bluuebunny/crossref_metadata_2025 huggingface dataset:
Central and peripheral information source use among rural and remote Registered Nurses
Authors: Kosteniuk Julie G. , D'Arcy Carl , Stewart Norma , Smith Barbara
Published: May 2006

Aims.  This paper reports a study examining the use of central (colleagues, inservice and newsletters) and peripheral information sources (Internet, library, journal subscriptions and continuing education) among a large sample of rural and remote nurses and explores the factors associated with the use of particular peripheral information sources.

Background.  There have been few studies of the specific sources of information accessed by Registered Nurses, particularly rural or remote nurses, and the characteristics of nurses and their organizations that are associated with the use of particular information sources.

Methods.  A questionnaire survey was conducted with 3933 Registered Nurses from all regions of rural and remote Canada between October 2001 and July 2002. We used frequencies and cross‐tabulations to describe rates of information use, and forward selection logistic regression with likelihood ratio selection to build the best‐fitting model of the variables that affected the odds of using each peripheral information source.

Results.  Nursing colleagues ranked as the information source most frequently used, and the Internet and library ranked lowest. On average, nurses used a statistically significantly greater number of central than peripheral sources. Peripheral information source use was higher among nurses who had access to current information, opportunities to share their knowledge with others, higher education levels, were in positions of authority and worked with healthcare students. The associations between age and geographical location varied according to the peripheral information source under consideration.

Conclusions.  The vast majority of rural and remote nurses used at least one peripheral information source to inform their practice. Increasing the number of research sources used by these nurses requires attention to issues of information access in these areas, as well as issues of staff recruitment and retention of staff in under‐serviced rural and remote regions.
Caring for adults with intellectual disabilities: perceived challenges for nurses in accident and emergency units
Authors: Sowney Margaret , Barr Owen G.
Published: May 2006

Aim.  This paper reports a study exploring the experiences of nurses in accident and emergency units caring for people with intellectual disabilities.

Background.  People with intellectual disabilities are increasingly in contact with healthcare professionals in accident and emergency units. Often this contact occurs within the accident and emergency service, an area in which staff care for a diverse range of people. The experiences of people with intellectual disabilities within acute general hospitals in the United Kingdom and internationally has largely been reported as quite negative. Conversely, little is known about the experiences of nurses working in acute general hospitals, nor the exact nature of any challenges they encounter, in providing care to people with intellectual disabilities. This lack of understanding weakens opportunities for nurses to reduce barriers to providing an equitable service for people with intellectual disabilities.

Method.  Five focus groups were conducted with 27 accident and emergency nurses from five hospitals in Northern Ireland in the spring of 2004. The data were then coded and recurring themes identified.

Findings.  This paper focuses on two themes: lack of knowledge of the nature of intellectual disability and dependence on carers. Whilst these themes have been acknowledged in the existing literature, they have received limited attention and exploration. The experience of fear and vulnerability was considered by participants to be a consequence of their lack of knowledge. The experience of these emotions is viewed as a key factor in nurses’ over‐dependence on patients’ informal carers.

Conclusion.  Increased awareness is needed among professionals in accident and emergency units of the abilities and needs of people with intellectual disabilities.
Provision of rehabilitation nursing in long‐term care facilities
Authors: Vähäkangas Pia , Noro Anja , Björkgren Magnus
Published: May 2006

Aim.  This paper reports an investigation into rehabilitation nursing provided in long‐term care settings in Finland, focusing on the amount of time spent with residents, types of rehabilitation nursing provided and resident characteristics associated with rehabilitation nursing.

Background.  In long‐term care, nurses have important roles as members of multidisciplinary care teams in the provision of rehabilitation care. Evidence suggests that rehabilitation nursing has a positive impact on maintaining residents’ functional performance. However, there is little information on the patterns and scope of rehabilitation nursing in long‐term care facilities.

Methods.  A quantitative, retrospective and cross‐sectional study was designed with the data collected between July and December 2002. Rehabilitation nursing was analysed using the Resident Assessment Instrument used in Finland (n = 5312). The frequency and focus of rehabilitation nursing were presented by mean scores and 95% confidence intervals. Univariate and multivariate logistic regression models were built to describe the factors associated with rehabilitation nursing. Odds ratios and confidence intervals were derived from these models.

Results.  About 64% of residents received some rehabilitation nursing. Residents assessed as having rehabilitation potential received statistically significantly more rehabilitation nursing than others, such as skills practice in transfer, walking and dressing. Resident factors associated with rehabilitation nursing were cognition, activities of daily living, urinary incontinence, instability of health condition, falls, depression and greater social engagement.

Conclusion.  Specific resident characteristics and nurses’ views of rehabilitation potential determine the provision of rehabilitation nursing. This information could be useful in both targeting and planning rehabilitation nursing in long‐term care.
The use of factor analysis for ascertaining patterns of psychopathology in children with intellectual disability
Authors: Tonge B. J. , Einfeld S. L. , Krupinski J. , Mackenzie A. , McLaughlin M. , Florio T. , Nunn R. J.
Published: May 2006

The Developmental Behaviour Checklist (DBC) was developed to assess psychopathology in children with intellectual disabilities. A cut–off point between ‘non–cases’ and ‘cases’ was determined by comparison of the total scores with psychiatric clinical assessment. This paper describes a method aimed at determining the types of psychiatric problems in those regarded as ‘cases’. Factor analysis with varimax rotation carried out on a sample of 1093 subjects extracted six faaors. Standardized factor scores were calculated for each subject in a community sample (n= 450), and the only or the dominant positive score was determined for each of the ‘cases’. Over 80% of ‘cases’ could be allotted to one condition. Only a small number had none, or three or more conditions. The same procedure was replicated on a validation sample (n= 448) with even more satisfactory results. Differences in the prevalence of the six conditions by sex, age and level of mental retardation were ascertained. The validity and clinical relevance of this method are discussed.
The effect of the presentation of visual and auditory stimuli on the breathing patterns of two girls with Rett syndrome
Authors: Woodyatt G. C. , Murdoch B. E.
Published: May 2006

