Differences In Tolerance Levels Research Articles

Salares versus coastal ecotypes of quinoa: Salinity responses in Chilean landraces from contrasting habitats

Quinoa (Chenopodium quinoa Willd.) is a highly salt-tolerant species subdivided into five ecotypes and exhibiting broad intra-specific differences in tolerance levels. In a greenhouse study, Chilean landraces belonging either to the salares (R49) or coastal lowlands (VI-1, Villarrica) ecotype with contrasting agro-ecological origins were investigated for their responses to high salinity. The effects of two levels of salinity, 100 (T1) and 300 (T2) mM NaCl, on plant growth and on some physiological parameters were measured. Leaf and root Na+ accumulation differed among landraces. T2 reduced growth and seed yield in all landraces with maximum inhibition relative to controls in R49. Salinity negatively affected chlorophyll and total polyphenol content (TPC) in VI-1 and Villarrica but not R49. Germination on saline or control media of seeds harvested from plants treated or not with NaCl was sometimes different; the best performing landrace was R49 insofar as 45–65% of seeds germinated on 500 mM NaCl-containing medium. In all landraces, average seedling root length declined strongly with increasing NaCl concentration, but roots of R49 were significantly longer than those of VI-1 and Villarrica up to 300 mM NaCl. Salt caused increases in seed TPC relative to controls, but radical scavenging capacity was higher only in seeds from T2 plants of R49. Total SDS-extractable seed proteins were resolved into distinct bands (10–70 kDa) with some evident differences between landraces. Salt-induced changes in protein patterns were landrace-specific. The responses to salinity of the salares landrace are discussed in relation to its better adaptation to an extreme environment.

Ethnic Attitudes of Hungarian Students in Romania

Participants in this study were ethnic Hungarian secondary students attending high schools in Romania in which Hungarian was the primary language of instruction. Attitudes of participants toward ethnic and cultural groups were measured using a variation of the Bogardus (1933) Scale of Social Distance. Results were consistent with predictions based on Allport's intergroup contact theory. Students reported a wide range of tolerance levels for majority and minority ethnic groups with which they were likely to have contact in Romania. However, the students reported little difference in tolerance levels for groups that are not a recognized part of the Romanian cultural landscape, such as people of Hispanic origin, and Native Americans.

Political tolerance in Portugal and Spain: The importance of circumstantial factors

A survey carried out in various European countries (the Citizenship, Involvement, Democracy [20012003] research project) revealed, rather surprisingly, that Portugal registered significantly higher overall levels of political tolerance than Spain (tolerance being measured by the number of minority groups the respondents excluded from participation in public meetings). The explanation put forward for these results was based on the distinction between structural tolerance, based on established dispositions and attitudes, and the circumstantial component of tolerance, which is dependent on the level of conflict with the minority groups. The greater presence in Spain than in Portugal of ideological extremism (Basque terrorism by ETA) and Islamic fundamentalism would explain this difference. In 2006, the same battery of questions measuring political tolerance was applied in Portugal and, partly, in Spain. In this study I seek to analyse (1) how these tolerance levels have developed, (2) whether the difference in tolerance levels between the two countries has been maintained and (3) whether the explanation for this difference is still valid.

Chlorination for power plant biofouling control: potential impact on entrained phytoplankton

Chlorination, used as anti‐fouling biocide in coastal power plants, has potential environmental consequences. Phytoplankton entrained into the cooling water circuit are subjected to chlorine stress. The paper reports a study on the effects of chlorination on phytoplankton entrained into the coolant system of a power plant operating on the East Coast of India. Field observations showed 1) a significant reduction (15–80%) in chlorophyll a as water passed from the intake point to the outfall and 2) partial restoration of chlorophyll a values as the discharged water mixed with the ambient sea. Laboratory experiments showed that growth rate, chlorophyll a and primary productivity of chlorine‐treated diatoms decreased, depending on dosage. There were species‐specific differences in tolerance levels and recovery pattern among the diatoms tested. Chaetoceros wighami and Amphiprora palludosa were sensitive, whereas Amphora coffeaeformis and Cocconeis scutellum were comparatively more tolerant. The paper discusses the impact of chlorine‐induced effects on entrained diatoms in light of the available data.

