Effects of 1-MCP on Ethylene Synthesis and Metabolismof Apple During Storage

Red Fuji apple(Malus domestica Borkh var. Red Fuji)fruits were used to study the effect of 1-MCP on ethylene biosynthesis metabolism during storage. The results showed that 1-MCP maintained the firmness and inhibited the respiration rate, LOX activity and ethylene production rate of fruits. Further study indicated that 1-MCP inhibited ACS(ACC synthase)activity from the 15th day, increased ACC accumulation, and delayed the appearance of ACO(ACC oxidase)activity peak. The increase of protein kinase activity was also inhibited by 1-MCP during fruit ethylene climacteric time.

Ethylene-inhibiting compound 1-MCP delays leaf senescence in cotton plants under abiotic stress conditions

Cotton （Gossypium hirsutum L.） plants produce more ethylene when subjected to abiotic stresses, such as high temperatures and drought, which result in premature leaf senescence, reduced photosynthetic efficiency, and thus decreased yield. This study was conducted to test the hypothesis that the ethylene-inhibiting compound 1-methylcyclopropene （I-MCP） treatment of cotton plants can delay leaf senescence under high temperature, drought, and the aging process in controlled environ- mental conditions. Potted cotton plants were exposed to 1-MCP treatment at the early square stage of development. The protective effect of 1-MCP against membrane damage was found on older compared to younger leaves, indicating 1-MCP could lower the stress level caused by aging. Application of 1-MCP resulted in reduction of lipid peroxidation, membrane leakage, soluble sugar content, and increased chlorophyll content, in contrast to the untreated plants under heat stress, suggesting that 1-MCP treatment of cotton plants may also have the potential to reduce the effect of heat stress in terms of delayed senescence. Application of 1-MCP caused reductions of lipid peroxidation, membrane leakage, and soluble sugar content, together with increases in water use efficiency （WUE）, water potential, chlorophyll content, and fluorescence quantum efficiency, compared to the untreated plants under drought, suggesting that 1-MCP treatment of cotton plants may also have the ability to reduce the level of stress under drought conditions. In conclusion, 1-MCP treatment of cotton should have the potential to delay senescence under heat and drought stress, and the aging process. Additionally, 1-MCP is more effective under stress than under non-stress conditions.

Effect of Internal Ethylene and 1-Methylcyclopropene on Ethylene Metabolism and Membrane Lipid Peroxidation in Papaya Fruit

[Objective] This study was conducted to evaluate the effect of 1-methylcy- clopropene （1-MCP） on fruit firmness, and the activity of the enzymes involved in ethylene metabolism and membrane lipid peroxidation. [Method] The nearly ripe fruits of the papaya cultivar Risheng were randomly assigned to one of four groups. Two groups were treated under hypobaric and hypoxic （HH） atmosphere condition for six hours, and immediately soaked in deionized water （HH alone）, or fumigated with 2.0 mg/L 1-MCP （HH＋I-MCP） for 24 h. The other two groups untreated under HH condition were also soaked in deionized water （negative control）, or fumigated with 2.0 mg/L 1-MCP （1-MCP alone） for 24 h. After that, the fruits of all the four treatments were stored at room temperature （23＋1） ℃. Cell membrane permeability, fruit firmness, respiration rate, ethylene release rate, SOD activity, POD activity, CAT activity, MAD content and LOX activity were measured once every three days during storage. [Result] Treatment with 1-MCP delayed the occurrence of the peaks of respiration rate and ethylene release rate, significantly reduced the accumulation of malondialdehyde （MDA）, and inhibited the decrease in papaya fruit firmness. Compared with the control, 1-MCP treatment significantly increased the SOD （su- peroxide dismutase）, POD （peroxidase） and CAT （catalase） activity, reduced the ac- tivity of lipoxygenase （LOX）, a product of lipid peroxidatlon in membranes, and in- hibited ethylene biosynthesis, thus delaying the aging process and prolonging the storage life of papaya fruits. [Conclusion] The results will provide a theoretical basis for analvzina the key factors controllinq postharvest maturity and aging of papaya fruits.

Effect of Internal Ethylene and 1-methylcyclopropene on Ripening of Papaya Fruit(Carica papaya L.)