The respiration patterns of individuals with Rett syndrome are known to be dysrhythmic during wakefulness, suggesting cortical involvement of brainstem respiratory control. To investigate this involvement further, the waking breathing patterns of two girls with Rett syndrome were analysed during three phases: a quiet phase, and two phases during which visual and auditory stimuli were presented in controlled intervals. Differences were noted between the two subjects’ respiratory patterns in both the quiet and stimulation phases. The usual quiet respiration patterns became more dysrhythmic for both girls during stimulation, with shortened breathing cycles and lengthened apmoeic pauses for the one subject, and increased numbers of apnoeic pauses and shallower breaths for the other. These results suggest that the cyclical brainstem control of breathing patterns in Rett syndrome may be subject to disruption as a result of cortical influences, including arousal subsequent to the engagement of attention.
Clinical factors affecting the outcome of occlusal splint therapy of temporomandibular joint disorders
Authors: EMSHOFF R.
Published: May 2006

summary  The purpose of this study was to test the hypothesis that (1) the presence of a clinical temporomandibular joint‐related disorder has effects on short‐term changes in temporomandibular joint pain, and that (2) clinical variables of time since pain onset predict treatment outcomes of occlusal splint therapy. The study comprised 76 patients with unilateral temporomandibular joint pain. The clinical disorder subgroup included 47 patients with a clinical pain side‐related diagnosis of internal derangement type I (n = 16), internal derangement type III (n = 19), and degenerative joint disease (n = 12). The clinical non‐disorder subgroup consisted of 29 patients without a temporomandibular joint disorder. A logistic regression analysis was used to compute the odds ratio for the clinical variables of time since pain onset, adjusted for age, gender, pretreatment pain level, and clinical subgroup. For the temporomandibular joint pain measurements there was no significant ‘session’/‘clinical subgroup’ interaction (P = 0·470). Significant increase in benefit of a successful outcome of ‘pain reduction >70%’ occurred with a time since pain onset of ≤6 months (15·1 odds ratio) (P = 0·003). The odds ratio that a patient with a time since pain onset of >2 years might belong to the unsuccessful treatment group of ‘pain reduction <30%’ was strong (6·0) and significant (P = 0·026). Diagnosis of temporomandibular joint disorder proved not to be linked to changes in therapeutic outcome measures of temporomandibular joint pain. Time since pain onset was an important prognostic determinant of successful occlusal splint therapy.
Mycophenolate mofetil introduction stabilizes and subsequent cyclosporine A reduction slightly improves kidney function in pediatric renal transplant patients: A retrospective analysis
Authors: Benz Kerstin , Plank Christian , Griebel Martin , Montoya Carmen , Dötsch Jörg , Klare Bernd
Published: May 2006

Abstract: Chronic allograft nephropathy (CAN) is the major cause of late graft loss. Among others, chronic calcineurin inhibitor toxicity (CNI) contributes to the development of CAN. Therefore, reduction in CNI dosage may delay the development of CAN, leading to longer graft survival. It was the aim of the present retrospective analysis to investigate the effect of mycophenolate mofetil (MMF) addition with subsequent cyclosporine A (CSA) reduction on renal function in pediatric kidney allograft recipients. Seventeen patients (aged 8.3–17.6 yr) with monotherapy with CSA and progressive loss of renal function at a median of 3.4 yr after kidney transplantation were enrolled. After at least three months of MMF treatment, CSA dosage was stepwise reduced to trough levels of 100, 80, and 60 ng/mL. In all patients, introduction of MMF prevented a further decrease of glomerular filtration rate (GFR). The mean GFR 12 months before study enrollment was 96.1±24.5 and 71.0±21.0 mL/min/1.73 m2 at start of MMF. After introduction of MMF and unchanged CSA dosage GFR was stabilized to 71.1±23.8 mL/min/1.73 m2. After CSA reduction to trough levels of 60 ng/mL, GFR was slightly ameliorated up to 76.3±24.1 mL/min/1.73 m2. Within the follow‐up period, one borderline rejection occurred in a patient in whom the CSA trough level was 60 ng/mL since seven months. In pediatric kidney allograft recipients with progressive loss of renal function reduction of CSA after introduction of MMF may stabilize and even slightly ameliorate renal function.
Ribulose bisphosphate carboxylase, protein and nitrogen in Scots pine seedlings cultivated at different nutrient levels
Authors: Gezelius Kerstin
Published: May 2006

Seedlings of Scots pine (Pinus sylvestris L.) of a northern provenance were cultivated in nutrient solution for 10 weeks in a climate chamber. The nutrient solution (renewed by solution exchange) contained 2.5, 10 or 50 mg N I−1. All other essential elements were added in optimal proportion to the nitrogen.

Seedlings cultivated at 10 and 50 mg N I−1 were similar with respect to all characteristics studied. Seedlings cultivated at 2.5 mg N I−1 showed a lower growth rate, especially for the shoot, and an altered morphology, with high root:shoot ratios and long, slender roots. The nitrogen concentrations in shoot and needles as well as in whole seedlings were not significantly affected by the nitrogen supply, while the nitrogen concentrations in the roots were somewhat lower at 2.5 mg N I−1.

