植物生长调节剂在植物体细胞胚发生中的应用

合理应用植物生长调节剂是成功诱导体细胞胚的决定因素,也是影响体细胞胚高频率发生的主要因素。本文从生长素类、细胞分裂素类、赤霉素、脱落酸以及各类植物生长调节剂间组合使用等几个方面综述了外源植物生长调节剂在体细胞胚发生中的应用进展,为植物体细胞胚的诱导提供了一定的参考价值。     

外源生长素和细胞分裂素对莴苣幼苗侧根原基发生和内源激素含量的影响

以莴苣幼苗为材料,以适应浓度的生长素类物质萘乙酸（ＮＡＡ）、吲哚丁酸（ＩＢＡ）和吲哚乙酸（ＩＡＡ）处理根部２０￣３０ｈ,可使大量的侧根原基得到的启动和突起,１０．０００ｍｇ／Ｌ的ＮＡＡ,ＩＢＡ或ＩＡＡ处理的侧根原基数分别为对照的２７．９,２６．５和１３．６倍;     

细胞分裂素:杨树气孔运动的调节剂

通过在三种杨树无性系，Ｉ－２１４（Ｐｏｐｕｌｕｓ×ｅｕｒａｎｅｒｉｃａｎａｃｖ．Ｉ－２１４）（ｌｔａｌｉｃａ）、中东杨（Ｐ．ｂｅｒｏｌｉｎｅｎｓｉｓ）（Ｂｅｒｏｌｉｎｅｎｓｉｓ）和群众杨（Ｐ．ｐｏｐｕｌａｒｉｓ３５－４４）（Ｐｏｐｕｌａｒｉｓ）一年生盆栽插条苗的木质部导入ＡＢＡ和细胞分裂素，研究了这两类激素在气孔调控中的作用。尽管不同无性系的气孔在对ＡＢＡ的敏感性上存在显著差异，但ＡＢＡ仍可导致气孔的关闭，然而在蒸腾流中的细胞分裂素（与ＡＢＡ共导入或分别导入）可以明显地抑制ＡＢＡ的作用。并且玉米素还能推迟土壤干旱所诱导的气孔关闭，在水分胁迫条件下，内源细胞分裂素浓度下降而同时ＡＢＡ上升．据此提出了复合胁迫信号的概念，即在根冠通讯中，是ＡＢＡ和细胞分裂素共同调控气孔的运动。另外还研究了玉米素、激动素、６－ＢＡ等不同细胞分裂素与ＡＢＡ的相互作用，结果发现６－ＢＡ与玉米素和激动素的作用相反，它不能抑制ＡＢＡ的作用，反而促进其对气孔的关闭     

Cytokinins in iris bulb-scales under flower-inducing conditions

Cytokinin activity was detected by means of the soybean callus test in the scales of Iris hollandica Hoog cultivar ‘Prof. Blaauw’ during the cold treatment for flower formation. A component of the biological activity extracted from the bulb scales coeluted with zeatin riboside when subjected to high-performance liquid chromatography. It is suggested that the cytokinins in the scales may be involved in flower formation.     

Morpho-Physiological Responses of Grape Rootstock ‘Dogridge’ to Arbuscular Mycorrhizal Fungi Inoculation Under Salinity Stress

Effects of arbuscular mycorrhizal fungi (AMF) alone or in combination with bacterial consortium (AMF+BC) inoculation prior to induced salinity (NaCl @ 150 or 250 mM) were studied on root growth; plant biomass; leaf area; Na⁺ and K⁺ contents; leaf water potential (Ψ_w); osmotic potential (Ψ_π); photosynthesis rate (P_n); and contents of chlorophyll, phytohormones, and polyamines in the grape rootstock ‘Dogridge’, popular among Indian vine growers. AMF inoculation in the NaCl untreated rootstocks plants increased root growth, root and shoot biomass, and leaf area and improved leaf Ψ_w, Ψ_π, P_n, and chlorophyll content, and also countered the stress-induced decline in the NaCl treated plants. The abscisic acid (ABA), cytokinins, and polyamine-spermidine and spermine contents in the leaves of NaCl untreated or treated were significantly increased by the AMF inoculation. Among the treatments, AMF with BC was relatively more effective than AMF alone with respect to changes in above morpho-physiological characters. The results depicted that AMF (AMF alone or AMF+BC) inoculation significantly improved salinity tolerance of grape rootstock and tolerance is induced by improvements in plant water balance, K⁺:Na⁺ ratio, and P_n, besides distinct accumulations in ABA and polyamines-spermine and spermidine. The above findings have potential in suggesting the AMF usefulness in improving the efficacy of ‘Dogridge’ rootstock in grape cultivation under salt affected soils.     

