bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Back of an Envelope
Authors: Mertens Stephan
Published: September 2008

Guesstimation
. Solving the World's Problems on the Back of a Cocktail Napkin.
By Lawrence Weinstein and John A. Adam
. Princeton University Press, Princeton, NJ, 2008. 319 pp. Paper, $19.95, £11.95. ISBN 9780691129495.

Working through this eclectic collection of estimation problems will hone one's ability to produce plausible quantitative answers.
Contrasts Across the 49th Parallel
Authors: Randall Stephen
Published: September 2008

Canada and the United States
. Differences That Count, 3rd ed.
David M. Thomas and Barbara Boyle Torrey, Eds.
. Broadview, Peterborough, Ontario, 2008 (). 434 pp. Paper, $42.95, C$42.95, £24.99. ISBN 9781551117126.

The contributors compare and contrast Canadian and US experiences with and approaches to a variety of political, social, legal, and demographic topics.
In defence of Kant’s moral prohibition on suicide solely to avoid suffering
Authors: Vong G
Published: August 2008

In Ian Brassington’s article in a previous issue of this journal, he argues that suicide for the purpose of avoiding suffering is not, as Kant has contended, contrary to the moral law. Brassington’s objections are not cogent because they rely upon the exegetically incorrect premise that according to Kant the priceless value of personhood is in the noumenal world that we have no perception of. On the basis of Kant’s normative, metaphysical and epistemological theory, I argue, contrary to Brassington, that according to Kant personhood’s moral value is explicitly in the sensible, phenomenal realm. While I argue that suicide solely to avoid suffering is immoral, I show that Kant’s normative system allows some acts of suicide to be morally permissible. In the course of the discussion of the value of humanity’s rationality and the immorality of suicide, I will discuss the broader modern medical ethical implications of Kant’s arguments, such as the moral impermissibility of using rationality depriving drugs, such as ketamine, solely to avoid pain.
To see for myself: informed consent and the culture of openness
Authors: Walter T
Published: August 2008

Informed consent needs to be practised within a culture of openness if it is to enhance public trust in medical procedures around death. Openness should entail patients not just receiving information from doctors, but also having the right to see certain medical procedures. This article proposes in particular that it would be desirable for the public to be allowed to attend an autopsy of a person they do not know. Evidence from the UK, where members of the public may go backstage to witness the process of cremation, the other technical process in which dead bodies are violently but legitimately assaulted, suggests benefits from a policy of openness. When a family consents to cremation in Britain, their consent is only minimally informed, but the system has nothing to hide, and trust is high. This suggests that the opportunity for lay people also to witness certain medical procedures might do more to restore public trust in medical procedures around death than a narrow interpretation of informed consent in which information is controlled by the profession.
Increasing the amount of payment to research subjects
Authors: Resnick D B
Published: August 2008

This article discusses some ethical issues that can arise when researchers decide to increase the amount of payment offered to research subjects to boost enrollment. Would increasing the amount of payment be unfair to subjects who have already consented to participate in the study? This article considers how five different models of payment—the free market model, the wage payment model, the reimbursement model, the appreciation model, and the fair benefits model—would approach this issue. The article also considers several practical problems related to changing the amount of payment, including determining whether there is enough money in the budget to offer additional payments to subjects who have already enrolled, ascertaining how difficult it will be to re-contact subjects, and developing a plan of action for responding to subjects who find out they are receiving less money and demand an explanation.
Decision-making in patients with advanced cancer compared with amyotrophic lateral sclerosis
Authors: Astrow A B , Sood J R , Nolan M T , Terry P B , Clawson L , Kub J , Hughes M , Sulmasy D P
Published: August 2008

Aim:

Patients with advanced cancer need information about end-of-life treatment options in order to make informed decisions. Clinicians vary in the frequency with which they initiate these discussions.

Patients and methods:

As part of a long-term longitudinal study, patients with an expected 2-year survival of less than 50% who had advanced gastrointestinal or lung cancer or amyotrophic lateral sclerosis (ALS) were interviewed. Each patient’s medical record was reviewed at enrollment and at 3 months for evidence of the discussion of patient wishes concerning ventilator support, artificial nutrition and hydration (ANH), resuscitation (DNR) and hospice care. A Kaplan–Meier analysis was also performed and 2-year survival calculated.

Results:

60 cancer and 32 ALS patients were enrolled. ALS patients were more likely than cancer patients to have evidence of discussion about their wishes for ventilator support (31% vs 0%, p<0.001), ANH (38% vs 0%, p<0.001), DNR (25% vs 0%, p<0.001) and hospice care (22% vs 5%, p = 0.03). At 6 months, 91% of ALS patients were alive compared with 62% of cancer patients; at 2 years, 63% of ALS patients were alive compared with 23% of cancer patients (p<0.001).