Ribulose bisphosphate carboxylase (EC 4.1.1.39) activity and the concentrations of carboxylase, total and soluble protein and of chlorophyll in the needles were consistently much lower for seedlings cultivated at 2.5 mg N I−1, than for seedlings grown at higher nutrient levels. A close correlation was observed between activity and concentration of the carboxylase (r=0.95). Carboxylase activity and protein were more sensitive to a low nutrient supply than was chlorophyll.

The data show how activity and concentration of ribulose bisphosphate carboxylase and the concentrations of soluble and total protein and of chlorophyll in needles of pine seedlings can be negatively affected by the nutrient supply, also when the nitrogen concentrations in the needles are close to those observed at optimal nutrient supply. It is suggested that pine seedlings store assimilated non‐protein nitrogen in the needles when protein synthesis is under restraint. The nitrogen concentration in needles and seedlings could not be used as a measure of the physiological state of the seedlings.
Biosynthesis and conjugation of indole‐3‐acetic acid in tobacco crown gall
Authors: Rausch Thomas , Kahl Günter , Hilgenberg Willy
Published: May 2006

The in vivo metabolism of [3H]‐tryptophan (TRP), [14C]‐indole‐3‐acetaldoxime (IAOX), and [14C]‐indole‐3‐acetic acid (IAA) has been studied in non‐transformed and Agrobacterium tumefaciens T 37 transformed cells of Nicotiana tabacum L. cv. White Burley. Metabolites were analyzed by thin‐layer chromatography (TLC) and high pressure liquid chromatography (HPLC). TRP was converted to IAOX and indole‐3‐ethanol (IEOH) in both cell types, while indole‐3‐acetamide (IAAM) occurred exclusively in transformed cells. The formation of IEOH was higher in transformed cells. IAOX was metabolized to IEOH and IAA in both tissues, whereas only in transformed cells some conversion to IAAM occurred. Furthermore, the conversion of the aldoxime to IAA was higher in transformed cells. Labelled IAA became rapidly conjugated to indole‐3‐acetylaspartic acid (IAAsp) in both cell types, the transformed cells showing a 100% increased uptake of IAA. In vitro incubations of [14C]‐IAOX with desalted extracts from transformed cells showed no significant enzymatic conversion to IAAM, whereas in the presence of flavin adenine dinucleotide (FAD) some chemical conversion was observed. The present results suggest that in an established line of transformed cells the integration of the T‐DNA leads to a permanent transcription of its own auxin genes. Furthermore, the in vivo studies suggest that the host cell's capacity for IAA biosynthesis and conjugation may be altered quantitatively. The potential role of IAOX in both transformed and non‐transformed cells is discussed.
A note on blue light‐induced potentials in Avena coleoptiles
Authors: Johnsson A. , Zachariassen E. , Grahm L.
Published: May 2006

Transverse electrical potentials were induced by 435.8 nm light, with lateral illumination of coleoptiles of Avena sativa L. cv. Blenda. The potentials were recorded with the aid of the vibrating electrode technique, thus avoiding touching of the plants. The light dose was varied by changing the illumination time, the irradiance always being 3.9.10‐3 W m‐2. The transverse potential varied in time after the start of illumination and the magnitude of it was dose‐dependent. Maximum voltages recorded were of the order of 15 mV, the illuminated side of the coleoptile then being negative with respect to the shaded side. Dose response curves were constructed and were very similar to dose response curves published in the literature for phototropic (blue light induced) curvatures.
Effects of exogenous cytokinins on root formation in pea cuttings
Authors: Bollmark Marie , Eliasson Lennart
Published: May 2006

Benzylaminopurine (BAP) or zeatin continuously supplied through the rooting solution to cuttings of pea (Pisum sativum L. cv. Weibull's Marma), inhibited root formation down to a concentration of 3.10−9M. The inhibitory effect of BAP in the concentration range 10−8–10−7M was readily reversible if the cuttings were transferred to solutions without cytokinin after treatment for 1–4 days. A slight increase in the number of roots formed was obtained after treatment with low cytokinin concentrations for 1–2 days. Evidence from microscopic studies of primordia formation indicates that BAP inhibits differentiation of primordia at an early stage in their development. Growth of already formed primordia, or root elongation, was considerably less sensitive to the inhibitory effect of BAP. The results indirectly support the hypothesis that endogenous cytokinins prevent root formation in stems of intact plants and may be of importance for the regulation of rooting in cuttings.
Quantitative characterization of protoplasts and vacuoles from suspension‐cultured cells of Catharanthus roseus
Authors: Renaudin J. P. , Brown S. C. , Barbier‐Brygoo H. , Guern J.
Published: May 2006

A simple and efficient procedure for isolation of protoplasts and then vacuoles from cultured cells of Catharanthus roseus (L.) G. Don is presented. Protoplasts were disrupted by an osmotic shock and the vacuoles vere purified by flotation on a single‐step gradient. A comparison of the content and concentration of solutes (proteins, sugars, organic acids, alkaloids, mineral ions) in protoplasts and cells showed that massive and selective losses occur for most solutes during protoplast preparation. These are attributed to the osmotic adjustment and changes of membrane permeabilities occurring during plasmolysis. Data concerning the size, yield and purity of the isolated vacuoles are discussed. By analysis of isolated vacuoles, the vacuolar concentration and localization of solutes within protoplasts have been determined. The limits of this latter approach are stressed, however. Some evidence in favour of the selection of a special class of vacuoles during isolation is reported and discussed.
Ethylene‐dependent action of gibberellin in seed germination of Amaranthus caudatus
Authors: Kȩpczyński Jan
Published: May 2006

