表油菜素内酯对黄瓜幼苗下胚轴过氧化物酶和IAA氧化酶活性的影响

黄瓜幼苗用0.1～1 ppm表油菜素内酯(epiBR)处理1～3d后,下胚轴中过氧化物酶活性明显低于对照;随着处理浓度的增加和处理时间的延长,与对照之间的差别愈趋增大。当浓度高于1ppm时,过氧化物酶的活性不再继续降低。表油菜素内醋对过氧化物酶活性的这种抑制作用需经约1O h的滞后期。IAA氧化酶的活性变化与过氧化物酶相似,epiBR处理时间愈长酶活性增加愈趋缓慢。 经IAA处理的下胚轴,过氧化物酶和IAA氧化酶的活性变化与对照无明显差异。这提示油菜素内酯与IAA促进生长可能是通过不同的作用方式。     

Changes in IAA,Phenolic Compounds,Peroxidase, IAA Oxidase,and Polyphenol Oxidase in Relation to Flower Formation in Crocus sativus

Changes in levels of IAA, phenolic compounds, peroxidase, polyphenol oxidase, and IAA oxidase activities in the corm and the apical bud of Crocus sativusL. during bud growth and development, with special emphasis on the flowering stage, were studied. In the bud, flower formation was accompanied by enhanced activities of peroxidase, polyphenol oxidase, IAA oxidase, and higher contents of phenolic compounds as well as lower levels of IAA. In the corm, during the flower formation, these enzymes showed an opposite behavior. Moreover, the contents of phenolics and IAA in the corm tissues during flower formation and growth were higher than at the other developmental stages. It may be concluded that the transition of saffron plants to flowering is correlated with peroxidase, polyphenol oxidase, and IAA oxidase. Furthermore, these enzymes might exert their roles in the regulation of flowering through their participation in IAA catabolism. The hypothesis of regulation of bud development by an interaction between phenolics and the enzymes involved in IAA catabolism is discussed.     

The Control of Sex Expression in Cucurbits by Ethephon

Application of ethephon to field-grown plants of both bush andtrailing forms of Cucurbita maxima and C. pepo caused leaf epinasty,suppression of male flowers and earlier production and increasein numbers of female flowers. This gave rise to an increasein the ratio of female to male flowers per plant and a decreasein the total number of flowers. Observations of C. pepo showed that even at the two true leafstage there are several nodes present in the unexpanded shoot.Each node has one main and several secondary buds. The sex ofthe main bud at the first five to six nodes is usually determinedat this stage but the secondary buds still have bisexual potential.The change in sex expression was brought about by all male flowerbuds that had formed by the spraying time aborting, and allbuds that developed (both main and secondary) for at least 7days after spraying became female flowers. Thus, nodes fiveand six had male flowers in the controls, whereas in ethephon-sprayedplants the presumptive male flowers aborted at the bud stageat these nodes and secondary primordia developed into functionalfemale flowers. Cucurbita maxima, Cucurbita pepo, sex expression, ethephon, ethylene, flower abortion, flower differentiation     

水分胁迫下荔枝叶片过氧化物酶和IAA氧化酶活性的变化

以适应山地栽培的抗旱性较强的东刘1号和适应河边栽培的抗旱性较弱的陈紫2年生荔枝（Litchi chinensis Sonn.)实生苗为试验材料,研究了水分胁迫下叶片细胞胞质,与（细胞）壁以离子键结合和壁以共价键结合的过氧化的酶（POD）和IAA氧化酶活性的变化。结果表明：在叶片中POD主要是以与壁以离子键结合的POD存在,占总活性的51．15％－52．15％,其次是细胞胞质POD,占44．20％－44．74％,与壁以共价键结合的POD活性最低,仅占3．44％－3．65％。与POD不同,IAA氧化酶绝大多数存在于细胞胞质中,占总活性的88．93％－89．29％,其次是少量的与壁以离子键结合的IAA氧化酶,占7．32％－7．63％,与壁以共价键结合的IAA氧化酶活性最低,仅占3．39％－3．44％;2个品种间差异不明显。水分胁迫下,叶片细胞胞质以及与壁以离子键和壁以共价键结合的POD和IAA氧化酶（比）活性均上升,抗旱笥较强的品种上升的幅度均大于抗旱性较弱的品种。     

Levels of IAA, Cytokinins, ABA and Ethylene in Rice Plants as Affected by a Gibberellin Biosynthesis Inhibitor, Uniconazole-P.