Conclusions:

Cancer patients were less likely than ALS patients to have had documented advanced care planning discussions despite worse survival. This may reflect perceptions that ALS has a more predictable course, that advanced cancer has a greater number of treatment options, or differing views about hope. Nevertheless, cancer patients may be less adequately prepared for end-of-life decision-making.
What reasons do those with practical experience use in deciding on priorities for healthcare resources? A qualitative study
Authors: Hasman A , Mcintosh E , Hope T
Published: August 2008

Background:

Priority setting is necessary in current healthcare services. Discussion of fair process has highlighted the value of developing reasons for allocation decisions on the basis of experience gained from real cases.

Aim:

To identify the reasons that those with experience of real decision-making concerning resource allocation think relevant in deciding on the priority of a new but expensive drug treatment.

Methods:

Semistructured interviews with members of committees with responsibility for making resource allocation decisions at a local level in the British National Health Service, analysed using modified grounded theory.

Results:

22 interviews were carried out. 14 reasons were identified. Four reasons were almost universally considered most important: cost effectiveness; clinical effectiveness; equality and gross cost. No one reason was considered dominant. Some considerations, such as political directives and fear of litigation, were thought by many participants to distort decision-making. There was a substantial lack of agreement over the relevance of some reasons, such as the absence of alternative treatment for the condition.

Conclusions:

There is a clear consensus on the importance and role of a limited number of reasons in allocation decisions among participants. A focus on the process of decision-making, however, does not obviate the need for those involved in the process to engage with problematical ethical issues, nor for the importance of further ethical analysis.
The remote prayer delusion: clinical trials that attempt to detect supernatural intervention are as futile as they are unethical: Figure 1
Authors: Paul G
Published: August 2008

Extreme rates of premature death prior to the advent of modern medicine, very low rates of premature death in First World nations with low rates of prayer, and the least flawed of a large series of clinical trials indicate that remote prayer is not efficacious in treating illness. Mass contamination of sample cohorts renders such clinical studies inherently ineffectual. The required supernatural and paranormal mechanisms render them implausible. The possibility that the latter are not benign, and the potentially adverse psychological impact of certain protocols, renders these medical trials unethical. Resources should no longer be wasted on medical efforts to detect the supernatural and paranormal.
What do medical students experience as moral problems during their obstetric and gynaecology clerkship?: Table 1
Authors: Olthuis G , Dukel L
Published: August 2008

This article reports on moral problems that were raised by medical students as the basis for an ethical case-conference in an obstetrics and gynaecology clerkship. After introducing the issue of teaching clinical ethics, the method of our case-conference is explained. Next, the variety of topics and related moral problems are presented. The article continues with a discussion of three distinct and challenging aspects that characterise obstetrics and gynaecology as a domain for teaching clinical ethics. The conclusion puts forward three significant points our review raises.
Life extension, overpopulation and the right to life: against lethal ethics
Authors: Cutas D E
Published: August 2008

Some of the objections to life-extension stem from a concern with overpopulation. I will show that whether or not the overpopulation threat is realistic, arguments from overpopulation cannot ethically demand halting the quest for, nor access to, life-extension. The reason for this is that we have a right to life, which entitles us not to have meaningful life denied to us against our will and which does not allow discrimination solely on the grounds of age. If the threat of overpopulation creates a rights conflict between the right to come into existence, the right to reproduce, the right to more opportunities and space (if, indeed, these rights can be successfully defended), and the right to life, the latter ought to be given precedence.
Making a difference: incorporating theories of autonomy into models of informed consent
Authors: Delany C
Published: August 2008

Background:

Obtaining patients’ informed consent is an ethical and legal obligation in healthcare practice. Whilst the law provides prescriptive rules and guidelines, ethical theories of autonomy provide moral foundations. Models of practice of consent, have been developed in the bioethical literature to assist in understanding and integrating the ethical theory of autonomy and legal obligations into the clinical process of obtaining a patient’s informed consent to treatment.

Aims:

To review four models of consent and analyse the way each model incorporates the ethical meaning of autonomy and how, as a consequence, they might change the actual communicative process of obtaining informed consent within clinical contexts.

Methods:

An iceberg framework of consent is used to conceptualise how ethical theories of autonomy are positioned and underpin the above surface, and visible clinical communication, including associated legal guidelines and ethical rules. Each model of consent is critically reviewed from the perspective of how it might shape the process of informed consent.

Results and discussion:

All four models would alter the process of obtaining consent. Two models provide structure and guidelines for the content and timing of obtaining patients’ consent. The two other models rely on an attitudinal shift in clinicians. They provide ideas for consent by focusing on underlying values, attitudes and meaning associated with the ethical meaning of autonomy.

