摘要:

An analysis of 134 reviews of manuscripts submitted to the North American Editorial Office of Physiologia Plantarum in 1993 compared personal/professional characteristics of the reviewers and the specificity of the interest and experience of the reviewers, relative to the reviewed paper, to the depth and tone of the reviews, the presence of constructive suggestions, and the recommendations for or against publication. There was no significant difference between the reviews from the reviewers of different ranks or degrees of seniority, of different employment sectors, of different degrees of interest and experience in the subject of the paper, or of other subgroups, except that reviewers whose interest and experience were very specific to the topic of the paper tended to give more constructive suggestions, and assistant professors tended to be less accepting of papers than editors more frequently than did reviewers in general. Recommendations regarding a manuscript were more similar than could be accounted for by chance, providing a positive indication of the reliability of the review‐system. Editors in their decisions tended to follow the recommendations of reviewers, but when reviewers took an extreme tone, either positive or negative, the editors tended to provide a balancing function. The data provide support for the reliability and lack of bias in a commonly used peer‐review sys

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1994.tb03021.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The ethylene precursor, 1‐aminocyclopropane‐1‐carboxylic acid (ACC), is actively transported across the tonoplast of plant cells, impacting cellular compartmentation of ACC and ethylene biosynthesis. In the present study, the effects of ACC and amino acid analogs on ACC uptake into isolated maize (Zea maysL. cv. Golden Cross Bantam) mesophyll vacuoles were investigated to identify the stereospecific and structural features that are important in molecular recognition by the ACC transport system. Of the four stereoisomers of l‐amino‐2‐ethylcyclopropane‐l‐carboxylic acid (AEC), (1S,2R)‐(–)‐AEC having a configuration corresponding to an L‐amino acid was the preferred substrate for the ACC transport system, competitively inhibiting ACC transport with a Ki of 18 μM. Of 11 neutral amino acid stereoisomers, L‐isomers were stronger inhibitors of ACC transport than corresponding D‐isomers. Neutral L‐amino acids with nonpolar side chains generally were more inhibitory than those with polar side chains, whereas several cationic and anionic L‐amino acids were ineffective antagonists of ACC transport. These observations suggest that the ACC transport system is stereospecific for relatively nonpolar, neutral L‐amino acids. This conclusion was supported by the observation that group additions, substitutions, or deletions at the carboxyl. α‐amino and the Pro‐ (R) methylene or hydrogen moieties (analogous to D‐amino acids) of ACC and other neutral amino acids and analogs essentially eliminated transport inhibition. In contrast, L‐amino acid analogs with variable substitutions at the distal end of the molecule remained antagonists. The relative activity of analogs was influenced by the length and degree of unsaturation of the side chain and by the location of side chain branching. Increasing the ring size of ACC analogs reduced antagonism whereas incorporating the α‐amino group into the ring structure as an L‐amino acid increased antagonism. The kinetics of L‐methoxyvinylglycine, L‐methionine.p‐nitro‐L‐phenylalanine and 1‐aminocyclobutane‐l‐carboxylic acid were competitive with Ki values of 3, 13, 16 and 19 μM, respectively. These results indicate that the ACC transport system can be classifie as a neutral L‐amino acid carrier having a relatively high affinity for ACC and other nonpolar amino acids. The results also suggest that the carrier interacts with the carboxyl, α‐amino and Pro‐(R) groups and wit

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1994.tb03022.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

EtiolatedVicia fabaseedlings were exposed to continuous red light to investigate whether changes in extracellular peroxidase activity were correlated in time and localization with changes in extension growth and/or lignin content in the subapical region of the epicotyl. Continuous red light: (a) increased extracellular peroxidase activity after a lag of ca 0.5 h, followed by a maximum peak after 2.5 h due to slightly acidic isoforms (pI = 6–6.5, according to isoelectrofocusing gels), a minimum after 4 h and a second maximum after 8 h due to acidic isoforms (pI=4–5), (b) increased lignin content and epicotyl resistance to bending after a lag of ca 4 h, i.e. simultaneously with changes in acidic extracellular peroxidase activity, and (c) reduced extension growth to a stable rate after a lag of ca 1 h, not coinciding with the kinetics of any of the extracellular peroxidase isoforms. These effects of continuous red light were at least partially mediated by phytochrome. Tissue printing and anatomical studies revealed red light effects on extracellular peroxidase activity and lignin content mainly in the outer cortical parenchyma. The results are consistent with the involvement of phyto‐chrome‐mediated effects on extracellular peroxidases (acidic isoforms) in the transduction chain leading to lignin responses to re

