bluuebunny/crossref_metadata_2025 huggingface dataset:
Feminist Approaches to International Law
Authors: Charlesworth Hilary , Chinkin Christine , Wright Shelley
Published: April 2006

The development of feminist jurisprudence in recent years has made a rich and fruitful contribution to legal theory. Few areas of domestic law have avoided the scrutiny of feminist writers, who have exposed the gender bias of apparently neutral systems of rules. A central feature of many western theories about law is that the law is an autonomous entity, distinct from the society it regulates. A legal system is regarded as different from a political or economic system, for example, because it operates on the basis of abstract rationality, and is thus universally applicable and capable of achieving neutrality and objectivity. These attributes are held to give the law its special authority. More radical theories have challenged this abstract rationalism, arguing that legal analysis cannot be separated from the political, economic, historical and cultural context in which people live. Some theorists argue that the law functions as a system of beliefs that make social, political and economic inequalities appear natural. Feminist jurisprudence builds on certain aspects of this critical strain in legal thought. It is much more focused and concrete, however, and derives its theoretical force from immediate experience of the role of the legal system in creating and perpetuating the unequal position of women.
The Principle Pacta Sunt Servanda and the Nature of Obligation Under International Law
Authors: Lukashuk I. I.
Published: April 2006

The principle that treaty obligations must be fulfilled in good faith is one aspect of the fundamental rule that requires all subjects of international law to exercise in good faith their rights and duties under that law.

In the sociopolitical sphere, this fundamental principle may be seen as manifesting the need perceived by states for an international legal system that can ensure international order and prevent arbitrary behavior and chaos. In the legal sphere, the principle is confirmation of the character of international law as law. Subjects of international law are legally bound under the principle to implement what the law prescribes.
Nuclear War Powers
Authors: Raven-Hansen Peter
Published: April 2006

As the Constitution enters its third century, its framework for the exercise of war powers is under siege. Presidential exercises of war powers to repel attacks, rescue lives, protect property, retaliate and threaten have posed the most persistent and visible challenge to that framework. But an equal theoretical challenge is posed by a power that the President has used only twice, the nuclear war power. Part I of this essay describes that challenge. Part II evaluates the constitutionality of the existing distribution of nuclear war powers. Part III identifies—but does not explore—alternatives.
Preemption of State Law: A Recommended Analysis
Authors: Maier Harold G.
Published: April 2006

The fundamental principles that guide determinations about the appropriate relationship between state and national authority in matters affecting the foreign affairs of the United States began to evolve even before the ratification of the Constitution in 1789. The centralization of governmental power in this field is reflected in microcosm in the three great state papers of the United States. The nation began in 1776 as “United Colonies” that were “Free and Independent States” under the Declaration of Independence; developed into a “firm league of friendship” under the Articles of Confederation in 1781; and became a “more perfect union” created by the people, not by its constituent political units, under the Constitution in 1789.
Compromissory Clauses and the Jurisdiction of the International Court of Justice
Authors: Charney Jonathan I.
Published: April 2006

Many governments are reluctant to submit disputes voluntarily to the International Court of Justice for binding adjudication. Only a few disputes are brought to the Court with the current agreement of all the parties. When that happens, no matter what the technical basis for the Court’s jurisdiction may be—acompromis, compulsory jurisdiction, or a compromissory clause in a substantive international agreement or an optional protocol—the Court’s jurisdiction is unlikely to be questioned. When the respondent state does not wish the dispute to be submitted to the Court, however, the applicant state must compel adjudication by relying on jurisdiction founded upon the respondent state’s consent given in the past. Consent may be found in declarations accepting the compulsory jurisdiction of the Court provided for in Article 36(2) of its Statute. Alternatively, such consent may be found under Articles 36(1) or 37, which permit jurisdiction to be based on compromissory clauses.
The Investment Provisions of the Canada—United States Free Trade Agreement: A Canadian Perspective
Authors: Raby Jean
Published: April 2006

This is a good deal, a good deal for Canada and a deal that is good for all Canadians. It is also a fair deal, which means that it brings benefits and progress to our partner, the United States of America. When both countries prosper, our democracies are strengthened and leadership has been provided to our trading partners around the world. I think this initiative represents enlightened leadership to the trading partners about what can be accomplished when we determine that we are going to strike down protectionism, move toward liberalized trade, and generate new prosperity for all our people.

