Ecology of Leaf Longevity


Book Description

Leaf longevity is a fundamental process underlying patterns of variation in foliar phenology and determining the distinction between deciduous and evergreen plant species. Variation in leaf longevity is associated with a wide array of differences in the physiology, anatomy, morphology and ecology of plants. This book brings together for the first time information scattered widely in the botanical literature to provide a clear and comprehensive introduction to the nature and significance of variation in leaf longevity. It traces the development of ideas about leaf longevity from the earliest descriptive studies to contemporary theory of leaf longevity as a key element in the function of leaves as photosynthetic organs. An understanding of variation in leaf longevity reveals much about the nature of adaptation at the whole plant level and provides fundamental insights into the basis of variation in plant productivity at the ecosystem level. The analysis of leaf longevity also provides a process-based perspective on phenological shifts associated with the changing climate. Readers will find this an informative synthesis summarizing and illustrating different views in a readily accessible narrative that draws attention to a central but too often unappreciated aspect of plant biology. The nature and causes of seasonal patterns in the birth and death of individual plant leaves are essential to the understanding of the health of plant communities, biomes, and consequently our planet.




Leaf Longevity


Book Description







On the Contribution of Leaf Surface Wetness, Leaf Size and Leaf Longevity to Variation in Leaf Water and Carbon Balance


Book Description

It is widely recognized that many aspects of plant form and function are coupled to variation in water availability. This is because plant persistence is ultimately dependent upon the process of carbon fixation and it is physically impossible for a plant to transport CO2 to the sites of photosynthetic metabolism inside the leaf without, at the same time, loosing water to the surrounding atmosphere. How the efficiency of water use changes as leaves differ in size and longevity, and where leaves acquire their water from, are often times not well defined. In general, the water lost to the atmosphere by leaves is thought to originate from the soil via uptake by roots. However, previous research has shown that water deposited on leaf surfaces is often available for use via direct foliar uptake. Using field observations and a greenhouse experiment I show that leaf water interception can represent an overlooked water source for leaves that temporarily, but significantly, decouples leaf-level water and carbon relations from variation in soil water availability (Chapter 1). Additionally, within a particular environment water loss per unit leaf area is expected to increase with leaf size. Recent research suggests the construction cost of a leaf also increases with size and/or longevity. If leaves have maximized the ability to transport water to surfaces for energy and gas exchange in order to maximize CO2 uptake from the atmosphere, then vascular network efficiency (Leaf hydraulic conductance) should be size invariant. Using a survey of 60 angiosperm species I show that leaf hydraulic conductance is maximized for a given surface area (Chapter 2). By extension, if the lifetime return (carbon gain) on dry-mass invested in leaf area (construction cost plus maintenance respiration per unit leaf area) is maximized, then leaf hydraulic conductance per unit leaf dry mass should scale isometrically with leaf lifespan. Using plants from a common garden and previously published values of leaf lifespan and leaf hydraulic conductance for species inhabiting a broad range of vegetation types and climate, I explored the relationship between leaf longevity and leaf hydraulic conductance per unit leaf mass. I observed a negative correlation between leaf hydraulic conductance per unit leaf mass and leaf lifespan. Further, the slope of the relationship describing the covariation between leaf hydraulic conductance per unit mass and leaf lifespan is not significantly different from one. Isometric scaling (slope = 1) provides strong support for a constant net carbon gain per leaf despite significant variation in leaf size, longevity and environment. Therefore, variation in gross primary productivity is a function of the number of leaves a plant maintains over a given unit of time (Chapter 3).










Climate Change and Terrestrial Ecosystem Modeling


Book Description

Provides an essential introduction to modeling terrestrial ecosystems in Earth system models for graduate students and researchers.




Plant Physiological Ecology


Book Description

Box 9E. 1 Continued FIGURE 2. The C–S–R triangle model (Grime 1979). The strategies at the three corners are C, competiti- winning species; S, stress-tolerating s- cies; R,ruderalspecies. Particular species can engage in any mixture of these three primary strategies, and the m- ture is described by their position within the triangle. comment briefly on some other dimensions that Grime’s (1977) triangle (Fig. 2) (see also Sects. 6. 1 are not yet so well understood. and 6. 3 of Chapter 7 on growth and allocation) is a two-dimensional scheme. A C—S axis (Com- tition-winning species to Stress-tolerating spe- Leaf Economics Spectrum cies) reflects adaptation to favorable vs. unfavorable sites for plant growth, and an R- Five traits that are coordinated across species are axis (Ruderal species) reflects adaptation to leaf mass per area (LMA), leaf life-span, leaf N disturbance. concentration, and potential photosynthesis and dark respiration on a mass basis. In the five-trait Trait-Dimensions space,79%ofallvariation worldwideliesalonga single main axis (Fig. 33 of Chapter 2A on photo- A recent trend in plant strategy thinking has synthesis; Wright et al. 2004). Species with low been trait-dimensions, that is, spectra of varia- LMA tend to have short leaf life-spans, high leaf tion with respect to measurable traits. Compared nutrient concentrations, and high potential rates of mass-based photosynthesis. These species with category schemes, such as Raunkiaer’s, trait occur at the ‘‘quick-return’’ end of the leaf e- dimensions have the merit of capturing cont- nomics spectrum.




Principles of Terrestrial Ecosystem Ecology


Book Description

Features review questions at the end of each chapter; Includes suggestions for recommended reading; Provides a glossary of ecological terms; Has a wide audience as a textbook for advanced undergraduate students, graduate students and as a reference for practicing scientists from a wide array of disciplines




Grasses and Grassland Ecology


Book Description

This book is the most up to date and thorough account of the natural history of the plants that comprise the most important food crop on Earth, the grasses and grasslands.