玉米赤霉烯酮对棉花花芽分化的影响

玉米赤霉烯酮浇根处理可促进棉花早现蕾。内源激素检测表明,外施玉米霉烯酮能够增加细胞分裂素含量,降低脱落酸含量。玉米赤霉烯酮能够促进棉花提早现蕾可能与其提高花芽分化期细胞分裂素含量,降低脱落酸含量,改变了棉花发育过程中内源激素平衡有关。     

Root Pruning—A Poorly Understood Management Practice in Fruit Trees

ABSTRACT

Root pruning (RP) is a management practice intended to reduce excessive shoot growth resulting from a disturbed root/shoot-balance. It appears to function by limiting the gibberellin activity in fruit trees by interfering with endogenous growth control. In this way, not only shoot growth but also fruit development and flower-bud formation can be influenced by one common mechanism. The results are contradictory and often unpredictable. The prospects of RP as a management practice are rather limited.     

The effect of growth regulators on meristem tip development and in vitro multiplication ofSolanum tuberosum L. plants

Summary We studied the effect of β-indoleacetic acid (IAA), α-naphthylacetic acid (NAA), kinetin (K), 6-benzylaminopurine (BAP) and gibberellic acid (GA₃) on development of isolated meristems of four potato cultivars (subsp. tuberosum). GA₃ had a stimulating effect on in vitro meristem growth. The differences among the cultivars are presented. K+IAA+GA₃ induced formation of multiple shoots. We describe a method of continual plant multiplication under in vitro conditions and propose the produce for maintenance, multiplication and virus eradication of potato germplasm and cultivars.

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Zusammenfassung Von vier Kartoffelsorten (Blanik, Cira, Nora und Radka) wurden die Meristemspitzen entnommen. Der N?hrboden enthielt Makround Mikroelemente gem?ss Murashige & Skoog (1962), Vitamine entsprechend B-5 (Gamborg et al., 1968), 100mg/l Inositol, 30 g/l Saccharose und 8 g/l Agar. Wir untersuchten die Wirkung von β-Indolessigs?ure (IAA), α-Naphytlessigs?ure (NAA), Kinetin (K), 6-Benzylaminopurin (BAP) und Gibberellins?ure (GA₃). Auf den N?hrb?den mit IAA und NAA wurde mangelhaftes Triebwachstum und unvollst?ndige Blattentwicklung (Abb. 1) festgestellt; die Pflanzen konnten nicht in Erde versetzt werden. K (0.1 μM) induzierte vollst?ndige Pflanzenentwicklung (Tabelle 1), w?hrend BAP (0,1μM) die Triebenentwicklung anregte, worauf die Bewurzelung auf N?hrboden mit 0,1 μM IAA (Abb. 2) erfolgte. Alle GA₃-Konzentrationen hatten einen vorteilhaften Einfluss auf die Entwicklung von Pfl?nzchen aus Meristemspitzen (Abb. 1 und Tabelle 1). Optimales Wachstum und rasche Entwicklung der Pflanzen aller vier Sorten wurde mit dem N?hrboden mit IAA+K+GA₃ erreicht. Mehrfache Triebbildung erfolgte auf den Medien mit erh?hten GA₃-Konzentrationen (5 und 10 μM), speziell bei den Sorten Cira und Blanik (Abb. 3). Die Pflanzen aus der Meristemspitzenkultur konnten unter sterilen Bedingungen in Perlit, das mit der Hoagland's-L?sung und mit einem Zusatz von 0,1 μM IAA ges?ttigt war, fortlaufend vermehrt werden. Die Pflanzen entwickeln sich aus Achselknospen. Ein Steckling aus einem Meristem ist f?hig, 5–8 Pflanzen in zwei Monaten hervorzubringen. Der Artikel beschreibt das System der mehrfachen Triebbildung und die laufende Fortpflanzung in vitro zur Erhaltung und Vermehrung von Kartoffel-Keimplasma (Westcott et al., 1977) und virusfreien Züchtungen (Abb. 4).

