赤霉素与果树的生长发育

本文分析讨论了分子结构不同的赤霉素在生理作用上的差异,以及不同种类赤霉素对果树不同生长发育阶段的影响,介绍了与果树生长发育相关的赤霉素类型,并指出了今后在研究应用上须解决的问题。     

赤霉素与果树地生长发育

本文介绍了分子结构不同的赤霉关生理作用上的差异,以及不同种类赤霉素对果树不同生长发育阶段的影响,介绍了与果树生长发育相关的霉素类型,并指出了今后在研究应用上须解决的问题。     

果树赤霉素代谢与信号途径研究进展

赤霉素作为5大植物激素之一,在果树的花芽分化、花序发育、开花坐果、果实的生长发育及植株的形态建成等方面扮演着重要的角色,但对果树赤霉素的分子生物学研究与其他大田作物相比差距较大。为了在果树生产中能更加合理有效地利用赤霉素调控果树花果发育,研究果树赤霉素的合成及其信号转导途径的分子调控机制十分必要。研究发现GA合成的关键酶KO、GA2ox及GA20ox的表达均与果树矮化呈负相关,而KS的含量则与植株高矮呈正相关,板栗雄性不育现象也与KO、KAO的表达量密切相关。GAMYB基因及LFY基因则在果树的成花诱导和雄蕊发育等生殖生长过程中发挥重要作用。DELLA蛋白在果树的GA信号途径中作为负调控因子可致使矮化植株形成,在果树的细胞周期循环过程、转录调控、花的形成、细胞的信号转导及许多生理过程中,DELLA蛋白泛素化降解均扮演着至关重要的角色。主要从果树赤霉素的合成及赤霉素的信号途径两大方面,着重对果树赤霉素合成过程中的关键酶基因及其定位、果树赤霉素信号途径的重要元件如赤霉素受体GID1、DELLA蛋白等进行了综述,以期为高效利用赤霉素调控果树生长发育提供重要的理论参考。     

植物生长调节物质对果实生长发育的调控

本文就赤霉素、细胞分裂素、乙烯利对果实生长发育的调控作用进行了较为系统的论述,并对其在果树上的利用方法、时期、浓度等作了说明。     

植物生物调节物质对果实生长发育的调控

本文就赤霉素、细胞分裂素、乙烯利对果实生长发育的调控作用进行了较为系统的论述,并对其在果树上的利用方法、时期、浓度等作了说明。     

赤霉素作用机制研究进展

赤霉素是一种常见的植物激素,在高等植物的各个生长发育阶段都具有重要的调控作用.赤霉素与其他所有激素间都存在相互作用,其作用的方向和类型取决于组织器官、发育阶段以及环境条件,使赤霉素对植物生长发育的调控及其在不同器官中的生理功能不同.本文对近年来国内外关于赤霉素的信号传导、作用机制以及赤霉素与其他植物激素间的相互作用及其调控机理的研究进行综述,以探讨赤霉素信号应答的复杂网络体系.     

赤霉素生物合成与信号传递对植物株高的调控

植物株高是影响作物产量和品质的重要农艺性状。赤霉素(Gibberellins,GAs)是调控植物株高的重要激素,GA相关株高基因的克隆与分子机制研究对于合理调控作物生长发育和农业生产具有极其重要的利用价值,在水稻、小麦等粮食作物育种中得到了广泛应用。为了促进GA在果树、花卉等园艺作物育种中的有效利用,文中在分子生物学水平上介绍GA生物合成和GA信号传递途径对植物株高的调控。     

赤霉素对拟南芥主根分生区和伸长区的调控

赤霉素是一类重要的植物激素,在植物整个生长发育的调控过程中起重要作用。近年来,人们发现赤霉素对拟南芥主根生长存在促进作用。本文从根系的解剖结构、赤霉素的源靶部位、促进作用的机理、赤霉素信号转导途径以及与其他激素的关系等方面,综述了赤霉素对拟南芥主根分生区和伸长区的影响。     

高等植物赤霉素代谢及其信号转导通路

赤霉素是一类重要的植物激素,对植物的生长发育,如种子的萌发、茎的延展、叶片的生长、休眠芽的萌发以及植物的花和种子的发育等生理具有重要的调控作用。从1926年被发现至今,阐明了赤霉素代谢机理及调控机制,明确了赤霉素在植物体内的信号转导途径。本文综述了赤霉素的生物合成途径及其平衡的调节;赤霉素受体GID1、DELLA蛋白在赤霉素信号转导途径中的作用及相关研究;泛素介导的DELLA蛋白降解在赤霉素信号转导中的研究进展。     