The role of gibberellins in the germination of seeds of Amaranthus caudatus L. was examined. Tetcyclacis (BAS 106), an inhibitor of gibberellin biosynthesis, inhibited germination of the seeds. The inhibition caused by BAS 106 was antagonised by gibberellin A4+7 (GA4+7). Ethephon (2‐chloroethylphosphonic acid) and 1‐aminocyclopropane‐1‐carboxylic acid (ACC) could replace GA4+7. Ethephon and ACC counteracted also the side effects of BAS 106 that are not reversible by GA4+7. The rate of seed germination was not increased by gibberellin in the presence of aminoethoxyvinylglycine (AVG). AVG increased the effect of BAS 106. GA4+7 could not reverse the effect of BAS 106 when AVG was simultaneously applied. The results indicate that the biosynthesis of endogenous gibberellins may be required for germination of A. caudatus seeds and that main physiological effects of GA4+7 on seed germination may depend on ethylene biosynthesis.
Cuticular transpiration and epicuticular lipids of primary leaves of barley (Hordeum vulgare)
Authors: Larsson Stig , Svenningsson Magnus
Published: May 2006

Twenty cultivars of barley and 15 eceriferum mutants from one of the cultivars have been analysed for cuticular transpiration and epicuticular lipids of their primary leaves. The relative cuticular transpiration rates of the cultivars ranged from 0.61 to 1.98. In spite of this variation in transpiration most of the cultivars had almost the same amount of epicuticular lipids per leaf area, about 16 μg cm−2. The eceriferum mutants showed a wider range in amount of epicuticular lipids, from 5.0 to 15.5 μg cm−2. Nevertheless, most of the mutants transpired almost at the same rate. Only a weak correlation was found between cuticular transpiration and total amount of epicuticular lipids. None of the analysed lipid components (alkanes, aldehydes, primary alcohols, esters or fatty acids) was better correlated to the cuticular transpiration than the total amount of lipids. When the cultivars were exposed to a mild water stress their cuticular transpiration rates decreased by about 11%. This reduction was not accompanied by any corresponding increase in total amount of epicuticular lipids. The most pronounced effect of the water stress treatment was a stimulation in the ester formation and a reduced formation of primary alcohols. This shift in lipid composition could not be correlated to the decreased cuticular transpiration rates of the individual cultivars. From this investigation it is concluded that the cuticular transpiration is poorly correlated to the amount or composition of the epicuticular lipids in this barley material. As a consequence it was not possible to use any characteristic of the epicuticular lipids as a selection criterion in breeding for drought resistance.
Rates of uptake and metabolism of indole‐3‐acetic acid and 2,4‐dichlorophenoxyacetic acid by cultured leaf segments at different stages of development in wheat
Authors: Wernicke Wolfgang , Milkovits Lydia
Published: May 2006

Immature leaf tissue of Triticum timopheevi Zukh. responded to supplied auxin and showed cell division in culture. The rates of uptake and of metabolism of indole‐3‐acetic acid and 2,4‐dichlorophenoxyacetic acid by such tissues were measured and compared with those of mature auxin‐unresponsive tissue. The purpose of these experiments was to determine whether or not the concentration of auxin in cultured mature tissue was a factor limiting the cell division response to auxin. The data indicate that neither alterations in rates of uptake nor alterations in rates of metabolism could explain the loss of responsiveness to auxin which apparently occurs during cell differentiation. The results are discussed in the context of the view that changes in cell sensitivity to growth substances and not only the concentration of these compounds, play an important role in plant growth and development.
Accumulation of potassium by differentiating metaxylem elements of maize roots
Authors: McCully M. E. , Canny M. J. , Van Steveninck R. F. M.
Published: May 2006

The previous demonstration that the large late metaxylem vessels of field‐grown maize (Zea mays L. cv. Rosella) roots do not lose their crosswalls until they are 20–30 cm from the tip, and that the presence of a soil sheath outside the root was indicative of immature vessels within, greatly strengthened the hypothesis that ion accumulation into these roots was by uptake into living xylem element vacuoles. Proposals that salt movement into the xylem was by leakage or secretion into dead vessels became much less plausible. Potassium concentration in the vacuoles of late metaxylem elements was measured by X‐ray microanalysis in unetched fracture faces of bulk, frozen‐hydrated pieces of sheathed roots, and found to be in the range 150–400 mM. Potassium concentration in open vessels of bare roots, measured both with the microprobe and by spectrophotometry of aspirated sap, was in the range of 5 to 25 mM. It is concluded that uptake of potassium (and possibly other ions) is into living xylem elements, and that its release to the transpiration stream occurs by the breakdown of their crosswalls and the addition of their vacuoles to the solution in the vessels above.
Factors affecting dry weight accumulation in developing barley endosperm
Authors: Renwick Fiona , Duffus Carol M.
Published: May 2006

Some factors that may be concerned in determining final grain weight in barley (Hordeum vulgare L. var. distichum) have been investigated. Variation in endosperm fresh and dry weight, volume and starch content have been recorded at different stages of grain development between anthesis and harvest‐ripeness for two barleys, cvs Kym and Golden Promise, differing in final grain weight. Results were recorded under both field and glasshouse conditions. The results suggest that the higher final dry weight of Kym, in comparison with Golden Promise, is a function of both rate and duration of grain filling. Only at later stages of endosperm development did the differences in volume become significant and the Kym endosperms continued to increased rapidly in volume for two to three days after endosperm volume had reached a maximum in Golden Promise. The rates of starch accumulation in both cultivars were very similar but starch deposition continued in Kym endosperms for four to five days after deposition in Golden Promise endosperms had slowed down.
Effects of indoleacetic acid and galactose on the UTP level and UDP‐glucose formation in Avena coleoptile and Vigna epicotyl segments
Authors: Inouhe Masahiro , Yamamoto Ryoichi , Masuda Yoshio
Published: May 2006

The effects of IAA and galactose on the endogenous levels of UDP‐sugars and nu‐cleotides were compared between a monocotyledon, using coleoptile segments of oat (Avena sativa L. cv. Victory I) and a dicotyledon, using epicotyl segments of azuki bean (Vigna angularis Owhi and Ohashi cv. Takara). The following results were obtained:

Exogenously applied galactose inhibited the IAA‐induced cell elongation of Avena coleoptile segments, but not that of Vigna epicotyl segments.

