volatile oil percentage in detached leaves during storage compared to the control. Among 1-MCP concentrations, 0.4 g m⁻³ resulted in the maximum shelf-life as well as improved postharvest quality of the leaves. The results clearly indicate that a single treatment with 1-MCP may provide a feasible technique for extending the shelf-life and maintaining higher volatile oil percentage of sweet basil leaves.     

1-MCP对果实采后生理变化的影响

对1-MCP作用效应的影响因素进行阐述,同时从果实风味、硬度、可滴定酸、可溶性固形物、果皮叶绿素、采后生理病害、乙烯生成和呼吸速率等几个方面描述1-MCP对果蔬采后贮藏保鲜的作用效果.     

1-MCP在果蔬体内的药代规律研究及产品开发进展

1-甲基环丙烯(1-MCP)是一种乙烯受体抑制剂,广泛应用于果蔬采后贮藏保鲜行业.本文从1-MCP在果蔬体内的吸收、与果实内部生物大分子互作及其机制、残留量及其法规约定等方面对1-MCP在果蔬体内的药代规律进行了分析.从产品开发和技术应用的角度概括了1-MCP常见的产品形式和发展趋势,梳理了1-MCP与预冷技术结合、与杀菌剂联用、与果蔬风味形成调控技术复合使用等多效保鲜技术的研发情况.通过概括分析可以发现,1-MCP的安全性高,残留量低,但有关其在果蔬体内的代谢规律和对果蔬品质的不利影响方面的研究较少,且大部分的研究集中于1-MCP的应用,长效稳定缓释剂型和复合保鲜技术将是今后的发展趋势.     

Combined treatment of aminoethoxyvinylglycine (AVG) and 1-methylcyclopropene (1-MCP) reduces melting-flesh peach fruit softening

The effects of postharvest application of aminoethoxyvinylglycine (AVG) and 1-methylcyclopropene (1-MCP) on ethylene production and fruit quality, and thus on transportation and shelf-life, were evaluated in melting-flesh peaches. AVG (150 mg L⁻¹) significantly reduced ethylene production, and the effect was enhanced in combination with 1-MCP (1 μL L⁻¹). However, fruit treated with AVG alone softened to untreated control levels 2 d after harvest (DAH). Treatment with 1-MCP significantly reduced the rate of softening until 2 DAH, but the fruit rapidly softened thereafter, and reached untreated control levels by 4 DAH. A combination of AVG and 1-MCP significantly reduced fruit tissue softening throughout ripening. The effect of each chemical on flesh firmness indicated that 1-MCP affected fruit response in the early stages of ripening up to 4 DAH, and AVG significantly reduced softening in the latter stages from 4 to 9 DAH. Peaches treated with AVG and 1-MCP retained their ground color during ripening, but the effect of each chemical on color is unclear. The present study indicates that combined treatment with AVG and 1-MCP significantly delays the ripening of melting-flesh peaches.