Effects of uniconazole-P, a triazole-type growth retardant,on endogenous levels of IAA, cytokinins, ABA and ethylene inrice seedlings were investigated. Endogenous levels of IAA andABA were similar between control and uniconazole-P-treated riceshoots. Evolution of ethylene was promoted slightly, being 1.8times greater under 0.3 ppm uniconazole-P treatment than thatof control. The most obvious effect was the increase of trans-Zand trans-RZ in shoots. Shoots treated with uniconazole-P (10mg/m² nursery box) contained 3.4 times and 3 times more trans-Zand trans-RZ than control, respectively. No significant differencesof cytokinin levels were recognized in roots except for cis-RZ.The increase of ethylene and active forms of cytokinins, andthe decrease of gibberellin in the shoots may be the basis forphysiological phenomena caused by uniconazole-P, namely thepromotion of flowering in woody plants and the enhancement offemaleness in cucumber. (Received September 9, 1987; Accepted October 20, 1987)     

黄瓜性别决定相关基因和性别表达机制

介绍黄瓜的性别决定相关基因,黄瓜性别决定的假说和性别决定的分子机制的研究进展.     

水分胁迫对棉花叶片中IAA从含量、IAA氧化酶和过氧化物酶活性的影响

整株干旱降低盐棉46号叶片中的IAA总量,叶龄愈小下降愈多。幼叶中IAA总量的下降主要是结合态IAA减少的结果。气干和-1.7MPa PEG溶液渗透胁迫处理也降低离体成熟叶片的IAA总量,其变化与叶片含水量呈直线相关(r=0.905)。整株干旱处理提高各叶片的过氧化物酶活性,叶龄愈小提高愈多,但IAA氧化酶活性无显著变化。离体和整株干旱时IAA总量的下降,可能是过氧化物酶活性增加所致。     

试管棉纤维发育中IAA氧化酶和POD活性的变化(简报)

试管棉纤维发育过程中,ＩＡＡ氧化酶和过氧化物酶的离子型与壁结合的酶活性和纤维细胞的伸长呈负相关,可溶性酶的活性总趋势和离子型的一致。     

Pathways of IAA Production from Tryptophan by Plants and by Tbeir Epipbytic Bacteria: a Comparison: I. IAA Formation by Sterile Pea Sections in vivo as Inftuenced by IAA Oxidase Inbibitors and by Transaminase Coenzyme

Under nonsterile conditions, IAA can be extracted from pea stem sections infiltrated with buffer, IAA, or tryptophan. This IAA has microbial origin, since its occurrence is prevented by antibiotics. All infiltrated IAA disappears in the sections. Under sterile conditions, several inhibitors of IAA oxidase prevent the complete disappearance of infiltrated IAA. Some of them permit, by preventing the disappearance of produced IAA, the formation in vivo of extractable IAA amounts from tryptophan. This IAA production is further increased by pyridoxal (phospbate), and by α-ketoglutarate.     

Levels of Indol-3yl-acetic acid (IAA), IAA-oxidase and Peroxidase in Developing Cucumber Seedlings

The level of indol-3yl-acetic acid (IAA) in the cotyledons of cucumber seedlings increases in the period 4 to 11 days after germination. In hypocotyls and roots the IAA level decreases. IAA-oxidase activity of homogenates of cotyledons, hypocotyls and roots decreases with age. The soluble fraction of all three organs contains an IAA-oxidase, which may be allosteric. It is suggested that this IAA oxidase limits the upper level of IAA in the cell. The cell wall fraction of the three organs contains IAA-oxidases with conventional kinetics. The function of this IAA oxidase is probably to degrade exogenous IAA.     