Environmental Risks Associated with Heavy Metal Contamination in Soil, Water and Plants in Urban and Periurban Agriculture

The India's population living in cities and urban areas has doubled to 27.8% since Independence. Our cities face enormous challenges of environmental pollution and health related problems. City authorities have often been reluctant to accept urban and periurban agriculture because of perceived health risks. Nevertheless, in most cities the world over, periurban agriculture is practiced on a substantial scale, despite prohibitive laws and regulations. Non-degradable pollutants added to the system through anthropogenic activities like heavy metals in air, soil, water and crops bother us more than others as these tend to bio-accumulate. Throughout history, heavy metal contamination has long plagued mankind - undermining intelligence and causing debasing behaviour. Toxicity of some of the heavy metals even leads to deficiency of essential metals like Zn, Cu, etc. in both human and animals. Climate, nutritional status, genetic predisposition, type of work and exposure level influence the intensity of impact on health. Permissible levels prescribed by different organizations differ because of differences in tolerance levels of people of different origins and differences in threat perception of the people. With our current level of knowledge a permanent and foolproof method to stop entry of heavy metals into the food chain is impossible. However, methods are available to reduce intensity of the effects. Alternative land use with crops not directly consumed by human beings and animals offers a better remedy to contain heavy metal entry into food chain. India has a wide ranging set of environmental laws that lay down norms for air, water, soil, wastes, etc. Legislative frame work has been developed in the belief that a policing model is sufficient. It does not go beyond that. Regulatory mechanisms may not be effective in isolated cases but are essential drivers to augment other approaches, by putting a "cap" on the level of degradation that is socially acceptable, as well as creating space for other, cleaner and more acceptable alternatives to be "viable".

Pollen morphological features and impact of temperature on pollen germination of various Pinus species

The aim of this study was to determine if differences in pollen morphology and response to temperature treatments were apparent among seven Pinus species used in an inter-specific hybridisation programme. The seven species included were: P. caribaea, P. elliottii, P. greggii, P. oocarpa, P. patula, P. radiata and P. tecunumanii. This study showed that pollen from the seven Pinus species displays the structure typical of the Pinaceae, having no visibly distinguishing structural characteristics. Differences in pollen grain diameter, measured across the distal region of the grain, were found among species and among different clones of Pinus patula. The mean grain diameters ranged from 42μm (P. patula) to 50μm (P. radiata). Within P. patula they ranged between 42μm and 47μm. Different species responded differently to temperature treatments of dry-stored and re-hydrated germinating pollen. Pollen stored at low humidity (below 10%) could tolerate relatively high temperatures up to 80°C, and still maintain some level of viability. P. caribaea and P. greggii maintained viability of 19 and 33%, respectively, after treatment at 80°C. The 90°C treatment resulted in zero viability for the three species investigated: P. caribaea, P. greggii and P. patula. In contrast to dry- stored pollen, re-hydrated pollen germinated in vitro at different temperatures, had lower levels of tolerance. Optimal germination occurred at 32°C and steadily declined for all species as the temperature was increased until 44°C at 2°C increments. P. caribaea, P. patula and P. tecunumanii still germinated, albeit at low levels at 40°C, but no germination occurred above 42°C. Differences in pollen tube length were observed between different species incubated at 30°C for 72h. P. caribaea displayed the longest tube length (242μm) while some clones of P. patula had the shortest pollen tubes (92μm). Morphological features cannot be used to distinguish among the species studied, but there were differences in tolerance levels to temperature treatments of dry-stored and re-hydrated pollen among these species.