Conclusions:

The paper concludes that models of practice that explicitly incorporate the underlying ethical meaning of autonomy as their basis, provide less prescriptive, but more theoretically rich guidance for healthcare communicative practices.
Reproductive cloning in humans and therapeutic cloning in primates: is the ethical debate catching up with the recent scientific advances?
Authors: Camporesi S , Bortolotti L
Published: August 2008

After years of failure, in November 2007 primate embryonic stem cells were derived by somatic cellular nuclear transfer, also known as therapeutic cloning. The first embryo transfer for human reproductive cloning purposes was also attempted in 2006, albeit with negative results. These two events force us to think carefully about the possibility of human cloning which is now much closer to becoming a reality. In this paper we tackle this issue from two sides, first summarising what scientists have achieved so far, then discussing some of the ethical arguments in favour and against human cloning which are debated in the context of policy making and public consultation. Therapeutic cloning as a means to improve and save lives has uncontroversial moral value. As to human reproductive cloning, we consider and assess some common objections and failing to see them as conclusive. We do recognise, though, that there will be problems at the level of policy and regulation that might either impair the implementation of human reproductive cloning or make its accessibility restricted in a way that could become difficult to justify on moral grounds. We suggest using the time still available before human reproductive cloning is attempted successfully to create policies and institutions that can offer clear directives on its legitimate applications on the basis of solid arguments, coherent moral principles, and extensive public consultation.
Challenges of informed choice in organised screening
Authors: Østerlie W , Solbjør M , Skolbekken J-A , Hofvind S , Sætnan A R , Forsmo S
Published: August 2008

Context:

Despite much research on informed choice and the individuals’ autonomy in organised medical screening, little is known about the individuals’ decision-making process as expressed in their own words.

Objectives:

To explore the decision-making process among women invited to a mammography screening programme.

Setting:

Women living in the counties of Sør- and Nord-Trøndelag, Norway, invited to the first round of the Norwegian Breast Cancer Screening Program (NBCSP) in 2003.

Methods:

Qualitative methods based on eight semistructured focus-group interviews with a total of 69 women aged 50–69 years.

Results:

The decision to attend mammography screening was not based on the information in the invitation letter and leaflet provided by the NBCSP. They perceived the invitation letter with a prescheduled appointment as if a decision for mammography had already been made. This was experienced as an aid in overcoming the postponements that easily occur in daily lives. The invitation to mammography screening was embraced as an indication of a responsible welfare state, “like a mother taking care.”

Conclusion:

In a welfare state where governmental institutions are trusted, mass screening for disease is acknowledged by screening participants as a valued expression of paternalism. Trust, gratitude, and convenience were more important factors than information about benefits, harms, and risks when the women made their decisions to attend screening. These elements should be included in the ethical debates on informed choice in preventive medicine.
Dutch criteria of due care for physician-assisted dying in medical practice: a physician perspective
Authors: Buiting H M , Gevers J K M , Rietjens J A C , Onwuteaka-Philipsen B D , van der Maas P J , van der Heide A , van Delden J J M
Published: August 2008

Introduction:

The Dutch Euthanasia Act (2002) states that euthanasia is not punishable if the attending physician acts in accordance with the statutory due care criteria. These criteria hold that: there should be a voluntary and well-considered request, the patient’s suffering should be unbearable and hopeless, the patient should be informed about their situation, there are no reasonable alternatives, an independent physician should be consulted, and the method should be medically and technically appropriate. This study investigates whether physicians experience problems with these criteria in medical practice.

Methods:

In 2006, questionnaires were sent to a random, stratified sample of 2100 Dutch physicians (response rate: 56%). Physicians were asked about problems in their decision-making related to requests for euthanasia or assisted suicide after enforcement of the 2002 Euthanasia Act.

Results:

Of all physicians who had received a request for euthanasia or assisted suicide (75%), 25% had experienced problems in the decision-making with regard to at least one of the criteria of due care. Physicians who had experienced problems mostly indicated to have had problems related to evaluating whether or not the patient’s suffering was unbearable and hopeless (79%) and whether or not the patient’s request was voluntary or well considered (58%).

Discussion:

Physicians in The Netherlands most frequently reported problems related to aspects in which they have to evaluate the patient’s subjective perspective(s). However, it can be questioned whether placing emphasis on these subjective aspects is an adequate fulfilment of the duties imposed on physicians, as laid down in the Dutch Euthanasia Act.
The search for clarity in communicating research results to study participants
Authors: Shalowitz D I , Miller F G
Published: August 2008

Current guidelines on investigators' responsibilities to communicate research results to study participants may differ on (1) whether investigators should proactively re-contact participants, (2) the type of results to be offered, (3) the need for clinical relevance before disclosure, and (4) the stage of research at which results should be offered. Lack of consistency on these issues, however, does not undermine investigators' obligation to offer to disclose research results: an obligation rooted firmly in the principle of respect for research participants.
The case for re-thinking incest laws
Authors: Farrelly C
Published: August 2008

The recent case of German siblings Patrick Stübing (age 30 years) and his sister Susan Karolewski (age 22 years) has reignited debate over the criminalisation of sexual intercourse among consanguine descendants. The primary justification for criminalising incest is the purported increased risk of genetic disabilities among offspring, but is criminalising sexual intercourse an empirically sound and proportionate response to this increased risk? To answer this question we must consider the specifics of the harm in question (eg, is it a harm to the child or a societal harm) and the magnitude of the harms of the intervention. The example of incest law has important implications for liberal societies. If we can justify imprisoning consenting adults for choosing partners who will increase the risk of having children with disabilities, then we set a troubling precedent for all couples who may pass on genetic disorders to their children.
The distribution and ultrastructure of chloroplasts in leaves differing in photosynthetic carbon metabolism. I. Wheat, Sorghum, and Aristida (Gramineae)
Authors: Bisalputra T. , Downton W. J. S. , Tregunna E. B.
Published: September 2008

