茎瘤固氮根瘤菌（Azorhizobium caulinodans）ORS 571产生的植物激素

茎瘤固氮根瘤菌（Ａｚｏｒｈｉｚｏｂｉｕｍｃａｕｌｉｎｏｄａｎｓ）ＯＲＳ５７１菌株在离体培养条件下,能利用色氨酸合成吲哚乙酸（ＩＡＡ）。随着菌龄的老化,合成的ＩＡＡ量也增加。除ＩＡＡ外,该菌株还产生类ＧＡ物质。本研究未检出细胞分裂素（Ｃｙｔｏｋｉｎｉｎ）类物质。     

紫外线诱变豇豆根瘤病512的研究

将活化后的豇豆根瘤菌５１２（Ｒ．Ｉｅｇｕｍｉｎｏｓａｒｍ５１２）涂抹于含有１ｇ／Ｌ琥珀酸钠和０．８％蛋白胨的ＹＥＭ固体培养基上,然后以紫外线照射,从中选出合成ＩＡＡ能力较高和抗性较强的突变菌株。测定结果表明,该菌株合成ＩＡＡ成力比原出发菌株高一倍左右。其合成ＩＡＡ能力与照射剂量、照射次数和培养基中蛋白胨的浓度有关。不仅如此,该突变菌株的耐碱和耐盐能力有明显提高。     

紫云英根瘤菌107菌株酸性胞外多糖的分离纯化及结构分析

用化学沉淀法和柱层析法,分离纯化了紫云英根瘤菌野生型１０７菌株,胞外多糖合成缺陷型变种ＮＡ０２及其回复子ＮＡ０２（Ｒ‘－１１）产生的酸性胞外多糖（ＥＰＳ）。结构组成分析表明：菌株１０７与ＮＡ０２（Ｒ’－１１）产生的ＥＰＳ糖组分均由葡萄糖、半乳糖、核糖和葡萄糖醛酸构成,而变种ＮＡ０２产生的ＥＰＳ只含葡萄糖、半乳糖和葡萄糖醛酸,与野生型显著不同。３个菌株的ＥＰＳ均有乙酰基取代,而无其它形式的取代基。Ｅ     

植物体中的吲哚丁酸（IBA）

吲哚丁酸（ＩＢＡ）是植物体内天然存在的一种生长素，具有比吲哚乙酸（ＩＡＡ）更好的促进生根能力，本文对ＩＢＡ在植物体内的生物合成，代谢和极性运输等方面作一介绍。     

普通结瘤基因探针鉴定根瘤菌的研究

普通结瘤基因（ｎｏｄＡＢＣ）是所有根瘤菌所特有的、最为保守的基因,用苜蓿根瘤菌结瘤基因（ｎｏｄＡＢＣ）和豌豆根瘤菌的（ｎｏｄＣ）基因片段为探钉,与５２株包括常见土壤细菌、已知根瘤菌、根瘤未知分离物的总ＤＮＡ进行斑点杂交,探索用普通结瘤基因（ｎｏｄＡＢＣ）或（ｎｏｄＣ）探针鉴定根瘤菌的可能性。结果,未找到合适实验条件,使来自这两个种的结瘤基因只能与根瘤菌菌株杂交,而不与土壤细菌的菌株杂交。但在高温条件下,两种探针都专一性的和种内菌株杂交。此结果表明：在一定的实验条件下,普通结瘤基因探针用做根瘤菌的鉴定,只能     