On January 2, 1988, President Ronald Reagan of the United States and Prime Minister Brian Mulroney of Canada signed the landmark comprehensive Free Trade Agreement (FTA) between the two countries that already enjoyed the largest bilateral trade relationship in the world. The FTA was subsequently ratified by the legislatures of both countries, if only after a bitterly fought election on the subject in Canada. On January 1, 1989, the FTA formally came into effect.
International Tin Council v. Amalgamet Inc.
Authors: Ratner Steven R.
Published: April 2006

Petitioner, International Tin Council (ITC), brought an action to stay an American Arbitration Association arbitration that was initiated by respondent, Amalgamet Inc., and that arose out of petitioner’s refusal to honor three contracts for the purchase of tin from respondent. Petitioner claimed that it was immune from suit in the United States by virtue of its status as an international organization under British law, and, in the alternative, that the arbitration clause in its contract with respondent was unenforceable. The Supreme Court of New York County (per Parness, J.) dismissed the petition, and held that petitioner lacked any basis under U.S. law for immunity from legal process and that petitioner had consented to the arbitration clause providing for arbitration in New York.
National Oil Corp. v. Libyan Sun Oil Co.
Authors: Pizzurro Joseph D.
Published: April 2006

Petitioner, the Libyan National Oil Corp. (NOC), filed the petition to confirm an arbitral award rendered in Paris against Libyan Sun Oil Co. (LSOC), a Delaware corporation. The petition was based on the UN Convention on the Recognition and Enforcement of Foreign Arbitral Awards (Convention). LSOC opposed the petition on the grounds that NOC was not entitled to access to U.S. courts because of the state of relations between the United States and Libya and that the Libyan Sanctions Regulations prevented NOC from maintaining its claim in the absence of a license from the Treasury Department’s Office of Foreign Assets Control. In addition, LSOC argued that confirmation of the award should be denied under various provisions of the Convention, including the “public policy” defense embodied in Article V(2)(b). The district court (per Latchum, J.) held that NOC had standing to bring the petitión and that the defenses set forth in the Convention were inapplicable. The award was thus confirmed.
The Legitimacy of the Collective Authority of the Security Council
Authors: Caron David D.
Published: April 2006

The ideal, once it is embodied in an institution, ceases to be an ideal and becomes the expression of a selfish interest, which must be destroyed in the name of a new ideal. This constant interaction of irreconcilable forces is the stuff of politics. Every political situation contains mutually incompatible elements of utopia and reality, of morality and power.

E. H. Carr

[T]he crucial question is not what principle is acknowledged but who is accepted as the authoritative interpreter of the principle or, to put it in institutional terms, how the process of legitimization works.

Inis Claude, Jr.

At this pivotal point in history, a fundamental and oft-raised issue is “international governance.” Means of effective governance are seen as necessary to more complex arrangements of world order. But achieving effective governance ultimately will mean the existence of institutions that legislate, that is, institutions that make decisions binding on the whole. As a general matter, states have been skeptical of, if not hostile toward and consequently unwilling to accept, such governance. The United Nations Security Council is a notable exception; in the sometimes broad, sometimes narrow, area of international peace and security, the Security Council has taken decisions in the name of, and binding upon, the entire international community.
The Montevideo Environmental Law Programme
Authors: Biggs Gonzalo
Published: April 2006

The Governing Council of the United Nations Environment Programme (UNEP) will hold its next annual meeting in May 1993, and, among other matters, will consider the report of a group of government experts (the report or Nairobi report) on the review, and continuation for another decade, of its Montevideo Programme of environmental law. This program was adopted by the Governing Council of UNEP in 1982 and has been instrumental in the development of domestic and international environmental law during the last decade.
The Cambodia Settlement Agreements
Authors: Ratner Steven R.
Published: April 2006

On October 23, 1991, representatives of nineteen states participating in the Paris Conference on Cambodia signed a set of accords aimed at ending the twenty-year-old conflict in that country. The solemn ceremony at the Kleber Center in Paris marked the conclusion of over three years of intensive negotiations at a variety of levels, including interfactional, regional and international, to end one of the world’s most tragic regional disputes. It also signaled the beginning of an unprecedented role for the United Nations in the resolution of such conflicts.
Drawing a Better Line: UTI Possidetis and the Borders of New States
Authors: Ratner Steven R.
Published: April 2006

It is now conventional wisdom that the proliferation of ethnic-based violence constitutes the greatest threat to public order and human rights since the lifting of the Iron Curtain. The eruption of hatreds, whether suppressed or ignored for a half century or newly arisen, has unleashed centrifugal forces that are pulling states apart from Africa to Europe to South and Central Asia. To date, the response of the effective decision makers in the international community has been ambiguous and inconstant: the United Nations member states reiterate the importance of the unity of all states, but they accept accomplished breakups after the fact, all the while insisting on the protection of minorities within states. Political philosophers struggle with the circumstances under which secession and dissolution are desirable; international law declares the lack of either a blanket right to, or prohibition against, secession and seemingly relegates its achievement to a pure power calculus.
The Participation of Nongovernmental Organizations in International Judicial Proceedings
Authors: Shelton Dinah
Published: April 2006

Nongovernmental organizations are playing an increasingly important role in international litigation. This study will analyze the participation of nongovernmental organizations, primarily as amici curiae, in the proceedings of four permanent international courts: the International Court of Justice, the European Court of Justice, the European Court of Human Rights and the Inter-American Court of Human Rights. After discussing the impact of amici in national and regional courts, it recommends that the International Court of Justice expand its acceptance of submissions from nongovernmental organizations in appropriate cases. The Court has a jurisdictional basis to do so and amici have usefully contributed to cases before other courts.
The United Nations Commission of Experts Established Pursuant to Security Council Resolution 780 (1992)
Authors: Bassiouni M. Cherif
Published: April 2006

