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"plant size"
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An integrated framework of plant form and function: The belowground perspective
Plant trait variation drives plant function, community composition, and ecosystem processes. However, our current understanding of trait variation disproportionately relies on aboveground observations. Here we integrate root traits into the global framework of plant form and function. We developed and tested an overarching conceptual framework that integrates two recently identified root trait gradients with a well-established aboveground plant trait framework. We confronted our novel framework with published relationships between above- and belowground trait analogues and with multivariate analyses of aboveground and belowground traits of 2510 species. Our traits represent the leaf- and root conservation gradients (specific leaf area, leaf and root nitrogen concentration and root tissue density), the root collaboration gradient (root diameter and specific root length), and the plant size gradient (plant height and rooting depth). We found that an integrated, whole-plant trait space required as much as four axes. The two main axes represented the fast-slow ‘conservation’ gradient on which leaf and fine-root traits were well aligned, and the ‘collaboration’ gradient in roots. The two additional axes were separate, orthogonal plant size axes for height and rooting depth. This perspective on the multi-dimensional nature of plant trait variation better encompasses plant function and influence on the surrounding environment.
Journal Article
Biological stoichiometry of plant production: metabolism, scaling and ecological response to global change
Biological stoichiometry theory considers the balance of multiple chemical elements in living systems, whereas metabolic scaling theory considers how size affects metabolic properties from cells to ecosystems. We review recent developments integrating biological stoichiometry and metabolic scaling theories in the context of plant ecology and global change. Although vascular plants exhibit wide variation in foliar carbon : nitrogen : phosphorus ratios, they exhibit a higher degree of 'stoichiometric homeostasis' than previously appreciated. Thus, terrestrial carbon : nitrogen : phosphorus stoichiometry will reflect the effects of adjustment to local growth conditions as well as species' replacements. Plant stoichiometry exhibits size scaling, as foliar nutrient concentration decreases with increasing plant size, especially for phosphorus. Thus, small plants have lower nitrogen : phosphorus ratios. Furthermore, foliar nutrient concentration is reflected in other tissues (root, reproductive, support), permitting the development of empirical models of production that scale from tissue to whole-plant levels. Plant stoichiometry exhibits large-scale macroecological patterns, including stronger latitudinal trends and environmental correlations for phosphorus concentration (relative to nitrogen) and a positive correlation between nutrient concentrations and geographic range size. Given this emerging knowledge of how plant nutrients respond to environmental variables and are connected to size, the effects of global change factors (such as carbon dioxide, temperature, nitrogen deposition) can be better understood.
Journal Article
How fundamental plant functional trait relationships scale-up to trade-offs and synergies in ecosystem services
1. Ecosystem services (ES) lie at the core of the interactions among humans and ecosystems. Fundamental understanding of the ecological mechanisms underlying the simultaneous provision of multiple ES has been lagging behind policy and management needs and stands out as a research priority. In this paper, we focus on interactions between ES resulting from fundamental functional mechanisms. 2. Plant diversity contributes significantly to the delivery of ES. Specifically, functional composition strongly determines different ecosystem properties and services. Knowledge on associations and trade-offs among different plant traits is well established, but the consequences for ecosystem functioning and the resulting ability for ecosystems to provide multiple services have only started to be explored. We present a conceptual framework linking environmental change to changes in ecosystem functioning and to changes in ES through plant traits. We explicitly consider the leaf economics and size axes of plant functional variation, and how their responses to key environmental variables are expected to scale-up to ecosystem properties and ES. 3. The framework was tested using a structural equation modelling formalism to understand the trait-based mechanisms driving trade-offs in ES in mountain grasslands. Variations along the leaf economics spectrum (LES) towards more exploitative strategies in response to increasing fertility led to a combined increase in several ES valued by local stakeholders, including agronomic value, cultural value and soil water retention. Surprisingly, and contrary to published hypotheses, soil carbon sequestration in the studied subalpine system did not increase at lower fertility which was associated with more conservative plant strategies. Independent variation in LES and height provided alternative pathways to biomass production. 4. Synthesis: A trait-based framework can support the understanding and aid the management of multiple ES. We recommend testing this framework in a variety of contexts and at larger scales, using additional trait axes such as wood density or seed size.