The ultrastructure of the chlorenchymatous tissues around the vascular bundles of three different types of grass leaves is described. In the temperate grass leaf, as exemplified by wheat, the inner mestom sheath contains proplastids. Normal chloroplasts are found only within the mesophyll cells. Smaller chloroplasts occur in cells of the ill-defined parenchymatic bundle sheath. This type of leaf has the photosynthetic pathway described by Calvin and a high carbon dioxide compensation value. In the tropical grasses, Sorghum and Aristida, the new photosynthetic pathway proposed by Hatch et al. and low carbon dioxide compensation are correlated with development of the parenchymatic bundle sheath. Cytological evidence indicates that cells of the bundle sheath are much more active than the surrounding mesophyll tissue. The specialized chloroplasts of the bundle sheath cells may be responsible for the physiological and biochemical differences between leaves of tropical and temperate grasses.
Growth responses of Marquillo × Kenya Farmer wheat dwarf 1 and 2 to gibberellic acid, kinetin, and indolebutyric acid under controlled environmental conditions
Authors: Yao Yun-te , Canvin David T.
Published: September 2008

A "grass-clump" dwarf wheat, Marquillo × Kenya Farmer 2 was grown in growth cabinets under continuous light or a 16-h photoperiod and a temperature regime of 8 h 21 °C and 16 h 16 °C. Plants were treated singly or with combinations of gibberellic acid (GA), indolebutyric acid, and kinetin. Indolebutyric acid and kinetin had no effect on plant height or development and did not alter the response to gibberellic acid. Gibberellic acid treatment increased culm height and induced plants to flower earlier but suppressed final yields of shoot and seed. Continuous light decreased plant height, time to ear emergence, and tiller number but did not alter shoot or seed yields.Marquillo × Kenya Farmer wheat dwarf 2 and Marquillo × Kenya Farmer wheat dwarf 1 were grown in growth cabinets under continuous illumination at various combinations of soil and air temperature. Plants were treated with gibberellic acid at 2-day intervals. The primary low temperature lesion in the grass dwarfs appears to affect early vegetative growth and leads to a premature cessation of the development of each tiller. If growth ceases before sufficient leaves are produced, the plants cannot become reproductive. Continuous light and GA treatment promotes reproductive development because both promote floral initiation at an earlier vegetative stage, i.e. a lower leaf number. Thus, if the temperature conditions allow the plants to grow to this vegetative stage before growth ceases, they will become reproductive if treated with GA but will not become reproductive if untreated. At 26 °C, where control plants develop normally, GA treatment results in earlier heading but much reduced seed yields.
Silicon as a nutrient element for Equisetum arvense
Authors: Chen Ching-hong , Lewin Joyce
Published: September 2008

Young vegetative plants (with 6–9 cm shoot length) of Equisetum arvense L. were collected from nature, washed with distilled water, and grown in plastic bottles in a defined nutrient solution with varying silicon concentrations.There was increased growth, as measured by dry weight, with increasing silicon in the nutrient solution. Plants with an adequate Si supply (40–80 mg Si/liter, replenished every 2 weeks) appeared normal and healthier than plants grown without added Si. Deficiency symptoms, such as necrosis of the branch tips, wilting or drooping of the branches, were observed in Si-deficient shoots.It was concluded that silicon is an essential element for the healthy growth of Equisetum arvense.
Redescription of some fossil gymnospermous pollen (Chasmatosporites, Marsupipollenites, Ovalipollis)
Authors: Pocock Stanley A. J. , Jansonius Jan
Published: September 2008

New morphological details of the monosulcoid form genera Chasmatosporites, Marsupipollenites, and Ovalipollis are given. Systematic descriptions include emendations of Chasmatosporites, Ovalipollis, and several species assigned to these genera. Possible phylogenetic relationships and paleobotanical affinities are discussed.
Temperature: collection of data and its analysis for the interpretation of plant growth and distribution
Authors: Cleary B. D. , Waring R. H.
Published: September 2008

Suggestions for more meaningful collection, processing, and interpretation of temperature data are offered. Our suggestions are based upon characteristics of the organism under study. Research on plant–temperature interactions is reviewed and another approach is illustrated.Temperature data, collected near shoots and roots of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings in different field situations, were assembled from computer-processed temperature traces. From laboratory studies in which day and night air and soil temperatures were controlled, potential seedling growth each day during a growing season was assessed. Then, by summation, a physiological index, expressed in equivalent units, was calculated to relate the possible effect of the field temperatures to plant distribution. This index was used to interpret the effect of temperature on the distribution of vegetation and patterns of leaf initiation in the field. The importance of interactions with the other environmental factors of moisture, chemicals, light, and mechanical forces is mentioned.
Oedogonium chaetophorum nomen novum
Authors: Hoffman Larry R.
Published: September 2008

