乙烯在植物形态发育中的作用（综述）

乙烯对植物生长发育的许多方面,如根的形成,花的诱导,器官衰老脱落均起重要的调节作用。拟南芥根表皮中的乙烯是根毛发育的一个正调控因子。兰花授粉诱导花被萎蔫过程的早期反应是提高了对内源乙烯水平的敏感性。     

微生物诱导的植物系统抗性

综述了由植物病原菌和非病原性的根际促生菌诱导产生的两种植物系统抗性:系统获得性抗性(SAR)和系统诱导抗性(ISR),比较了两类系统抗性的诱导、信号分子和机理的异同点,阐述了信号分子水杨酸在系统获得性抗性诱导过程中的作用及茉莉酸和乙烯在系统诱导抗性产生过程中的作用。     

苹果圆片诱导呼吸和乙烯产生的研究

跃变期前苹果圆片陈化后发生显著的伤诱导呼吸,乙烯也大量增生。Ag~+和AVG都明显抑制诱导呼吸发生,表明伤诱导乙烯对于诱导呼吸发生有重要作用。ACT、CHI和CHL强烈抑制乙烯和诱导呼吸。GA、IAA和ABA不同程度促进乙烯产生,但GA和IAA抑制,而ABA促进诱导呼吸。对诱导呼吸、乙烯产生和蛋白质合成作用的关系及激素对它们的调节进行了讨论。     

小麦黄化苗伤害诱导乙烯形成的一些性质

小麦黄化苗受伤后(切段)经过约15分钟滞后期,ACC和伤害诱导乙烯增加相平行,两者都能被AVG抑制。环己酰亚胺、DNP,KCN等能抑制诱导乙烯生成,自由基清除剂如抗坏血酸、没食子酸丙酯、苯甲酸钠,也有一定抑制作用,放线菌素D则没有作用。表明伤害诱导乙烯生成亦是遵循Met→SAM→ACC→乙烯途径,伤害刺激了ACC合成,导致乙烯增加。几种不同类型的表面活性剂(SDS,Tween,Triton及CTMA)都具有抑制作用。诱导乙烯的消失并不是由于ACC减少,也不是ACC转化为乙烯的能力下降,推测在伤害诱导乙烯生成和消失过程中,可能还有其它调节步骤或方式存在。     

乙烯及配子诱杀剂对水稻花粉不育的诱导

近年来,试用乙烯利诱导水稻雄性不育有一定的效果(Perez 1973,王熹等1981),但乙烯利诱导作物雄性不育机理的研究还不多。本研究试图从了解乙烯能否诱导水稻花粉不育,以及诱导水稻花粉不育的配子诱杀剂能否诱生内源乙烯这两个方面去认识乙烯在诱导雄性不育过程中的作用。 材料 供试水稻品种是迟熟早籼广陆矮4号;试验用40％乙烯利(CEPA)系上海彭浦化工厂生产,50％甲基砷酸钠(MSMA)、10％氨基磺酸钠(AWN)系中国科学院广州化学所实验室制品。     

低温诱导绿豆黄化幼苗乙烯产生过程中活性氧的作用

低温明显诱导绿豆 (PhaseolusradiatusL .)黄化幼苗乙烯产生速率的升高 ,同时也诱导活性氧产生速率不同程度的提高 ,显示二者之间有密切的关系。乙烯合成抑制剂AVG (2 aminoethoxyvinlglycine)、AOA(aminooxyaceticacid)能明显减弱低温对绿豆黄化幼苗乙烯产生的诱导作用 ,但对活性氧的产生没有明显的影响 ,说明低温诱导的乙烯产生的增加并不是活性氧产生增加的原因。超氧阴离子自由基 (O- ·2 )的特异性清除剂SOD和DABCO(1,4 diazabicyclo 2 ,2 ,2 octane)能有效削弱低温对乙烯产生的诱导作用 ,外源O- ·2 产生系统明显促进经过低温处理的幼苗回到常温下生长初期乙烯产生的增加 ,说明O- ·2 产生的增加可能是低温诱导乙烯产生增加的原因之一。低温诱导的H2 O2 产生的增加则被证明与乙烯产生速率的升高没有直接关系。     

小麦受渍后MACC的形成和ACC含量及乙烯产生的关系

大量的资料指出,植物在渍水条件下产生逆境乙烯(Bradford和Yang 1981)。这是由于渍水造成土壤厌氧环境,使植物根部合成大量ACC,ACC向上运输,在地上部因O_2分压高而转化为乙烯,从而发生一系列生理效应,如引起节根形成,偏上生长,加速衰老等(Bradford和Yang 1980a)。这种渍害诱导乙烯的生成亦遵循Met→SAM→SCC→C_2H_4途经(Adams和Yang 1979)。一般在     