Galactose was not found in the neutral free sugar and phosphate sugar fractions in the control segments of either Avena or Vigna. Galactose caused a strong increase in the level of Gal‐1‐P but little increase in the level of free galactose in the two plant tissues.

Galactose caused a rapid decrease in the amount of UDP‐glucose and an accumulation of UDP‐galactose in Avena coleoptile segments. Also, galactose caused a decrease in the UTP level but affected the ATP and GTP levels only little, suggesting that galactose inhibits the UDP‐glucose formation by decreasing the UTP level due to a predominant formation of UDP‐galactose.

In Vigna, galactose increased the level of UDP‐galactose to a lesser extent than in Avena, and was virtually without effect on the levels of UDP‐glucose, UTP or other nucleotides.

In the absence of galactose, IAA caused an increase in the levels of UDP‐glucose and UTP in Avena. In Vigna, IAA gave increased levels of UDP‐glucose and UTP in both the presence and absence of galactose. IAA also increased the levels of ATP and GTP in both plants, suggesting that IAA stimulates the UDP‐glucose formation by activating the metabolism of nucleotides and thus increasing the UTP level.

From these results, we conclude that UTP is involved in the IAA action and also in the differential effects of galactose on the UDP‐glucose formation, which is needed for cell wall synthesis and ensuing cell elongation.
Solute adjustments in leaves of two species of wheat at two different stages of growth in response to salinity
Authors: Weimberg Ralph
Published: May 2006

Changes in leaf solute concentrations in response to salinity were measured at two growth stages in two species of wheat, Triticum turgidum L. cv. Aldura (Durum group) and Triticum aestivum L., cv. Probred that differed in their salt tolerances. Both species at 55 days of age were Na+‐excluders, but the concentration of Na+ was 10 times higher in T. turgidum than T. aestivum at low to moderate levels of stress. The ratio then decreased until it was 2:1 at – 1.2 MPa. In T. turgidum, K+ concentrations decreased with increasing Na+ concentrations so that the sum of the two cations remained constant at all stress levels, but in T. aestivum K+ decreased more rapidly than Na+ increased. In both species growing in media at 0 to –0.6 MPa, the amounts of Mg2+ and Ca2+ in 55‐day‐old plants that could be extracted with hot water were below 0.1 mmol (g dry weight)−1. Then, as osmotic potentials of media decreased further, hot water‐extractable Ca2+ increased greatly until, at – 1.2 MPa, Ca2+ concentrations were almost equal to the sum of Na+ and K+. In the range of 0 to –1.0 MPa, the ratio of Cl− to total cationic charge remained constant at 1:6 in T. aestivum and 1:2 in T. turgidum. However, at – 1.2 MPa, the ratio in both species had changed to 2:3. Sucrose and betaine concentrations were 4 and 48 μmol (g dry weight)−1, respectively, in non‐stressed plants of both species. At – 1.2 MPa, sucrose had increased 30‐fold but betaine had increased only 2.5‐fold. Proline increased exponentially relative to foliar Na+ in T. turgidum. In T. aestivum only plants grown at –1.2 MPa contained sufficient Na+ to stimulate the accumulation of proline. Although the quantities of the solutes in leaves of non‐stressed 96‐day‐old plants differed from those in non‐stressed younger plants, the patterns of change of organic solutes as the older plants were subjected to increasing saline stresses were the same as in younger plants with the exception of sucrose. Sucrose concentrations were much higher in leaves of non‐stressed older plants and this sugar first increased and then decreased with decreasing osmotic potentials of media.
Monoclonal antibodies against the plant cytokinin isopentenyl adenosine
Authors: Trione E. J. , Krygier B. B. , Kathrein J. M. , Banowetz G. M. , Sayavedra‐Soto L. A.
Published: May 2006

Sixteen monoclonal antibodies against isopentenyl adenosine (iPA) were developed and characterized for reactivity towards this cytokinin and structurally related molecules by use of a competition fluorescence enzyme immunoassay. Antibodies with suitable affinity and specificity were used in an immunoassay to detect and quantify isopentenyl adenosine. Logit/log plots of fluorescence vs pmol of the cytokinin indicated that the assay had a measurement range of 0.03–256 pmol (10–8500 pg) with high linearity (r =–0.98). This competition fluorescence enzyme immunoassay showed that three antibodies cross‐reacted with N‐6‐benzyladenine and its riboside: cross‐reactivity with dihydrozeatin and its riboside, cis‐zeatin, trans‐zeatin riboside, adenine and adenosine was minor. When an immunoaffinity‐HPLC technique was used to measure the cross‐reactivity of two of the antibodies in the presence of known quantities of multiple cytokinins, iPA was bound in preference to the other cytokinins. One of the antibodies was used to quantify this cytokinin in developing wheat (Triticum aestivum L. cv. Stephens) seeds and in wheat seeds spiked with known amounts of certain other cytokinins. The use of these antibodies in immunoassay in combination with HPCL for quantification of iPA in plant extracts is discussed.
Photosynthesis, reserve mobilization and enzymes of sucrose metabolism in soybean (Glycine max) cotyledons
Authors: Brown Christopher S. , Huber Steven C.
Published: May 2006