Oedogonium chaetophorum nom. nov. is proposed as a substitute for the binomial O. setigerum Hoffman.
Crystalline bodies in an algal chloroplast
Authors: Stein Janet R. , Bisalputra Thana
Published: September 2008

Crystalline inclusions are reported for the first time in the chloroplast of an alga. The cryophilic chlorophycean alga, isolated from snow, lacks a pyrenoid and is tentatively identified as a species of Chlamydomonas. The inclusions are similar to those reported in higher plants and are more abundant in material grown at the optimum temperature of 5 °C. The possibility of a proteinaceous nature of the inclusions is briefly discussed.
Circadian rhythms of flower induction and their significance in photoperiodic response
Authors: Cumming Bruce G.
Published: September 2008

Endogenous rhythms of flower induction in Chenopodium rubrum provide at least a partial basis for time measurement and control of flower induction in daily light: dark (photoperiodic) cycles. The results support Bünning's hypothesis of the physiological clock.The following three intrinsic components can exert a primary control in both the endogenous free-running and the externally forced system.(1) GenotypeThe endogenous rhythmic flowering responses of different latitudinal ecotypes show specific characteristics that are also expressed in daily photoperiodic cycles.(2) PhytochromeChanges in the level of Pfr (the active form of phytochrome) cause shifts in endogenous phase and photoperiodic optima that are qualitatively similar. Changes in Pfr level have effects on flower induction that are similar in both the photophile phase of an endogenous rhythm and in the light period of inductive daily photoperiodic cycles—just as the effects obtained in the transduction (skotophile) phase of the endogenous rhythm are similar to those obtained in the dark period of daily photoperiodic cycles.(3) Photosynthetic Energy MetabolismThe effects on flower induction obtained by changing light intensity and (or) quality, and by applying sugars, suggest that there is a greater utilization and (or) availability of substrates (arising from carbohydrate metabolism and involved in Pfr pacemaker effects) in the photophile than in the transduction phases of prolonged darkness. This appears to reflect the sequence that would normally be imposed in daily photoperiodic cycles.A basis for the overt relationships between endogenous rhythmic and photoperiodic response could exist if there are endogenous oscillations in energy metabolites derived from photosynthesis. Such a system could have become selectively evolved as an adaptive response to natural alternations of light and darkness. Demultiplication of higher frequency oscillations may be a significant adaptive mechanism in circadian timing of flower induction.
Effect of light and temperature on nitrate uptake and nitrate reductase activity in rye and oat seedlings
Authors: Chen T. M. , Ries S. K.
Published: September 2008

The effect of light and temperature on nitrate uptake and the activity of nitrate reductase was investigated in rye (Secale cereale L. cv. MSU Exp. 1) and oat (Avena sativa L. cv. Garry).Light enhanced nitrate uptake and led to the induction of more enzyme. However, in plants that received a 16-h dark period before both nitrate and dark treatment, no enzyme was induced, although considerable nitrate accumulated in the plants. Enzyme induction increased with light intensities up to 1500 ft-c during 12 hours exposure of light and during the subsequent dark period. Nitrate uptake in the dark was saturated at 300 ft-c of light pretreatment.Nitrate and nitrate reductase of oat seedlings, grown at 22 °C (day) and 17 °C (night) for 3.5 days, decreased with increasing light intensities.
Conidium ontogeny in hyphomycetes. Trichothecium roseum and its meristem arthrospores
Authors: Kendrick W. B. , Cole G. T.
Published: September 2008

The sporogenesis of Trichothecium roseum is illustrated by time-lapse photomicrography. The first conidium develops murogenously by growth and conversion of the conidiophore apex. Subsequently a short section of the conidiophore just below the first conidium becomes secondarily meristematic, expanding unilaterally and being converted into a conidium. A basipetal succession of such meristematic zones produces a chain of organically isolated conidia while the conidiophore axis becomes progressively shorter. The conidia are considered to be meristem arthrospores of a kind previously described for the Basipetospora state of Monascus ruber. T. roseum is placed in the recently proposed section VB of Hughes's 1953 classification of hyphomycetes.
Cotton embryogenesis: pollen tube development in the nucellus
Authors: Jensen William A.
Published: September 2008

The nucellus of cotton (Gossypium hirsutum) contains a column of specialized cells which degenerate before the pollen tube reaches the nucellus. The pollen tube grows between the walls of these degenerate cells. The growth of the pollen tube crushes most of these cells but does not cause the degeneration of additional nucellar cells. An electron-dense material is found in the nucellar cell walls associated with the growth of the pollen tube for about one-half the thickness of the nucellus. This material appears to spread in a wave-like fashion from the tube through the walls of the nucellar cells. Both the walls and cytoplasm of the cells do not appear changed after the passage of the material. The dense material never reaches the embryo sac itself.
Diversity, dominance, stability, and net production in the grasslands at Varanasi, India
Authors: Singh J. S. , Misra R.
Published: September 2008