Throughout modern history, there have only been three internationally established commissions to investigate war crimes and prepare for eventual prosecutions before international and national judicial bodies: the 1919 Commission on the Responsibilities of the Authors of the War and on Enforcement of Penalties for Violations of the Laws and Customs of War (1919 Commission), the 1943 United Nations War Crimes Commission (UNWCC), and the Commission of Experts established pursuant to Security Council Resolution 780 (1992) to investigate violations of international humanitarian law in the former Yugoslavia (Commission of Experts). Even though there are no connections among the three bodies, there is enough historical precedential value in the first two as the antecedents of the Commission of Experts to warrant a brief examination.
Effects of virus infection and growth irradiance on fitness components and photosynthetic properties of Eupatorium makinoi (Compositae)
Authors: Funayama Sachiko , Hikosaka Kouki , Yahara Tetsukazu
Published: April 2006

We examined the effects of geminivirus infection on fitness components and on photosynthetic properties of the host plant, Eupatorium makinoi, grown at two irradiance levels in a natural‐light greenhouse. Under the low‐light condition (13% full sunlight), more than a half of the infected plants died during the 9‐mo experiment, while most of uninfected plants survived. Growth rate was also lowered by infection. At high light (50% full sunlight), by contrast, virus infection did not cause mortality despite slight decrease in growth rate. Flowering occurred only at high light, and reproductive outputs of the plants were markedly reduced by the infection. Infected leaves had distinct yellow variegations and, when compared with uninfected leaves, they showed (1) comparable light‐saturated photosynthetic rate per unit area, but (2) lower initial slope of light‐response curve of photosynthesis on an incident irradiance basis. The lower initial slope was mainly due to reduction of light‐harvesting chlorophyll‐protein complexes in the variegated parts. Since the differences in plant performance, depending both on infection and on growth irradiance, were largely explained by the differences in growth rate and/or plant size, the reduced photosynthetic production in the infected plants would be a major factor explaining the inferior performance of the host plants.
Studies in Annonaceae. XXVIII. Macromorphological variation of recent invaders in northern Central America: the case of Malmea (Annonaceae)
Authors: Chatrou Lars W.
Published: April 2006

Cluster analysis is used to reveal patterns of macromorphological variation in a species complex of Malmea (Annonaceae) distributed in eastern Mexico, Guatemala, Belize, and Honduras. Of 53 characters, 24 are important for the clustering of 238 herbarium specimens into 12 clusters. No cluster is exclusively specified by any character or combination of characters. Neither can any geographical pattern be detected, except for the clustering of specimens from Los Tuxtlas Tropical Biological Station, Veracruz. A new subspecies from this area, M. depressa subsp. abscondita, is described. Malmea gaumeri and M. leiophylla are brought into synonymy with M. depressa. Distribution patterns of Mexican and Central American taxa of Malmea are largely concordant with those of South American taxa, which spread into Cental America after the Pliocene closure of the Isthmus of Panama. A phytogeographical novelty is presented, however, as the distribution of M. depressa subsp. abscondita within the Sierra de los Tuxtlas shows an hitherto unknown pattern: the new subspecies is distributed only on the northeastern slopes of this mountain range, and is geographically separated from M. depressa subsp. depressa, which occurs only on the southwestern slopes.
Evolution and homology of bird pollination syndromes in Erythrina (Leguminosae)
Authors: Bruneau Anne
Published: April 2006

Erythrina L. (Leguminosae: Phaseoleae) is a pantropical genus of over 100 species, all of which are either hummingbird or passerine pollinated. Phylogenetic hypotheses based on morphological and chloroplast DNA restriction site characters suggest that shifts from passerine to hummingbird pollination have occurred a minimum of four times in the genus. In hummingbird‐pollinated species the inflorescences are held upright, the flowers are arranged radially along the axis, and the narrow standard petal is conduplicately folded to form a pseudotube. In most of the passerine‐pollinated species, the inflorescences are held horizontally, the flowers are secund, and the standard petal is open so that the nectar and androecium are easily visible and accessible. Nectar amino acid concentrations and sucrose to hexose ratios are closely associated with pollination mode. Despite the general resemblance in flower and inflorescence morphology among species with the same pollination type, homology assessment reveals that petal morphology and size, and calyx and pollen morphology differ. Morphological characters, even if comprising modifications associated with adaptive pollination systems, therefore provide useful phylogenetic information.
Ellesmeris sphenopteroides, gen. ET SP. NOV., a new zygopterid fern from the Upper Devonian (Frasnian) of Ellesmere, N.W.T., Arctic Canada
Authors: Hill Stewart A. , Scheckler Stephen E. , Basinger James F.
Published: April 2006