赤霉素解除木本植物季节性休眠机制的研究进展

赤霉素是一种高效能的广谱植物生长调节剂,能够促进植物的生长发育,具有重要的生物学功能。该文主要对国内外近年来有关赤霉素在木本植物季节性休眠解除中的应用、赤霉素解除木本植物季节性休眠的生理机制、赤霉素代谢相关基因在木本植物季节性休眠中的作用以及赤霉素解除木本植物季节性休眠的分子机制等方面的研究进展进行综述,同时对下一步的研究方向进行了展望,以期能够更好地阐述赤霉素解除木本植物季节性休眠的分子机制,为赤霉素在木本植物季节性休眠解除中的应用提供理论依据。     

Auxin-induced Fruit Set in Capsicum annuum L. Requires Downstream Gibberellin Biosynthesis

A hierarchical scheme for the central role of the plant hormones auxin and gibberellins in fruit set and development has been established for the model plants Arabidopsis and tomato. In the fruit crop Capsicum annuum, the importance of auxin as an early signal in fruit set has also been recognized; however, the effect of gibberellins and their interaction with auxin has not yet been studied. The aim of this study was to determine the role of gibberellin and the hierarchy between auxin and gibberellin. We applied gibberellin alone or in combination with auxin or with the gibberellin biosynthesis inhibitor paclobutrazol on stigmas of emasculated flowers. Gibberellin application enhanced fruit set, whereas application of paclobutrazol reduced fruit set. The effect of paclobutrazol treatment could be counteracted by coapplication of gibberellin but not by auxin_. These results indicate that in C. annuum, like in Arabidopsis and tomato, auxin is the major inducer of fruit set that acts in part by inducing gibberellin biosynthesis. Interestingly, gibberellin does not significantly contribute to the final fruit size but seems to play an important role in preventing flower and fruit abscission, a major determinant of production loss in C. annuum. At the same time, gibberellin together with auxin seems to balance cell division and cell expansion during fruit growth.     

施硼和赤霉素对‘李广杏’坐果率及果实品质的影响

该研究以8年生盛果期的‘李广杏’植株为试材,于花蕾膨大期喷施0.1%(P1)、0.3%(P2)和0.5%(P3)硼砂和盛花初期喷施50(C1)、100(C2)和150 mg/L(C3)赤霉素,测定不同处理下李广杏的坐果率、果实品质及营养生长指标的变化,并用主成分分析不同处理的效果进行综合评价,为敦煌寒旱区‘李广杏’的栽培提供理论依据。结果表明:(1)‘李广杏’叶面积增长量在C1浓度处理下显著高于CK,不同浓度的硼处理对其均具有抑制作用,但C1、P2浓度下新稍生长量高于其他处理。(2)适宜浓度的硼和赤霉素处理可一定程度减少‘李广杏’花的败育率,从而有效提高果树的坐果率,其中硼处理以P3浓度下最优,但P3与P2处理下坐果率无显著差异,赤霉素处理以C2浓度下最优。(3)适宜浓度硼和赤霉素能够明显提高‘李广杏’果实品质,C1浓度处理下的果实糖酸比、可溶性固形物含量显著高于CK,P2处理下的果实维生素C、可滴定酸含量显著高于其他处理;适宜浓度赤霉素和硼对果实的单果重、果形指数、侧径有明显的促进作用。(4)主成分分析结果显示,各处理效果的综合得分由高到低依次为P2(1.20)>C2(0.91)>P1(0.13)>C1(-1.01)>CK(-1.68)>P3(-2.13)>C3(-7.76);果实可溶性糖、可溶性蛋白、糖酸比等主成分占比较高,可作为评价‘李广杏’果实品质的重要依据。研究发现,花期喷施适宜浓度的硼和赤霉素可有效提高‘李广杏’果树的生长状况、坐果率及果实品质,且甘肃敦煌地区以花蕾膨大期喷施0.3%硼和盛花初期喷施100 mg/L赤霉素效果最佳。     

巴西橡胶树赤霉素信号转导途径HbRGA1结构和功能分析

DELLA蛋白是赤霉素激素信号负调控因子,具有抑制植物生长发育的作用。解析其家族成员结构与功能将有助于揭示橡胶树DELLA蛋白家族成员调控橡胶树生长发育的机制。本研究从橡胶树热研73397叶片中克隆HbRGA1的cDNA全长序列。该基因长为2136 bp,含1839 bp的ORF,编码613个氨基酸。HbRGA1蛋白序列包含DELLA和GRAS保守结构域,与杨树、木薯和橡胶树DELLA基因相似性高达82.5%。qRT-PCR分析发现HbRGA1在橡胶树叶片中表达量高,在树皮和胶乳中表达量极低。叶片中HbRGA1表达量受喷施赤霉素和脱落酸等诱导显著上调。本研究表明HbRGA1与橡胶树赤霉素等激素信号密切相关,为深入研究其在橡胶树生长发育中的结构和功能打下良好基础。     