Journal Article
Optimizing plant size for vertical farming by editing stem length regulators
Summary Vertical farming offers the advantage of providing a stable environment for plant cultivation, shielding them from adverse conditions such as climate change. For fruit‐harvesting plants like tomato, vertical farming necessitates the optimization of plant growth and architecture. The gibberellin 3‐oxidase (GA3ox) genes encode gibberellin 3‐oxidases responsible for activating GA within the pathway and modulating stem length. Among the five SlGA3ox genes, we targeted the coding regions of three SlGA3ox genes (named SlGA3ox3, SlGA3ox4 and SlGA3ox5) using multiplex CRISPR genome editing. The slga3ox4 single mutants exhibited a slight reduction in primary shoot length, leading to a smaller stature. In contrast, the slga3ox3 and slga3ox5 single mutants showed subtle phenotypic changes. Notably, the slga3ox3 slga3ox4 double mutants developed a more compact shoot architecture with minor physiological differences, potentially making them suitable for vertical farming applications. We observed a correlation between total yield and plant size across all genotypes through multiple yield trials. Observations from vertical farm cultivation revealed that slga3ox3 slga3ox4 plants possess a markedly compact plant size, offering potential benefits for space‐efficient cultivation. Our research suggests that targeted manipulation of hormone biosynthetic genes can effectively tailor plant architecture for vertical farming.
Journal Article
Prices, Plant Size, and Product Quality
Drawing on uncommonly rich and representative data from the Colombian manufacturing census, this paper documents new empirical relationships between input prices, output prices, and plant size and proposes a model of endogenous input and output quality choices by heterogeneous firms to explain the observed patterns. The key empirical facts are that, on average within narrowly defined sectors, (1) larger plants charge more for their outputs and (2) larger plants pay more for their material inputs. The latter fact generalizes the well-known positive correlation between plant size and wages. Similar correlations hold between prices and export status. We show that the empirical patterns are consistent with a parsimonious extension of the Melitz (2003, \"The Impact of Trade on Intra-Industry Reallocations and Aggregate Industry Productivity,\" Econometrica, 71, 1695-1725) framework to include endogenous choice of input and output quality. Using a measure of the scope for quality differentiation from Sutton (1998, Technology and Market Structure: Theory and History. Cambridge: MIT Press), we show that differences across sectors in the relationships between prices and plant size are consistent with our model. Available evidence suggests that differences in observable measures of market power do not provide a complete explanation for the empirical patterns. We interpret the results as supportive of the hypothesis that quality differences of both inputs and outputs play an important role in generating the price-plant size correlations.
Journal Article
Universal scaling of respiratory metabolism, size and nitrogen in plants
The scaling of respiratory metabolism to body size in animals is considered to be a fundamental law of nature and there is substantial evidence for an approximate 3/4-power relation. Studies suggest that plant respiratory metabolism also scales as the 3/4-power of mass, and that higher plant and animal scaling follow similar rules owing to the predominance of fractal-like transport networks and associated allometric scaling. Here, however, using data obtained from about 500 laboratory and field-grown plants from 43 species and four experiments, we show that whole-plant respiration rate scales approximately isometrically (scaling exponent approximately 1) with total plant mass in individual experiments and has no common relation across all data. Moreover, consistent with theories about biochemically based physiological scaling, isometric scaling of whole-plant respiration rate to total nitrogen content is observed within and across all data sets, with a single relation common to all data. This isometric scaling is unaffected by growth conditions including variation in light, nitrogen availability, temperature and atmospheric CO2 concentration, and is similar within or among species or functional groups. These findings suggest that plants and animals follow different metabolic scaling relations, driven by distinct mechanisms.