咖啡酸和氯化钴对茉莉酸甲酯诱导抗病相关酶活性的影响

烟草愈伤组织在含咖啡酸（5 mmol/L）和/或CoCl2(10 mmol/L,乙烯合成抑制剂)的MS培养基上暗培养,同时用茉莉酸甲酯（1 mg/ml,简称MJ）处理愈伤组织。处理后测定乙烯、水杨酸和病程相关蛋白（PR）含量及一些抗病相关酶活性。MJ明显促进乙烯产生、增加水杨酸和PR蛋白含量,提高苯丙氨酸解氨酶（PAL）、β1,3-葡聚糖苷酶和几丁酶的活性。咖啡酸降低MJ对乙烯和水杨酸诱导,CoCl2明显降低MJ对乙烯的诱导,但没有明显影响MJ对水杨酸的诱导,两者都促进MJ诱导PAL活性而抑制MJ诱导β1,3-葡聚糖苷酶活性。咖啡酸明显影响MJ诱导内切几丁酶,几乎完全抑制对外切几丁酶的诱导;CoCl2对MJ诱导内切几丁酶没有影响,促进对外切几丁酶的诱导。实验结果表明,不同的抗病相关酶活性诱导有不同的信号传递途径,在所测几种酶的诱导中,水杨酸起主要作用,乙烯作用较小,MJ的诱导作用主要是由水杨酸所转导。     

乙烯对UV-B辐射诱导蚕豆气孔关闭的调控效应(英文)

UV-B辐射作为一种重要的环境信号影响着植物的生长与发育,它能够调控气孔运动和诱导乙烯产生.该试验利用乙烯生物合成抑制剂和乙烯受体抑制剂处理蚕豆叶片表皮条,结合气孔开度分析和乙烯释放量测定,研究乙烯在UV-B辐射调控表皮条气孔运动中的作用.结果发现,将蚕豆叶片表皮条置于0.8 W·m-2的UV-B辐射下1～4 h,乙烯生成和气孔关闭均被显著诱导,且乙烯释放峰先于气孔关闭的起始;乙烯生物合成抑制剂和乙烯受体抑制剂处理均能显著逆转UV-B辐射诱导的气孔关闭;外源乙烯处理也能模拟UV-B辐射的效应诱导可见光下蚕豆表皮条的气孔关闭.可见,乙烯介导了UV-B辐射诱导的蚕豆气孔关闭.     

咖啡酸和氯化钴对茉莉酸甲酯诱导抗病相关酶活性的影响

烟草愈伤组织在含咖啡酸(5mmol/L)和／或CoCl2(10mmol/L,乙烯合成抑制剂)的MS培养基上暗培养,同时用莱莉酸甲酯(1mg／d,简称MJ)处理愈伤组织。处理后测定乙烯、水杨酸和病程相关蛋白(PR)含量及一些抗病相关酶活性。MJ明显促进乙烯产生、增加水杨酸和PR蛋白含量,提高苯丙氨酸解氨酶(PAL)、β1,3—葡聚糖苷酶和几丁酶的活性。咖啡酸降低MJ对乙烯和水杨酸诱导,CoCl2明显降低MJ对乙烯的诱导,但没有明显影响MJ对水杨酸的诱导,两者都促进MJ诱导PAL活性而抑制MJ诱导β1,3—葡聚糖苷酶活性。咖啡酸明显影响MJ诱导内切几丁酶,几乎完全抑制对外切几丁酶的诱导;CoCl2对MJ诱导内切几丁酶没有影响,促进对外切几丁酶的诱导。实验结果表明,不同的抗病相关酶活性诱导有不同的信号传递途径,在所测几种酶的诱导中,水杨酸起主要作用,乙烯作用较小,MJ的诱导作用主要是由水杨酸所转导。     

Hormonal control of root development on epiphyllous plantlets of Bryophyllum (Kalanchoe) marnierianum: role of auxin and ethylene