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1994.tb03023.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Evacuolated protoplasts, P(–), have been prepared from mesophyll protoplasts. P(+), ofNicotiana tabacumL. (cv. Samsun) by centrifugation in an iso‐osmotic Percoil gradient. In comparative analyses performed with these two types of cells, vacuole proteins should appear in P(+) extracts, but be absent from freshly isolated P(–). Such differences were detectable in total protein extracts after two‐dimensional electrophoresis. Four spots were located that are likely to represent soluble vacuolar proteins. They have low molecular mass (around 20 kDa) and slightly acidic isoelectric points. In culture, evacuolated tobacco protoplasts regenerated a vacuole de novo. The vacuolation process as observed microscopically correlated welt with the reappearance of vacuolar marker enzymes. Likewise, the protein spots that were missing in the P(–)‐pattern immediately after evacuolation reappeared within the first days of protoplast culture. By immunoblotting the same behaviour was demonstrated for the well‐known vacuolar protein, ton

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1994.tb03024.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Aqueous leachates of roots of the perennial weedPluchea lanceolata(DC.) C. B. Clarke, its root‐incorporated soil and rhizosphere soil, interfered with the seedling growth of certain plant species. The soils from the rhizosphere zone of this plant had significantly higher total phenolics and HPLC analysis revealed that phenolic fractions represented by retention times of 1.6, 1.9, 2.5 (simple phenol, chlorogenic acid and phloroglucinol respectively), 3.7 and 4.3 min were contributed by roots of the weed to the soil. The phenolic fraction represented by the retention time 3.3 (formononetin 7‐O‐glucoside) was detected in the weed's rhizosphere soils and not in the rootincorporated soils. UV spectral studies established the presence of phloroglucinol, simple phenol, chlorogenic acid, formononetin 7‐O‐glucoside, and methylated coumarins in the root leachate, which affect the seedling growth of mustard (Brassica juncea). Present research established the allelopathic potential ofP. lanceolataroots, and the possible involvement of allelopathy in its interferenc

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1994.tb03025.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The relationship between susceptibility to photoinhibition, zeaxanthin formation and chlorophyll fluorescence quenching at suboptimal temperatures was studied in chilling‐sensitive maize and in non‐acclimated and cold‐acclimatedOxyria digyna, a chilling‐tolerant plant of arctic and alpine habitats. In maize, zeaxanthin formation was strongly suppressed by chilling. Zeaxanthin formed during preillumination at 20°C did not protect maize leaves from photoinhibition during a subsequent high‐light, low‐temperature treatment, as judged from the ratios of variable to maximal fluorescence, Fv/Fm. However, such preillumination significantly increased non‐photochemical quenching (qN) at low temperatures, mainly due to an enhancement of the fast‐relaxing qNcomponent (i.e., of energy‐dependent quenching. qE). InO. digyna, cold‐acclimation resulted in an increased zeaxanthin formation in the temperature range of 2.5–20°C. Cold‐acclimation substantially decreased the susceptibility towards photoinhibition at 4°C, but qNremained nearly unchanged between 2 and 38°C, as compared to control plants. Effects of cold acclimation on photosynthesis, photochemical quenching and quantum efficiency of photosystem II were small and indicated a slight amelioration only of the function of the photosynthetic apparatus at suboptimal temperatures (2–20°Ct. I) is concluded, that the xanthophyll cycle is strongly influenced by cold acclimation, while effects on the photosynthetic carbon assimilation only

