Glycolytic Control of Respiration during Aging of Carrot Root Tissue

Changes in respiration in aging carrot slices are correlated with a characteristic sequence of activation of the irreversible reactions of the glycolytic pathway. The induced "wound" respiration increases in two stages; these appear to correspond to a period of active synthesis, when ADP, produced in the cytoplasm from synthetic reactions, activates pyruvate kinase, and a period of readjustment when ATP, no longer reacting in synthetic reactions, activates phosphofructokinase. Although ATP is cited frequently as a negative effector of phosphofructokinase, unless the concentration of ATP at the site of phosphofructokinase is 50-fold higher than the concentration expressed per unit fresh weight of the tissue, it cannot act in this way in carrot slices. The activation of the oxidative pentose phosphate pathway observed by ap Rees and Beevers is restricted to the first stage of the induced respiration.     

Ethylene-induced Isocoumarin Formation in Carrot Root Tissue

The concentrations of 3-methyl-6-methoxy-8-hydroxy-3,4-dihydroisocoumarin (MMHD) formed in carrot roots inoculated with certain fungi or treated with indole-3-acetic acid, 2,4-dichlorophenoxyacetic acid, or 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), were related to the amount of ethylene produced by the root tissue. Ethylene applied exogenously in concentrations above 0.3 ppm induced the formation of MMHD in carrot root discs. Continued production of MMHD required the continued presence of ethylene. The amounts of MMHD in the discs were reduced by CO₂, an inhibitor of ethylene action, and by reduction of the partial pressure of ethylene in fungus-inoculated or 2,4,5-T-treated carrot root discs. The results indicate that ethylene is required for the induction of MMHD formation by carrot root tissue.     

Absorption of Potassium and Sodium Ions by Carrot Root Tissue Cultures

The absorption of potassium and sodium ions by cultured explantsof young secondary phloem of carrot has been examined. Muchsmaller differences were observed between slowly growing andrapidly growing tissues than in the work of Steward and Millar(1954). This discrepancy is attributed to the use by Stewardand Millar of media of dissimilar mineral salts compositionto grow the two types of tissue. At first, potassium uptake per unit of fresh weight proceededmore rapidly in the actively proliferating cultures than theslowly growing ones, but these ultimately had the greater capacityfor potassium absorption. The rapidly growing cultures showeda higher selectivity towards potassium vis-à-vis sodiumions than did those growing slowly. The effect was evident throughouta culture period of 5 weeks, but was most marked during theearly stages of growth. Some possible explanations of theseobservations are discussed.     

Effects of Chloramphenicol on the Uptake and Incorporation of Amino-acids by Carrot Root Tissue

The uptake of uniformly labelled L-glutamic acid-¹⁴C, glycine-¹⁴C,and L-proline-¹⁴C by carrot root tissue is inhibited by chloramphenicolat a concentration of 2 g./l. L-glutamic acid absorption isaffected to a much greater extent than is the uptake of theother two amino-acids. It is shown that the ¹⁴C from the labelledamino-acids is incorporated into protein of the carrot slices,and that the amount of incorporation from glycine and L-prolineis about six times as large as that from L-glutamic acid undercomparable conditions. Almost all the ¹⁴C detected in the proteinafter feeding labelled L-proline or glycine remains in the amino-acidsupplied; in the case of L-glutamic acid some of the label istransferred to other amino-acid residues, but most of it remainsin glutamic acid. Chloramphenicol is found to inhibit ¹⁴C-incorporationfrom L-proline and glycine in short-term, but not in long-term,experiments whereas incorporation from L-glutamic acid is inhibitedin both long- and short-term experiments. Chloramphenicol alsoinhibits incorporation of ¹⁴C from L-glutamic acid into proteinsof preparations of isolated subcellular particles from carrotroot tissue. Under some conditions, ¹⁴C incorporation into proteinproceeds for some time after the slices have been removed fromthe radioactive solution. Such incorporation is not inhibitedsignificantly by chloramphenicol when ¹⁴C-labelled L-prolineis supplied, but it is reduced by about 50 per cent. when glycineand L-glutamic acid are used. It is shown that chloramphenicolinhibits net protein synthesis in carrot root slices suspendedin aerated solutions. It is concluded that amino-acid incorporationinto the protein of carrot slices proceeds by at least two mechanisms,one of which is related to protein synthesis and is sensitiveto chloramphenicol and the other is unrelated to protein synthesisand insensitive to the drug. Most of the L-proline and glycineincorporation into carrot root tissue protein seems to occurby the chloramphenicol-insensitive mechanism while much of theL-glutamic acid-¹⁴C incorporation seems to take place by thechloramphenicol-sensitive one.     