Foliar Paclobutrazol Application Suppresses Olive Tree Growth While Promoting Fruit Set

In some agricultural practices, application of plant growth regulators is very useful as an efficient means to modulate olive tree vigour to optimize fruit production. However, the physiological mechanisms underlying these effects are still poorly understood. Here, we evaluated the effectiveness of paclobutrazol, chlormequat and prohexadione on the modulation of vegetative growth and fruit set, with a special emphasis on the underlying effects exerted by phytohormones, in one-year-old olive trees (Olea europea cv. Arbosana). Paclobutrazol and chlormequat were tested using both foliar spraying and soil irrigation, while prohexadione was applied by foliar spraying only, and all treatments were compared to a control. Among treatments, paclobutrazol and chlormequat were the most effective in promoting vegetative growth retardation, when applied through foliar spray. Growth retardation by foliar application of paclobutrazol was associated with proline accumulation and reduced gibberellin contents in leaves. Furthermore, hormonal profiling revealed that not only all treatments were effective in reducing the endogenous contents of gibberellins, but also that the entire hormonal profiling was altered upon treatments. It is concluded that (i) various plant growth regulators can be effectively used to control olive tree growth, and (ii) paclobutrazol seems to be more efficient on vegetative growth retardation than the other tested treatments, being foliar application more effective than soil treatment.

     

The Solanum lycopersicum AUXIN RESPONSE FACTOR 7 (SlARF7) mediates cross-talk between auxin and gibberellin signalling during tomato fruit set and development

Transgenic tomato plants (Solanum lycopersicum L.) with reduced mRNA levels of AUXIN RESPONSE FACTOR 7 (SlARF7) form parthenocarpic fruits with morphological characteristics that seem to be the result of both increased auxin and gibberellin (GA) responses during fruit growth. This paper presents a more detailed analysis of these transgenic lines. Gene expression analysis of auxin-responsive genes show that SlARF7 may regulate only part of the auxin signalling pathway involved in tomato fruit set and development. Also, part of the GA signalling pathway was affected by the reduced levels of SlARF7 mRNA, as morphological and molecular analyses display similarities between GA-induced fruits and fruits formed by the RNAi SlARF7 lines. Nevertheless, the levels of GAs were strongly reduced compared with that in seeded fruits. These findings indicate that SlARF7 acts as a modifier of both auxin and gibberellin responses during tomato fruit set and development.     

Paclobutrazol and Its Use in Fruit Production: A Review

There are documentary records referring to paclobutrazol (PBZ) as a growth bioregulator that inhibits the gibberellin synthesis and its application increases yields in fruit and vegetable crop productions. Its agronomic management includes it as an emerging technology to reduce vigour, promote flower induction and flower development in fruit trees with increased economic returns. Its use is banned in some countries because of concerns about residues that can cause harmful effects on the environment. Therefore, the aim of this article was to collect, analyse and summarise relevant information on the use of PBZ in fruit tree production and its possible risks to the environment. The results obtained indicated that the application of PBZ can be effective in solving some problems related to flowering if it is applied in the right amount and at the right time. However, it is necessary to elucidate the physiological processes with which it is associated and its response to be taken into account to increase yield. PBZ is currently used in fruit trees such as mango, lime, apple and guava, increasing their productivity. However, some studies have shown its residual effect on the environment. Therefore, PBZ is a viable strategy, because it presents a series of advantages in the production of fruit trees. However, it is vital to generate protocols that seek its regulation with a rational and sustainable approach.     

柑橘果实生长发育过程中果实不同部位的4种内源激素含量变化的研究

以单性结实的国庆1号温州蜜柑和自花结实的华农本地早橘为材料,研究了果实生长发育过程中果实不同部位的吲哚乙酸(IAA)、脱落酸(ABA)、赤霉素(GA1/3)和玉米素核苷(ZR)含量的变化。结果表明:(1)国庆1号果皮IAA、GA1/3和ZR含量在幼果阶段均相对较高,随后果皮和果肉IAA含量均趋下降,而在果实膨大期内果肉ABA和果皮、果肉GA1/3、ZR含量均出现上升峰值,果实成熟采收时果皮和果肉ABA含量均明显回升。(2)华农本地早种子、果皮和果肉IAA及其种子ABA含量均在果实膨大期内出现明显峰值,在幼果阶段至果实膨大初期内种子GA1/3和ZR含量均居较高并出现明显上升,对应的果皮、果肉4种内源激素水平均相对较低且变幅小。还就两结实类型柑橘果实生长发育与其内源IAA、ABA、GA1/3和ZR含量动态的关系进行了讨论。