A study conducted on the grassland of Varanasi (Tropical), has shown that species diversity increases productive efficiency of the ecosystem while dominance makes the system stable, though less efficient for production. These results are contradictory to McNaughton's observation that diversity decreases efficiency and generates community stability, and thus call for further work before generalization for all situations can be drawn.
Developmental potentialities of leaf primordia of Osmunda cinnamomea. V. Toward greater understanding of the final morphogenetic expression of isolated set I cinnamon fern leaf primordia
Authors: Haight Thomas H. , Kuehnert Charles Carroll
Published: September 2008

Arguments supported by the data given favor the interpretation that (1) adaxial buds are produced by Osmunda cinnamomea leaf primordia; (2) they are produced in addition to the leaf which bears them; (3) they are to be considered adventitious rather than axial; (4) they are of a strictly foliar rather than cauline nature; and (5) they are produced only when a primordium has been isolated from the rest of the shoot system.In O. cinnamomea, the bud, which is formed in addition to the leaf primordium, is evident at the end of the fifth to sixth week on singly cultured P3 and P4 leaf primordia. With younger leaf primordia, e.g. P2’s, often the only evidence of bud formation at the termination of an 8-week culturing period is the presence of the new apical meristem (the SAM′). In the case of older primordia, however, such as P4’s, whether cultured singly or isolated from the shoot apical meristem (SAM) on a plug of tissue, the bud is observed to consist of the SAM′, and from one to seven new leaf primordia. At this stage, the meristematic outgrowth can be considered to be in the true bud state. If the culturing period is extended beyond 8 weeks, the SAM′ develops from the bud state into the plantlet state bearing miniature juvenile leaves, and roots.
Stereospecific regulation of plant glucan synthetase in vitro
Authors: Thomas D. des S. , Smith J. E. , Stanley R. G.
Published: September 2008

Glucan synthesis from uridine diphosphate glucose (UDP-glucose), mediated by particulate-bound enzyme from a variety of plants, is stimulated by a number of sugars and glycols. Glucose and glycerol appear to have a common site of action. Erythritol competitively inhibits glycerol-stimulated glucan synthesis. A marked disparity in stimulation by optical isomers of arabitol is indicative of a stereospecific activator mechanism.At 50 °C, particulate-bound β-1,3-glucanase hydrolyzes most of the glucan previously formed at 22 °C in the presence of glycerol, leaving a resistant glucan residue. Glucan formed in the absence of glycerol was not hydrolyzed.The supernatant above the 12 000 × g particulate fraction contains a heat-stable stimulator, and a heat-labile inhibitor, of glucan synthesis.
Injured cells required for the initiation of plant virus infections
Authors: Kimmins W. C. , Casselman M. D.
Published: September 2008

To investigate whether a plant virus infection could be initiated in uninjured cells, the trifoliate leaves of Phaseolus vulgaris var. Prince were dipped into suspensions of tobacco necrosis virus. It is concluded that infection can only be established through injured leaf cells.
A comparison of the inositol contents of illuminated and etiolated seedlings of Phaseolus vulgaris
Authors: Gibbins L. N. , Norris F. W.
Published: September 2008

Seedlings of Phaseolus vulgaris, grown for 15 days in the dark, contained 15–20% less inositol than plants that had been illuminated for the last 4 days of this period. This loss was reflected in the values for both the free and bound forms of inositol. The data presented do not indicate whether the observed difference is due to the necessity for the etiolated plants to utilize inositol as a source of energy, or to the net synthesis of inositol by the illuminated plants.
The germination ecology of Saponaria officinalis from riverside gravel banks
Authors: Lubke Marguerite A. , Cavers P. B.
Published: September 2008

On unstable gravel banks along the Thames River, seeds of Saponaria officinalis are dormant at maturity but many give rise to seedlings in the spring following production. The effects on seed dormancy of several environmental factors which would be experienced by the seeds during the winter were investigated. All seeds which remained submerged for 2 months or more germinated as soon as they were exposed to air and alternating temperatures in the spring. Scarification by moving gravel only promoted germination when combined with subsequent exposure to winter conditions. Only about half of the seeds which were not inundated germinated the next spring. Soaking, rather than low temperature, was shown to be the more important factor in overcoming seed coat dormancy.
Petroderma maculiforme on the coast of Nova Scotia
Authors: Edelstein T. , McLachlan J.
Published: September 2008

Petroderma maculiforme (Wollny) Kuckuck is recorded for the first time along the coats of Nova Scotia. This species occurs as small crusts on pebbles and stones, and dense populations have been found in a number of localities. The vegetative habit of the plants and their reproductive structures are described.
Inhibition of tryptophan synthase by extracts from pea roots
Authors: Chen James , Boll W. G.
Published: September 2008

