Abscisic Acid and Gibberellic Acid Contents in Ripening Barley Seeds

The ABA and GA3 contents were investigated in barley seeds during maturation and after harvest. The highest amount of ABA was found in milk and wax ripeness – 13 ng and 11 ng per seed respectively. The level decreased during the later stages of maturation and during release of dormancy and was 1 ng per seed 6 weeks after harvest. The content of gibberellic acid decreased in a similar way but in an earlier stage of maturation. The determined amounts of GA₃ were: 0.4, 0.1, 0.03 and about 0.05 ng per seed respectively, in milk, wax and full ripeness and after harvest. The results of quantitative determination, obtained with the GLC method, corresponded to the growth effects in the test of the first leaf of oat.     

The Effects of Gibberellic Acid on Organelle Biogenesis in the Endosperm of Germinating Castor Bean Seeds

Mature seeds of castor bean (Ricinus communis L.) were imbibedin tap water or 0.3 mM GA₃, planted in vermiculite moistenedwith tap water or 0.3 mM GA₃, and incubated at 32 ?C. Duringthe course of germination, GA₃ promoted marked increases inthe activities of the glyoxysomal marker enzyme isocitrate lyaseand certain mitochondrial marker enzymes, but did not affectthe ER marker enzyme choline phosphotransferase. Glyoxysomaland ER protein and phospholipid were not increased in amountby GA₃, whereas mitochondrial protein and phospholipid were.SDS-polyacrylamide gels of the glyoxysomal matrix polypeptidesfrom GA₃-treated beans exhibited two polypeptides additionalto those found to be common to both GA₃-treated and controltissue. Incorporation of CDP-(methyl ¹⁴C)-choline into intactendosperm tissue and the distribution amongst the glyoxysomes,mitochondria, and ER of newly synthesized phosphatidyl-(methyl¹⁴C)-choline was unchanged by GA₃.     

萌发大麦种子水溶性蛋白组分提取

采用二次回归正交旋转组合试验方法,对大麦种子中水溶性蛋白组分的提取工艺进行了研究,得出了大麦种子水溶蛋白组分提取量与料液浓度,浸提温度和浸提时间的数学模型,确定了大麦籽粒水溶蛋白组分最佳提取条件为料液浓度9．1％,浸提温度20℃,浸提时间3h;通过连续检测萌发大麦种子水溶蛋白含量发现：随萌发时间增长,蛋白含量逐渐升高,麦芽中水溶蛋白含量约为大麦的4倍．     

Identification and Content of 1-Malonylaminocyclopropanecarboxylic Acid in Germinating Cocklebur Seeds

A major conjugate of 1-aminocyclopropanecarboxylic acid in germinatingcocklebur (Xanthium pennsylvanicum Wallr.) seeds was isolatedand identified as 1-malonylaminocyclopropanecarboxylic acid(MACC). The change in MACC content during the germination periodof this seed also was examined. (Received November 4, 1983; Accepted March 15, 1984)     

The Influence of Abscisic Acid, Adenosine 3', 5' Cyclic Phosphate, and Gibberellic Acid on the Induction of Isocitrate Lyase Activity in the Endosperm of Germinating Castor Bean Seeds

Isocitrate lyase, one of the key enzymes of the glyoxylate cycle,provides a convenient marker for the development of metabolicactivity in castor bean endosperm. Gibberellin GA₇ (0.3 mM)was equally as effective as GA₃ in stimulating both the rateof appearance and total activity of the enzyme. Physiologicallyhigh levels of adenosine 3', 5' cyclic phosphate (1 mM and 5mM) had the same effect as gibberellins, but lower concentrationsdid not produce a response greater than the water controls.Application of 0.03 mM abscisic acid markedly inhibited germinationof the seeds and the induction of isocitrate lyase activitybut its action could be relieved by simultaneous addition ofequimolar concentrations of GA₃.     

Abnormalities Induced in Barley Ears by Gibberellic Acid

Five varieties of spring barley were sprayed with gibberellicacid (GA) at various growth stages from the one-leaf to thefive-leaf stage. In short days a number of abnormalities ofthe ear were found. These abnormalities are described in themature ear, and in the case of the branched ear, the ontogenyof the abnormality is shown. The relationship of the abnormalitiesto the environment, to the stage at which the plant was treated,and to the variety is analysed. The role of CA in inducing these abnormal features is discussedand their resemblance to abnormalities induceed geneticallyand by enviromental manipulations is pointed out.     

Gibberellic Acid Induces Vacuolar Acidification in Barley Aleurone

The roles of gibberellic acid (GA3) and abscisic acid (ABA) in the regulation of vacuolar pH (pHv) in aleurone cells of barley were investigated using the pH-sensitive fluorescent dye 2[prime],7[prime]-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF). BCECF accumulated in vacuoles of aleurone cells, but sequestration of the dye did not affect its sensitivity to pH. BCECF-loaded aleurone cells retained their ability to respond to both GA3 and ABA. The pHv of freshly isolated aleurone cells is 6.6, but after incubation in GA3, the pHv fell to 5.8. The pHv of cells not incubated in hormones or in the presence of ABA showed little or no acidification. The aleurone tonoplast contains both vacuolar ATPase and vacuolar pyrophosphatase, but the levels of pump proteins were not affected by incubation in the presence or absence of hormones. We conclude that GA3 affects the pHv in aleurone cells by altering the activities of tonoplast H+ pumps but not the amounts of pump proteins.     