A new fern‐like fossil plant is described from the lower Upper Devonian of southern Ellesmere Island, Canadian Arctic Archipelago. The plant occurs in an Archaeopteris‐dominated flora preserved in the Nordstrand Point Formation (Mid‐Late Frasnian) near Bird Fiord. The plant has a pinnate vegetative system with three branch orders and laminate sphenopteroid pinnules. Primary pinnae usually diverge from the main axis in distichous pairs (quadriseriate), but can depart singly (biseriate). Each primary pinna bears a basal catadromic aphlebia. Anatomically, the plant exhibits a mesarch, bipolar protostele that is ribbon‐ to clepsydropsoid‐shaped in the main axis. Primary pinna traces are also initially bipolar and crescent‐shaped, but may become four‐ribbed before dividing into a pair of bipolar traces. The morphology and anatomy of this plant are nongymnospermous and are most similar to Zygopteridales (particularly Rhacophytaceae and Zygopteridaceae). The Frasnian age of Ellesmeris shows that laminated foliage had evolved in some zygopterid ferns much earlier than previously recognized. The Sphenopteris‐like pinnules of Ellesmeris indicate the need for caution when attributing such a convergent foliar design to other plant groups, such as the Devonian gymnosperms.
Pollination biology and outcrossing rates in hermaphroditic schiedea lydgatei (Caryophyllaceae)
Authors: Norman Joanna K. , Weller Stephen G. , Sakai Ann K.
Published: April 2006

The influence of outcrossing and pollination biology on the maintenance of hermaphroditism was studied for Schiedea lydgatei (Caryophyllaceae: Alsinoideae), a species endemic to Moloka‘i in the Hawaiian Islands. Schiedea lydgatei is the only hermaphroditic species in an otherwise dimorphic clade and hermaphroditism is likely the result of a reversal from a gynodioecious ancestor. Both wind and native moths in the family Pyralidae are responsible for pollination in S. lydgatei. Outcrossing rates were generally high (0.80), especially in years when the greatest number of plants were flowering. The combination of high outcrossing rates and substantial inbreeding depression indicates that at present females would not be favored in the population. Pollination by both wind and insects is consistent with the hypothesis that hermaphroditism is the result of a relatively recent reversal, as the ancestor of S. lydgatei was probably wind pollinated and gynodioecious with few females in the populations. A shift from wind to predominately insect pollination on Moloka‘i may have resulted in increased outcrossing rates and prevented the expression of high inbreeding depression among progeny of hermaphrodites, a condition that would select against females and favor a reversal to hermaphroditism. Because few females were likely to have been present in ancestral populations that colonized Moloka‘i, founder effect is another potential explanation for loss of females. In either case, current high levels of outcrossing prevent re‐establishment of females in populations of S. lydgatei.
Molecular Phylogeny and Evolution of Monilinia (Sclerotiniaceae) based on coding and Noncoding rDNA Sequences
Authors: Holst‐Jensen Arne , Kohn Linda M. , Jakobsen Kjetill S. , Schumacher Trond
Published: April 2006

The nuclear internal transcribed spacers, the 5.8S subunit, ≈560 bp of the small subunit, and ≈320 bp of the large subunit of the nuclear ribosomal DNA repeat from 17 species of Monilinia and eight species of closely related genera were sequenced. Phylogenies were constructed using maximum parsimony. The results support the hypothesis that Monilinia is not monophyletic. A fundamental distinction was found between the section Junctoriae and the section Disjunctoriae. Four evolutionary lineages were identified within the Disjunctoriae: one species on Crataegus, one group of species on dry stone fruits of rosaceous hosts, one group of species on capsular fruits of ericaceous hosts, and one group of species on sweet berry fruits of ericaceous hosts. Comparisons between branching topologies of hosts and Monilinia species suggest that although cospeciation among hosts and parasites has been the rule, several host jumps have taken place. Sclerotinia pirolae was determined to be a true member of the Disjunctoriae. The closest taxon groups to the Junctoriae were found to be Botrytis and Sclerotinia, with Ciborinia being the closest taxon group to the Disjunctoriae. There is evidence of an increased rate of ssrRNA evolution in the lineage of species that attack ericaceous berries.
The effects of herbivory on neighbor interactions along a coastal marsh gradient
Authors: Taylor Katherine L. , Grace James B. , Marx Brian D.
Published: April 2006

Many current theories of community function are based on the assumption that disturbances such as herbivory act to reduce the importance of neighbor interactions among plants. In this study, we examined the effects of herbivory (primarily by nutria, Myocastor coypus) on neighbor interactions between three dominant grasses in three coastal marsh communities, fresh, oligohaline, and mesohaline. The grasses studied were Panicum virgatum, Spartina patens, and Spartina alterniflora, which are dominant species in the fresh, oligohaline, and mesohaline marshes, respectively. Additive mixtures and monocultures of transplants were used in conjunction with exclosure fences to determine the impact of herbivory on neighbor interactions in the different marsh types. Herbivory had a strong effect on all three species and was important in all three marshes. In the absence of herbivores, the impact of neighbors was significant for two of the species (Panicum virgatum and Spartina patens) and varied considerably between environments, with competition intensifying for Panicum virgatum and decreasing for Spartina patens with increasing salinity. Indications of positive neighbor effects (mutualisms) were observed for both of these species, though in contrasting habitats and to differing degrees. In the presence of herbivores, however, competitive and positive effects were eliminated. Overall, then, it was observed that in this case, intense herbivory was able to override other biotic interactions such as competition and mutualism, which were not detectable in the presence of herbivores.
Light Perception for Sun‐tracking is on the Lamina in Crotalaria pallida (Fabaceae)
Authors: Schmalstig Judy Gougler
Published: April 2006