With papaya fruit （ Carica papaya ） as an experimental material, variations of its physiological indices were investigated through hypobaric hypoxia （HH, 10 kPa, 1.5 kPa O 2） treatment followed by fumigation with 1-methylcyclopropene （1-MCP）, so as to discuss the effect of interaction between 1-MCP and internal ethylene on ripening of papaya fruit during postharvest storage. The results indicated that HH treatment significantly reduced internal ethylene concentration （IEC） by 57.6%. However, there were no remarkable differences in other physiological indices between various treatments and control （CK）. The 1-MCP and HH＋1-MCP treatments could significant postpone the softening process and color change of papaya fruit. The two treatments achieved the effects of significantly inhibiting the occurrence of fruit disease and the increase of pericarp cell membrane permeability, effectively delaying the variation of soluble solid and Vc contents, and better maintaining soluble solid and Vc contents in fruit, thereby better keeping nutritional substances and flavor quality in fruit in later storage period and prolonging the storage time of fruit.

1-MCP对采后果蔬生理及品质影响的研究进展

从生理、品质和病理 3个方面概述了 1 甲基环丙烯 (1 MCP)对采后果蔬的影响 ,并对 1 MCP抑制乙烯作用、抑制植物呼吸作用、延缓果蔬成熟衰老、保持果实硬度、减缓色泽转变、减轻部分生理病变等方面作了初步探讨。

1-MCP/β-CD包结物的合成及表征

针对乙烯受体抑制剂1-甲基环丙烯稳定性差的问题,利用β-环糊精“内疏水,外亲水”的独特空间结构,用溶液法制备了β-环糊精和1-甲基环丙烯的包结配合物,并利用X射线粉末衍射(X-RPD)、差热分析(DTA)、紫外(UV)和红外吸收光谱(IR)等测试方法对此包结物进行了研究.通过比较β-环糊精及其与1-甲基环丙烯形成的包结物在光谱上的差异,证实了包结物的生成.

Effect of 1-MCP on Senescence and Decay of Vegetable Soybean Pods During Storage

The effects of 1-MCP on decay and senescence in vegetable soybean pods during storage were investigated. Treatments with 0. 5,1, or 2μl L-1 1-MCP significantly inhibited the senescence process of harvested vegetable soybean pods, as manifested in lower levels of ethylene production, respiratory rate, MDA and superoxide contents and higher levels of SOD, ASA-POD activities, Vc and chlorophyll contents. Moreover, 1-MCP promoted PAL activity and lignin synthesis, inhibited decay incidence. 2μl L-1-MCP treatment, however, inhibited PAL activity during the later period of storage, thereby increasing decay incidence.

Effects of 1-MCP on proline,polyamine,and nitric oxide metabolism in postharvest peach fruit under chilling stress

Peach(Prunus persica Batsch‘Yuhualu’)fruit are sensitive to chilling injury(CI).Proline,polyamine(PA),and nitric oxide(NO)are important small regulators of various metabolic pathways under chilling stress that mitigate CI.Ethylene is known to promote senescence and CI,while 1-methylcyclopropene(1-MCP)is an antagonist that inhibits the effects of ethylene.However,how1-MCP and ethylene affect proline,PA,and NO levels under chilling stress remains unclear.To address these questions,1-MCP(1μL·L^(−1))and ethylene(1μL·L^(−1))treatments were applied to peach fruit.Fruit were stored at 4°C for 28 d,then moved to 25°C for 3 d immediately after cold storage.Peach fruit exhibited CI symptoms after 7 d of cold storage with enhanced electrolyte leakage and malondialdehyde contents.The 1-MCP treatment significantly(P<0.05)restrained peach CI,and fruit did not exhibit CI symptoms until 14 d of cold storage.Proline and PAs in peach under chilling stress weremostly synthesized from glutamate and arginine,which were catalyzed by1-pyrroline-5-carboxylate synthetase and arginine decarboxylase,respectively.1-MCPtreated fruit exhibited higher proline and PA contents and enhanced chilling tolerance compared to the control,while ethylene-treated fruit had lower proline and PA contents and reduced chilling tolerance.Ethylene-treated fruit,which exhibited more severe CI symptoms compared to the control,had significantly(P<0.05)lower NO contents and NO synthase activities.However,NOmay not be a direct acting factor in 1-MCPinduced chilling tolerance,as 1-MCP-treated fruit had lower NO contents and NO synthase activities compared to the control.In conclusion,proline and PA clearly played direct and important roles in 1-MCP-induced peach chilling tolerance,while NO may not be actively involved.

