Biochemical changes in primary wheat leaves during growth and senescence

Changes in the different forms of the total activity of peroxidases (soluble, ionically and covalently bound), in the soluble isoperoxidase composition, and in the content of protein and chlorophyll during growth and senescence of the intact primary leaves of spring wheat were studied. The forms of peroxidases are in inverse relationship to the growth and increase during development and senescence, especially towards the end of senescence. The activity of peroxidases does not follow the physiological age of wheat leaves during the whole period of vegetation unlike the contents of protein and chlorophyll. The intensity of anodic and cathodic peroxidase isoenzyme bands 1 and 5 increases during senescence, but anodic bands number 2 and 4, cathodic bands 2 and 3 decrease. Changes in the activity of peroxidases and in the content of protein and chlorophyll as indicators of senescence are discussed.     

“艾西丝”南瓜诱导生根过程中过氧化物酶活性及同工酶的研究

以“艾西丝”南瓜组培苗为材料,研究其在诱导不定根形成过程中过氧化物酶活性及同工酶谱的变化。结果表明,当南瓜无根苗从含有较高浓度的ＢＡ培养基转入１／２ＭＳ培养基后,可诱导无根苗茎基部不定根生成,一般在转入生根培养基第３ｄ开始生根,至第６ｄ生根率达７０％以上。在此期间,南瓜茎内过氧化物酶活性由低增高,即在不定根形成之前,过氧化物酶活性处在较低水平,而当不定根形成时,过氧化物酶活性迅速升高,以后一直维持     

AMD与CHM对伊贝母茎段鳞茎发生及过氧化物酶同工酶的影响

伊贝母黄化茎段培养在含有NAA 0.5 mg/1 6BA 0.2 mg/l的MS培养基上。鳞茎发生过程中过氧化物酶活性及同工酶带逐渐增加。AMD和CHM都抑制鳞茎的发生,茎段培养后最初12 h对AMD最为敏感,以后敏感程度逐渐减弱,茎段对CHM的敏感程度更强,敏感时期亦更长。茎段培养后过氧化物酶活性和同工酶的出现和增加受到CHM的抑制,而不受AMD的抑制。     

Peroxidase Activity and Isoperoxidase Pattern in Tobacco Leaves Infected with Tobacco Necrosis Virus and Other Viruses Inducing Necrotic and Non-Necrotic Alterations

The level of peroxidase activity was greatly enhanced in tobacco leaves infected by tobacco necrosis virus (TNV) and other viruses which induce necrotic symptoms (TMV, ToMV and PVY^N). The intensity was related to the age of the leaves infected: absent or neglible in mature leaves and very pronounced in young growing infected leaves. On the contrary, changes in peroxidase activity were negligible when the infection was provoked by viruses which do not produce necrotic reactions (TMV and PVY^O). Analysis of the peroxidase isoenzymes, pattern in tobacco leaves infected by TNV and other necrosis-inducing viruses revealed in all cases, a slight increase in anionic (pl 3.5–3.7) and a considerable increase in moderately anionic isoenzymes particularly the pl 4.6 isoenzyme which in TNV and PVY^N-infected leaves reached levels up to 21 and 72 times the healthy control values. A considerable increase in the cationic (pl9.3–8.8) isoenzymes and the appearance of one moderately cationic isoenzyme (pl 8.2) was also detected. In leaf extracts from-virus-infected tobacco leaves with nonnecrotic response, no, or negligible alterations on the isoenzyme pattern were detected. However, infection by a fungal parasite (Erisyphe cichoracearum), which established a fully compatible, non-necrotic, interaction with tobacco leaves, like the necrosis-inducing viruses, changed the isoperoxidase pattern. The data suggest the necrotic alterations and associated changes in the peroxidase activity and isoperoxidase pattern in virus-infected leaves are not clearly related.     

Changes in chloroplast peroxidase activities in relation to chlorophyll loss in barley leaf segments

Total peroxidase activity increased during senescence of excised barley ( Hordeum vulgare L. cv. Kashimamugi) leaves. Kinetin treatment furter increased total peroxidase activity but repressed chlorophyll degradation in excised barley leaves. When isoperoxidases were extracted from barley leaf segments. 4 cationic and 4 anionic isozymes were found in polyacrylamide gel electrophorests during leaf senescence. The chloroplasts contained only two cationic isoperoxidase activities. One (designated C4) was repressed by kinetin. and the other (C3) was increased by kinetin. Glucosamine, which also repressed the degradation of chlorophyll, completely repressed C4 activity but did not affect C3 activity. The induction with senescence, and the repression with kinetin and glucosamine, suggest chat chloroplast isoperoxidase C4 may function as a chlorophyll-degrading enzyme during barley leaf senescence.     