Trifoliolate leaves of Crotalaria pallida Aiton (Fabaceae) exhibit sun‐tracking behavior in simulated days and in response to a fixed, oblique light. The site of light perception for sun‐tracking is on the lamina, necessitating transport of a signal from the lamina to the site of response (the pulvinule at the base of the leaflet). Evidence for the site of light perception on the lamina includes the following: (1) leaflet movement in response to oblique light is not affected by shading the pulvinule or by illuminating the pulvinule with vertical light; (2) leaflet movement is stopped by shading the lamina while illuminating the pulvinule with oblique light. The proximal end of the leaflet is the most sensitive region for light perception. Light reaching the midveins is not necessary for leaflet reorientation. Presentation times of as little as 10 min followed by darkness resulted in partial leaflet movement in young leaves. This indicates that the signal was not inductive in nature. Estimates of the rate of signal transport range from 3 to 12 cm/h, within the range of phloem transport.
Immunochemical localization of Tetrahydrocannabinol (THC) in Cryofixed Glandular Trichomes of Cannabis (Cannabaceae)
Authors: Kim Eun‐Soo , Mahlberg Paul G.
Published: April 2006

Delta 9‐tetrahydrocannabinol (THC) localization in glandular trichomes and bracteal tissues of Cannabis, prepared by high pressure cryofixation—cryosubstitution, was examined with a monoclonal antibody—colloidal gold probe by electron microscopy (EM). The antibody detected THC in the outer wall of disc cells during the presecretory cavity phase of gland development. Upon formation of the secretory cavity, the immunolabel detected THC in the disc cell wall facing the cavity as well as the subcuticular wall and cuticle throughout development of the secretory cavity. THC was detected in the fibrillar matrix associated with the disc cell and with this matrix in the secretory cavity. The antibody identified THC on the surface of secretory vesicles, but not in the secretory vesicles. Gold label also was localized in the anticlinal walls between adjacent disc cells and in the wall of dermal and mesophyll cells of the bract. Grains were absent or detected only occasionally in the cytoplasm of disc or other cells of the bract. No THC was detected in controls. These results indicate THC to be a natural product secreted particularly from disc cells and accumulated in the cell wall, the fibrillar matrix and surface feature of vesicles in the secretory cavity, the subcuticular wall, and the cuticle of glandular trichomes. THC, among other chemicals, accumulated in the cuticle may serve as a plant recognition signal to other organisms in the environment.
A Taxodiaceous Seed Cone from the Triassic of Antarctica
Authors: Yao Xuanli , Taylor Thomas N. , Taylor Edith L.
Published: April 2006

A silicified seed cone is described from the lower Middle Triassic of Antarctica. The cone measures up to 3.4 cm long and 1.4 cm wide, and consists of helically arranged cone scales attached to a eustelic axis. Bract and ovuliferous scale are approximately of equal length and fused at the base. The bract is entire and vascularized by a single trace. The ovuliferous scale contains five distal lobes, each vascularized by a terete strand that divides to form a smaller trace to each of the five inverted ovules. Ovules are small and flattened with the three‐parted integument attenuated into oppositely positioned lateral wings. The Triassic specimens are compared with both extant and fossil conifer seed cones and believed to have their closest affinities within the Taxodiaceae.
Fly pollination of Gorteria diffusa (Asteraceae), and a possible mimetic function for dark spots on the capitulum
Authors: Johnson S. D. , Midgley J. J.
Published: April 2006

We investigated the functional significance of raised black spots on the ray florets of Gorteria diffusa (Asteraceae) in South Africa. Field observations showed that G. diffusa is pollinated by a small bee‐fly, Megapalpus nitidus (Bombyliidae), which is strikingly similar to the raised spots that occur on some of the ray florets. Removal of the spots resulted in a significant decrease in the rate of fly visits to capitula, but did not significantly affect seed set. Replacement of the spots with simple ink spots also significantly reduced the rate of pollinator visits, suggesting that flies respond to details in the structure of the spots. Investigations using scanning electron microscopy showed that the spots of G. diffusa consist of a complex of different cell types. Differences in epidermal sculpturing may partly explain the UV reflectance pattern of these spots, which is similar to that of the flies. Male flies are strongly attracted to the spots, as well as to other flies sitting in the capitula, although female flies also visit the capitula. We conclude that the spots of G. diffusa mimic resting flies, thereby eliciting mate‐seeking and aggregation responses in fly pollinators. Similar dark spots have evolved in unrelated South African Gazania, Dimorphotheca, and Pelargonium species pollinated by bee‐flies.
Cladistic Analysis of Phylogenetic Relationships Among Tribes Cicereae, Trifolieae, and Vicieae (Leguminosae)
Authors: Endo Yasuhiko , Ohashi Hiroyoshi
Published: April 2006

