scholarly journals Trajectories: how functional traits influence plant growth and shade tolerance across the life-cycle

2016 ◽  
Author(s):  
Daniel S. Falster ◽  
Remko A. Duursma ◽  
Richard G. FitzJohn

AbstractPlant species differ in many functional traits that drive differences in rates of photosynthesis, biomass allocation, and tissue turnover. Yet, it remains unclear how – and even if – such traits influence whole-plant growth, with the simple linear relationships predicted by existing theory often lacking empirical support. Here we present a new theoretical framework for understanding the effect of diverse functional traits on plant growth and shade-tolerance, extending a widely-used theoretical model that links growth rate in seedlings with a single leaf trait to explicitly include influences of size, light environment, and five other prominent traits: seed mass, height at maturation, leaf mass per unit leaf area, leaf nitrogen per unit leaf area, and wood density. Based on biomass production and allocation, this framework explains why the influence of prominent traits on growth rate and shade tolerance often varies with plant size and why the impact of size on growth varies among traits. Considering growth rate in height, we find the influence of: i) leaf mass per unit leaf area is strong in small plants but weakens with size, ii) leaf nitrogen per unit leaf area does not change with size, iii) wood density is present across sizes but is strongest at intermediate sizes, iv) height at maturation strengthens with size, and v) seed mass decreases with size. Moreover, we show how traits moderate plant responses to light environment and also determine shade tolerance, supporting diverse empirical results. By disentangling the effects of plant size, light environment and traits on growth rates, our results provide a solid theoretical foundation for trait ecology and thus provide a platform for understanding growth across diverse species around the world.

2018 ◽  
Vol 115 (29) ◽  
pp. E6789-E6798 ◽  
Author(s):  
Daniel S. Falster ◽  
Remko A. Duursma ◽  
Richard G. FitzJohn

Plant species differ in many functional traits that drive differences in rates of photosynthesis, biomass allocation, and tissue turnover. However, it remains unclear how—and even if—such traits influence whole-plant growth, with the simple linear relationships predicted by existing theory often lacking empirical support. Here, we present a theoretical framework for understanding the effect of diverse functional traits on plant growth and shade tolerance by extending a widely used model, linking growth rate in seedlings with a single leaf trait, to explicitly include influences of size, light environment, and five prominent traits: seed mass, height at maturation, leaf mass per unit leaf area, leaf nitrogen per unit leaf area, and wood density. Based on biomass growth and allocation, this framework explains why the influence of traits on growth rate and shade tolerance often varies with plant size and why the impact of size on growth varies among traits. Specifically, we demonstrate why for height growth the influence of: (i) leaf mass per unit leaf area is strong in small plants but weakens with size; (ii) leaf nitrogen per unit leaf area does not change with size; (iii) wood density is present across sizes; (iv) height at maturation strengthens with size; and (v) seed mass decreases with size. Moreover, we show how traits moderate plant responses to light environment and also determine shade tolerance, supporting diverse empirical results.


2006 ◽  
Vol 33 (5) ◽  
pp. 421 ◽  
Author(s):  
Eric L. Kruger ◽  
John C. Volin

Technological advances during the past several decades have greatly enhanced our ability to measure leaf photosynthesis virtually anywhere and under any condition. Associated with the resulting proliferation of gas-exchange data is a lingering uncertainty regarding the importance of such measurements when it comes to explaining intrinsic causes of plant growth variation. Accordingly, in this paper we rely on a compilation of data to address the following questions: from both statistical and mechanistic standpoints, how closely does plant growth correlate with measures of leaf photosynthesis? Moreover, in this context, does the importance of leaf photosynthesis as an explanatory variable differ among growth light environments? Across a wide array of species and environments, relative growth rate (RGR) was positively correlated with daily integrals of photosynthesis expressed per unit leaf area (Aarea), leaf mass (Amass), and plant mass (Aplant). The amount of RGR variation explained by these relationships increased from 36% for the former to 93% for the latter. Notably, there was close agreement between observed RGR and that estimated from Aplant after adjustment for theoretical costs of tissue construction. Overall, based on an analysis of growth response coefficients (GRCs), gross assimilation rate (GAR), a photosynthesis-based estimate of biomass gain per unit leaf area, explained about as much growth variation as did leaf mass ratio (LMR) and specific leaf area (SLA). Further analysis of GRCs indicated that the importance of GAR in explaining growth variation increased with increasing light intensity. Clearly, when considered in combination with other key determinants, appropriate measures of leaf gas exchange effectively capture the fundamental role of leaf photosynthesis in plant growth variation.