花生根瘤菌的数值分类

从我国 １１个省、 １６种土壤类型、 ２０多个花生（Ａｒａｃｈｉｓ ｈｙｐｏｇａｅａ Ｌ．）品种上分离到的花生根瘤菌［Ｂｒａｄｙｒｈｉｚｏｂｉｕｍ ｓｐ．（Ａｒａｃｈｉｓ）］中选取５０个代表菌株、并与从津巴布韦引进的４株花生根瘤菌及７株慢生根瘤菌常用的参比菌株共６１株菌进行了１２８项表型特征的测定。数值分类的结果表明,全部菌株在７５％水平上相聚,并在７６％和７７％的水平上分别聚成两大群（群Ⅰ、群Ⅱ）,每大群以较高的相似性（８５％- ９４％）各聚成６个亚群。所用数值分类方法不能将花生根瘤菌和大豆根瘤菌在属的水平上分开,但亚群和未归入亚群的菌株可能暗示亚种或种存在,同时本文结果还表现出花生根瘤菌的地域分布差异及其多样性。     

促乳素抑制培养的大鼠颗粒细胞中卵泡素介导的组织纤溶酶原激活因子的表达

本文主要是观察促乳素（ＰＲＬ）是否曩体外培养的大鼠颗粒细胞中,组织纤溶酶原激活因子（ｔＰＡ）和Ｉ型纤溶酶原激活因子抑制因子（ＰＡＩ－Ｉ）基因表达间的协调作用。我们采用了多种方法,例如ＳＤＳ－ＰＡＧＥ、免疫印迹等,来检测ＰＲＬ对ｔＰＡ和ＰＡＩ－Ｉ基因表达的作用。结果证实：（１）在离体条件下促乳素（ＰＲＬ）能刺激颗粒细胞（ＧＣ）中ＰＡＩ－Ｉ ｍＲＮＡ的合成,而ＦＳＨ无此作用。但ＦＳＨ可与ＰＲＬ协同增加     

花生根瘤菌的数值分类*

从我国 １１个省、 １６种土壤类型、 ２０多个花生（Ａｒａｃｈｉｓ ｈｙｐｏｇａｅａ Ｌ．）品种上分离到的花生根瘤菌［Ｂｒａｄｙｒｈｉｚｏｂｉｕｍ ｓｐ．（Ａｒａｃｈｉｓ）］中选取５０个代表菌株、并与从津巴布韦引进的４株花生根瘤菌及７株慢生根瘤菌常用的参比菌株共６１株菌进行了１２８项表型特征的测定。数值分类的结果表明,全部菌株在７５％水平上相聚,并在７６％和７７％的水平上分别聚成两大群（群Ⅰ、群Ⅱ）,每大群以较高的相似性（８５％- ９４％）各聚成６个亚群。所用数值     

紫云英根瘤菌107菌株exo基因簇非连锁突变位点的克隆

用鸟枪法从３株紫云英根瘤菌１０７菌株的胞外多糖合成缺陷变种ＮＡ－０５、ＮＡ－０７和ＮＡ－０８中克隆获得含有１０７菌株ｅｘｏ基因及Ｔｎ５的ｅｘｏ：Ｔｎ５片段。以ｐＲＫ４１５为载体构建１０７菌株ＥｃｏＲＩ酶切后ＤＮＡ片段的部分库,用ｅｘｏ：Ｔｎ５做探针原位杂交得到一个阳性克隆。该克隆的外源片段４．２ｋｂ能恢复３个变种的多糖表型及结瘤固氮能力。酶切分析和Ｓｏｕｔｈｅｒｎ杂交表明,３株变种中Ｔｎ５插入位点     