A cladistic analysis of tribes Cicereae, Trifolieae, and Vicieae was carried out using 33 morphological, anatomical, karyological, and chemotaxonomical characteristics. Transformation polarities of the character states were developed by comparison with the character states of the genus Galega, the sister group of the tribes. Cicereae and Vicieae were found to be a monophyletic group, and Trifolieae was its sister group. The seven synapomorphic characters of Cicereae and Vicieae were presumed to be: germination hypogeal vs. epigeal; first leaf in seedlings scarious vs. laminous; leaves paripinnately and tendrilous vs. imparipinnately and etendrilous; postchalazal vascular bundle present in seed coats vs. absent; a cotyledon flap present at antihilar side vs. absent; radicles short in seeds vs. long; and plumules long in seeds vs. short.
Vessel contents of leaves after excision—a test of Scholander's assumption
Authors: Canny Martin J.
Published: April 2006

A test was attempted of the assumption that, when a leaf is cut, the xylem still contains water under tension beyond the first vessel cross walls. This assumption enabled Scholander to argue that the balance pressure in his pressure chamber measured the tension in water columns in the vessels before cutting. The numbers of embolized vessels were counted, after rapid freezing of petiole and midrib samples of sunflower leaves, in the cryo‐scanning electron microscope. Counts were made on leaves still attached to the plant and at intervals after cutting from the plant (up to 16 min) during a short spring day's transpiration. The lengths of vessels in the leaves, measured by latex particle perfusion, showed that 8% of vessels in the mid‐petioles and 0% in the midribs should be opened by cutting. The changing percentages of embolized vessels (E) with time showed that: (1) in intact plants E was close to zero until midday when it rose to ~40%, and then fell progressively to near zero by 1600; (2) in excised leaves there was no detectable change in E immediately after cutting, and, in all but two time courses, no change as large as the 8% of opened vessels within 16 min; (3) but briefly, when E was high (midday), it rose further after cutting to a plateau (ΔE = 30–40%) in 4 min. From this rate of emptying, the estimated maximum pressure difference between vessels and parenchyma was of the order of 0.05–0.2 MPa (0.5 to 2 bar) at this time. (4) All these changes occurred in the petioles 1 h before they were found in the midribs. The test failed because the expected large pressure difference between vessels and parenchyma was not present. Further, the embolized vessels were refilled at the time of peak transpiration, which would be impossible with any substantial tension in the vessels. Because these results contradict the whole basis of the Cohesion Theory, a second experiment was carried out to test them, and is reported in a companion paper.
Vessel contents during transpiration—embolisms and refilling
Authors: Canny Martin J.
Published: April 2006

A test was made of the previous unexpected observation that embolized vessels were refilled during active transpiration. The contents of individual vessels in petioles of sunflower plants were examined, after snap‐freezing at 2‐h intervals during a day's transpiration, in the cryo‐scanning electron microscope, and assessed for the presence of liquid or gas (embolism) contents. Concurrent measurements were made of irradiance, leaf temperature, transpiration rate, and leaf water potential (by pressure chamber). Up to 40% of the vessels were already embolized by 0900 (transpiration rate ~5 µg·cm−−2·s−−1, water potential about –300 J/kg), and the proportion declined to a minimum (as low as 4%) at 1500. This was the time of highest transpiration rate (~25 µg·cm−−2·s−−1) and most negative water potential (–600 to –700 J/kg). Images of vessels with mixed gas and liquid contents showed water being extruded through pits in the walls of the vessels to refill them. The data indicate that: (1) the water columns are weak and break under quite small tensions; (2) embolisms are repaired by refilling the vessels with water on a short time scale (minutes) throughout the day; (3) the vigor of this refilling process is adjusted by the plant on a longer time scale (hours) to the intensity of the water stress; (4) the pressure chamber balance pressure (P) does not measure tension in the vessels; (5) P is also not a measure of water stress (as measured by vessel embolization); and (6) P is a measure of the plant's response to water stress, i.e., a measure of the vigor of the refilling process. The test confirms the previous observations and negates all the assumptions and evidences of the Cohesion Theory. The data are fully consistent with the Compensating Pressure Theory, which predicted the relations demonstrated in this experiment. Using the assumptions of that theory it is easy to outline a simple mechanism by which the refilling of vessels might be achieved by reverse osmosis, and the adjustment in (3) might be achieved by osmoregulation in the starch sheath.
Microgeographic genetic structure and gene flow in Hibiscus moscheutos (Malvaceae) populations
Authors: Kudoh Hiroshi , Whigham Dennis F.
Published: April 2006