Knowledge, attitudes and behavior regarding secondhand smoke among Asian Americans

Background This study seeks to measure exposure to secondhand smoke and to evaluate potential differences in knowledge, attitudes, and tolerance of secondhand smoke among subgroups of Asian Americans in the Delaware Valley region of Pennsylvania and New Jersey. Methods A cross-sectional study was conducted among 1374 Asian Americans, which included Chinese, Koreans, Vietnamese, and Cambodians. The sample was selected by using a stratified-cluster proportional sampling technique. Study measures included demographic variables, smoking status, exposure to secondhand smoke, and knowledge, attitudes, and behavior regarding secondhand smoke. Data were analyzed using SPSS. Results Involuntary exposure to secondhand smoke remains a common public health hazard among Asian Americans, with 38.3% reporting exposure at home and 40.3% at the worksite. Knowledge and tolerance differed significantly by ethnic groups, gender, education, and smoking status. Knowledge level had a significant effect on tolerance behavior. Conclusions Findings indicate an urgent need for a smoke-free policy at home, in the work place, and in public areas. Tobacco prevention/intervention and cessation programs for Asian Americans should emphasize the adverse health effects of secondhand smoke and promote a smoke-free environment. Further studies are needed to explore the unexplained differences in tolerance levels regarding secondhand smoke across ethnic groups.

Tolerance to the Herbicide Glufosinate in Transgenic Cranberry (Vaccinium macrocarpon Ait.) and Enhancement of Tolerance in Progeny

The American cranberry (Vaccinium macrocarpon Ait.) was genetically transformed with the bar gene, conferring tolerance to the phosphinothricin-based herbicide glufosinate. Plants of one `Pilgrim' transclone grown under greenhouse conditions were significantly injured by foliar treatments of 100 mg·L-1 glufosinate, although the injury was less severe when compared to untransformed plants. However, the same transclone grown outdoors in coldframes survived foliar sprays of 500 mg·L-1 glufosinate and higher, while untransformed plants were killed at 300 mg·L-1. Actively growing shoot tips were the most sensitive part of the plants and at higher dosages of glufosinate, shoot-tip injury was evident on the transclone. Injured transgenic plants quickly regrew new shoots. Shoots of goldenrod (Solidago sp.) and creeping sedge (Carex chordorrhizia), two weeds common to cranberry production areas, were seriously injured or killed at 400 mg·L-1 glufosinate when grown in either the greenhouse or coldframe environment. Stable transmission and expression of herbicide tolerance was observed in both inbred and outcrossed progeny of the above cranberry transclone. Expected segregation ratios were observed in the outcrossed progeny and some outcrossed individuals demonstrated significantly enhanced tolerance over the original transclone, with no tip death at levels up to 8000 mg·L-1. Southern analysis of the original transclone and two progeny selections with enhanced tolerance showed an identical banding pattern, indicating that the difference in tolerance levels was not due to rearrangement of the transgene. The enhanced tolerance of these first generation progeny was retained when second generation selfed progeny were tested.

A Greenhouse Screening Technique for Acid Soil Tolerance in Maize

AbstractEvaluating maize (Zea mays L.) in the field for tolerance to soil acidity is expensive and provides variable results. To identify alternative screening techniques for maize, the present study adapted a pot bioassay already used for other crops. Two experiments were conducted. One included a set of diallel crosses from eight parents and the other a set of 10 open‐pollinated cultivars. These materials were evaluated under field conditions, in nutrient solution, and in pots containing 2 kg of soil. The best results were obtained after growing plants for 14 d in pots containing soils having intermediate stress (45–65% AI saturation). Fresh root weight, total length (or lateral root length), and visual scoring provided the best separation between tolerant and susceptible genotypes, lacked a significant genotype ✕ soil interaction, and were efficient, simple, and rapid measurements. Significant phenotypic correlations (≈ 0.55) were observed between these variables and yield in the field. While efficiently distinguishing tolerant from susceptible genotypes, the pot bioassay could not clearly detect differences in levels of tolerance. This technique should be useful mainly in the early stages of maize breeding. Results suggest that maize possesses several mechanisms for tolerance to soil acidity.