Soybean (Glycine max L. [Merr] cv. Ransom II) seedlings were grown under a light/ dark regime or in continuous darkness. Cotyledons were harvested daily for measurements of reserve mobilization, net carbon exchange rate, chlorophyll content and activities of certain enzymes involved in sucrose metabolism. Seedlings lost dry weight for the first 3 to 4 days after planting, then maintained a constant dry weight in the etiolated seedlings, and gained dry weight (via net fixation of CO2) in the light‐grown seedlings. In general, the patterns of reserve mobilization were as expected based on the collective work of other investigators. Soluble sugars were mobilized first, followed by protein and lipid. Galactinol, previously uncharacterized in soybean cotyledons, was present at low concentrations and was rapidly depleted within 2 days after planting. Mobilization of reserves was most important during the first 8 days after planting, whereas net cotyledonary photosynthesis began at 6 days after planting and was the primary source of assimilates after 8 days. Maximum rates of cotyledon photosynthesis were higher [up to 18 mg CO2 (g dry weight)−1 h−1] than previously reported and accounted for about 75% of the assimilates transported from the cotyledons to the growing seedling during the functional life of the cotyledon. Enzyme activities in light‐grown cotyledons peaked 7 to 10 days after planting and then declined. Sucrose phosphate synthase (EC 2.4.1.14) and sucrose synthase (EC 2.4.1.13) activities were similar in etiolated and light‐grown seedlings, whereas uridine‐5′‐di‐phosphatase (EC 3.6.1.6) activity was substantially higher in light‐grown seedlings. During the period of reserve mobilization, the maximum sucrose phosphate synthase activity in cotyledonary extracts was in excess of the calculated rate of sucrose formation. However, when the cotyledons had highest net photosynthetic rates (14 days after planting), sucrose phosphate synthase activity was similar to the rate of carbon assimilation. It appears that soybean cotyledons are adapted for high rates of sucrose formation (from reserve mobilization and/or photosynthesis) for export to the rapidly growing tissues of the seedling.
Initiation of roots on hypocotyl cuttings of Pinus contorta in vitro
Authors: Grönroos Roland , von Arnold Sara
Published: May 2006

The origin of roots and wound tissue after treatments for induction of roots on hypocotyl cuttings of three‐week‐old Pinus contorta Dougl. ex Loud, is discussed. The cuttings were cultured in vitro and treated with 1.2 μM to 1.5 M IBA (indole‐3‐butyric acid) for 6 h to 10 days. The control, which was not treated with IBA developed a wound tissue from which roots formed. Cuttings treated with IBA developed roots directly from the hypocotyl. Direct rooting was faster than indirect rooting via a wound tissue. Rooting was considered to be optimal if more than 80% of the cuttings rooted within 19 days and half of the cuttings which possessed roots after one month had acquired them within 14 days. This type of rooting was obtained after treatment with either 80 μM IBA for 4 to 6 days or 1.25 to 5.0 mM IBA for 6 h. Suboptimal treatments gave lower rooting percentages and superoptimal treatments resulted in delayed rooting. In IBA‐treated cuttings, large increases in mitotic activity (number of mitoses per mm hypocotyl) were found in the pericycle and parenchyma inside endodermis. However, the control also had similar mitotic activities as the IBA‐treated cuttings but closer to the cut surface. This led us to the conclusion that similar tissues may produce either wound tissue or roots. Almost all roots obtained through direct rooting originated outside resin ducts.
Plasmalemma from the roots of cucumber: Isolation by two‐phase partitioning and characterization
Authors: Memon Abdul Razaque , Sommarin Marianne , Kylin Anders
Published: May 2006

Plasmalemma was isolated from the roots of 2‐week‐old cucumber plants (Cucumis sativus L. cv. Rhensk druv) by utilizing an aqueous polymer two‐phase system with 6.5%:6.5% (w/w) Dextran T500 and polyethylene glycol (PEG) 3350 at pH 7.8. The plasmalemma fraction comprised ca 6% of the membrane proteins contained in the microsomal fraction. The specific activity of the plasma membrane marker enzyme (K+, Mg2+‐ATPase) was 14‐ to 17‐times higher in the upper (PEG‐rich) than in the lower (Dextran‐rich) phase, and the reverse was true for marker enzymes (cytochrome c oxidase, EC 1.9.3.1, and antimycin A‐resistant NADPH cytochrome c reductase) of intracellular membranes. The ATPase was highly stimulated by the addition of detergent (Triton X‐100), so that the isolated plasmalemma vesicles appear tightly sealed and in a right‐side‐out orientation. Further characterization of the ATPase activities showed a pH optimum at 6.0 in the presence of Mg2+. This optimum was shifted to pH 5.8 after addition of K+. K+ stimulated the ATPase activity below pH 6 and inhibited above pH 6. The ATPase activity was specific for ATP and sensitive to N,N‐dicyclohexylcarbodiimide and sodium vanadate, with K+ enhancing the vanadate inhibition. The enzyme was insensitive to sodium molybdate, NO−3, azide and oligomycin. No Ca2+‐ATPase was detected, and even as little as 0.05 mM Ca2+ inhibited the Mg2+‐ATPase activity.
Endogenous gibberellins in young seedlings of wheat (Triticum aestivum) cultivars
Authors: Jensen Einar , Junttila Olavi
Published: May 2006

Gibberellins A1, A3, A4 and A7 were identified by combined gas chromatography mass spectrometry (GC‐MS) in leaf and stem tissues of 17‐day‐old seedlings of wheat (Triticum aestivum L.), cvs Siete Cerros (semi‐dwarf, Rht1) and Møystad (tall), of F1, hybrids from the cross Møystad × Siete Cerros and of 2 selected lines from the cross Møystad x Sonora 64 (Rht1 and Rht2). GA, and GA, were identified by full scan mass spectra separately in all 5 extracts, GA4 and GA7, were identified by selected ion monitoring in a bulked fraction. About 90% of the biological activity (Tan‐ginbozu dwarf rice bioassay) in all 5 extracts was due to the GA1/GA3‐fraction.
Irradiance‐dependent senescence of isolated leaves
Authors: Velerskov Bjarke
Published: May 2006

Isolated leaves from pea (Pisum sativum L. cv. Alaska or the genotype L‐1107), oat (Avena sativa L. cv. Victory), and fuchsia (Fuchsia triphylla L. cv. Koralle) were retained at irradiances between 0 and 130 μmol m‐2 s‐1 PAR (photosynthetic active radiation). Irradiance‐dependent CO2 fixation was measured when the leaves were excised, and time‐dependent changes in light compensation point were determined. If the irradiance was below the light compensation point for CO2 fixation, the respiratory quotient was low, indicating that lipids were respired. The isolated leaves senesced at these low light levels. At higher light intensities the decrease in chlorophyll level was not accompainied by diminished protein level, and the respiratory quotient was close to unity. Only an irradiance equal to or slightly above the light compensation point maintained a stable chlorophyll level for a long time. This suggested that depletion of reserves in darkness or at low levels of irradiance is important for the initiation of the senescence syndrome. At high levels of irradiance, the decrement in chlorophyll level may be caused by photooxidation. Only in leaves placed under an irradiance close to the compensation point, was CO2 fixation able to prevent aging of the leaves.
Effect of thidiazuron on abscisic acid content in apple bud relative to dormancy
Authors: Wang S. Y. , Ji Z. L. , Sun T. , Faust M.
Published: May 2006

The effect of N‐phenyl‐N′‐1,2,3,‐thidiazol‐5‐ylurea (thidiazuron, Dropp, SN 49537) on abscisic acid (ABA) level in apple (Malus domestica Borkh. cv. York Imperial) buds associated with bud break and bud development was determined. The data showed that increased ABA content in apple buds was associated with thidiazuron‐induced bud break and bud development. ABA stimulated growth of apple buds that had emerged from dormancy by thidiazuron treatment. The ABA in apple buds was confirmed by GC‐EIMS and GC‐CIMS.
Pressure‐volume analyses on shoots ofPicea abiesand leaves ofCoffea libericaat various temperatures
Authors: Gross K. , Pliant‐Nguyen T.
Published: May 2006

Shoots from two ecologically different evergreen tree species,Picea abies(L.) Karst andCoffea libericaHiern, were used to carry out pressure volume (PV) measurements at 5–35°C. For this purpose a pressure chamber was equipped with thermoelectric temperature regulation. The non‐linear sections of the resultant PV curves were sigmoidal for both species, with recognizable points of inflexion. These points, at around ψ= 1.12 MPa and relative water content (RWC) = 88.5% forPiceaand at ψ= 0.92 MPa and RWC = 95.5% forCoffea, were characterised by a temporary increase in the resistance to water flow of the entire shoot (R5).

The maximum value of the bulk modulus of elasticity (ɛ max) was also in the region of the point of inflexion. This value was considerably higher inCoffeathan inPicea. The osmotic pressures at full water saturation (π0) and at turgor loss point (πp) showed a clear temperature dependence between 15 and 35°C differing only slightly from the theoretically expected situation. At 25°C these values were 1.72 and 2.48 MPa. respectively, forPiceaand 1.58 and 1.87 MPa. respectively, forCoffea. The turgor loss point occurred at 76–77% RWC inPiceaand at 86% RWC inCoffea, the proportion of apoplastic water varied between 22 and 25% inPiceabut was only 9–10% inCoffea. The ecological differences between the two species are reflected in their temperature dependence for R5, which was much steeper forCoffeathan forPicea. The energy of activation for the water conductance of the whole shoots was 13.0–14.4 kJ mol−1inPiceaand about 23 kJ mol−1inCoffea.
Effects of water stress on nitrogenase activity in Abuts incana
Authors: Sundstrom Karl‐Ragnar , Huss‐Danell Kerstin
Published: May 2006

Tolerance to water stress was studied in plants of grey alder, Alnus incana (L.) Moench, grown in a climate chamber in pots of sand supplied with a nitrogen‐free nutrient solution. The plants were subjected to a single drying and recovery cycle, during which acetylene reduction, transpiration and stomatal resistance were measured. At different stress levels the plants were placed in a closed system to equilibrate the water potential in the plant‐soil system. The water potential of the plants was determined, after which they were watered and their recovery studied. Nitrogenase activity showed low tolerance to water deficit. At moderate stress (−0.6 to −0.8 MPa) acetylene reduction was reduced by half, and at more severe stress, (< −1 MPa) activity was near zero. There was a rapid decrease in nitrogenase activity coincident with stomatal closure, which indicates a continuous need for photoassimilates for nitrogenase activity. Nodules or nitrogenase activity seemed to be weak sinks for assimilates compared with root pressure bleeding. Measurements of nitrogenase activity in root nodule homogenates supplied with ATP and reductant suggested a loss of active nitrogenase in the nodules in response to water stress. The recovery from moderate stress or long dark treatment took several days, and recovery from severe stress took still longer. Shortage of assimilates and disturbances in oxygen and nitrogen balances in the nodules are discussed as reasons for the reduced nitrogenase activity in response to water stress.
Effects of salinity and phosphate on ion distribution in lupin leaflets
Authors: Treeby Michael T. , van Steveninck Reinhard F. M.
Published: May 2006