Microgeographic genetic variation in populations of a wetland macrophyte, Hibiscus moscheutos L. (Malvaceae), was investigated using allozyme polymorphism. The species is a self‐compatible insect‐pollinated perennial, and seeds are water dispersed (hydrochory). Six hundred plants were analyzed from eight brackish and two freshwater populations within the Rhode River watershed/estuarine system. The genetic structure of the populations was assessed by fixation indices and spatial autocorrelation analyses. The degree of genetic differentiation among sites and gene flow between all paired combinations of sites (M̂) was analyzed using three hypothetical gene flow models. Fixation indices indicated almost complete panmixia within populations, and spatial autocorrelations showed that genotypes were randomly distributed within sites, most likely the result of water dispersal of seeds. Allele frequencies were significantly different among sites, and estimated FST indicated moderate genetic differentiation (θ = 0.062). Genetic differences between populations were mostly explained by a gene flow model that accounted for the location of populations relative to the tidal stream. The importance of hydrochory in affecting spatial genetic structure was thus suggested both within and among H. moscheutos populations.
Demographic change and microhabitat Variability in a Grassland Endemic, Silene Douglasii Var. oraria (Caryophyllaceae)
Authors: Kephart Susan R. , Paladino Christy
Published: April 2006

Variable spatial and temporal environments are known to affect the population dynamics of plants, but studies of localscale variability and its relationship to demographic change within a population remain limited. Using mapped plants, we examined the population dynamics of a coastal grassland endemic, Silene douglasii var. oraria, in two habitats over 10 yr. We hypothesized that ecological differences between rocky and grassy habitats might influence demographic parameters, including adult survival, growth, and density. Soil pH, soil moisture, and other abiotic variables differed little between habitats, but microsite differences in light, soil depth, and vegetation height were related to variation in Silene density and plant circumference. We also found significantly higher population densities, lower adult mortality, and more juvenile recruitment in rocky areas. Finite rates of population growth varied across years and habitats (λ = 0.82–1.12), with different patterns evident in the two habitats. In both, observed population sizes in 1992 were similar to matrix projections using 1982–1985 data. Populations declined in size in some years despite high adult survivorship and variable recruitment. More intensive study of seedlings is needed, including experimental evaluation of the role of light and competition. However, the habitat‐specific differences we observed imply that ecological studies and conservation plans developed for rare plants should consider the effect of local scale variability on demography.
Concepts and terminology of apical dominance
Authors: Cline Morris G.
Published: April 2006

Apical dominance is the control exerted by the shoot apex over lateral bud outgrowth. The concepts and terminology associated with apical dominance as used by various plant scientists sometimes differ, which may lead to significant misconceptions. Apical dominance and its release may be divided into four developmental stages: (I) lateral bud formation, (II) imposition of inhibition on lateral bud growth, (III) release of apical dominance following decapitation, and (IV) branch shoot development. Particular emphasis is given to discriminating between Stage III, which is accompanied by initial bud outgrowth during the first few hours of release and may be promoted by cytokinin and inhibited by auxin, and Stage IV, which is accompanied by subsequent bud outgrowth occurring days or weeks after decapitation and which may be promoted by auxin and gibberellin. The importance of not interpreting data measured in Stage IV on the basis of conditions and processes occurring in Stage III is discussed as well as the correlation between degree of branching and endogenous auxin content, branching mutants, the quantification of apical dominance in various species (including Arabidopsis), and apical control in trees.
Influence of atmospheric CO2 enrichment, soil N, and water stress on needle surface wax formation in Pinus palustris (Pinaceae)
Authors: Prior Stephen A. , Pritchard Seth G. , Runion G. Brett , Rogers Hugo H. , Mitchell Robert J.
Published: April 2006

Interactive effects of increasing atmospheric CO2 with resource limitations on production of surface wax in plants have not been studied. Pinus palustris seedlings were grown for 1 yr at two levels of soil N (40 or 400 kg N·ha−−1·yr−−1) and water stress (‐0.5 or ‐1.5 MPa xylem pressure potential) in open‐top field chambers under two levels of CO2 (365 or 720 µmol/mol). Needle surface wax content was determined at 8 mo (fall) and 12 mo (spring) and epicuticular wax morphology was examined using scanning electron microscopy (SEM) at 12 mo. Wax content expressed on both a leaf area and dry mass basis was increased due to main effects of low N and water stress. No main effects of CO2 were observed; however, a CO2 × N interaction at 12 mo indicated that under low soil N the elevated CO2 treatment had less wax (surface area or dry mass basis) compared to its ambient counterpart. Morphologically, low N needle surfaces appeared rougher compared to those of high N needles due to more extensive wax ridges. Although the main effect of water treatment on wax density was not reflected by changes in wax morphology, the CO2 × N interaction was paralleled by alterations in wax appearance. Decreases in density and less prominent epicuticular wax ridges resulting from growth under elevated CO2 and limiting N suggest that dynamics of plant/atmosphere and plant/pathogen interactions may be altered.
Submarine pollination in the marine angiosperm Zostera marina (Zosteraceae). II. Pollen transport in flow fields and capture by stigmas
Authors: Ackerman Josef Daniel
Published: April 2006

