Reversal of ethylene inhibition of tulip stem elongation by silver thiosulphate

Cut flowering stems of Tulipa cultivars were treated with a range of silver thiosulphate (STS) solutions (0.01–2.0 mM) for different times (10 min–24 h). The extension of the stem and longevity of the perianth were then observed at 18°C with the stems in water. At the highest dose (2.0 mM STS), a metallic silver sheen appeared on the surface of the STS solution and leaves were damaged. At non-toxic levels there appeared to be no effect on perianth longevity. However, the STS treatment completely reversed the inhibition of stem elongation caused by treatment with ethephon (48 mg l^?1 for 24 h) or with ethylene (C₂H₄, 1 v.p.m. for 41 h). The results suggest that in spite of the lack of effect of STS on corolla longevity, the STS is freely mobile in the vascular tissue and in trace amounts blocks the effects of C₂H₄. Silver nitrate was not as effective as STS.Measurements of STS uptake suggest that about 1 μmol of silver is sufficient to counter the inhibitory effects of ethylene on stem elongation.     

纳米银对瓶插月季切花乙烯作用的拮抗效应

 以月季‘影星’（Rosa hybrida‘Movie Star’）切花为试材,用5、10和30 mg · L^-1纳米银（nano-silver,NS）溶液,0.5 mmol · L^-1硫代硫酸银（silver thiosulfate,STS）溶液和去离子水（对照）分别预处理花枝（长为25 cm）基端2 h后再移至去离子水中瓶插,之后用10 μL · L^-1外源乙烯处理24 h,观测切花瓶插期间的观赏品质,瓶插寿命,花径和花枝鲜样质量等指标的变化。结果表明：乙烯处理可加快切花失水凋萎及叶片脱落,并抑制花朵开放,而NS处理可显著减轻乙烯处理的不利影响,其中以30 mg · L^-1 NS处理效果最佳,该处理月季切花的瓶插寿命比乙烯处理延长7 d。另外,取月季切花的花朵（带5 cm花茎,无叶）进行上述试验,进一步证实乙烯处理可抑制花朵开放,而NS处理可显著减轻乙烯对花朵开放的抑制作用。     

Application of 1-MCP as a liquid formulation prevents ethylene-induced senescence in Phalaenopsis orchid flowers and Kalanchoë blossfeldiana inflorescences

This study provides a very first report on the use of a sprayable formulation of 1-MCP, Harvista^TM, on ornamental plant species. Individual florets of Phalaenopsis and inflorescences of Kalanchoë blossfeldiana were sprayed with 1, 2, 4, or 6% Harvista^TM and this was compared to the commonly used 1-MCP formulation, SmartFresh^TM, which is administered as a powder releasing gas. Harvista^TM treatments for Kalanchoë were in addition also compared to plants treated with an alternative ethylene receptor blocker, STS, as well as with transgenic plants expressing the etr1-1 mutant gene of Arabidopsis thaliana.

In the presence of ethylene, Harvista^TM at all concentrations (except 1% for Kalanchoë), as well as the conventional SmartFresh^TM treatment, prevented wilting of florets and significantly extended their display life compared to that of control treatments: up to twofold for Kalanchoë and up to fourfold for Phalaenopsis. For Kalanchoë the best display life was, however, presented by etr1-1 transgenic plants. The efficacy and suitability of using Harvista^TM, a sprayable formulation of 1-MCP, was compared to using the gaseous application of SmartFresh^TM, or the environmental hazardous silver treatment, against having to consider expensive and lengthy genetic modification with etr1-1 as commercial alternatives to achieve protection against the detrimental effects of ethylene.

Abbreviations: 1-MCP, 1-methylcyclopropene; STS, silver thiosulfate     

ABA和乙烯利处理下番茄的生理反应和Nr基因的表达

 为了探讨乙烯受体蛋白Nr基因与植株抗逆性的关系，研究了乙烯利和ABA处理下的番茄植 株代谢反应。研究结果表明：ABA处理诱导了Nr基因的大量表达，并被乙烯抑制剂Ag 所抑制；ABA还 能促进黄化苗的乙烯三重反应，并使呼吸作用降低，植株黄化。50~mol／L的乙烯利处理未能诱导Nr基因 的表达，虽有蒸腾作用和气孔导度的增加，但呼吸作用和细胞间cO 浓度无明显变化，植株生长正常。因 此，Nr基因的大量表达是由于ABA等环境胁迫诱导了内源乙烯的大量合成，是导致植物黄化和衰老的主 要原因之一。     

The role of ethylene in abscission of sweet orange promoted by exogenous application of the abscission agent 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP)

Mature ‘Valencia’ fruit were treated with 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP), and the ethylene inhibitors aminoethoxy vinyl glycine (AVG) and silver thiosulfate (STS), to assess involvement of ethylene in abscission via CMNP. Fruit detachment force (FDF) and ethylene evolution were measured over time. Accumulation of the ethylene precursor 1-aminocyclopropane-1-carboxylate (ACC) in peel upon CMNP application was assessed and impact of application of ACC on FDF was estimated when applied 1 cm away from the abscission zone (AZ), to determine its potential as a signaling molecule in promoting fruit loosening. CMNP when applied alone reduced FDF by 50%. AVG and STS inhibited fruit loosening considerably at 500 µM and 10 mM, respectively, when applied with 2 mM CMNP. ACC accumulation in peel was highest 2 days after CMNP application, which preceded the maximum decline in FDF which occurred a day later, indicating that ACC serves as a potential signaling molecule that triggers abscission in the AZ. The results of the study support the hypothesis that abscission via CMNP application is at least partly ethylene dependent. However, the decline in FDF by ACC was less than 50% of control which suggested involvement of another pathway in abscission via CMNP in sweet orange.     

Poststorage quality and rooting ability of Epipremnum pinnatum cuttings after treatment with ethylene action inhibitors

Summary

The influence of the ethylene action inhibitors STS and 1-MCP on poststorage performance and subsequent rooting of cuttings was investigated in Epipremnum pinnatum. Unfavourable storage conditions resulted in decreasing poststorage quality of single-eye cuttings, expressed as leaf drop and yellowing. 1-MCP and STS prohibited leaf drop and yellowing in E. pinnatum. STS pretreatment decreased rooting ability significantly, measured as percentage of rooted cuttings, number of roots, total root length and dry weight. STS caused severe injuries to the cuttings, which were worse if the cuttings were stored rather than propagated immediately. There was no significant difference in rooting between 1-MCP treated cuttings and untreated control in either stored or unstored cuttings. The influence of ethylene action inhibitors on rooting and a possible use of 1-MCP for practical use to increase poststorage performance in cuttings are discussed.     

ABA 和乙烯对荔枝果实成熟和着色的调控

 荔枝果实幼果期ABA 含量很高, 之后下降, 在转红前1 周急剧上升, 形成一个峰值。果皮、果肉乙烯释放量的变化与ABA 相似, 但其跃变发生在ABA 之后, 且跃变较小。伴随着乙烯的跃变, 有一个糖代谢和转化酶活性的跃变。于转熟前用STS 处理荔枝果实, 导致果实转色和成熟延迟。果实发育后期, ABA 急剧增加可能诱导了乙烯的合成, 乙烯启动果实成熟, 果皮转红着色。     

12MCP延缓观赏植物衰老的研究与应用

 1-MCP (1 - 甲基环丙烯) 是一种新型乙烯作用抑制剂, 能有效地抑制内源和外源乙烯对植物的作用, 延缓乙烯诱导的器官衰老和脱落。本文综述了12MCP的作用机理和在观赏植物上的研究与应用现状以及最新进展。     

Determination of pineapple (Ananas comosus, MD-2 hybrid cultivar) plant maturity,the efficiency of flowering induction agents and the use of activated carbon

Natural flowering is one of the major agronomic problems in pineapple (Ananas comosus) cultivation. It causes heterogeneous flowering and fruit development with multiple harvest passes of the same field as an inevitable consequence. To avoid natural flowering, pineapple plants are induced to synchronize flowering by external ethylene treatments. In this research it is shown that pineapple plants (MD-2 hybrid cultivar) are already sensitive to external ethylene treatments at an early developmental stage, i.e. 3 months after planting, although no natural flowering occurs during this early stage of plant development. These results indicate that young pineapple plants already posses all the necessary factors to induce flowering in response to ethylene treatments. Additionally the efficiencies of flowering induction of different external ethylene treatments, including a novel agent developed at our lab, called ‘zeothene’, were evaluated. Zeothene (=zeolite containing ethylene gas) and ethylene dissolved in water (both applied in the central cup of the plant) were proved to be very efficient flowering induction agents. The commercial cultivation practice, in which ethylene gas is sprayed with water over whole plants, was found less efficient confirming that central cup applications are more efficient than whole plant spraying. Cup applications allow the active ingredient (ethylene or ethephon) to be taken up immediately by the apical meristem resulting in an efficient flowering induction signal. The addition of activated carbon to enhance the flowering induction treatment was found to be useful only with a very high dose of activated carbon (5%) and a long interaction time (at least 5–30 min) between the activated carbon and the flowering induction solution.     

The effect of silver thiosulphate pre-treatment on 1-aminocyclopropane-1-carboxylic acid content and action in cut carnations

Endogenous 1-aminocyclopropane-1-carboxylic acid (ACC) levels, and the ACC → ethylene (C₂H₄) conversion of exogenously applied ACC in naturally senescing and silver thiosulphate (STS) pre-treated cut carnations, were investigated. Under natural conditions, increase in ACC accumulation coincided with the onset of the climacteric rise in C₂H₄ production. Flowers pre-treated with STS did not show this increase in ACC content. Exogenously applied ACC caused wilting within 24 h and an increase in C₂H₄ production up to 1300 nl/h/flower. Flowers successively treated with STS and ACC produced C₂H₄ at quantities much higher than the controls, but showed no wilting. Together, these data suggest that the binding of C₂H₄ to its receptor leads to an increase in the production of ACC and of C₂H₄. By blocking the C₂H₄ action, the silver ion inhibits the autocatalytic increase in C₂H₄ and the accompanying rise in ACC content.     

非洲菊切花活性氧代谢的研究

 以非洲菊( Gerbera jamesonii) 切花为材料, 研究衰老过程中活性氧的变化, 比较外源乙烯、外源活性氧对衰老的效应, 寻找缓解衰老的措施。结果表明, 非洲菊切花衰老过程中活性氧代谢活跃, 对外源活性氧的敏感性大于外源乙烯, 采用以抑制活性氧为主要成分的瓶插液能有效缓解切花衰老。     

Critical ethylene exposure for Capsicum annuum ‘Janne’ is dependent on an interaction between concentration,duration and developmental stage

Summary

Two ethylene experiments were designed to show the reaction of the pot plant Capsicum annuum ‘Janne’ to ethylene and to define the critical level of ethylene exposure. The ethylene exposure consisted of 72 h of darkness at 19°C, an ethylene duration of 6–72 h and ethylene concentrations of 0.05–5.0 µl l^?1. After the plants had been exposed to ethylene they were placed in a post-production evaluation room. The response of capsicum to ethylene, as expressed by leaf and fruit abscission, was dependent on developmental stage, duration of ethylene exposure and ethylene concentration. Leaves were the most ethylene-sensitive plant parts, followed by the green and maroon fruits. Ethylene did not affect the rate of development into red fruits. The most developed plants were less sensitive to ethylene. Capsicum is very sensitive to ethylene, e.g. there was significant abscission of leaves after exposure to an ethylene concentration of 1.0 µl l^?1 for 12 h and a significant abscission of leaves and green fruit after exposure to 0.05 µl^?1 for 72 h. A critical ethylene exposure is suggested, dependent on plant sensitivity, duration of ethylene exposure and ethylene concentration.     