河南木兰属9种植物过氧化物同工酶分析

本文采用聚丙烯酰胺凝胶电泳系统,测定了河南木兰属8种、1变种50多份的成熟叶片材料的过氧化物同工酶酶谱。测定结果表明,该属植物9种、变种的酶谱均有差异性,每种、变种均有特征酶谱,种间酶谱显著大于种内酶谱,根据其酶谱差异性,可以进行生物种、变种的鉴别和良种的选择。为免除其酶带Rf单一指标,鉴别生物种、变种可能出现的问题,作者创立了"酶谱多指标综合判断距离法"分析技术,首次将该属植物种、变种酶谱的酶带数目、Rf、酶带宽度及其活性强弱4个因子的差异性,进行编码联机、电脑运算分析,其结果与该属玉兰亚属内的玉兰派和辛夷派的形态分类相吻合。但是,从酶学观点不支持椭圆叶玉兰作为独立种的存在,以作为河南玉兰的变种为宜,也不支持河南玉兰派和腋花玉兰派的成立,以并入辛夷派为佳。     

九连小檗悬浮培养细胞生理生化特性的研究——Ⅱ.干物质积累与过氧化物酶同工酶和蛋白质的变化

本文报道了九连小檗细胞悬浮培养过程干物质积累与过氧化物酶同工酶和可溶性蛋白质的变化。实验表明在悬浮培养过程中细胞干物质积累可分为四个时期,即延迟期、缓慢增重期、线性增重期和减慢静止期。过氧化物酶同工酶谱的变化与干物质积累相关,在延迟期和减慢静止期的同工酶谱带较少,活力较低,在增重期的同工酶谱带较多,活力较高。蛋白质含量在接种后的第2至5天达到高峰,随后便逐渐降低,这些大分子的变化是在一定条件下基因表达的引发或阻抑的结果。     

The isoperoxidase pattern changes and the pigment changes of pedilanthus tithymaloides L. Variegatus calli as a result of sucrose concentration and phytoregulator content of the culture medium and daily temperature differences

In vitro, stem slices growing in calli exhibited the same pigment changes as the previously described ones with developing leaves. These changes were controlled by daily temperature differences, but they were also modulated by the sugar type or the sucrose concentration of the culture medium. The electrophoretic isoperoxidase patterns of the calli showed quantitative and qualitative changes during pigment evolution. Each of the three peroxidasic band groups which was correlated in situ with a characteristic pigment expression in the leaves was also correlated in vitro with a similar pigmentation in the calli. Calli cultured on media supplemented only with naphtalene-acetic acid as phytoregulator exhibited a brown pigmentation and produced the fast migrating isoperoxidase group. Calli grown in the presence of 6-benzylaminopurine only had no pigmentation and expressed the slow migrating isoperoxidase group. The calli grown without any phytoregulator were green coloured and expressed the medium migrating isoperoxidase group.     

Peroxidase activity and isoenzyme patterns in wheat during ontogenesis

Protein content, total and specific peroxidase activity and isoperoxidase patterns were determined in crude protein preparations from individual parts of field-grown wheat (Triticum aestivum L., cv. Jubilar). Protein content in roots, leaves, and stalks increased at the beginning of ontogenesis and then decreased from 6th, 9th, and 10th development phase (according to Feekes), respectively. Steady increase of the protein content in the ears was observed. Highest peroxidase activity was found in the roots; it diminished from the onset of ontogenesis till maturity of the plants. In the leaves and stalks a slight decrease of peroxidase activity till the 10th development phase and then an increase till maturity was found. The ears exhibited a gradual increase of peroxidase activity. The course of specific peroxidase activity was found to be very similar to that of total activity. Isoperoxidase patterns did not change significantly. In the leaves, a decrease of activity of C₄ and C₅ isoperoxidases was recorded. In the stalks, C l isoenzyme emerged at the end of ontogenesis. A gradual increase of A₁ and A₅ isoperoxidase intensity took place both in the leaves and stalks.     