Sex differences in levels of tolerance and attribution of blame for sexual harassment on a university campus

Although the issue of sexual harassment on college campuses has been discussed in the literature for the last five years, little attention has been paid to sex differences in levels of tolerance and attribution of blame in harassment. The current survey, based on a random sample of faculty, students, and staff at a large southern university, details sex differences in definitions of harassment, in attitudes toward causes, in attitudes toward romantic relationships between faculty and students, and in attitudes toward university policy. The authors suggest that sex differences reflect differing perceptions by men and women of their own self-interests within the university, and the organizational environment. Attention is also directed to the explanatory power of attribution theory.

Genetic and cytogenetic analyses of the A genome of Triticum monococcum. III. Cytology, breeding behavior, fertility, and morphology of autotriploids

Mature triploid seed from reciprocal (2n = 4x × 2n = 2x) crosses in Triticum monococcum was minute and shrivelled because of endosperm collapse and therefore failed to germinate. This necessitated the excision of embryos from successful pollinations and their growth in vitro to ensure subsequent germination so as to obtain viable and vigorous autotriploids. A comparison of these triploids with their diploid and tetraploid progenitors revealed that cell size, kernel weight, and pistil size increased with an increase in ploidy level. However, unlike other species, optimum expression was observed in these triploids for plant height, tillering, size of spikes, number of spikelets/spike, and leaf size. Earliness, althoughenhanced in tetraploids relative to diploids, was delayed in the triploids. Mean numbers of univalents, bivalents, and trivalents per microsporocyte were 2.65, 2.60, and 4.38, respectively. Only chains (93.5%), which formed V-shaped metaphase I (MI) configurations, frying pan (5.0%), and Y-shaped (1.5%) trivalent associations occurred. On the average, two reciprocal exchanges occurred per bivalent and trivalent. Trivalents corriented randomly at MI. At anaphase I, all sets of three homologues segreated randomly to the two poles, lagging univalents always divided equationally, and only meiocytes with such chromosomes formed micronuclei. The reasons for similarities and differences in meiotic behaviour of T. monococcum triploids with those of other species are discussed. Confirmation of the conclusions drawn with respect to the cytology of the triploids was obtained from similar cytological observations with primary single trisomics. These triploids produced euploids, primary single trisomics as well as some double and triple trisomics all of which differed phenotypically from diploids. Triticum monococcum, like most diploid species, is highly intolerant of aneuploidy. Possible reasons for the differences in levels of tolerance of aneuploidy in species like T. monococcum and those like Petunia hybrida, which are highly tolerant of aneuploidy, are discussed. Pollen fertility was high and seed fertility was very low. Reasons for the latter as well as the high fertility in species that are highly tolerant of aneuploidy and allotriploids are discussed.Key words: Triticum monococcum, autotriploid, trisomic, cytology, breeding behavior, fertility, morphology.

Influence of Maturation Temperature and Stage of Kernel Development on Sprouting Tolerance of Wheat and Triticale1

This study was conducted to provide some basic information regarding the influence of (i) stage of kernel maturation and (ii) temperature during kernel maturation on sprouting tolerance of triticale (X Triticosecale Wittmack) and wheat (Triticum aestivum L.). Tolerances were compared using in vitro germination tests (17 and 25°C germination temperatures), and by rain simulation. Developing seed harvested from the 2nd to 7th week postanthesis, exhibited a significantly higher rate of loss of sprouting tolerance when germinated at 17°C relative to a 25°C germination temperature. Genotypic differences in tolerance levels, however, were more marked at the 25°C regime. Results from rain simulation closely paralleled those from the 2S°C in vitro germination tests, albeit tolerance scores of the four genotypes tested were approximately 25% lower. The influence of temperature on sprouting tolerance during seed maturation was clearly defined using the 25°C germination test, with the four genotypes under study retaining a highly consistent tolerance score ranking for each of three temperatures maintained during kernel development. From these results it was concluded that the 25°C in vitro germination test provided a suitable alternative for the rain‐simulator facility that may not always be available. The germination test also produced tolerance ratings that consistently differentiated among genotypes over a range of stages of kernel development as well as different temperatures during kernel maturation.

Differences in Teacher Tolerance: An Illusory Phenomena?