Flow chamber observations of the filamentous pollen of Zostera marina L. (Potamogetonales) revealed that pollen rotated and moved toward inflorescences where they were captured by stigmas. The mechanics of this abiotic pollination process were examined and found to be related to the flow environment around emergent flowers. The translational movement of pollen was imparted by the advection of the fluid (e. g., pollen kinetic energy, K, ranged from 0.8 × 10−−14 to 2.4 × 10−−14 J, and the average K of the fluid was ≈ 0.7 × 10−−14 J), while the rotational motion was imparted by the fluid shear stress (τ) within the velocity gradient (e. g., pollen shear stress, σt = ωµ where ω is the rotational velocity and µ is the dynamic viscosity, ranged from 3.4 × 10−−14 to 26 × 10−−14 Pa, and the average fluid shear stress was τ ≈ 10 × 10−−4 Pa; Ackerman, 1997, American Journal of Botany 84: 1099–1109). These results indicate that there is a greater potential for pollination by filamentous pollen relative to spherical pollen. Functionally, while spherical pollen needs to be directly upstream from stigmas to be captured, filamentous pollen need only be in the vicinity of inflorescences and flowers to be captured by stigmas. Thus, in addition to direct interception on stigmas, filamentous pollen can be captured while they rotate past flowers or when they are redirected through the velocity gradient towards flowers. Filamentous pollen is an adaptation to submarine pollination in seagrasses.
Systematics of Nothofagus (Nothofagaceae) based on rDNA spacer sequences (ITS): taxonomic congruence with morphology and plastid sequences
Authors: Manos Paul S.
Published: April 2006

Phylogenetic relationships were examined within the southern beech family Nothofagaceae using 22 species representing the four currently recognized subgenera and related outgroups. Nuclear ribosomal DNA sequences encoding the 5.8s rRNA and two flanking internal transcribed spacers (ITS) provided 95 phylogenetically informative nucleotide sites from a single alignment of ~ 588 bases per species. Parsimony analysis of this variation produced two equally parsimonious trees supporting four monophyletic groups, which correspond to groups designated by pollen type. These topologies were compared to trees from reanalyses of previously reported rbcL sequences and a modified morphological data set. Results from parsimony analysis of the three data sets were highly congruent, with topological differences restricted to the placement of a few terminal taxa. Combined analysis of molecular and morphological data produced six equally parsimonious trees. The consensus of these trees suggests two basal clades within Nothofagus. Within the larger of the two clades, tropical Nothofagus (subgenus Brassospora) of New Guinea and New Caledonia are strongly supported as sister to cool‐temperate species of South America (subgenus Nothofagus). Most of the morphological apomorphies of the cupule, fruit, and pollen of Nothofagus are distributed within this larger clade. An area cladogram based on the consensus of combined data supports three trans‐Antarctic relationships, two within pollen groups and one between pollen groups. Fossil data support continuous ancestral distributions for all four pollen groups prior to continental drift; therefore, vicariance adequately explains two of these disjunctions. Extinction of trans‐Antarctic sister taxa within formerly widespread pollen groups explains the third disjunction; this results in a biogeographic pattern indicative of phylogenetic relationship not vicariance. For the biogeographically informative vicariant clades, area relationships based on total evidence support the recently advanced hypothesis that New Zealand and Australia share a unique common ancestry. Contrary to previous thought, the distribution of extant Nothofagus is informative on the area relationships of the Southern Hemisphere, once precise phylogenetic relationships are placed in the context of fossil data.
Hybridization and introgression in Carpobrotus spp. (Aizoaceae) in California II. Allozyme evidence
Authors: Gallagher Kelly G. , Schierenbeck Kristina A. , D'Antonio Carla M.
Published: April 2006

Morphological evidence has indicated that hybridization and introgression are occurring between Carpobrotus edulis L., a nonindigenous, invasive species in California (Bolus), and its putative native congener, C. chilensis. The identification of allozyme markers has enabled us to quantify hybridization and the extent of introgression between these species. Samples from 20 individuals of each of five morphological types (both parent species and three hybrid phenotypes) were collected from 39 populations along the coast of California from the Mexico to Oregon borders. Ten enzyme systems revealed a total of 17 resolvable loci, eight of which were polymorphic for the genus. Five of the polymorphic loci easily differentiate C. edulis and C. chilensis. Allele frequencies among the morphologically defined types are consistent with estimations of allele frequency changes due to first‐ and second‐generation backcrossing. In comparison to long‐lived, herbaceous perennials and widespread species, C. edulis and intermediate types have more variation in their populations (P = 41.73, Ap = 2.11, Ho = 0.246, and P = 38.13, Ap = 2.06, Ho = 0.216, respectively) than C. chilensis (P = 11.76, Ap = 2.00, Ho = 0.082). Indirect estimates of gene flow indicate four of the five morphological types are outcrossing. Gene flow between previously allopatric species may have broad implications if it results in an increase in fitness; further experimentation is needed to determine the ultimate ecological consequences of this phenomenon and its possible threat to limited, remaining natural habitat in California.