植物转座子类型及其插入突变对园艺植物花发育影响的研究进展

转座子是一类广泛存在于原核生物和真核生物基因组内重复可移动的遗传元件，根据其结构和转座机制分为反转录转座子和DNA转座子。反转录转座子以mRNA分子为中间体、反转录为cDNA后再整合到基因组，其转座模式是“复制—粘贴”。DNA转座子以DNA为中间体，其转座模式是“剪切—粘贴”。两类转座子都包含有自主和非自主转座元件。作为基因组的主要构成元件，植物转座子在基因组和基因进化、结构重排、表达调控等方面发挥关键作用，进而改变植物的基因型和表现型。综述了近年来有关植物转座子结构特征、转座机制以及功能等方面的研究进展，特别是转座子插入突变改变基因活性而控制园艺植物花发育的研究进展，并对今后研究前景进行了展望，旨在为深入了解植物转座子园艺学功能提供参考。     

Ethylene production as an indicator of stress conditions in hydroponically-grown strawberries

As a soilless system, hydroponics eliminates competing weeds and soil-born pests while conserving water and providing conditions that can be quickly altered to suit specific crops. However, stress-induced physiological conditions may arise within the system from factors such as mechanical injury, pests, or inconsistent nutrient flow rates that result in some plants receiving too much or too little water. Most abiotic stress conditions result in increased production of the plant hormone ethylene. High levels of ethylene inhibit growth, cause premature ripening, and induce the onset of senescence, potentially reducing the productivity of hydroponically-grown crops. In this study, we demonstrate that assessing ethylene levels from leaves of hydroponically-grown strawberry plants can be used as an early indicator of stress conditions. Our results demonstrate that there is no significant correlation between ethylene production and temperatures ranging from 15 to 37 °C or with light intensities ranging from 63 to 1500 μmol m⁻² s⁻¹. However, an increase in ethylene production tended to be positively correlated with sampling time; levels were higher during midday compared to early morning or later afternoon. The daily ethylene fluctuations under greenhouse conditions due to sampling time, light intensity, or temperature changes were not significantly high enough to indicate stress conditions. Overall, three system analyses showed altered ethylene production in plants farthest from the pump supplying the nutrient solution. This effect was interpreted to be caused by excess accumulation of nutrient solution around the plant roots, causing increased ethylene production in the leaves. Our results indicate that different watering patterns, manifested as pump pressure or drainage control, was the more difficult component to control in the design of these hydroponic systems. For example, in one system, an increase in ethylene production was measured for the position farthest from the pump, and resulted in those plants having a lower number of flowers and significantly reduced overall plant radii relative to the system average. In a separate experiment, plants from trays that had been flooded for 24 h showed a significant decrease in the plant radii and number of leaves and flowers 1 month after the flooding treatment. We conclude that system-wide ethylene measurements can be used to identify stressed plants within hydroponic systems. This type of analysis would be especially useful as an indicator of general stress conditions no matter the cause, identifying locations that may result in lower plant productivity.     