皮质酮快速抑制PC12细胞乙酰胆碱诱发电流影响及机制探讨

目的和方法：本研究采用全细胞膜片箝技术,观察皮质酮（Ｂ）对ＰＣ１２细胞上乙酰胆碱诱发电流（ＩＡＣｈ）的快速作用并初步探讨其可能机制。结果：ＰＣ１２细胞上ＩＡＣｈ是通过烟碱受体（ｎＡＣｈＲ）引起的。箝制电压为－８０ｍＶ时,ＡＣｈ（３０μｍｏｌ／Ｌ）诱发一内向电流;细胞外灌流同时给予ＡＣｈ和Ｂ（１０－５ｍｏｌ／Ｌ）时,Ｂ对ＩＡＣｈ的抑制作用较弱;用Ｂ（１０－５ｍｏｌ／Ｌ）对细胞进行预处理,可提高Ｂ对ＩＡＣｈ峰值的抑制率,作用呈可逆性、浓度依赖性和非电压依赖性;细胞外用ＲＮＡ合成抑制剂放线菌素Ｄ（４×１０－５～４×１０－３ｍｏｌ／Ｌ）或蛋白合成抑制剂放线菌酮（１０－４～１０－３ｍｏｌ／Ｌ）孵育细胞１～２ｈ阻断基因机制,但均不影响Ｂ对ＩＡＣｈ的快速抑制作用。结论：Ｂ对ＰＣ１２细胞上ＩＡＣｈ有快速抑制作用,此作用可能是由非基因组机制介导的。     

The Effect of Growth Substances on Growth of Excised Embryo Shoot Apices of Wheat in Vitro

Excised embryo shoot apices of wheat were grown on media containingeither indolylacetic acid (IAA), kinetin, gibberellic acid (GA),or adenine. GA and adenine stimulate the activity of the apicalmeristem whereas IAA and kinetin do not. No combination of anytwo substances significantly stimulated growth when comparedwith the most active substance present. GA can overcome theinhibitory effect of IAA or kinetin. The possible function ofthese substances in the apical meristem is discussed.     

The Effects of Plant Growth Substances on Rind-Regeneration after Girdling in Solanum melongena cv. esculantum

This paper deals with the effects of four plant growth substances, ic. IAA, NAA, 2,4-D and GA and their different concentration on rind-regeneration after girdling in Solanum melongen var. esculantum. The formation of callus was promoted by IAA, NAA and GA, but retarded by 2,4-D in early stage. The initiation of vascular cambium in callus was retarded by all these substances. However, an increase in amount of xylem was promoted by IAA at low concentrations. The different concentrations of NAA and GA affected a decrease in amount of xylem. The formation of "bundled" vascular tissue was impelled by NAA, GA and 2,4-D. The initiation of phellogen was promoted by IAA and NAA at high concentrtion. In addition, the nest-like tracheid mass was induced in callus by IAA and NAA frequently.     

Identity of Products of Indol-3yl-acetic Acid Oxidation

The product of IAA decomposition which gives the pink colourin the Salkowski reaction is not N-hydroxy-IAA and its identityis still unknown, as is also that of other substances foundduring metabolism of IAA by pea seedlings.     

The influence of growth regulators on membrane permeability in cultures of winter wheat cells

The effect of plant growth substances (IAA, 2,4-D, zeatin, kinetin, zearalenone) were studied on membrane properties of the cells of embryogenic (E) and non-embryogenic (NE) calli derived from immature inflorescences (inf) or embryos (emb) of winter wheat. Calli initiated from inflorescences show higher permeability. The ion leakage from cells of E calli was higher than from cells of NE calli. Growth regulators were used in concentrations of 2-30 mg/l (about 10-140 microM). All tested growth substances increased ion leakage from NE emb cells, IAA, zeatin and kinetin being most effective. In NE inf cells the effect of growth substances was similar as in NE emb, but much weaker. In E cells of both types (inf and emb) growth substances decreased ion leakage. Changes in the leakage of potassium and calcium ions were similar to those in total ion leakage. The uptake of labelled auxins (IAA and 2,4-D) was higher in NE cells (especially in NE inf) than in E cells. The endogenous level of IAA was higher in E cells than in NE cells and in inf cells than in emb cells. The importance of auxin in determining permeability of cell membranes is discussed.     