1-MCP Improved Diverse Sensorial, Biochemical and Physical Apple Traits during Cold Storage Based on Cultivar

Apple cultivars’ storability could be strengthened through known techniques of cold storage, advanced industries of control atmosphere or other routine usages like fruit pre-cooling followed by immersion in CA++ solution, depending on genetic potential of the plant material. At the end of pomology and cold storage assessments of 93 apple cultivars, two high yielding native 'Dirras-e Mashhad' and 'Wealthy' were treated by single and combined 1-MCP and ethylene nano-absorbent (ENA) to assess eventual improvements in cold storage span, fruit eating quality and role of cultivar. For this purpose, directs effects and interactions between all sources of variance were studied. Ethylene emission and CO2 amounts were measured. The results showed that reduced weight loss and flesh firmness, were registered in the treated samples of both cultivars compared with the control. Using of 1-MCP affected significantly (p 0.05) on these characteristics. The native apple 'Dirras-e Mashhad' showed higher pH value than 'Wealthy' under the combined treatment (ENA+1-MCP). Genetic source revealed significant difference through lower 'Wealthy' storability. Ethylene emission increased to 53.64 ppm/Kg·hr after 5th month, which resulted in significant difference at p > 0.01 level related to the initial value of 3.26 ppm/Kg·hr. The combined treatment (ENA+1-MCP) affected significantly (p < 0.05) most of the fruit characteristics in both of the cultivars. The treatments demonstrated different results by cultivar.

Effect of 1-MCP on Boll Development and Subtending Leaves of Cotton (<i>Gossypium hirsutum</i>L.) Plants

Ethylene regulates multiple physiological processes in cotton (Gossypium hirsutum L.) ranging from square and boll abscission to senescence. This field study investigated the effect of an ethylene inhibiting compound 1-methylcyclopropene (1-MCP) on boll development and the corresponding subtending leaves. The study was conducted in 2011 and 2012 at the Texas A & M Agri-LIFE Research Farm in Burleson County, TX. The study consisted of two rates of 1-MCP (0 and 10 g a.i. ha-1) applied at one and two weeks after first flower. Boll development and subtending leaves were studied on the tagged flowers during the growing season. 1-MCP treatment increased cotton boll weight at 20 days after flowering. This study showed that 1-MCP-treated subtending leaves exhibited decreased membrane damage and lipid peroxidation, and higher chlorophyll content and photosynthetic efficiency at 20 to 30 days after flowering. The healthier state of subtending leaves should have provided more carbohydrates for the fruits which could partially explain the reason for the increased boll weight. However, this beneficial effect of 1-MCP did not last to the end of the growing season and failed to result in a yield increase ultimately. Multiple applications or extending effective duration of 1-MCP is desirable to enhance the activity of 1-MCP to make a significant difference in cotton yield.

Functional mechanism study of the allelochemical myrigalone A identifies a group of ultrapotent inhibitors of ethylene biosynthesis in plants

Allelochemicals represent a class of natural products released by plants as root,leaf,and fruit exudates that interfere with the growth and survival of neighboring plants.Understanding how allelochemicals function to regulate plant responses may provide valuable new approaches to better control plant function.One such allelochemical,Myrigalone A(MyA)produced by Myrica gale,inhibits seed germination and seedling growth through an unknown mechanism.Here,we investigate MyA using the tractable modelDictyostelium discoideum and reveal that its activity depends on the conserved homolog of the plant ethylenesynthesis protein 1-aminocyclopropane-1-carboxylic acid oxidase(ACO).Furthermore,in silico modeling predicts the direct binding of MyA to ACO within the catalytic pocket.In D.discoideum,ablation of ACO mimics the MyA-dependent developmental delay,which is partially restored by exogenous ethylene,and MyA reduces ethylene production.In Arabidopsis thaliana,MyA treatment delays seed germination,and this effect is rescued by exogenous ethylene.It also mimics the effect of established ACO inhibitors on root and hypocotyl extension,blocks ethylenedependent root hair production,and reduces ethylene production.Finally,in silico binding analyses identify a rangeof highlypotentethylene inhibitorsthatblock ethylene-dependent responseand reduce ethyleneproduction in Arabidopsis.Thus,we demonstrate a molecular mechanism by which the allelochemical MyA reduces ethylene biosynthesis and identify a range of ultrapotent inhibitors of ethylene-regulated responses.