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Résumé Des méristèmes apicaux ont été prélevés sur quatre variétés de pommes de terre: Blanik, Cira, Nora et Radka. Le milieu de culture contenait des macro-et microéléments d'après les indications de Murashige & Skoog (1962), des vitamines B-5 (d'après Gamborg et al., 1968), 100 mg/l d'inositol, 30 g/l de sucrose et 8 g/l d'agar. Nous avons étudié l'action de l'acide β-indoleacetic (IAA), de l'acide α-naphtylacétique (NAA), de la kinétine (K), de la 6-benzylaminopurine (BAP) et de l'acide gibberellic (GA₃). Sur les milieux contenant de l'IAA et du NAA, nous avons observé un développement imparfait des pousses, et un développement partiel des feuilles (fig. l); les plantes ne pouvaient pas être transplantées en terre. K (0,1 μM) a induit un développement complet des plantes (tableau 1) tandis que le BAP (0,1 μM) a stimulé le développement des pousses suivi de leur enracinement dans le milieu contenant 0,1 μM d'IAA (fig. 2). Toutes les concentrations de GA₃ ont eu un effet bénéfique sur le développement des plantules issues de méristèmes apicaux (fig. 1 et tableau 1). La croissance optimale et le développement rapide des plantes des 4 variétés ont été observés sur le milieu contenant IAA+K+GA₃. Des pousses multiples se sont formées sur les milieux contenant des concentrations élevées en GA₃ (5 et 10 μM), notamment sur les variétés Cira et Blanik (fig. 3). Les plantes obtenues à partir de culture de méristèmes apicaux ont p? être continuellement propagées en conditions stériles dans de la perlite saturée d'une solution de Hoagland avec addition de 0,1 μM de IAA. Les plantes se développent à partir des bourgeons axillaires; une plantule d'origine méristématique est capable de donner naissance à 5 à 8 plantes en 2 mois. L'article décrit le système de formation des pousses multiples et la propagation continue in vitro pour la maintenance et la multiplication de variétés de pommes de terre indemnes de maladies (Westcott et al., 1977) et de virus (fig. 4).

     

Bioregulatory Effects of the Fungicidal Strobilurin Kresoxim-methyl in Wheat (Triticum aestivum)

Apart from its fungicidal effect, the strobilurin kresoxim-methyl (BAS 490 F) was found to induce physiological and developmental alterations in wheat (Triticum aestivum L.) which are seen in connection with improved yield. In a series of biotests including heterotrophic maize and photoautotrophic algal cell suspensions, duckweed, isolated mustard shoots and germinating cress seeds, kresoxim-methyl showed a similar response pattern to standard auxins (e.g. indol-3-ylacetic acid, IAA; 2-(1-naphthyl)acetic acid, α-NAA). Auxin-like activity of kresoxim-methyl was also found when stem explants of tobacco were cultured on a hormone-free medium. Kresoxim-methyl stimulated shoot formation, particularly at 10^-7 M . The same effect was induced by 10^-8 M IAA. The determination of phytohormone-like substances in shoots of wheat plants foliar-treated with 7×10^-4 M kresoxim-methyl revealed only slightly changed levels of endogenous IAA, gibberellins and abscisic acid. In contrast, the contents of dihydrozeatin riboside-type cytokinins increased to 160% of the control, while trans-zeatin riboside- and isopentenyladenosine-type cytokinins remained nearly unchanged. The most remarkable alterations were the reductions in 1-aminocyclopropane-1-carboxylic acid (ACC) levels and ethylene formation which were demonstrated in intact plants, leaf discs and the shoots of wheat subjected to drought stress. Kresoxim-methyl affected the induction of ACC synthase activity which converts S-adenosyl-methionine to ACC in ethylene biosynthesis. In shoots from foliar-treated wheat plants, 10^-4 M kresoxim-methyl inhibited stress-induced increases in endogenous ACC synthase activity, ACC levels and ethylene formation by approximately 50%. Reductions in ACC synthase activity and ACC levels of 30% were also obtained at low concentrations of α-NAA (10^-6 M ). In contrast, ACC synthase activity in vitro was not influenced by adding the compounds. In wheat leaf discs, the inhibiting effect of kresoxim-methyl, α-NAA and IAA on ethylene formation was accompanied by delayed leaf senescence, characterized by reduced chlorophyll loss. However, in contrast to kresoxim-methyl which showed only inhibitory activity on ethylene synthesis over a wide range of concentrations applied, the auxins stimulated ethylene production at high concentrations of about 10^-4 M . The inhibition of ethylene biosynthesis by kresoxim-methyl, together with an increase in endogenous cytokinins could explain the retardation of senescence and the intensified green leaf pigmentation in wheat exposed to this strobilurin. © 1997 SCI.     

Grain yield,nitrogen use efficiency and physiological performance of indica/japonica hybrid rice in response to various nitrogen rates

Utilizing the heterosis of indica/japonica hybrid rice (IJHR) is an effective way to further increase rice grain yield.Rational application of nitrogen (N) fertilizer plays a very important role in using the heterosis of IJHR to achieve its great yield potential.However,the responses of the grain yield and N utilization of IJHR to N application rates and the underlying physiological mechanism remain elusive.The purpose of this study was to clarify these issues.Three rice cultivars currently used...