Untersuchungen über die Bindung pflanzlicher Wuchsstoffe an verschiedene Komponenten des Chromatins in vitro

Summary Several growth substances (IAA, -NAA) are able to reduce thermal stability of artificially reconstituted nucleoproteins without splitting off measurable amounts of protein from DNA. This effect is not shown by substances structurally related to auxins (-NAA, tryptophan), but other growth substances (GA, KI) also reduce thermal stability of several reconstituated nucleoproteins.The effect of growth substances on the Tm of nucleoproteins strongly depends upon the concentration of the growth substances. The effective concentrations of IAA are lowered by increasing acidity of the protein component in the nucleoprotein. IAA and GA diminish the binding capacity of histones and residual nucleoproteins to DNA at different concentrations.Nucleoproteins containing histones and residual nuclear proteins (DNA/resid. prot. 1:0,5: 0,5) exhibited different thermal stability depending on whether part of the histones or residual nuclear proteins were first bound to DNA. Furthermore, these nucleoproteins showed different thermal stability after treatment with growth substances.     

Degradation of Indol-3yl-acetic Acid in Homogenates and Segments of Cabbage Roots

Plots of reaction rate versus substrate concentration of the enzymatic decarboxylation of IAA yield sigmoid, rather than the usual, hyperbolic curves, suggesting that the IAA oxidase of cabbage roots is an allosteric enzyme. The quantity of this enzyme in roots is so high that the IAA concentration is likely to limit IAA degradation in intact cells. Thus, variations in the level of this enzyme seem not to be essential for the regulation of the endogenous IAA concentration. Cabbage roots contain substances that can inhibit IAA oxidase. These substances are spatially separated from IAA oxidase in intact cells, but the same inhibitors are able to reach the enzyme when added exogenously to tissue segments. The possibility that added IAA is treated by tissue segments in another manner than endogenous IAA is discussed.     

Effects of phenolic substances on metabolism of exogenous indole-3-acetic acid in maize stems

Four-day-old stem segments of Zea mays L. cv. Seneca 60 were treated sequentially with phenolic substances and indole-3-acetic [2-¹⁴C] acid ([2-¹⁴C]IAA). Formation of bound IAA was rapid, but a pretreatment with p-coumaric acid, ferulic acid or 4-methylumbelliferone decreased the level of bound IAA. The decrease is not likely related to the effect of the phenolics on enzymic oxidation of IAA, since the level of free IAA was not limiting and the activity of ferulic acid in enzymic oxidation of IAA is different from that of p-coumaric acid and 4-methylum-belliferone. Apparently these compounds inhibited the formation of bound IAA and consequently caused an accumulation of free IAA. In contrast, caffeic acid, protocatechuic acid and 2,3-dihydro-2, 2-dimethyl-7-benzofuranol had little effect. After the uptake of IAA there was a slow but steady incorporation of the radioactivity into the 80% ethanol-insoluble, 1 M NaOH-soluble fraction. Phenolic substances also affected this process. The compounds which are cofactors of IAA-oxidase increased the incorporation while those which are inhibitors of IAA-oxidase decreased the incorporation. Results suggest that the phenolics also affected the enzymic oxidation of IAA in vivo in the same way as in vitro.     

Development of Seeded and Seedless Hypanthium of Rosa Canina After Application of Growth Substances

Dog rose (Rosa canina L.) plants in the bloom stages of flowering were sprayed by indole-3-acetic acid (IAA) in concentrations of 0.06 and 0.60 mM and gibberellic acid (GA₃) in concentrations of 0.60 and 1.50 mM. Ascorbic acid, total sugar, reducing sugar and carotenoid contents gradually increased, while the protein content remained unchanged and the content of phenolic substances decreased during hypanthium development. Ascorbic acid, total sugar, reducing sugar and carotenoid contents increased in hypanthium sprayed by GA₃ and IAA. However, IAA and GA₃ applications (except low concentrations) decreased contents of phenolic substances. IAA and GA applications might be a good way to produce the high quality hypanthium in R. canina.     

Effect of plant growth substances on the growth of axillary buds in cultured stem segments of Phaseolus vulgaris L.