胡萝卜组织培养和高效遗传转化体系的建立

为了建立高效的胡萝卜遗传转化体系,本实验选用3个胡萝卜(Daucuscarotavar.sativa)栽培品种:‘金笋五寸’、‘Carol’和‘改良黑田七寸’,以它们的下胚轴和子叶为外植体,首先建立了高频愈伤诱导体系。在此基础上,以Carol的下胚轴和愈伤组织为受体材料,利用根癌农杆菌LBA4404介导转化质粒pBI121。经X-Gluc染色,证明GUS基因瞬间表达成功,经PCR方法鉴定,证明GUS基因已整合到胡萝卜的染色体中,从而建立了高效的胡萝卜遗传转化体系。     

Endogenous Elicitor Activity from Damaged Carrot Root Tissue and Induced Resistance to Botrytis cinerea

A peptide-containing fraction (mol. wt. c 5000 Da) extractedfrom carrot root tissues damaged by slicing or freeze-thawing,induced active defence mechanisms in carrot slices against Botrytiscinerea. Endogenous elicitor activity was present in homogenatesof fresh and freeze-thawed tissues and those treated with germinationfluid, but was absent in autoclaved tissue. The detection ofthe elicitor in homogenates within 2h of treatment, suggeststhat it is released or activated during the early stages ofcell damage. Botrytis cinerea, carrot, induced resistance, endogenous elicitor     

The Influence of External Concentration on Sodium Ion Absorption by Carrot Root Tissue 4

The influence of external concentration on sodium ion absorptionby slowly and rapidly growing carrot root tissue cultures hasbeen examined. In conflict with the observations of Stewardand Millar (1954) it is observed that absorption by the twokinds of cultures is affected similarly by external concentration.The discrepancy between the two investigations is discussedand an alternative interpretation of the results of Stewardand Millar is proposed.     

Physiological Changes of Carrot Cells in Suspension Culture during Growth and Senescence

Changes in the synthetic activities of nucleic acids and protein and in the amount of adenine nucleotides in Daucus carota cells have been examined during a period of rapid cell division and during the stationary phase. Cell growth and the syntheses of those macromolecules in the logarithmic phase were significantly enhanced by increasing the concentration of phosphate in the medium. In a phosphate-rich medium, RNA and protein rapidly degraded and the number of cells with denatured cytoplasm increased when the culture entered into a stationary phase because of exhaustion of glucose. On the other hand, when the growth ceased by exhaustions of phosphate and nitrogen, the cells slowly underwent physiological changes leading to cellular senescence. The value of adenylate energy charge during the growth period was about 0.8–0.9 irrespective of the growth rate. After cessation of growth the value declined to about 0.5.     

苹果无融合生殖矮生砧木的组织培养

1植物名称苹果属创新无融合生殖矮生砧木资源,即"扎矮山定子"(Malus baccata)与平邑甜茶(M.hupehensis)杂交后代优系93-10和93-24.     

Effects of Cyanide on Respiration, Growth, and Potassium Absorption by Carrot Root Tissue 4

Slowly and rapidly growing carrot root tissue cultures havebeen found to be similarly sensitive to inhibition by cyanideat 10^-4 M in respect of respiration, growth, and potassium absorption.These observations conflict with those of Steward and Millar(1954), who reported that the actively proliferating cultureswere strikingly insensitive to the inhibitor at this level.It is suggested that the failure of these authors to detectany effects of cyanide on their cultures was due to the dilutionof the inhibitor by evaporation.     

铁皮石斛组织培养及试管苗营养器官和原球茎的结构观察

以铁皮石斛的茎尖为外植体,诱导产生原球茎,进一步培养形成幼苗.结果表明:原球茎诱导以1/2 M S+6-BA 0.3 m g.L-1+KT 0.1 m g.L-1+LH 1.0 g.L-1为最优,而生根培养以M S+NAA 0.05 m g.L-1+KT0.1 m g.L-1+叶酸2.0 m g.L-1+L a稀土10 m g.L-1为佳.对铁皮石斛试管苗营养器官及原球茎的解剖学研究表明,根由复表皮、皮层和维管柱组成,皮层发达,初生木质部五原型,中央具髓;茎由表皮、基本组织和散生维管束构成;叶为等面叶,在上下表皮处分布有厚壁组织;原球茎是由顶端分生组织后面的薄壁细胞脱分化形成胚性细胞经球状胚发育而来.     