Current progress in application of 1-Methylcyclopropene to improve postharvest quality of cut flowers

Floral senescence or petal abscission that determine cut flower quality and longevity are primarily caused by the regulation of endogenous ethylene and perception of endogenous and exogenous ethylene in floral organs(such as the petals and gynoecium),in ethylene-sensitive species.Several attempts have been made to prolong flower quality and longevity using silver ions and other chemicals that inhibit ethylene production and perception in floral organs.Among the available compounds,1-methylcyclopropene(1-MCP)has been increasingly used as ethylene-action/perception inhibitor because of its ability to inhibit ethylene action/perception and it is environmentally safe.Although 1-MCP has been used in several cut flower crops for about 25 years,there has been no review yet that critically emphasizes the benefits or difficulties of using this compound for the prolongation of cut flower quality and longevity.Here,we outline the role of 1-MCP in inhibiting ethylene action/perception and petal senescence in cut flowers through the blocking of receptor binding sites,and we discuss how various factors affecting efficacy of 1-MCP(such as concentration,treatment time and temperature,genotype,and flower stage)are involved in the achievement of flower longevity.Moreover,we highlight the advantages of applying nonvolatile and liquid 1-MCP formulation types,as opposed to using the conventional 1-MCP treatment(powder formulation type).We expect that this review will provide useful information for the future utilization of 1-MCP for the maintenance of cut flower longevity.

Effects of salt stress on rice growth, development characteristics, and the regulating ways： A review

Rice （Oryza safiva L.） is highly susceptible to the rhizosphere salinity than other cereals. High sensitivity has been ob- served, mainly at vegetative and reproductive stages in rice. It is the duty of plant physiologists to comprehend the growth, development, and physiological processes of rice plants under stress. This paper includes the overview of rice growth and developmental processes influenced by salt stress and the regulation pathways involved in these processes. It also includes the promising salt tolerance strategies, i.e., genetic modification techniques, agronomic practices to improve rice growth, yield; and role of phytohormones and their management, especially inhibition of ethylene biosynthesis by using inhibitors 1-methylcyclopropene （1-MCP）. Rice cultivation may be a first choice for improvement of salt tolerance through plant growth regulators and improved cultivation techniques. This study will significantly improve the understanding toward low rice grain yield and poor rice resistance under salt stress and will also stream scientific knowledge for effective utilization of salt affected soils by using different regulating ways.

双孢蘑菇出菇的气体自抑物质研究进展

双孢蘑菇覆土出菇的机理尚不明晰。用无菌活性炭或通以无菌空气可以诱导双孢蘑菇出菇,表明双孢蘑菇菌丝生长过程中有抑制原基形成的气体自抑物质产生。目前,一种观点认为双孢蘑菇菌丝合成的气体自抑物质是乙烯,另一种观点认为是1-辛烯-3-醇。通过查阅相关研究文献,评述近年来有关这两种气体自抑物质的合成途径、功能及其抑制双孢蘑菇出菇的机理,提出双孢蘑菇出菇的气体自抑物质需满足以下特征:在原基形成前后合成量剧增,抑制原基形成,能够被特定细菌类群所利用。根据这些特征,认为双孢蘑菇菌丝合成的气体自抑物质是乙烯,而非1-辛烯-3-醇。

Effects of Different Treatments on Decay Rate of Lapins Sweet Cherry

[Objective] This paper was to study the effects of different treatments on decay rate of Lapins sweet cherry.[Method] The effects of MAP packaging, 1-MCP tablet and It’s Fresh ethylene adsorbent paper, fludioxonil and natamycin on decay rate of Lapins sweet cherry stored at 0℃ were observed.[Result] MAP packaging significantly reduced the decay rate of sweet cherry. After stored for 30 d, MAP+1-MCP tablet, MAP+It’s Fresh ethylene adsorbent paper, MAP+200 μL/L fludioxonil and MAP+0.3% natamycin did not significantly reduce the decay rate of sweet cheery. After stored for 60 d, MAP+It’s Fresh ethylene adsorbent paper, fludioxonil and natamycin significantly reduced the decay rate of sweet cherry.[Conclusion] The use of preservatives in late storage inhibits the decay of sweet cherry.

果蔬冷藏中乙烯的时空分布CFD模拟

根据苹果贮藏期间存在的乙烯浓度急剧升高进而影响贮藏质量的问题,需要采取相关措施抑制贮藏环境中乙烯浓度,如通风、使用1-MCP乙烯抑制剂等。然而,对于果蔬在冷藏库中乙烯的浓度具体在时间和空间的分布达到最大值,需要进行CFD(computational fluid dynamics)模拟。因此,建立冷库果蔬乙烯扩散模型,研究冷藏中乙烯的时空分布情况,为有效抑制乙烯的浓度提供依据。结果表明:预测纸箱内气流的复杂和不均匀分布,即随着空气由入口到出口的过程,空气流速降低,气流均匀性提高;乙烯气体分布与温度分布正相关关系;验证了冷库装载苹果时计算模型离散与网格无关的结论。