The hormonal control of axillary bud growth was investigated in cultured stem segments of Phaseolus vulgaris L. When the stem explants were excised and implanted with their apical end in a solid nutrient medium, outgrowth of the axillary buds-located at the midline of the segment-was induced. However, if indoleacetic acid (IAA) or naphthaleneacetic acid (NAA) was included in the medium, bud growth was inhibited. The exposure of the apical end to IAA also caused bud abscission and prevented the appearance of new lateral buds.In contrast to apically inserted segments, those implanted in the control medium with their basal end showed much less bud growth. In these segments, the auxin added to the medium either had no effect or caused a slight stimulation of bud growth.The IAA transport inhibitor N-1-naphthylphthalamic acid (NPA) relieved bud growth inhibition by IAA. This suggests that the effect of IAA applied at the apical end requires the transport of IAA itself rather than a second factor. With the apical end of the segment inserted into the IAA-containing medium, simultaneous basal application of IAA relieved to some extent the inhibitory effect of the apical IAA treatment. These results, together with data presented in a related article [Lim R and Tamas I (1989) Plant Growth Regul 8: 151–164], show that the polarity of IAA transport is a critical factor in the control of axillary bud growth.Of the IAA conjugates tested for their effect on axillary bud growth, indoleacetyl alanine, indoleacetic acid ethyl ester, indoleacetyl-myo-inositol and indoleacetyl glucopyranose were strongly inhibitory when they were applied to the apical end of the stem explants. There was a modest reduction of growth by indoleacetyl glycine and indoleacetyl phenylalanine. Indoleacetyl aspartic acid and indoleglyoxylic acid had no effect.In addition to IAA and its conjugates, a number of other plant growth substances also affected axillary bud growth when applied to the apical end of stem segments. Myo-inositol caused some increase in the rate of growth, but it slightly enhanced the inhibitory effect of IAA when the two substances were added together. Gibberellic acid (GA₃) caused some stimulation of bud growth when the explants were from younger, rather than older plants. The presence of abscisic acid (ABA) in the medium had no effect on axillary bud growth. Both kinetin and zeatin caused some inhibition of axillary buds from younger plants but had the opposite effect on buds from older ones. Kinetin also enhanced the inhibitory effect of IAA when the two were applied together.In conclusion, axillary buds of cultured stem segments showed great sensitivity to auxins and certain other substances. Their growth responded to polarity effects and the interaction among different substances. Therefore, the use of cultured stem segments seems to offer a convenient, sensitive and versatile test system for the study of axillary bud growth regulation.     

Function of phenolic substances in the degradation system of indole-3-acetic acid in strawberries

The homogenate of different strawberry organs inhibits the degradation of IAA in the presence of horse radish peroxidase, while intact strawberry tissues are able to degrade IAA. The chemical nature of peroxidase inhibitors present, in strawberry tissues was in vestigated. Using paper chromatography the following polyphenolic substances inhibiting peroxidase activity were identified: chlorogenic, caffeic, ellagic, gentisic, gallic, and vanillic acids, quercetin and pelarginidin. Monophenolic compounds, also present in strawberry, such as p-hydroxy-phenyloacetic acid and p-hydroxybenzoic acid, are strong stimulators of IAA oxidase. Abscisic acid in very high concentration (1×10^?4M) enhances degradation of IAA by peroxidase. When both poly-and monophenolic compounds at equimolar concentrations are present in the system, only the inhibition of IAA degradation occurs. Tissue explants from the strawberry leaves and petiole degrade less IAA if they are previously forced to synthetize more polyphenols under illumination. Although the difference in IAA-decarboxylation activity between the illumination and dark treated explants was relatively small, nevertheless it was consistent and appears to be very important from a physiological point of view suggesting that there exists a regulatory relationin vivo between IAA degradation and the presence of phenolsin plant tissue. Electron microscope data revealed that phenolic substances are specially isolated from cytoplasm of the receptacle cells.