Functional analysis of the relative growth rate, chemical composition, construction and maintenance costs, and the payback time of Coffea arabica L. leaves in response to light and water availability

In this study, the combined effects of light and water availability on the functional relationships of the relative growth rate (RGR), leaf chemical composition, construction and maintenance costs, and benefits in terms of payback time for Coffea arabica are presented. Coffee plants were grown for 8 months in 100% or 15% full sunlight and then a four-month water shortage was implemented. Plants grown under full sunlight were also transferred to shade and vice versa. Overall, most of the traits assessed were much more responsive to the availability of light than to the water supply. Larger construction costs (12%), primarily associated with elevated phenol and alkaloid pools, were found under full sunlight. There was a positive correlation between these compounds and the RGR, the mass-based net carbon assimilation rate and the carbon isotope composition ratio, which, in turn, correlated negatively with the specific leaf area. The payback time was remarkably lower in the sun than in shade leaves and increased greatly in water-deprived plants. The differences in maintenance costs among the treatments were narrow, with no significant impact on the RGR, and there was no apparent trade-off in resource allocation between growth and defence. The current irradiance during leaf bud formation affected both the specific leaf area and leaf physiology upon transferring the plants from low to high light and vice versa. In summary, sun-grown plants fixed more carbon for growth and secondary metabolism, with the net effect of an increased RGR

Case Study 3: Movement Lawyers and Community Organizers in Litigation: Issues of Finances and Collaboration

This essay represents one of several Case Studies published as the Movement Lawyering Roundtable Symposium by Hofstra Law Review. The Case Studies were developed within a roundtable of movement lawyers, community organizers, and legal ethics experts convened in March, 2018 by the Monroe H. Freedman Institute for the Study of Legal Ethics at Hofstra University’s Maurice A. Deane School of Law. This Case Study addresses the ethical tensions encountered by movement lawyers and community organizers engaged in public interest litigation. The Study consists of three topics, with resulting ethics analyses of the issues that arise in the differing settings. The first involves questions of financing the broad work of a community organizing client, while honoring the mandates of the rule of professional conduct prohibiting a lawyer from offering financial assistance to clients in litigation. The second issue addressed how lawyers might share attorneys’ fees awards with community groups who are ongoing clients. The third issue pivots to questions of how movement lawyers might counsel community organizations about disagreements with other pro bono lawyers representing the clients. Each of these sets of legal ethics issues arises in movement lawyering practice, and can be confounding. This essay seeks to offer guidance to lawyers navigating these sometimes delicate ethical waters

Ontogenetic changes in leaf traits of tropical rainforest trees differing in juvenile light requirement

Relationships between leaf traits and the gap dependence for regeneration, and ontogenetic changes therein, were investigated in juvenile and adult tropical rainforest tree species. The juveniles of the 17 species included in the study were grown in high light, similar to the exposed crowns of the adult trees. The traits were structural, biomechanical, chemical and photosynthetic. With increasing species gap dependence, leaf mass per area (LMA) decreased only slightly in juveniles and remained constant in adults, whereas punch strength together with tissue density decreased, and photosynthetic capacity and chlorophyll increased. Contrary to what has been mostly found in evergreen tropical rainforest, the trade-off between investment in longevity and in productivity was evident at an essentially constant LMA. Of the traits pertaining to the chloroplast level, photosynthetic capacity per unit chlorophyll increased with gap dependence, but the chlorophyll a/b ratio showed no relationship. Adults had a twofold higher LMA, but leaf strength was on average only about 50% larger. Leaf tissue density, and chlorophyll and leaf N per area were also higher, whereas chlorophyll and leaf N per unit dry mass were lower. Ranking of the species, relationships between traits and with the gap dependence of the species were similar for juveniles and adults. However, the magnitudes of most ontogenetic changes were not clearly related to a species’ gap dependence. The adaptive value of the leaf traits for juveniles and adults is discussed

Vegetation dynamics and plant constraints: separating generalities and specifics

Vegetation dynamics is a stochastic process of species replacement after disturbance. It occurs because individual species are limited by general constraints and trade-offs. As these constraints and trade-offs are becoming better known, we understand more about the relationships between disturbance dynamics, species pools, and vegetation dynamics. This paper provides a summary of recent work on plant scaling and ecological trade-offs, and explores its implications for vegetation dynamics. Those aspects of succession that are predictable . given the local species complement . can be understood as consequences of these general patterns and constraints. Several are explored in this paper. The inherently stochastic nature of the process derives from the disturbance dynamics that forces it, from the sampling processes that are responsible for selecting potential invaders, and from the chance processes involved in species interactions. The dynamics of species that invade established communities is the least understood but potentially the most crucial aspect of vegetation dynamics. The relation of community invasion to gap creation and to scaling constraints is briefly discussed