Regular and special educators (92) completed the Teacher Tolerance Scale to identify group differences in levels of tolerance for behavior problems commonly found in the regular class. A one-way multivariate analysis of variance indicated no significant differences between groups. Of the 11 behavioral clusters, the most outer-directed behaviors (Negative Aggressive, Poor Peer Cooperation) were identified as least tolerable by both groups. Results suggest that concerns of regular and special educators may be more alike than different, yielding implications for consultative services and future research.

Sexual Assault and Harassment: A Campus Community Case Study

EDITORS' NOTE: Howz serious and widespread a problem is sexual harassment in our universities? What means will effectively diminish its incidence without violating the rights of individuals? Each of thefollowing essays answers one of these two questions. In the first, Bernice Lott, Mary Ellen Reilly, and Dale Howard describe the results of a 1979 survey that examined a sample of the entire University of Rhode Island population. Its purpose was to determine how many of the respondents in the sample group had personal knowledge of or had experienced any form of sexual assault, intimidation, or insult; how they had responded to assault; and their beliefs about harassment in general. In the second essay, Judith Berman Brandenburg delineates a response to the problem worked out at Yale University: the establishment of a grievance procedure administered through a specially selected board. The process of this honest search for answers uncovers other questions: Do we have a definition of sexual harassment upon which most people will agree? Is power thefactor that transforms what may be cajolery into harassment? If so, power in what forms? Do these forms make the problem invulnerable to any solution? With these essays we open a dialogue on such questions. We invite your letters in response, in the hope that through the exchange we canfurther advance feminist efforts to analyze-and to overcome-this pernicious form of sexual injustice.

EFFECT OF FEEDING VOMITOXIN-CONTAMINATED WHEAT TO PIGS

Two groups each of three gilts (39 ± 4 kg) were given ad libitum a diet containing 70% vomitoxin-contaminated (1 ppm) wheat (V) and two other groups (controls) the same diet with 70% clean wheat (C). Similarly, for 18 gilts (75 ± 4 kg), two groups were given diet C, two diet V and two groups diet CV containing 35% contaminated and 35% clean wheat. Pigs fed diet V lost weight during the first few days and their weight was less than that of the C pigs; the effect was less pronounced for the CV pigs. Intakes of diets V and CV declined initially then improved; variation in response indicated individual differences in tolerance level during the 21-day experiments. Fifty-six pigs (43 ± 6 kg) were allocated to seven diets and by two sexes in four replicates. Dietary treatments were 0, 14, 28, 42, 56 and 100% vomitoxin-contaminated (1 ppm) wheat in a grower diet with a corn-based diet acting as positive control. There was a linear decrease (P < 0.01) in feed intake with increasing vomitoxin level; weight gains differed significantly in the first week but the differences were not maintained over the 7-wk experimental period. A similar experiment with 56 younger (21 ± 2 kg) pigs for a 4-wk feeding period gave differences in feed intake and weight gain which were not significant; although, differences in gain reached significance (P < 0.05) when positive control data were excluded. Postmortem examinations were undertaken for pigs in all but the first experiment; some discoloration of the stomach and large intestine suggested differences among diets, but none was significant. Key words; Vomitoxin, wheat, pigs, feeding

Greenbug Resistance in Commercial Sorghum Hybrids in the Seedling Stage12

In the seedling stage, commercial sorghum hybrids that were resistant to Schizaphis graminum (Rondani) displayed various degrees of tolerance. Antibiosis and nonpreference in the resistant hybrids were not detected in newly emerged seedlings in laboratory or field tests. Data indicated that greenbug damage sustained in the seedling stage was due to more than localized leaf-tissue destruction. No significant differences in tolerance levels were detected among the 3 sources of resistance in the commercial hybrids tested. Heterozygous resistant hybrids withstood 1.5–2X as many greenbugs as did the susceptible hybrid, and the homozygous resistant hybrid withstood more than twice as many greenbugs as its susceptible counterpart. Results demonstrate the value of greenbug resistance in seedling stage sorghum. High infestations at the time of plant emergence could result in economic damage and require insecticide treatment of resistant hybrids.