Epiphyllous plantlets develop on leaves of Bryophyllum marnierianum when they are excised from the plant. Shortly after leaf excision, plantlet shoots develop from primordia located near the leaf margin. After the shoots have enlarged for several days, roots appear at their base. In this investigation, factors regulating plantlet root development were studied. The auxin transport inhibitor 2,3,5-triiodobenzoic acid (TIBA) abolished root formation without markedly affecting shoot growth. This suggested that auxin transport from the plantlet shoot induces root development. Excision of plantlet apical buds inhibits root development. Application of indole-3-acetic acid (IAA) in lanolin at the site of the apical buds restores root outgrowth. Naphthalene acetic acid (NAA), a synthetic auxin, reverses TIBA inhibition of plantlet root emergence on leaf explants. Both of these observations support the hypothesis that auxin, produced by the plantlet, induces root development. Exogenous ethylene causes precocious root development several days before that of a control without hormone. Ethylene treatment cannot bypass the TIBA block of root formation. Therefore, ethylene does not act downstream of auxin in root induction. However, ethylene amplifies the effects of low concentrations of NAA, which in the absence of ethylene do not induce roots. Ag(2)S(2)O(3), an ethylene blocker, and CoCl(2), an ethylene synthesis inhibitor, do not abolish plantlet root development. It is therefore unlikely that ethylene is essential for root formation. Taken together, the experiments suggest that roots develop when auxin transport from the shoot reaches a certain threshold. Ethylene may augment this effect by lowering the threshold and may come into play when the parent leaf senesces.     

Ethylene upregulates auxin biosynthesis in Arabidopsis seedlings to enhance inhibition of root cell elongation

Ethylene represents an important regulatory signal for root development. Genetic studies in Arabidopsis thaliana have demonstrated that ethylene inhibition of root growth involves another hormone signal, auxin. This study investigated why auxin was required by ethylene to regulate root growth. We initially observed that ethylene positively controls auxin biosynthesis in the root apex. We subsequently demonstrated that ethylene-regulated root growth is dependent on (1) the transport of auxin from the root apex via the lateral root cap and (2) auxin responses occurring in multiple elongation zone tissues. Detailed growth studies revealed that the ability of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid to inhibit root cell elongation was significantly enhanced in the presence of auxin. We conclude that by upregulating auxin biosynthesis, ethylene facilitates its ability to inhibit root cell expansion.     

Effects of antagonists and inhibitors of ethylene biosynthesis on maize root elongation

During the first days of development, maize roots showed considerable variation in the production of ethylene and the rate of elongation. As endogenous ethylene increases, root elongation decreases. When these roots are treated with the precursor of ethylene aminocyclopropane- 1-carboxylic acid (ACC), or inhibitors of ethylene biosynthesis 2-aminoethoxyvinyl glycine (AVG) or cobalt ions, the root elongation is also inhibited. Because of root growth diminishes at high or reduced endogenous ethylene concentrations, it appears that this phytohormone must be maintained in a range of concentrations to support normal root growth. In spite of its known role as inhibitor of ethylene action, silver thiosulphate (STS) does not change significantly the root elongation rate. This suggests that the action of ethylene on root elongation should occur, at least partially, by interaction with other growth regulators.Key words: 2-aminoethoxyvinyl glycine, cobalt, ethylene, root elongation, silver thiosulphate, Zea mays     

Auxin and ethylene promote root hair elongation in Arabidopsis

Genetic and physiological studies implicate the phytohormones auxin and ethylene in root hair development. To learn more about the role of these compounds, we have examined the root hair phenotype of a number of auxin- and ethylene-related mutants. In a previous study, Masucci and Schiefelbein (1996) showed that neither the auxin response mutations aux1 and axr1 nor the ethylene response mutations etr1 and ein2 have a significant effect on root hair initiation. In this study, we found that mutants deficient in either auxin or ethylene response have a pronounced effect on root hair length. Treatment of wild-type, axr1 and etr1 seedlings with the synthetic auxin, 2,4-D, or the ethylene precursor ACC, led to the development of longer root hairs than untreated seedlings. Furthermore, axr1 seedlings grown in the presence of ACC produce ectopic root hairs and an unusual pattern of long root hairs followed by regions that completely lack root hairs. These studies indicate that both auxin and ethylene are required for normal root hair elongation.     

Ethylene and phosphorus availability have interacting yet distinct effects on root hair development