Effect of Tobacco Mosaic Virus Infection on Amino Acid Incorporation into Isolated Mitochondria from Tobacco Leaves

Mitochondria isolated from tobacco leaves incorporated ¹⁴C-leucine into the protein and the rate was enhanced by tobacco mosaic virus (TMV) infection as compared with noninfected level. In vitro amino acid incorporation by mitochondria required adenosine triphosphate (ATP), Mg²⁺, and KC1 and the energy sources from oxidative phosphorylation as well as from ATP-generating system. This incorporation was inhibited by ribonuclease (RNase), deoxyribonuclease (DNase), actinomycin D, mitomycin C, puromycin, and chloramphenicol added in the reaction medium. The pretreatment of the mitochondria with DNase and actinomycin D reduced the rate of incorporation. The mitochondria incorporated ³H-guanosine triphosphate (GTP) and this activity was blocked by actinomycin D. The presence in this system of 15,000 g supernatant cell sap fraction or bacterial contamination was carefully checked obtaining a negative result. The reaction product into which ^l4C-amino acids incorporated was solubilized by trypsin. The nature of the amino acid incorporating activity of isolated mitochondria obtained from TMV-infected tobacco leaves is discussed.     

Comparative analysis of the action of cytokinin and light on the formation of ribulosebisphosphate carboxylase and plastid biogenesis

The role of cytokinin in plastid biogenesis was investigated in etiolated rye leaves (Secale cereale L.) and compared with the effect of white light. Cytokinin deficiency of the leaves was induced by early excision of the seedling roots and reversed by the application of kinetin. The cytokinin supply had a much greater influence on plastid biogenesis than on leaf growth in general. The activities of several chloroplastic enzymes were increased 200%–400% after kinetin treatment of cytokinin-depleted leaves. The activity of ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39) and the amount of fraction-I protein even showed a sevenfold increase. In cytokinin-depleted leaves the development of ribulose-1,5-bisphosphate carboxylase and NADP-glyceraldehydephosphate dehydrogenase was specifically, and markedly inhibited by actinomycin D. The inhibition was partially or even completely overcome after treatment with kinetin. However, under all conditions, RNA synthesis of the leaves, was only partially inhibited by actinomycin D. According to immunologic studies, all dark-grown leaves, in addition to the complete enzyme, contained an excess of free small subunit of ribulose-1,5-bisphosphate carboxylase that was absent in mature light-grown leaves. The most striking accumulation of free small subunit, protein occurred in cytokinin-depleted dark-grown leaves, indicating a deficiency of the plastidic synthesis of the large subunit. The capacity as well as the activity of plastidic protein synthesis was preferentially increased by cytokinin and light. Cytokinin increased, the amount of plastidic ribosomes per leaf and relative to the amount of cytoplasmic ribosomes. While the percentage of cytoplasmic ribosomes bound as polyribosomes was little affected by the cytokinin supply, the proportion of plastidic polyribosomes was increased from 11% to 18% after kinetin treatment of cytokinin-depleted leaves. In the light, the proportion of plastidic polyribosomes reached 39% of the total plastidic ribosomes.Abbreviations RuBP carboxylase ribulose-1,5-bisphosphate carboxylase - NADP-GAP dehydrogenase NADP-dependent glyceraldehyde-3-phosphate dehydrogenase     

Metabolism of barley seed during early hours of germination

The growth process in germinating barley seeds and its inhibition by actinomycin D and puromycin were investigated. Soon after seeds are imbided, their respiratory activity increases several fold, and the protein- and carbohydrate-synthesizing systems become active. The immediate activation of protein synthesis and its inhibition by actinomycin D and puromycin suggest that the dry seed has all the components necessary for protein synthesis.     

多裂骆驼蓬提取物对玉米幼苗生长和细胞保护酶系的影响

以不同浓度的多裂骆驼蓬提取液浸种处理玉米,研究对幼苗生长和细胞保护酶系的影响。结果表明,多裂骆驼蓬提取液浸种处理种子的萌发和种子中α-淀粉酶活性受到明显抑制,抑制作用随处理浓度提高而增强,随培养时间延长而减弱。随着培养时间的延长,浸种处理可显著提高幼苗根系活力和叶片硝酸还原酶活性,促进植株生长,根和茎叶生长量增加,根冠比增大。多裂骆驼蓬提取液浸种后显著降低叶片过氧化氢酶(CAT)、抗坏血酸氧化酶(ACO)活性,提高过氧化物酶(POD)活性,促进根系和叶片过氧化物同工酶谱的数量表达。     

Changes in phenol content and peroxidase activity during in vitro organogenesis in Xanthosoma sagittifolium L.