Low tryptophan synthase (L-serine hydro-lyase (adding indole), EC 4.2.1.20) activity in extracts of pea roots is a consequence of both a low concentration of the enzyme in roots and the presence of inhibitors at least some of which may be removed by homogenizing the fresh tissue with acetone. Inhibition by root extracts, and fractions thereof, was assayed against tryptophan synthase from seedling buds. At least three inhibitory components were detected, namely (1) a dialyzable, thermostabile component, (2) an undialyzable, thermolabile component, and (3) an undialyzable, thermostabile component. A dialyzable factor which protects an undialyzable inhibitory factor against heat inactivation is also indicated.Fractionation of crude root extracts by gel filtration on a column of Sephadex G-50 shows inhibitor with a molecular weight of about 10 000 or larger.
Pathological changes in ultrastructure: false plasmolysis
Authors: Hanchey Penelope , Wheeler Harry
Published: September 2008

Shrinkage of plant protoplasts in hypotonic solutions or even in distilled water has been long known as an erratic response to injury. Although the mechanism for it is not known, this phenomenon, termed "induced", "stimulative", or "false" plasmolysis, has been considered to be comparable to spore formation in algae and fungi or to vacuolar contraction in protozoa. Studies of the mechanism of false plasmolysis have been precluded by the inability to induce the phenomenon consistently in large numbers of cells. Victorin treatment of root cap cells from Victoria-blight susceptible oats was found to result consistently in false plasmolysis. Ultrastructure studies of such cells showed that synthesis of new membranes was not involved in victorin-induced false plasmolysis. Discontinuities in the plasmalemma and tonoplast rule out active movement of water as a causative factor for protoplast shrinkage. The mechanism responsible for false plasmolysis appears to be an increased permeability of membranes to water, followed by disruption of the vacuole and a reduction of plasmalemma area by a process similar to pinocytosis.
Alterations of the host wall surrounding the infection peg of powdery mildew fungi
Authors: McKeen W. E. , Smith R. , Bhattacharya P. K.
Published: September 2008

A chemical and morphological alteration of the epidermal wall of barley, clover, strawberry, and sunflower occurred around the infection peg of Erysiphe graminis, E. polygoni, Sphaerotheca macularis, and Erysiphe cichoracearum respectively while the peg was passing through the epidermal wall. A disc-shaped area with the peg as the central point always stained more heavily than other zones after epidermal strips were treated with azure dyes and cotton blue. The "classic" zinc–chlor–iodide and the IKI–H2SO4 cellulose tests indicated that cellulose was lacking in the disc-shaped zone. This zone stained only faintly with the periodic acid – Schiff's test, indicating that the amount of polysaccharide was reduced around the penetration tube. After differential extraction of polysaccharides the PAS-negative halo was always surrounded by a PAS-positive band even after pectin, hemicellulose, and noncellulosic polysaccharides had been removed. Electron micrographs showed that the morphology was altered and electron density was increased in the disc-shaped zone. Sometimes the altered zone was swollen. Thus, the cytochemical tests and electron micrographs suggest very strongly that the cellulose wall in the zone around the infection peg is degraded by enzyme(s), such as cellulase, produced by powdery mildews.
A microbiological control of Melampsora medusae
Authors: McBride Richard P.
Published: September 2008

Bacillus cereus Frankland and Frankland, Bacillus mycoides Flugge, and a third unidentified species of Bacillus occurred commonly as part of the saprophytic microflora on healthy foliage of Pseudotsuga menziesii (Mirb.) Franco. In greenhouse experiments, application of a mixture of nutrient broth cultures of these bacteria on P. menziesii seedlings resulted in control of the needle rust Melampsora medusae Thüm. Less effective control occurred when aqueous suspensions of the bacteria and cell-free (Millipore-filtered) filtrates of the nutrient broth cultures were applied to the seedlings, before inoculation.
Respiration of tobacco leaves infected with different strains of potato virus X
Authors: Dwurazna M. M. , Weintraub M.
Published: September 2008

A study was made of the effects on respiration by four strains of potato virus X varying in the severity of symptoms they produce on tobacco leaves. No effects on respiration rates were observed in either inoculated or systemically infected but symptomless leaves, even though there was a significant increase in virus concentration during the experimental period. However, a significant increase was detected in any leaves on which symptoms developed, this increase being directly correlated with the severity of symptom expression. At the same time a great increase in virus concentration was found. Measurement of respiration patterns of single local lesions showed that an increase in respiration occurred each time a chlorotic and necrotic ring formed in the tissues. The use of metabolic inhibitors indicated that metabolic controls are different in the leaves infected with latent or mild strains, as compared to those infected with the severe, necrotizing strains.
The effect of mineral nutrition on apogamy in Pteridium
Authors: Treanor L. L. , Whittier D. P.
Published: September 2008

The effect of mineral nutrition on apogamy was studied because earlier investigators proposed that low mineral levels induced apogamy. The weight of the gametophytic tissue and the number of apogamous plants per culture and per gram of gametophytic tissue were determined in relation to variations in the levels of mineral elements. The apogamous response was promoted only by high concentrations of phosphorus, and an increase in the gametophytic weight was produced by high levels of potassium. The omission of any of the elements from the nutrient medium inhibited apogamy and, except calcium, reduced the gametophytic weight.
The metabolism of succinic semialdehyde by a psychrophilic basidiomycete
Authors: Davies Parker N. , Strobel Gary A.
Published: September 2008