Potassium Transport in Non-Growing Corn Root Tissue as Affected by IAA and GA3

Experiments were done to determine if the spontaneous recoveryof non-growing segments of corn root (Zea mays L.) from excisioninjury is dependent on auxin. Washing the segments with 5 runindoleacetic acid (IAA) for 2 to 4 hours gave a small but significantincrease in K⁺ (⁸⁶Rb) influx, used here as a parameter reflectingrecovery of electrogenie H⁺-efflux pumping. This promotive effectwas obtained only after an hour of washing, and was sustainedby 100 nm gibberellic acid (GA₃). Any early responses to auxinwere obscured by an adverse reaction of the root cells to externalIAA which resulted in a transitory inhibition of H⁺ pumpingand K⁺ influx. Pretreatment of excised root tips with 10 µM IAA in thegrinding medium protected a plasmalemma-enriched fraction ofthe microsomes during isolation, giving increased uncoupler-sensitiveATPase activity. Non-growing root tissue thus shows three responses to auxin:an adverse reaction at the outer surface of the plasmalemmawhich blocks H⁺ pumping; a protective or restorative effecton the H⁺-ATPase; an increased capacity for K⁺ influx duringthe developmental phase of washing, which is augmented by thepresence of GA₃. (Received March 31, 1986; Accepted September 8, 1986)     

Peroxidase Ontogeny in a Dwarf Pea Stem as Affected by Gibberellin and Decapitation

The ontogeny of peroxidase activity and isoenzyme pattern wasinvestigated in the stem of dwarf pea plants. Peroxidase activityper unit soluble protein was a given internode is highest inthe youngest growth stage, drops during elongation, remainsconstant upon cessation of growth, and increase at senescence.The lower the internode on the stem the higher is its peroxidaseactivity. These developmental differences are already apparentat the youngest growth stage of the internodes adn increaseduring elongation. Several anodic and five cathodic isoperoxidasesare apparent after starch gel electrophoresis. This patternis constant for all internodes at all growth stages, but therelative importance of particular isoenzymes changes with time. Gibberellic acid (GA₃) treatment causes greatly elongated internodes,decreased soluble protein, and inhibition of the rise in peroxidaseactivity within 4–8 h. Application of GA₃ to young internodesleads to a persistent depression in peroxidase activity, whiletreated older internodes suffer only a temporary depression.GA₃ causes no qualitative changes in the isoenzyme pattern butproduces some quantitative alterations in internodes in whichits influence on peroxidase activity is persistent. Decapitation of untreated and GA₃-treated dwarfs has littleinfluence on internode elongation, causes an increase in peroxidaseactivity, especially in the upper internodes, and alters therelative activity of particular isoenzymes. By contrast, decapitationinhibits elongation of young internodes in genetically tallpea plants.     

Changes in Phenolics, Polyphenol Oxidase and its Isoenzyme Patterns in Relation to Resistance in Taro against Phytophthora colocasiae

The effect of Phytophthora leaf blight disease, caused by Phytophthora colocasiae Raciborski, on the accumulation of phenolics and polyphenol oxidase (PPO) activity in ex vitro plants was studied in three resistant (DP‐25, Duradim and Jhankri) and one susceptible (N‐118) genotypes of taro [Colocasia esculenta (L). Schott]. The inoculation of taro leaves with P. colocasiae spores resulted in a quantitative change in both biochemical parameters and induction of PPO isoforms in resistant genotypes. The amount of phenolics was increased owing to blight by 68.02%, 58.87%, 52.67% and 11.50% in DP‐25, Duradim, Jhankri and N‐118, respectively. The per cent increase in PPO under stress over non‐stress condition was also highest in DP‐25 (49.14%) followed by Duradim (41.56%), Jhankri (40.55%) and N‐118 (17.08%). The resistant genotypes showed higher activity of PPO as compared with susceptible ones, which was reflected through its banding pattern in isoenzyme analysis, detecting four different isoforms. The intensity of the bands was higher in the resistant genotypes than in susceptible N‐118. The appearance of high intensity bands and/or reduction in the intensity of particular isoform(s) in the zymograms of all the three resistant taro genotypes studied, led to the apparent conclusion of linking PPO isoenzyme expression with blight resistance in taro. The blight incidence (per cent leaf infection and leaf area infection) was lower in the resistant genotypes than in susceptible, N‐118. The yield reduction owing to blight was below 20% in DP‐25, Jhankri and Duradim, while the same was more than 40% in N‐118. The phenolics and PPO activity was negatively correlated with disease incidence and yield reduction owing to blight. Based on the results of disease incidence, biochemical contents and yield, the pattern of stress tolerance was DP‐25 > Duradim > Jhankri > N‐118. The studied parameters, i.e. phenolics and PPO could be used as biochemical markers for leaf blight stress tolerance studies in taro.     