Experimental studies on macroinvertebrate predator–prey impact of pesticides. The reactions of Rhyacophila and Hydropsyche (Trichoptera) larvae to Simulium larvicides

Acute toxicity tests with the predaceous trichopteran larvae of Rhyacophila dorsalis and Hydropsyche pellucidula in a laboratory-simulated stream have shown that both species have a high survival rate after short exposures, 15 min to 1 h, to concentrations of temephos(Abate) and chlorpyrifos methyl that produce a mortality of 90% or more in late-instar Simulium larvae. A similar differential reaction to the synthetic pyrethroid permethrin was demonstrated in the case of Hydropsyche but not Rhyacophila.The implication of these findings is discussed firstly in relation to the environmental impact of Simulium control programmes based on application of larvicides to rivers and streams, and secondly to the wider problem of evaluating the impact of pesticides and allied toxic chemicals on stream ecosystems.It is concluded that although significant differences in tolerance level to some insecticides between prey (Simulium) and predator (trichopteran larvae) can be demonstrated in the laboratory, the margin of safety is not sufficiently wide to assure selective control of Simulium larvae by these chemicals under the less precise conditions of larvicide application in the field.

Influence of post mortem changes on experimental safety belt injuries.

Belt protected car occupants involved on head-on collisions do not seem to suffer as severe injuries as unembalmed cadavers subjected to comparable simulated head-on collisions. Therefore it has been questioned if cadavers constitute adequate test specimens for study of thoracic tolerances. This investigation compares injuries in safety belt wearing living and dead pigs which have been subjected to simulated head-on collisions on an acceleration tract. Tests were performed on all 20 pigs (10 living and 10 dead). The arterial side of the circulatory system of the dead pigs was infused. The force in the safety belts, the intraaortic pressure, the impact velocity and the deceleration of the sled were recorded. The tests were high speed filmed. Post mortem examination of the pigs revealed differences in injury severity. Dead pigs more easily suffered rib fractures. Deformation of the rib cage due to stripping of the periosteum and laceration of surrounding tissue occurred mainly in the dead pigs. Laceration of intrathoracic blood vessels was seen in dead pigs while isolated heart lesions were seen only in living animals. The main cause of these differences in tolerance level seems to be post mortem changes of the mechanical properties of the different tissues. The results are valid for pigs but indicate that great care has to be exercised when results obtained from cadaver experiments are evaluated concerning thoracic tolerance.

Tolerance to Pierce’s Disease and the Associated Rickettsia-like Bacterium in Muscadine Grape1

Abstract Rickettsia-like bacteria, implicated as the casual agent of Pierce’s disease, were easily observed by electron microscopy in the xylem of muscadine grape (Vitis rotundifolia Michx.) with symptoms of Pierce’s disease. The symptoms included severe stunt, marginal leaf burn, and dieback. The bacterium was observed only in the tracheary elements of the xylem. Differences in levels of tolerance to Pierce’s disease were found in muscadine cultivars and breeding selections. Muscadine cultivars and selections developed at Experiment, GA were generally more tolerant to the disease than those developed at Meridian, MS or Raleigh, NC, however, there were some highly tolerant cultivars from all 3 locations. Cultivars from MS were much more tolerant to the disease than were selections from that location which were never considered acceptable for release to commercial growers.

Ultraviolet radiation thresholds for corneal injury in antarctic and temperate-zone animals

The threshold for corneal damage was determined for a series of antarctic and temperate-zone animals. 1. 1. Keratitis was produced in all animals tested. 2. 2. Susbtantial differences in tolerance levels were found. The thresholds ranged from about 0·3 × 10 6 to 0·6 × 10 6 ergs/cm 2 except for the California ground squirrel, which had a higher threshold of 1·5 · 10 6 ergs/cm 2. 3. 3. The domesticated birds were more sensitive than the antacrtic birds, indicating that adaptation of the cornea to u.v. radiation may be important as protection against snow blindness. 4. 4. Transmission spectra of the cornea showed that the cornea absorbed most of the damaging short wave length u.v. radiation, and that absorption was complete above wave lengths which have the most damaging effect, i.e. near 290 mμ.