The hypothesis that ethylene participates in the regulation of root hair development by phosphorus availability in Arabidopsis thaliana was tested by chemically manipulating ethylene synthesis and response and with ethylene-insensitive mutants. Low phosphorus-induced root hair development could be mimicked by adding the ethylene precursor, 1-aminocyclopropane-1-carboxylate (ACC), to high phosphorus media, and inhibited by adding ethylene inhibitors to low phosphorus media. Ethylene-insensitive mutants showed a reduced response to low phosphorus, indicating ethylene involvement in root hair responses to phosphorus deficiency. To dissect the nature of this involvement, the morphological and anatomical changes associated with increased root hair density were investigated. Growth in low phosphorus resulted in smaller, more numerous cortical cells, resulting in a larger number of root hair-bearing epidermal cell files. Cortical cell number was not affected by ethylene inhibitors, ACC, or mutations reducing ethylene sensitivity in roots grown with low phosphorus, indicating that ethylene does not participate in this response. The exception was the eir1 mutation, which strongly reduced this change in radial anatomy, supporting a role for polar auxin transport in this process. Trichoblast cell length was reduced by low phosphorus availability in all genotypes, but even more so for ein2-1 and ein4. The proportion of epidermal cells forming hairs and root hair length were reduced in ethylene-insensitive mutants, especially in the presence of low phosphorus. These results demonstrate multiple effects of low phosphorus from the earliest stages of root hair development, and cross-talk between ethylene and phosphorus in the control of a subset of the low phosphorus effects, concentrating on those later in development.     

Interactions between jasmonates and ethylene in the regulation of root hair development in Arabidopsis

Root hair formation is an important model with which to study cell patterning and differentiation in higher plants. Ethylene and auxin are critical regulators of root hair development. The role of jasmonates (JAs) was examined in Arabidopsis root hair development as well as their interactions with ethylene in this process. The results have shown that both methyl jasmonate (MeJA) and jasmonic acid (JA) have a pronounced effect on promoting root hair formation. However, the effect of MeJA and JA on root hair formation was blocked by ethylene inhibitors Ag+ or aminoethoxyvinylglycine (AVG). The stimulatory effects of MeJA and JA were also diminished in ethylene-insensitive mutants etr1-1 and etr1-3. Furthermore, the JA biosynthesis inhibitors ibuprofen and salicylhydroxamic acid (SHAM) suppressed 1-aminocyclopropane-1-carboxylic acid (ACC)-induced root hair formation, and decreased the root hairs in seedlings of the ethylene over-producing mutant eto1-1. These results suggested that JAs promote root hair formation, through an interaction with ethylene.     

Ethylene responses in Arabidopsis seedlings include the reduction of curvature values in the root cap

Recently, curvature was described as a new trait useful in the analysis of root apex shape. Treating the root profile as a geometric curve revealed that root apex curvature values are lower in ethylene-insensitive mutants (Cervantes E, Tocino A. Geometric analysis of Arabidopsis root apex reveals a new aspect of the ethylene signal transduction pathway in development. J Plant Physiol 2005;162:1038-45). This fact suggests that curvature is regulated by ethylene. In this work, we have determined the curvature values in embryonic roots of wild-type Columbia as well as in ethylene signal-transduction mutants, and found smaller values in embryos of the mutants. We also report on the evolution of root curvature during early development after seed germination. The line Lt16b that expresses GFP in the cell wall has allowed us to investigate the evolution of curvature values in three successive cell layers of seedling roots by confocal microscopy. Treatment of seedlings with norbornadiene resulted in lower curvature values. Our results show details illustrating the effect of ethylene in root curvature.     

Ethylene Controls Adventitious Root Initiation Sites in <Emphasis Type="Italic">Arabidopsis</Emphasis> Hypocotyls Independently of Strigolactones

Adventitious root formation is essential for cutting propagation of diverse species; however, until recently little was known about its regulation. Strigolactones and ethylene have both been shown to inhibit adventitious roots and it has been suggested that ethylene interacts with strigolactones in root hair elongation. We have investigated the interaction between strigolactones and ethylene in regulating adventitious root formation in intact seedlings of Arabidopsis thaliana. We used strigolactone mutants together with 1-aminocyclopropane-1-carboxylic acid (ACC) (ethylene precursor) treatments and ethylene mutants together with GR24 (strigolactone agonist) treatments. Importantly, we conducted a detailed mapping of adventitious root initiation along the hypocotyl and measured ethylene production in strigolactone mutants. ACC treatments resulted in a slight increase in adventitious root formation at low doses and a decrease at higher doses, in both wild-type and strigolactone mutants. Furthermore, the distribution of adventitious roots dramatically changed to the top third of the hypocotyl in a dose-dependent manner with ACC treatments in both wild-type and strigolactone mutants. The ethylene mutants all responded to treatments with GR24. Wild type and max4 (strigolactone-deficient mutant) produced the same amount of ethylene, while emanation from max2 (strigolactone-insensitive mutant) was lower. We conclude that strigolactones and ethylene act largely independently in regulating adventitious root formation with ethylene controlling the distribution of root initiation sites. This role for ethylene may have implications for flood response because both ethylene and adventitious root development are crucial for flood tolerance.