Glycosidases in Carrot Cells in Suspension Culture: Localization and Activity Change during Growth

Localization of four glycosidases, -galactosidase (-Gal), ß-galactosidase(ß-Gal), -glucosidase (-Glu) and ß-glucosidase(ß-Glu) in suspension-cultured carrot cells was studied.Wall-bound enzymes were made soluble when the cells were convertedto protoplasts by cellulase and pectinase. -Gal was separatedinto two forms, designated I and II, by chromatography on aSephadex G-200 colunm. -Gal I was located exclusively in thecytoplasm whereas -Gal II was found in both the cytoplasmicand cellwall fractions. The pH optimum was in the neutral regionfor -Gal I and in the acidic region for the other glycosidases,including -Gal II. Both intact cells and protoplasts in suspensionculture secreted these glycosidases, except -Gal I, into themedium. Specific activities of the glycosidases, especiallythe activity of ß-Gal, decreased in the early logarithmicgrowth phase and increased as cells went through late logarithmicand stationary phases. In protoplast culture, glycosidase activitygradually increased as cell wall regeneration proceeded. (Received December 13, 1980; Accepted February 10, 1981)     

唐菖蒲花色突变株开花后子房组织培养与植株再生的研究

以唐菖蒲花色突变株开花后的子房为外植体,接种于MS+1.0mg/L BA+0.01-0.1mg/L NAA或MS+1.0mg/LBA+1.0mg/L KT+0.01-0.1mg/LNAA的培养基中,从膨大的组织表面直接诱导不定芽.膨大的组织或带不定芽的组织每隔周转入1/2MS_1.0mg/L BA+0.01-0.1mg/L ANN培养基中,不断地诱导产生不定芽,分化的不定芽转入不含激素的1/2MS培养基中,形成幼苗、然后生根,最后可形成小球茎.幼苗转入1/2MS+0.1mg/L NAA培养基中,幼苗生根,再可形成小球茎.1个唐葛蒲突变株子房,经6—7个月培养,获得了上千株试管苗.     

濒危植物盐桦离体组织培养特性的研究

目的:探讨新疆濒危植物盐桦离体组织培养的特性。方法:从盐桦原生地阿尔泰阿拉哈克盐湖边采摘盐桦休眠实生苗上的落叶枝条,待其萌发后分别取带芽嫩茎、嫩茎茎段及嫩叶芽尖三种不同材料接种于启动培养基,比较三种盐桦离体组织的诱导分化,继而设计不同激素、不同水平的单因子试验和正交试验,筛选适宜盐桦外植体芽增殖和生根的分化培养基。结果:诱导盐桦芽增殖的最佳外植体是带芽嫩茎,盐桦外植体增殖、壮苗最适培养基为:MS 6-BA 1.0mg/L IBA 0.5mg/L;盐桦外植体生根最适培养基为:1/2MS IBA 0.5mg/L 蔗糖30g/L 琼脂7% 暗光处理3d。结论:本研究筛选获得适宜盐桦芽增殖和生根的最佳培养条件,为高效扩繁和保存盐桦种质资源奠定了基础。     

芍药组织培养中污染现象的克服

针对芍药在组织培养过程中外植体污染难于控制的问题进行了研究。试验分别于不同的季节取材后对外植体进行不同的表面消毒处理。结果表明：以芍药带芽茎段、顶芽、侧芽为外植体,采用0.1%~0.2% HgCl2消毒8 min,结合母株黄化处理、4℃消毒液+搅拌的表面消毒处理,可降低外植体初期培养污染率;在培养基中添加抗菌素,可明显控制内生菌的污染。     

Repression of Staphylococcus aureus in Associative Culture

The growth of Staphylococcus aureus MF 31 was suppressed when grown in association with Streptococcus diacetilactis and other lactic streptococci. The data indicated that the initial proportion of staphylococci present in the medium was of less importance than the depletion of vital nutrients. Investigation revealed that factors present in Yeast Nitrogen Base medium could reverse the inhibition which was due to antagonism. The major factor found was nicotinamide, and further study revealed that the biological availability of this compound was influenced by the pH of the medium. The addition of nicotinamide to depleted media with careful control of the pH resulted in increased growth of S. aureus in the test system. Further data indicated that additional factors may affect the degree of growth by S. aureus in depleted media.