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1994.tb03026.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Protein turnover is generally regarded as a major maintenance process, but experimental evidence to support this contention is scarce. Here we quantify the component of dark respiration rate associated with overall protein turnover of tissues in vivo. The effect of an inhibitor of cytosolic protein synthesis (cycloheximide, CHM) on dark respiration was tested on a cell suspension from potato (Solanum tuberosumL.) and quantified on leaf discs of expanding and full‐grown primary leaves of bean (Phaseolus vulgarisL.). The in vivo effect of CHM on protein biosynthesis was assessed by monitoring the inhibition of the induction of the ethylene‐forming enzyme (EFE) activity. The present method yields the energy costs of turnover of the total pool of proteins irrespective of their individual turnover rates. Average turnover rates were derived from the respiratory costs and the specific costs for turnover.Inhibition of respiration by CHM was readily detectable in growing‐cell suspensions and discs of expanding leaves, The derived respiratory costs of protein turnover in expanding leaves were maximally 17–37% of total respiration. Turnover costs in full‐grown primary leaves of bean amounted to 17–21% of total dark respiration. The maximum degradation constants (i.e. Kd‐values) derived for growing and full‐grown leaves were up to 2.42 × 10−6and 1.12 × l0

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1994.tb03027.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Shoots ofPolygonum hydropiperL. (waterpepper), especially in the leaves and flower‐heads, contain significant amounts of the sesquiterpenoid polygodial, a compound with a potential use as a natural pesticide. The polygodial content of the tepals is particularly high: up to 8.5% of the dry weight. Roots and seeds do not contain detectable amounts of polygodial. Polygodial containing organs e.g. leaves and tepals, were found to contain cavities. Fourier transform infra‐red (FTIR) microspectroscopy demonstrated that polygodial or its congeners are found in these cavities but not in other tissues or cells. Comparable cavities containing polygodial‐like compounds were absent in the closely related speciesPolygonum persicariaL.Callus cultures and cell suspensions as well as root‐ and shoot cultures were initiated from matureP. hydropiperplants. Polygodial could be detected only in shoot cultures. Our results indicate that functioning plastids may be essential for polygodial production and cavities for its accum

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1994.tb03028.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The ability of ascorbic acid to induce cell proliferation of non‐cycling cells was investigated in quiescent embryo root ofPisum sativumL. cv. Lincoln, as well as in the active plantlet root meristem, where a minor portion of the cells is non‐proliferating. Quiescent embryo cells speeded up the G0–G1transition during germination in the presence of ascorbic acid. In addition, proliferating cells present in the root tip of 3‐day‐old plantlets, arrested at the G1/S boundary by hydroxyurea, resumed the cycle earlier than the control, when treated with ascorbic acid. In contrast, ascorbic acid was unable to induce the proliferation of non‐cycling cells present in the active meristem. Therefore, these data suggest that the ability of ascorbic acid lo induce cell proliferation depends on the physiological status of the cell. In particular the data indicate that ascorbic acid is involved in cell proliferation as a factor necessary to enable already competent cells to progress through the cell cycle phases, but not as a factor able to induce non‐competent cells to overcome prolife

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1994.tb03029.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Paclobutrazol (PB) only slightly stimulated the rooting of mung bean cuttings but, interestingly, the number of adventitious roots formed was dramatically increased when PB was used together with indole‐3‐butyric acid (IBA). Application of PB in the first phase of root formation, when root initials are induced, caused the greatest enhancement of the promotive effect of IBA on rooting. Investigation of the effect of PB on uptake, transport and metabolism of [5‐3H]‐IBA in mung bean cuttings revealed some changes in the rate of metabolism of IBA in comparison with control cuttings. PB was found to be involved in the partitioning of carbohydrates along the cuttings. Application of sucrose, like PB to the base of IBA‐treated cuttings enhanced the effect of IBA. The patterns of the effects of PB and IBA, separately and together, on rooting were similar in defoliated and intact cuttings, however the number of roots was much lower in the defoliated cuttings, which lacked a source of assimilates. PB counteracted the effect of GA3in the upper regions of the cuttings and seemed to increase the sink capacity at the base of the cuttings. The results of the present study clearly demonstrated the enhancing influence of PB on IBA stimulation of the rooting of mung bean cuttings. It is suggested that PB may affect the rate of metabolism of IBA during rooting and the status of the local sink, in the base of the cuttings, thus partially contributing to the enhancement of the rooting‐promotive ef

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1994.tb03030.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY