bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vivo manipulation of cuticular water permeance and its effect on stomatal response to air humidity
Authors: KERSTIENS GERHARD 
Published: March 2003

summaryCuticular water permeance was manipulated in Corylus avellana L., Hypericum androsaemum L. and Populus tremula L. by (1) long‐term application of low doses of various systemic herbicides inhibiting biosynthesis of cuticular waxes, (2) very short‐term application of organic solvents to the leaf surface, and (3) exposure to natural strong winds. Treatment effects were very variable, but increased the natural range of permeances by a factor of 10 or so in undamaged leaves. All species had hypostomatous leaves. Relative change of leaf conductance (g) in response to stepwise increases of leaf‐to‐air water vapour pressure difference (VPD) was measured for individual leaves (Corylus) or groups of leaves at the shoot or branch tip. Adaxial cuticular water permeance (P) was determined for the same leaves after measurement of the VPD‐response. A proportional measure of relative change of g with VPD, d(log e.g)dVPD, was then plotted against P. No increase in the strength of the closing response to increasing VPD was found with increasing P, as would have been expected if water loss through the cuticle was involved in stomatal response to changes in VPD via a direct effect on guard cell turgor. By contrast, high P coincided, most clearly in Corylus, with a reduced strength of the stomatal closing response to increasing VPD, i.e. less negative d(logeg)dVPD. As the responses were non‐linear, the value of d(logeg)dVPD changed with VPD. With rising VPD, all three species and a fourth one previously studied showed a decline in the value of [d(logeg)dVPD]/d(log P), reaching negative values in one species. This is interpreted in terms of two independent and antagonistic effects of increased cuticular water permeance on guard cell response to VPD, one acting by reducing the backpressure exerted on guard cells by the epidermis, and the other one possibly causing greater depression of guard cell turgor through delivery of more chemical messengers (such as abscisic acid) to the guard cells with the cuticular transpiration stream.
The influence of air pollution on the concentration of mineral elements, on the spectral reflectance response and on the production of stress–ethylene in the lichen Ramalina duriaei
Authors: GARTY J. , KLOOG N. , WOLFSON R. , COHEN Y. , KARNIELI A. , AVNI A. 
Published: March 2003

summaryTwo parameters were applied to estimate the degree of stress induced by exposure of the lichen Ramalina duriaei (De Not.) Bagl. to air pollution in urban‐industrial sites in Israel. Changes in the spectral reflectance response of the thallus and in the production of stress‐ethylene, were compared with the concentration of sulphate‐S, V, Ni, K, Pb, P, Cu, Cr, Fe, Mn and Mg in either in situ or in transplanted thalli of the lichen.The concentrations of Cu, Mg, Fe, Ni, Pb, V, Cr, Mn and sulphate‐S in in situ thalli collected in a nature reserve in an industrial town (Ashdod, SW Israel) were higher than those detected in in situ thalli collected in a forest (HaZorea Forest) in the north‐east of Israel. The high concentrations of these mineral elements in R. duriaei from the nature reserve coincided with a high rate of production of stress‐ethylene and with a low normalized difference vegetation index (NDVI) indicating that changes in the spectral reflectance response relate to damage to the chlorophyll.Lichens collected in the unpolluted forest in February 1994, either resuspended in the same site or transplanted in nine sites in the Ashdod region, and retrieved in November of the same year, contained a higher concentration of sulphate‐S, Pb, Cu, Ni, V and Cr in the urban‐industrial sites than in most of the rural localities. Statistical analysis revealed a positive correlation between the amount of ethylene produced by R. duriaei and the concentration of V and Ni in the same thalli.To test the integrity of the ethylene‐producing system, lichens were soaked in either 5 mM or 10 mM FeCl2 at pH 3–7. Thalli exposed to a very polluted environment produced less ethylene after this treatment. The NDVI correlated positively with the concentration of K in the thallus but negatively with the concentration of Mn, Ni, Pb and sulphate‐S in the same material.It may be concluded that the in situ thalli of R. duriaei in the nature reserve are severely stressed and possibly‐endangered by the pollution produced by the combustion of heavy fuel oil in the local power plant and oil refineries and by acid rain.
Is the threshold size for flowering in Cynoglossum officinale fixed or dependent on environment?
Authors: DE JONG TOM J. , GOOSEN‐DE ROO LEENTJE , KLINKHAMER PETER G. L. 
Published: March 2003

In the monocarpic perennial Cynoglossum officinale L. the probability of flowering is related to the size of the plant. In previous work it was observed that this relation varies between years. We hypothesized that variable conditions during the winter, the period of vernalization, explain this variation.We collected plants from the field in autumn and placed these under different simulated winter conditions in a climate room. In contrast to our hypothesis, the probability of initiating flowering at a given size was not affected by: (a) the temperature during the cold period, (b) the duration of the cold period, or (c) the application of a plant hormone (GA3) or an inhibitor of gibberellin synthesis (paclobutazol) during the cold period. Winter cold is not necessary for floral initiation, and is only required for elongation of the inflorescence. It is unlikely that winter temperature affects the fraction of plants flowering.Subsequent morphological investigation of flower development in material collected in the field showed that large plants had primordial inflorescences well before vernalization, sometimes as early as August. In plants grown from seeds under constant conditions in a climate room, the probability of initiating the inflorescence differed for plants grown at various temperatures (34·1% at 15°C, 100% at 20°C, and 95% at 25°C). Our results suggest that environmental conditions in August and September, up to 10 months before actual flowering, could affect the fraction of flowering plants.
Influence of plant age on ozone resistance in Plantago major
Authors: LYONS T. M. , BARNES J. D. 
Published: March 2003

The impact of O3 at different stages of plant development was investigated in growth‐chamber‐cultivated Plantago major L. Six‐d‐old plants of an O3‐sensitive population (‘Valsain’) were exposed to one of the following six treatments; 56 d charcoal/Purafil®‐filtered air (CFA): 56 d CFA plus 70 nmol mol−1 O3 for 7 h d−1; CFA with a 14‐d episode of O3 administered at days 1, 14, 28 or 42. Harvests were made every 14 d, and at the final harvest (56 d) the influence of O3 on reproductive structures was assessed.Analysis of the effects of O3 on growth and reproductive performance confirmed the sensitivity of the population to the pollutant. In the absence of the development of typical visible symptoms of foliar damage, the total d. wt of plants maintained in O3 over a 56‐d period was 35% lower than that of control plants. However, the impact of the pollutant was found to decrease as plants aged. Plant relative growth rate (R) was only affected in seedlings, suggesting that effects of O3 on seedling growth were largely responsible for the decrease in accumulated biomass; the growth rate of older plants was not affected by O3. The observed shift in O3 resistance with plant age was mediated by both ‘acclimation’ and ontogenetic changes. ‘Acclimation’ was not associated with changes in O3 uptake, and there was some evidence to support the existence of compensatory growth responses. In addition to effects on vegetative growth, plants exhibited an O3‐induced decline in reproductive performance; O3 reducing the number of flower spikes and seed capsules produced per plant. Ozone episodes administered at different stages of development indicated that reproductive development was particularly sensitive to O3 during the early stages of flowering.The findings of this study are discussed in relation to evolutionary adaptation to O3 in natural plant communities.The importance of plant age, prior exposure to the pollutant and the timing of O3 episodes in relation to plant developmental stage are highlighted.
Effect of free‐air CO2 enrichment (FACE) on CO2 exchange at the flood‐water surface in a rice paddy field
Authors: Koizumi Hiroshi , Kibe Takeshi , Mariko Shigeru , Ohtsuka Toshiyuki , Nakadai Toshie , Mo Wenhong , Toda Hideshige , Seiichi Nishimura , Kobayashi Kazuhiko 
Published: March 2003

Summary

Diurnal and seasonal changes in CO2 exchange between flooding water and the atmosphere are reported in a rice (Oryza sativa) paddy field under ambient and free‐air CO2 enrichment (FACE) conditions.
Measurements of CO2 exchange were made in a randomized complete‐block design experiment with two CO2 mole fractions (ambient; FACE, ambient +200 mmol mol−1) and four blocks.
Evolution of CO2 from the flooding water occurred throughout the entire day under ambient CO2, although the rate decreased in the daytime. By contrast, under FACE, CO2 evolution from the flooding water was observed at night, and CO2 absorption from the atmosphere was observed in the daytime. The time course of CO2 exchange was similar to that of solar radiation.
The diurnal pattern is similar to that for photosynthesis of terrestrial plant communities. This suggests that photosynthesis of the free‐floating weeds and algae in the flooding water is related to the CO2 exchange between the flooding water and the atmosphere. In addition, the amplitude of the diurnal cycle of CO2 exchange was larger under the FACE than under ambient conditions.
Elevated CO2, drought and soil nitrogen effects on wheat grain quality
Authors: Kimball B. A. , Morris C. F. , Pinter P. J. , Wall G. W. , Hunsaker D. J. , Adamsen F. J. , LaMorte R. L. , Leavitt S. W. , Thompson T. L. , Matthias A. D. , Brooks T. J. 
Published: March 2003

Summary

The likely consequences of future high levels of atmospheric CO2 concentration on wheat (Triticum aestivum L.) grain nutritional and baking quality were determined.
Two free‐air CO2 enrichment (FACE; 550 mmol mol−1) experiments were conducted at ample (Wet) and limiting (Dry) levels of irrigation, and a further two experiments at ample (High‐N) and limiting (Low‐N) nitrogen concentrations. Harvested grain samples were subjected to a battery of nutritional and bread‐making quality tests.
The Dry treatment improved grain quality slightly (protein +2%; bread loaf volume +3%). By contrast, Low‐N decreased quality drastically (protein −36%; loaf volume −26%). At ample water and N, FACE decreased quality slightly (protein −5%; loaf volume −2%) in the irrigation experiments and there was no change in the nitrogen experiments. At Low‐N, FACE tended to make the deleterious effects of Low‐N worse (protein −33% and −39%, at ambient CO2 and FACE, respectively; loaf volume −22% and −29% at ambient CO2 and FACE, respectively).
The data suggest that future elevated CO2 concentrations will exacerbate the deleterious effects of low soil nitrogen on grain quality, but with ample nitrogen fertilizer, the effects will be minor.
Novel infection process in the indeterminate root nodule symbiosis between Chamaecytisus proliferus (tagasaste) and Bradyrhizobium sp.
Authors: Vega‐Hernández M. C. , Pérez‐Galdona R. , Dazzo F. B. , Jarabo‐Lorenzo A. , Alfayate M. C. , León‐Barrios M. 
Published: March 2003

Summary

The main characteristics of the symbiosis of tagasaste (Chamaecytisus proliferus ssp. proliferus var. palmensis), a woody legume forming N2‐fixing indeterminate nodules in response to infection by strains of Bradyrhizobium sp. (Chamaecytisus), are reported here.
The infection process in this legume was examined by bright field, phase contrast and transmission electron microscopy, and was found to be unlike any other previously described.
First steps in the infection process involve initiation of infection threads within deformed root hairs and induction of foci of host‐cell divisions in the inner root cortex. However, infection of root hairs aborts early, and instead, the bacteria use the crack‐entry mode of host infection, whereby they penetrate the periphery of the emerging nodule through an intercellular route, eventually infecting host nodule cells directly through altered cell walls. No successful infection threads were detected at any stage of primary‐host infection or nodule invasion. Indeterminate nodules were mainly formed on unbranched areas of lateral roots.
This is the first description of such a combination of events in an infection process in the Rhizobium–legume root‐nodule symbiosis.
Mycorrhizal development in a low nodulating pea mutant
Authors: Resendes C. M. , Geil R. D. , Guinel F. C. 
Published: March 2003

Summary

E107 is a pleiotropic mutant of Pisumsativum (pea) characterized by a decreased ability to form nodules. Its colonization by the arbuscular mycorrhizal fungus Glomusaggregatum is reported, and the mycorrhizal phenotype compared with the nodulation phenotype.
Four cleared lateral roots from 21‐d‐old plants were chosen randomly, and their lengths scanned for any fungal structures. Colonization success was determined by counting the numbers of extraradical hyphae, and calculating epidermal entry and cortical entry. Graft experiments were performed to establish which organ regulates mycorrhiza‐formation.
Two blocks to infection were obvious, at the root surface, and at the interface between the epidermis and the outermost cortical cell layer. Once the fungus breached this interface, it spread within the cortex and formed normal arbuscules. The mutant phenotype was controlled by the shoot.
The E107 mycorrhizal phenotype was designated as app+, low pen, low coi. The development of the fungal infection was similar to that of rhizobial infection and under the same shoot control. The phenotype of the mutant E107 strongly supports the hypothesis that mycorrhiza formation and nodulation are regulated by the same processes.
Radiation modifies the effect of water availability on the carbon isotope composition of beech (Fagus sylvatica)
Authors: Geßler Arthur , Schrempp Stefan , Matzarakis Andreas , Mayer Helmut , Rennenberg Heinz , Adams Mark A. 
Published: March 2003

Summary

Water availability and flux and carbon isotope and other chemical compositions of wood, foliage and phloem sap were quantified in a replicated field test examining the effects of exposure (north‐east, south‐west) and stem density on beech ecophysiology (Fagus sylvatica).
Standard techniques for quantifying water potential, water flux in stems and carbon isotope composition of wood and foliage were complemented with chemical analysis of phloem sap collected using the ‘phloem bleeding’ technique.
Phloem sap was similar in composition to other hardwoods. The δ13C signatures of sap reflected short‐term fluctuations in water availability and intercepted radiation, whereas foliar δ13C was a poor reflection of current environmental conditions.
δ13C of tree rings suggested that the south‐west‐facing site experienced a greater shortage of water during summer than the paired north‐east‐facing site. However, phloem δ13C analysis showed that interpreting the effects of water availability using δ13C might be confounded by radiation. Better integration of hydrological models with reliable indices of water stress in beech will be required for reliable predictions of growth, especially if (when) climates change.
Plant reproduction under elevated CO2 conditions: a meta‐analysis of reports on 79 crop and wild species
Authors: Jablonski Leanne M. , Wang Xianzhong , Curtis Peter S. 
Published: March 2003

Summary

Reproductive traits are key characteristics for predicting the response of communities and ecosystems to global change.
We used meta‐analysis to integrate data on eight reproductive traits from 159 CO 2 enrichment papers that provided information on 79 species.
Across all species, CO 2
enrichment (500–800 µl l
−1
) resulted in more flowers (+19%), more fruits (+18%), more seeds (+16%), greater individual seed mass (+4%), greater total seed mass (+25%), and lower seed nitrogen concentration, (N) (−14%). Crops and undomesticated (wild) species did not differ in total mass response to elevated CO
2
(+31%), but crops allocated more mass to reproduction and produced more fruits (+28% vs +4%) and seeds (+21% vs +4%) than did wild species when grown at high CO
2
. Seed [N] was not affected by high CO
2 concentrations in legumes, but declined significantly in most nonlegumes.
Our results provide robust estimates of average plant reproductive responses to CO 2
enrichment and demonstrate important differences among individual taxa and among functional groups. In particular, crops were more responsive to elevated CO
2 than were wild species. These differences and the substantial decline in seed [N] in many species have broad implications for the functioning of future natural and agro‐ecosystems.
Phenazines and their role in biocontrol by Pseudomonas bacteria
Authors: Chin‐A‐Woeng Thomas F. C. , Bloemberg Guido V. , Lugtenberg Ben J. J. 
Published: March 2003

SummaryVarious rhizosphere bacteria are potential (micro)biological pesticides which are able to protect plants against diseases and improve plant yield. Knowledge of the molecular mechanisms that govern these beneficial plant–microbe interactions enables optimization, enhancement and identification of potential synergistic effects in plant protection. The production of antifungal metabolites, induction of systemic resistance, and the ability to compete efficiently with other resident rhizobacteria are considered to be important prerequisites for the optimal performance of biocontrol agents. Intriguing aspects in the molecular mechanisms of these processes have been discovered recently. Phenazines and phloroglucinols are major determinants of biological control of soilborne plant pathogens by various strains of fluorescent Pseudomonas spp. This review focuses on the current state of knowledge on biocontrol by phenazine‐producing Pseudomonas strains and the action, biosynthesis, and regulation mechanisms of the production of microbial phenazines.
Consumer goals/skills that mothers want their children to learn
Authors: Carruth Betty Ruth , Skinner Jean D. 
Published: March 2003

AbstractThe study purpose was to assess consumer practices and attitudes of mothers (n= 117), and consumer goals/skills that their children were to learn. Mothers with at least one child aged 5–9 years were recruited from an ongoing study and through posters, flyers and referrals. Mail‐out surveys included a validated consumer questionnaire and requests for information related to socioeconomic status (SES), age, paid‐employment and gender/age of children. Responses were analysed using SAS, Cronbach’s alpha and qualitative analyses. Results indicated that mothers were of middle/upper SES and had 2.3 children/family, and 64% were in paid‐employment. Mother–child co‐shopping and mothers’ role modelling were major means of teaching consumer goals/skills. Children were to learn about getting the best buy and quality for the money, cost/unit comparison, being knowledgeable about products and avoidance of impulse buying. Mothers were consciously consumer training their children.
Association of nutrition concerns and socioeconomic status with exercise habits
Authors: Rimal Arbindra 
Published: March 2003

AbstractThe purpose of this study was to examine the association between socio‐economic characteristics and individual health behaviour patterns. Specifically, we looked at how individual demographics (i.e. age, gender, race, marital status, geographic location of households), socio‐economic status (i.e. education, income, children in the households) and respondents’ nutrition concern were related to the major health behaviour (i.e. exercise). Telephone interviews were conducted to collect the data from 2880 US households. A Poisson regression model was estimated to analyse the factors influencing physical exercise habits of adults. Results showed that the key socio‐economic variables influencing the exercise habit of US population were household income, education and family composition. The direct association of nutrition concern with exercise habits implied that health and nutrition programmes should emphasize good eating habit as well as healthy lifestyle.
Comparing online and non‐online shoppers
Authors: Lokken Sheri L. , Cross Ginger Wigington , Halbert Linda K. , Lindsey Gail , Derby Christy , Stanford Carla 
Published: March 2003

AbstractA web‐based survey was completed by 130 faculty and staff from a university located in the south‐eastern United States. The purposes of this study were to investigate: (a) consumer characteristics related to online shopping; (b) benefits of online shopping as perceived by online shoppers; and (c) concerns about online shopping as perceived by non‐online shoppers. Responses were analysed using SPSS for tests of chi‐square. Findings suggest that the differences between online shoppers and non‐online shoppers correspond with Rogers’1 categories of adopters, and that the educational needs of consumers also differ based on their previous experience with online shopping.
Expression of cyclin‐dependent kinase 5 and its activator p35 in models of induced apoptotic death in neurons of the substantia nigra in vivo
Authors: Neystat Michael , Rzhetskaya Margarita , Oo Tinmarla F. , Kholodilov Nikolai , Yarygina Olga , Wilson Alexandria , El‐Khodor Bassem F. , Burke Robert E. 
Published: March 2003

Cyclin‐dependent kinase 5 is predominantly expressed in postmitotic neurons and plays a role in neurite elongation during development. It has also been postulated to play a role in apoptosis in a variety of cells, including neurons, but little is known about the generality and functional significance of cdk5 expression in neuronal apoptosis in living brain. We have therefore examined its expression and that of its known activators, p35, p39 and p67, in models of induced apoptosis in neurons of the substantia nigra. We find that cdk5 is expressed in apoptotic profiles following intrastriatal injection of 6‐hydroxydopamine and axotomy. It is expressed exclusively in profiles which are in late morphologic stages of apoptosis. In these late stages, derivation of the profiles from neurons, and localization of expression to the nucleus, can be demonstrated by co‐labeling with a neuron‐specific nuclear marker, NeuN. In another model of induced apoptotic death in nigra, produced by developmental striatal lesion, kinase activity increases in parallel with cell death. While mRNAs for all three cdk5 activators are expressed in nigra during development, only p35 protein is expressed in apoptotic profiles. We conclude that cdk5/p35 expression is a general feature of apoptotic neuron death in substantia nigra neurons in vivo.