Co2+对香石竹切花瓶插期间膜脂过氧化作用的影响

以"Yellow sim"香石竹为试验材料,比较了Co2+与硫代硫酸银(STS)对香石竹切花采后主要膜脂过氧化指标的影响。结果表明:Co2+处理与STS处理相比,可有效减缓花瓣含水量和可溶性糖含量的下降,抑制细胞膜透性的上升幅度,延缓SOD活性下降,有效减缓膜脂过氧化的伤害,延长切花瓶插寿命。Co2+处理比STS处理具有更好的保鲜效果,可作为STS的一种安全环保替代剂。     

乙烯和葡萄糖处理对‘洛阳红’牡丹切花花色和花青素苷合成的影响

以‘洛阳红’牡丹（Paeonia suffruticosa‘Luoyanghong’）切花为试材,研究10 μL ? L-1乙烯处理、1 μL ? L-1乙烯抑制剂1-MCP处理、90 g ? L-1葡萄糖处理、90 g ? L-1葡萄糖 + 10 μL ? L-1乙烯复合处理对切花花色和花青素苷含量的影响,以蒸馏水处理为对照。研究结果表明：乙烯处理的切花花色明度增加,红度和彩度下降,花瓣花青素苷含量下降;1-MCP处理与对照无显著差异;葡萄糖处理花色明度下降,红度和彩度增加,花瓣花青素苷含量增加;葡萄糖乙烯复合处理对切花花色及花青素苷积累也有明显改善与促进作用。对花青素苷合成相关基因表达量分析的结果表明,乙烯处理对基因表达有抑制作用,而葡萄糖处理有显著的正调控作用,葡萄糖乙烯复合处理则显著缓解了单独乙烯处理对基因表达的负调控作用。葡萄糖信号和乙烯信号之间一定程度上存在互作,葡萄糖缓解了乙烯对牡丹切花花青素苷合成的抑制作用。     

乙烯对荔枝果实成熟的影响

荔枝果实发育过程中,乙烯含量不断下降,转红期（ 花后７０ ｄ 左右） 略有上升,但无明显峰值,后又逐步下降,直到果实成熟。乙烯形成抑制剂ＳＴＳ（ 硫代硫酸银） 显著抑制果实的成熟,转熟前用ＳＴＳ处理荔枝果实,导致果实脱落明显加重,部分果抗病力下降,发病率增加,裂果严重,果实转红变慢,果肉含糖量偏低。上述结果表明,乙烯对荔枝果实的成熟具有积极的促进作用。     

Inoculation of growing media with the rhizobacterium Variovorax paradoxus 5C-2 reduces unwanted stress responses in hardy ornamental species

Inoculation of growing media with plant growth promoting rhizobacteria (PGPR) has a number of potential benefits for the production of ornamental plants. Certain rhizobacteria synthesise the enzyme ACC deaminase, which cleaves ACC, the precursor of the plant hormone ethylene. Bacterial metabolism is now known to lead to a reduction in [ACC] in the plant transpiration stream and bacteria are hypothesised to act on ACC exuded from roots. This in turn reduces the ethylene generated in plants growing in growing media inoculated with these bacteria. Here we tested if applications of the ACC deaminase containing rhizobacteria Variovorax paradoxus⁵C–²could be of benefit to ornamental growers by reducing ethylene generation in stressed plants. Ethylene is produced at levels that are inhibitory to growth and development under a number of abiotic stresses. The propagation and production of hardy ornamentals is deleteriously affected by abiotic stresses that involve ethylene signalling, including drought and physical wounding. Inoculation of growing media with V. paradoxus 5C-2 lowered ethylene emission from mature leaves of Cytisus × praecox experiencing drought stress. In addition, bacterial inoculation of the growing media resulted in significantly reduced abscission of the mature leaves under drought treatment. Beneficial effects of inoculation where also found in the wounding response of Fargesia murielae following divisional propagation and late season senescence in Aquilegia × hybrida in response to drought stress. Together these results demonstrate that V. paradoxus⁵C–²has real potential for use on ornamental nurseries in situations where plant stresses are unavoidable.     

小品配饰在花境中的应用

花境设计在现今园林中越来越受到重视,植物材料受到品种限制,无法突破时,我们可以考虑通过其他非植物材料来提升花境的设计空间。通过使用花钵、花架、小雕塑、吊盆和组合盆栽、石头等园林元素,为花境增添一份亮色,可以为花境设计提供了更多的设计元素。