转trxS基因大麦发芽种子水解酶活性的变化

利用转基因技术是改良大麦品种品质的有效途径.研究了转trxS基因对大麦种子发芽过程中水解酶活性的影响,结果表明转基因种子中α-淀粉酶、自由态β-淀粉酶和极限糊精酶的活性比未转基因种子高;转基因种子醇溶蛋白和谷蛋白中巯基的含量提高,说明该基因能够表达,为大麦育种和品质改良提供新的途径.     

The Influence of Abscisic Acid on the Gibberellin Content in Apple Seeds During Stratification

Auto?i sledovali obsah endogenních giberelin? GA₄ a GA₇ v embryích jabloně pěstovaných ve vodě nebo v roztoku abscisové kyseliny (ABA). Embrya pocházela ze semen odpo?ívajících nebo ze semen stratifikovaných ve vodě nebo v roztoku ABA. Bylo zji?těno, ?e ABA vyvolává sní?ení obsahu giberelin?. Závislost mezi vlivem ABA a stadiem stratifikace bylo u GA₄ výrazněj?í ne? u GA₇. Auto?i p?edpokládají, ?e ABA inhibuje biosynthesu giberelin?.     

Acid Phosphatase in Cotyledons of Germinating Vigna mungo Seeds

A marked increase in acid phosphatase activity took place incotyledons of germinating Vigna mungo seeds. The attachmentof axis organs was not required for this development of enzymeactivity in cotyledons. DEAE-cellulose column chromatographyrevealed that the phosphatase is composed of at least threeforms. (Received August 19, 1981; Accepted October 30, 1981)     

Light, Seed Coat and Gibberellic Acid in Relation to the Amylase Activity in Germinating Scots Pine Seeds (Pinus silvestris)

The amylolytic activity in homogenates from both embryos and endosperms of Scots pine seeds depends on the presence of α-amylase. The activity of this enzyme has been studied in relation to the light factor during the first 24 hours of the germination process. No positive correlations have been found between the observed activities and earlier observed enhancement of the starch degradation in light. The endosperm activities have been shown to be affected both by the presence of an intact coat and the presence of the embryo. The embryo influence could not be restored by gibberellic acid. The results have been discussed in relation to the physiology of gibberellin and ethylene. The author wishes to express his thanks to the Swedish Natural Science Research Council for financial support and to Miss Brigitte Thierbach for skilful, technical assistance.     

The Appearance of Lactic Acid in Phaseolus Seeds Germinating under Wet Conditions

Under normal conditions of germination, there is never muchlactate in bean cotyledons, but when beans are germinated underwet conditions lactate accumulates for about 30 h and then slowlydisappears, as radicle emergence begins. Removal of the testaefrom soaked seeds prevents subsequent lactate accumulation.Lactate also appears in beans germinated under nitrogen. Lactate dehydrogenase activity is enhanced in wet or anaerobicconditions. Incubation with pyruvate increased lactate dehydrogenaseby 50 per cent. There was also a temporary accumulation of alcohol in beansgrown under wet conditions. Under wet conditions the production of respiratory carbon dioxidewas particularly slow during the period of lactate accumulation.     

外源赤霉素对紫斑牡丹种子萌发的影响

以紫斑牡丹种子为试验材料,研究不同浓度的赤霉素(GA_3)处理对种子生根以及生根过程中营养物质、酶活性和内源激素水平变化的影响,为探讨紫斑牡丹种子萌发机制提供依据。结果表明:(1)GA_3处理能够促进种子生根,并以300 mg/L GA_3处理对种子生根效果最好,与对照相比可提前14.67 d生根,生根率可达71.00%。(2)与对照相比,GA_3处理可以在0～15 d时促进种子淀粉水解和可溶性糖的积累,并加速可溶性蛋白的消耗,在0～30 d促进过氧化物酶(POD)活性的提高,从而促进种子萌发生根。(3)在种子沙藏生根过程中,种子脱落酸(ABA)含量呈下降趋势,赤霉素(GA)、玉米素核苷(ZR)和吲哚乙酸(IAA)含量均表现出先上升后下降的趋势,与对照相比,GA_3处理可使种子GA、ZR和IAA的含量在沙藏前期明显上升,以解除种子休眠。研究发现,外源GA_3处理可以调控紫斑牡丹种子内源激素含量和POD活性的变化,促进营养物质转化,从而提前解除种子休眠使其萌发。     

Effects of Gibberellic Acid on the Activation, Synthesis, and Release of Acid Phosphatase in Barley Seed

Acid phosphatase activity was present in unimbibed barley seed,but rose during incubation of embryoless half-seeds and isolatedaleurone layers, and was further increased by 10^–6 M gibberellicacid (GA₃). Release of total acid phosphatase activity fromhalf-seeds and aleurone layers was markedly enhanced by GA₃.Inhibitor studies with cycloheximide and actinomycin D suggestedthat de novo synthesis of acid phosphatase occurred followingimbibition. Gel nitration, electrophoresis, and [¹⁴C]leucineincorporation studies revealed that a single molecular formof acid phosphatase was present in dry seed, whereas on incubationtwo further forms arose. A proportion of the three molecularforms of the enzyme was synthesized de novo. Gibberellic acidstimulated activation, but not de novo synthesis, of all threemolecular forms of acid phosphatase. Although a small amountof one of the molecular forms was secreted in the absence ofGA₃, the presence of gibberellin greatly increased secretionof the same form of acid phosphatase.