1980 ◽  
Vol 7 (4) ◽  
pp. 435 ◽  
Author(s):  
DM Whitfield ◽  
DJ Connor

The interaction of single plants of tobacco with direct-beam light was investigated using coordinate data describing the three-dimensional display of foliage. The projection of unit leaf area of single plants showed little variation with either plant size or azimuth angle of sight but showed a major dependence on the zenith angle. In contrast, the beam-lit area of foliage varied with each of these factors. Zenith angle also had the largest effects on the distribution of beam-lit foliage area with respect to the leaf-beam angle. These variables were also estimated with a model which took account of the basic structural features of the plants. The assumption of a uniform distribution of the leaf projections on the plane normal to the beam led to systematic errors in estimates of the proportion of beam-lit foliage. These deviations were used for estimates of an empirical index of the dispersion of the projections of the elements of foliage. The index varied with plant size and zenith angle of sight. Satisfactory estimates of the projections of unit leaf area and of distributions of the beam-lit foliage with respect to the leaf-beam angle were obtained from the model orientation distributions and assuming that foliage intercepts light in proportion to its frequency in the orientation distributions. Results are discussed in terms of changes in the structure of the plant associated with growth and development.


2010 ◽  
Vol 56 (No. 3) ◽  
pp. 101-111 ◽  
Author(s):  
R. Gebauer ◽  
D. Volařík ◽  
T. Funda ◽  
I. Fundová ◽  
A. Kohutka ◽  
...  

Detailed research is necessary to better understand ecological adaptations of <I>Pinus pumila </I>(Pall.) Regel as a species, whose biological properties are vital for its survival. In the Svyatoi Nos Peninsula, three sites differing in altitude were selected. At all sites the growth form of <I>P. pumila</I> was determined. At the high and medium sites, the following parameters were measured: linear increment on terminal branches, leaf mass per area and the content of nitrogen per unit leaf area. Anatomical studies were carried out on shoots and four needle-year classes. It was found that needles were longer and narrower at the medium site when compared to the high site. Leaf mass per area was higher and a substantial increase in older needles occurred at the high site. Nitrogen content per unit leaf area served as an indicator of assimilation capacity and was higher at the high site. We can conclude that <I>P. pumila</I> has xeromorphic needles, higher assimilation capacity, better protection ability against pathogens and slower growth rate of terminal branches at the high site. Important is also a significant increment of the growth rate of terminal branches at the high site in recent years. Therefore, data obtained from sites at the upper forest limit are valuable in assessing the climate changes and are useful for the forest management practice in mountain areas.


1975 ◽  
Vol 23 (2) ◽  
pp. 253 ◽  
Author(s):  
HM Rawson ◽  
CL Craven

Changes in stomatal density and size were followed in tobacco and sunflower leaves expanding from 10% of final area (10% Amax) to Amax under different levels of radiation. Lower radiation increased final leaf area, reduced stomatal densities, and increased area per stoma but had little effect on stomatal area per unit leaf area at Amax. In very young leaves (20% Amax) there was a wide range in the sizes of individual stomata, some stomata being close to full size, but by Amax differences were small. The possible relationship between the developmental patterns described and photosynthesis is briefly discussed.


Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 534-540 ◽  
Author(s):  
Ronald E. Jones ◽  
Robert H. Walker

Greenhouse and growth chamber experiments with potted plants were conducted to determine the effects of interspecific root and canopy interference, light intensity, and soil moisture on water uptake and biomass of soybean, common cocklebur, and sicklepod. Canopy interference and canopy plus root interference of soybean with common cocklebur increased soybean water uptake per plant and per unit leaf area. Root interference with soybean decreased common cocklebur water uptake per plant. Canopy interference of soybean with sicklepod increased soybean water uptake per unit leaf area, while root interference decreased uptake per plant. Combined root and canopy interference with soybean decreased water uptake per plant for sicklepod. Soybean leaf area and shoot weight were reduced by root interference with both weeds. Common cocklebur and sicklepod leaf area and shoot weight were reduced by root and canopy interference with soybeans. Only common cocklebur root weight decreased when canopies interfered and roots did not. The relationship between light intensity and water uptake per unit leaf area was linear in both years with water uptake proportional to light intensity. In 1991 water uptake response to tight was greater for common cocklebur than for sicklepod. The relationship between soil moisture level and water uptake was logarithmic. Common cocklebur water uptake was two times that of soybean or sicklepod at −2 kPa of pressure potential. In 1991 common cocklebur water uptake decreased at a greater rate than soybean or sicklepod in response to pressure potential changes from −2 to −100 kPa.