Preinoculation with Tobacco Necrosis Virus Enhances Peroxidase Activity and Lignification in Cucumber, as a Resistance Response to Sphaerotheca fuliginea

Abstract Cucumber plants were mechanically inoculated with TNV and challenge-inoculated after 7 days with Sphaerotheca fuliginea. The development of the fungus was followed by light microscopy and the modifications of the host leaf cells were studied by histochemical and cytochemical reactions. Conidial germination was similar in control and TNV-infected plants, and in the following 2 or 3 days S. fuliginea development was also similar. Thereafter in control plants S. fuliginea development progressed steadily and no modifications appeared in the leaf host cells, while in TNV-infected plants strongly autofluorescing papillae were formed, and peroxidase activity was detected in the walls of many epidermal cells of the challenge-inoculated, leaf. Lignification ensued, and fungal growth was strongly inhibited. Protection was obtained provided the number of necrotic lesions was at least 12 per cotyledon, and was elicited even if the TNV-infected leaf was removed 7 days after infection, before challenge inoculation. No protection was induced when the TNV-infected leaf was removed 3 days after infection.     

Peroxide Levels and the Activities of Catalase, Peroxidase, and Indoleacetic Acid Oxidase during and after Chilling Cucumber Seedlings

The activities of catalase, peroxidase, indoleacetic acid (IAA) oxidase and peroxide levels in cucumber plants during and after chilling were determined. During 96 hours at 5 C and 85% relative humidity, catalase activity declined, IAA oxidase activity increased, and peroxide concentrations increased. Peroxidase activity was not affected by chilling. When chilled plants were returned to 25 C to recover, enzyme activities and peroxide concentration were restored to their prechilling levels. The increase in peroxide and IAA oxidase activity may inactivate or destroy IAA and thus retard growth.     

水杨酸、乙酰水杨酸对番茄幼苗叶片中PPO和POD的诱导作用

以番茄品种改良美国908和合作906为试验材料,研究了水杨酸(SA)和乙酰水杨酸(ASA)喷雾处理6-7叶期幼苗后,叶片内多酚氧化酶(PPO)和过氧化物酶(POD)活性在120 h内的变化.结果显示:SA和ASA对2个番茄品种的适宜诱导浓度分别为1 mmol/L和1.39 mmol/L;SA和ASA对PPO活性的诱导效果无显著差异,但对POD活性的诱导效果SA极显著强于ASA;合作906的PPO活性增幅显著大于改良美国908,而POD活性增幅却显著小于改良美国908,且合作906对诱导处理反应更敏感.研究表明,SA和ASA能显著提高番茄幼苗叶片的PPO、POD活性,而酶活性变化在品种和诱导剂间有显著差异.     

Physical Activity Patterns of People Affected by Depressive and Anxiety Disorders as Measured by Accelerometers: A Cross-Sectional Study

Background

Exercise can relieve both depressive and anxiety disorders and it is therefore of importance to establish movement patterns of mildly to moderately affected sufferers to estimate the treatment potential. The aim is to describe the physical activity patterns of people affected by mild to moderate depressive and/or anxiety symptoms using objective measures of physical activity.

Methods

The design of the study was cross-sectional using data from 165 people aged 18–65 years, with mild to moderate depressive and/or anxiety disorder symptoms (scoring ≥10 on the PHQ-9). Diagnoses were made using Mini International Neuropsychiatric Interview (MINI) and symptom severity was measured with the Montgomery-Åsberg Depression Rating Scale (MADRS). The participants wore accelerometers for a week to evaluate physical activity patterns.

Results

No statistically significant differences were detected between different diagnoses, though depressed participants tended to be less active and more sedentary. Only one-fifth of the sample followed public health guidelines regarding physical activity. Each one point increase in MADRS was associated with a 2.4 minute reduction in light physical activity, independent of moderate-to-vigorous physical activity and sedentary time. MADRS was positively associated with number of sedentary bouts.

Conclusions

The physical activity pattern of people with depressive and/or anxiety disorders was characterized by large amounts of sedentary time and low fulfillment of physical activity guidelines. There is therefore a large treatment potential for this group by increasing exercise. The results suggest that instead of focusing exclusively on high intensity exercise for treating depressive and anxiety disorders, health care providers might encourage patients to reduce sedentary time by increasing light physical activity and decreasing the number of sedentary bouts, though further studies are needed that can determine directionality.