A plant-pathogenic psychrophilic basidiomycete metabolized succinic semialdehyde-14C to 14CO2 and various compounds labelled with 14C that appeared in the cation, anion, and neutral fractions of the fungus. The major portion of succinic semialdehyde taken into the cell was oxidized to succinic acid. A crude extract of the fungus possessed a soluble succinic semialdehyde dehydrogenase that was characterized as to stability, pH optimum, Km, substrate specificity, and coenzyme specificity. Electrophoresis of the crude extract on acrylamide gels showed that there were either several enzymes able to oxidize succinic semialdehyde or that several forms of the same enzyme exist in the fungus.
The effect of light on ribulose diphosphate carboxylase in corn leaves
Authors: Habig William , Racusen David
Published: September 2008

The level of certain enzymes was compared in albino, etiolated, and normal corn leaves. It was found that malic dehydrogenase and peroxidase were highest in light-grown albinos. Ribulose-1,5-diphosphate carboxylase, considered a chloroplast enzyme, was present in increasing amounts in the order albino < etiolated green < green. The level of this enzyme corresponded to the degree of chloroplast ultrastructure as determined by electron microscopic examination and insoluble protein. Only light-grown normal leaves had high catalase activity. All plants responded to light by an increased level of soluble protein, but only normal (i.e. non-albino) leaves showed an increase in insoluble protein. At least part of the higher soluble protein level could be accounted for by an electrophoretically distinct protein found only in light-grown plants.
Electron microscopic observations of the flagellar hairs of Phytophthora palmivora zoospores
Authors: Desjardins P. R. , Zentmyer G. A. , Reynolds D. A.
Published: September 2008

The whiplash flagellum of zoospores of Phytophthora palmivora bears fine lateral hairs 500 mμ long and 15 mμ wide. The lateral hairs on the tinsel flagellum of this species were similar in length, structure, and distribution to those in some other species of Phytophthora. Glutaraldehyde fixation of the zoospores is superior to osmic acid fixation for the preservation of flagellar hairs.
Notes on clavarioid fungi. XI. Miscellaneous notes on Clavaria
Authors: Petersen Ronald H. , Olexia Paul D.
Published: September 2008

Evidence is given for acceptance of Clavaria inaequalis Müller ex Fr. as a valid species, including description of a specimen from the herbarium of Fries. Four species of Clavaria (including C. californica Pet., sp. nov. and C. neonigrita Pet., sp. nov.) are described with spiny spores, and comments on their phylogenetic relationships are made. A discussion of the appropriateness of separation of Clavaria from Clavulinopsis is included with special reference to Clavaria longispora, Clavulinopsis appalachiensis, and Clavulinopsis corallino-rosacea. Clavaria americana Pet., sp. nov., is proposed.
Mechanisms of pathogenesis in Sclerotium bataticola on sunflowers. 1. Production and translocation of a necrosis-inducing toxin
Authors: Chan Yu-Ho , Sackston W. E.
Published: September 2008

Necrotic spotting of leaves is an early symptom of attack by Sclerotium bataticola on sunflowers. Spots appear after invasion of vascular tissues by the pathogen, which does not spread appreciably from the point of inoculation.Inoculation of one stem of plants split apically to give twin stems on one root system resulted in necrotic spotting of leaves first on the inoculated, and later on the uninoculated stem. Introducing cell-free filtrates of cultures of S. bataticola into sunflower plants or detached leaves resulted in production of the same type of necrotic spots. Introduction of eosin dye, which is translocated in the vascular system, into whole plants and detached leaves produced patterns of coloration similar to the patterns of necrotic spotting. The necrosis may be attributed to a translocatable toxin produced by the fungus.It is indicated that the toxin is neither an enzyme nor a protein. It has not been eluted after adsorption by activated carbon.
Numerical chemotaxonomy in the genus Secale
Authors: Dedio W. , Kaltsikes P. J. , Larter E. N.
Published: September 2008

Thin-layer chromatographic patterns of fluorescent compounds in young leaves of 11 species of the genus Secale and similarity indices supported the general taxonomic relationships of the species based on morphological and cytological studies. Thus S. silvestre had a distinct chromatogram of its own; S. cereale, S. dighoricum, S. segetale were all grouped together, while the rest of the wild species, i.e. S. montanum, S. africanum, S. dalmaticum, S. kuprijanovii were more closely related to each other than to the rest of the species. S. vavilovii was distinguished by the presence of four compounds not present in any other species. The differences in the chromatographic patterns of the Cerealia and Kuprijanovia sections were sufficient to maintain these as separate sections, which is in agreement with earlier studies. Two of the species used in this study, designated S. fragile and S. anatolicum, seem to have been incorrectly identified.