Journal Article
Size-dependent variations in individual traits and trait scaling relationships within a shade-tolerant evergreen tree species
Premise of Study The plant size–trait relationship is a fundamental dimension in the spectrum of plant form and function. However, it remains unclear whether the trait scaling relationship within species is modified by tree size. Investigating size‐dependent trait covariations within species is crucial for understanding the ontogenetic constraints on the intraspecific economic spectrum and, more broadly, the structure and causes of intraspecific trait variations. Methods We measured eight morphological, stoichiometric, and hydraulic traits for 604 individual plants of a shade‐tolerant evergreen tree species, Litsea elongata, in a subtropical evergreen forest of eastern China. Individual trait values were regressed against tree basal diameter to evaluate size‐dependent trait variations. Standardized major axis regression was employed to examine trait scaling relationships and to test whether there was a common slope and elevation in the trait scaling relationship across size classes. Key Results Small trees tended to have larger, thinner leaves and longer, slenderer stems than larger trees, which indicates an acquisitive economic strategy in juvenile trees. Leaf nitrogen concentrations increased with plant size, which was likely due to a high ratio of structural to photosynthetic nitrogen in the evergreen leaves of large trees. Bivariate trait scaling was minimally modified by tree size, although the elevation of some relationships differed between size classes. Conclusions Our results suggest that there are common economic and biophysical constraints on intraspecific trait covariation, independent of tree size. Small and large trees tend to be located at opposite ends of an intraspecific plant economic spectrum.
Journal Article
Effects of body size and root to shoot ratio on foliar nutrient resorption efficiency in Amaranthus mangostanus
Premise of the Study Nutrient resorption is essential for plant nutrient conservation. Large‐bodied plants potentially have large nutrient sink pools and high nutrient flux. Whether and how nutrient resorption can be regulated by plant size and biomass allocation are yet unknown. Methods Using the herbaceous plant Amaranthus mangostanus in greenhouse experiments for two consecutive years, we measured plant biomass, height, and stem diameter and calculated the root to shoot biomass ratio (R/S ratio) and nutrient resorption efficiency (NuRE) to assess the effects of plant body size and biomass allocation on NuRE. NuRE was calculated as the percentage reduction in leaf nutrient concentration from green leaf to senesced leaf. Key Results NuRE increased with plant biomass, height, and stem diameter, suggesting that the individuals with larger bodies, which led to a larger nutrient pool, tended to resorb proportionally more nutrients from the senescing leaves. NuRE decreased with increasing root to shoot ratio, which might have reflected the nutrient acquisition trade‐offs between resorption from the senescent leaves and absorption from the soil. Increased root biomass allocation increased the proportion of nutrient acquisition through absorption more than through resorption. Conclusions This study presented the first experimental evidence of how NuRE is linked to plant size (indicated by biomass, height, and stem diameter) and biomass allocation, suggesting that nutrient acquisition could be modulated by the size of the nutrient sink pool and its partitioning in plants, which can improve our understanding of a conservation mechanism for plant nutrients. The body size and root to shoot ratio effects might also partly explain previous inconsistent reports on the relationships between environmental nutrient availability and NuRE.
Journal Article
Convergent xylem widening among organs across diverse woody seedlings
Xylem conduit diameter (D
max) of woody angiosperm adults scales with plant size and widens from the stem apex downwards. We hypothesized that, notwithstanding relative growth rate (RGR), growth form or leaf habit, woody seedling conduit D
max scales linearly with plant size across species; this scaling should be applicable to all vegetative organs, with consistent conduit widening from leaf via stem to main root and coupling with whole-leaf area and whole-stem xylem area.
To test these hypotheses, organ-specific xylem anatomy traits and size-related traits in laboratory-grown seedlings were analyzed across 55 woody European species from cool-temperate and Mediterranean climates.
As hypothesized, conduit D
max of each organ showed similar scaling with plant size and consistent basipetal widening from the leaf midvein via the stem to the main root across species, independently of growth form, RGR and leaf habit. We also found a strong correlation between D
max and average leaf area, and between stem xylem area and whole-plant leaf area.
We conclude that seedlings of ecologically wide-ranging woody species converge in their allometric scaling of conduit diameters within and across plant organs. These relationships will contribute to modeling of water transport in woody vegetation that accounts for the whole life history from the trees’ regeneration phase to adulthood.
Journal Article