Lupin (Lupinus luteus L. cv. Weiko III) were grown in nutrient solution over a range of inorganic phosphate (Pi) concentrations, with or without 50 mM NaCl. Plants with high Pi (2 mM) and salt showed progressive leaf necrosis and had higher concentrations of total phosphate than plants grown with high Pi alone. Most of the extra total phosphate in salt treated plants was in the Pi form. Pi supply did not influence Na+, K+ or Cl− concentrations in epidermal vacuoles or mesophyll cells. However, epidermal vacuoles accumulated more monovalent cations (Na+ and K+) than Cl−, and in vacuoles of plants grown with 0.1 mM Pi additional Pi was accumulated, possibly to maintain charge balance. Plants grown with 2 mM Pi did not accumulate additional Pi in epidermal vacuoles, but showed higher phosphorus levels in cell walls. It is suggested that at moderate phosphorus concentrations Pi plays a role in epidermal osmotic adjustment, possibly explaining the beneficial role of additional phosphorus on salt stressed plants. At high Pi supply with salt, Pi does not contribute to osmotic adjustment and instead accumulates in cell walls. However, the cause of leaf damage under conditions of high phosphorus supply and salinity is still not entirely clear.
A plasma membrane‐bound enzyme oxidizes l‐tryptophan to indole‐3‐acetaldoxime
Authors: Ludwig‐Müller Jutta , Hilgenberg Willy
Published: May 2006

The in vitro conversion of [14C]‐tryptophan to [14C]‐indole‐3‐acetaldoxime (IAOX) by microsomal membranes of Chinese cabbage (Brassica campestris ssp. pekinensis cv. Granat) has been studied. The reaction product was identified by thin‐layer chromatography (TLC) and high performance liquid chromatography (HPLC). Furthermore. IAOX was identified as an endogenous compound of Chinese cabbage by mass spectroscopy. The tryptophan‐oxidizing enzyme (TrpOxE) was characterized. MnCl2 was required as cofactor, H2O2, and 2,4‐dichlorophenol (DCP) stimulated the reaction. The enzyme showed a pH optimum at pH 8–9 and a Km for l‐tryptophan of 20 μM. The membranes containing TrpOxE activity were identified as plasma membranes by means of aqueous polymer two‐phase partitioning. The TrpOxE from Chinese cabbage was purified 3‐fold from plasma membranes by solubilization followed by (NH4)2SO4‐fractionation, affinity‐chromatography with concanavalin A, and native gel electrophoresis. Enzyme activity was reduced by a tunicamycin pretreatment. Several other plant species, e.g. maize (Zea mays L. Inrakorn), sunflower (Helianthus annuus L. cv. Hohes Sonnengold), tobacco (Nicotiana tabacum L. cv. White Burley), and pea (Pisum sativum L. cv. Krombeck) showed a similar conversion of [14C]‐tryptophan to [14C]‐IAOX by phase‐partitioned plasma membranes.
Glycosyl‐linkage composition of tomato fruit cell wall hemicellulosic fractions during ripening
Authors: Tong Cindy B. S. , Gross Kenneth C.
Published: May 2006

Hemicelluloses were extracted from isolated tomato (Lycopersicon esculentum Mill. cv. Rutgers) pericarp cell wall material at 3 different stages of ripeness with 4 M and 8 M KOH. Little change in molecular weight or composition of 4 M KOH‐extracted material was observed during ripening. However, the composition of 8 M KOH‐extracted material changed, and a relative increase in polymers of < 40 kDa was observed during ripening. Changes in glycosyl linkage composition of the 8 M KOH hemicellulosic material were detected, including increases in 4‐linked mannosyl, 4,6‐linked mannosyl, and 4‐linked glucosyl, and decreases in 5‐linked arabinosyl residues in polymers of < 40 kDa, and decreases in terminal glocosyl residues in polymers of > 40 kDa. These data may indicate that de novo hemicellulose synthesis occurs throughout tomato fruit ripening, even at the red ripe stage.
Freezing injury in spinach leaf tissue: Effects on water‐soluble proteins, protein‐sulfhydryl and water‐soluble non‐protein‐sulfhydryl groups
Authors: Stuiver C. Elisabeth E. , de Kok Luit J. , Kuiper Pieter J. C.
Published: May 2006

Freezing of spinach leaf discs (Spinacia aleracea L. cv. Estivato) resulted in an irreversible and parallel loss of protein‐sulfhydryl (SH) and water‐soluble protein. This decrease was inversely related to the increase in freezing injury as determined by the loss of electrolytes from the tissue after thawing. Loss of proteins and protein‐SH occurred during freezing of the tissue and was not enhanced by thawing. The parallel decreases in content of soluble proteins and SH groups make it impossible to determine whether oxidation of protein‐SH groups is the primary step in decline of protein content. During freezing the content of non‐protein‐SH compounds, mainly glutathione (GSH), was decreased to a lesser extent than that of protein‐SH. Contrary to protein‐SH, the levels of non‐protein‐SH declined substantially after thawing. The data indicate that GSH is not directly involved in protection of soluble proteins against freezing‐induced denaturation.