Direct plant regeneration, multiple shoot formation and callogenesis were induced from cocoyam shoot tips cultured in vitro. At different stages of culture, phenol content, peroxidase activity and acidic soluble isoperoxidase patterns were analysed in plantlets. Results showed that phenol content of plantlets cultured on auxin-free media decreased with time, while it increased in those cultured on media supplemented with an auxin. Each form of morphogenesis induced with a growth regulator was preceded by an increase in total peroxidase activity. On hormone-free medium, organogenesis occurred (single shoot development and rhizogenesis), but there was no increase in total peroxidase activity. The appearance of isoperoxidase A2 was associated with root initiation, while the disappearance of isoperoxidase A5 and the appearance of isoperoxidase A6 preceded multiple shoot formation. These results indicate that total peroxidase activity was not a proper marker for organogenesis in cocoyam. Each form of morphogenetic differentiation is associated with an alteration of the acidic isoperoxidase pattern. These enzymes can be used as biochemical markers for rooting and multiple shoot initiation in cocoyam.     

Peroxidase Isoenzymes in Development of Tall and Dwarf Cultivars of Rice

Four cultivars of rice, Hansraj (tall), Jamuna, Padma and Sabarmati(all dwarf) were analysed for variation in isoperoxidase patternsduring development by horizontal starch-gell electrophoresis.The samples were taken at weekly intervals, starting with soakedseeds (12 h) until the post panicle stage. There is a distinctpattern of peroxidase isoenzymes in the tall and dwarf cultivarsstudied. Some isoenzymes appear at a particular developmentalstage while others disappear while some remain fairly constantonce they are activated. Hansraj showed more qualitative fluctuationsin peroxidase than did the three dwarf varieties. A few isoperoxidaseswere specific to some varieties such as bands A₃ and A₇ forHansraj and band A₄ for Sabarmati. These specific bands of peroxidasemay have some role to play in development of Hansraj (tall)and Sabarmati (with aroma). Besides this, greater fluctuationsin peroxidase activity in the tall variety may be due to loosecontrol in the regulation of peroxidase activity. The significanceof controlling elements of enzyme activity is discussed.     

Biochemical differences in Cannabis sativa L. depending on sexual phenotype

Hemp (Cannabis sativa L.) is a species considered as having one of the most complicated mechanisms of sex determination. Peroxidase and esterase isoenzymes in leaves of the two sexual phenotypes of hemp were studied. Significant differences in isoperoxidase and isoesterase patterns were found between male and female plants, both in the number and stain intensity of bands. For both esterase and peroxidase, the isoenzymatic spectrum is richer for staminate plants. Also, some differences are obvious between the two sexes concerning catalase and peroxidase activities, as well as the level of soluble protein. The quantitative analysis of flavones, polyholozides and polyphenols emphasized differences depending not only on sex, but also on tested organ.     

The O-diphenol-oxygen-oxidoreductase of Agaricus bisporus: Activity and multiple forms during ageing

Mushroom o-diphenol oxidase was separated into multiple forms by isoelectric focusing. Three major bands, as opposed to the four isoenzymes previously found, were separated over the pH range 3.5–9.5. A fourth form was obtained when the pH range was narrowed to 5.0–8.0. Changes in the enzyme activity were investigated during post-harvest ageing at different temperatures. Rapid ageing using tissue discs with or without inhibitors of protein synthesis showed that an increase in activity of the enzyme took place during this time, but was prevented by actinomycin D and 6 methyl purine.     

Peroxidase and α-Amylase Activities in Relation to Germination of Dormant and Nondormant Wheat

Germination capacity, and α-amylase production in relation to the peroxidase and isoperoxidase activities in the grains of three varieties of wheat have been analysed and compared. A high percentage of germination and α-amylase producation at 25°C are associated with low peroxidase activity of the isolated embryo. This correlation is lacking when the intact grain is considered. A 2-day treatment at 4°C which further increases the percentage germination and enhances α-amylase synthesis, lowers the activity of peroxidase in the embryos. A general decrease in activity of all the isoenzymes is observed. Based on the above data and on differences in the activity of the most cathodic isoperoxidasic bands, a hypothesis is put forward which suggests that a sufficiently low peroxidase activity and a minimum auxin level of the embryo are responsible for the onset of germination.