1992 ◽  
Vol 19 (2) ◽  
pp. 171 ◽  
Author(s):  
FC Meinzer ◽  
NZ Saliendra ◽  
C Crisosto

Although carbon isotope discrimination (Δ) has been reported to decline in plants growing under reduced soil moisture, there is little information available concerning the dynamics of adjustments in Δ and gas exchange following a change in soil water availability. In this study Δ, photosynthetic gas exchange, and growth were monitored in container-grown coffee (Coffea arabica L.) plants for 120 days under three soil moisture regimes. At the end of 120 d, total leaf area of plants irrigated twice weekly was one half that of plants irrigated twice daily, although their assimilation rates on a unit leaf area basis were nearly equal throughout the experiment. This suggested that maintenance of nearly constant photosynthetic characteristics on a unit leaf area basis through maintenance of a smaller total leaf area may constitute a major mode of adjustment to reduced soil moisture availability in coffee. Intrinsic water-use efficiency (WUE) predicted from foliar Δ values was highest in plants irrigated weekly, intermediate in plants irrigated twice weekly and lowest in plants irrigated twice daily. When instantaneous WUE was estimated from independent measurements of total transpiration per plant and assimilation on a unit leaf area basis, the reverse ranking was obtained. The lack of correspondence between intrinsic and instantaneous WUE was attributed to adjustments in canopy morphology and leaf size in the plants grown under reduced water supply which enhanced transpiration relative to assimilation. Values of Δ predicted from the ratio of intercellular to ambient CO2 partial pressure determined during gas exchange measurements were not always consistent with measured foliar Δ. This may have resulted from a patchy distribution of stomatal apertures in plants irrigated weekly and from a lag period between adjustment in gas exchange and subsequent alteration in Δ of expanding leaves. The importance of considering temporal and spatial scales, and previous growth and environmental histories in comparing current single leaf gas exchange behaviour with foliar Δ values is discussed.


1974 ◽  
Vol 82 (2) ◽  
pp. 339-342 ◽  
Author(s):  
Ali T. Ayoub ◽  
H. M. Ishag

SummaryLeaf burn and gradual death were the characteristic symptoms of injury in P. vulgaris sown on a sodic soil. Plant growth, total leaf area per plant, number of stomata and epidermal cells per unit leaf area, and relative water content were drastically reduced in injured plants; these were associated with large sodium accumulation in the shoot resulting in cation imbalance.


1988 ◽  
Vol 15 (2) ◽  
pp. 107 ◽  
Author(s):  
WS Chow ◽  
L Qian ◽  
DJ Goodchild ◽  
JM Anderson

The photosynthetic acclimation of Alocasia macrorrhiza (L.) G. Don, a species naturally occurring in deep shade in rainforests, has been studied in relation to a wide range of controlled irradiances during growth (~3-780 �mol photons m-2 s-1 of fluorescent or incandescent light, 10 h light/ 14 h dark). At the maximum growth irradiances, the light- and CO2-saturated rates of O2 evolution per unit leaf area were ~4 times as high as at low irradiance, and approached those of glasshouse-grown spinach. Growth at maximum irradiances reduced the quantum yield of O2 evolution only slightly. Changes in the anatomy of leaf tissue, the ultrastructure of chloroplasts and the composition of chloroplast components accompanied the changes in photosynthetic functional characteristics. At low growth irradiance, palisade cell chloroplasts were preferentially located adjacent to the distal periclinal cell walls and had large granal stacks, and the destacked thylakoids had a very low surface charge density. In contrast, at higher growth irradiance, palisade cell chloroplasts were preferentially located adjacent to the anticlinal cell walls; they had small granal stacks, large stromal space, and a high surface charge density on the destacked thylakoids. The number of chloroplasts per unit section length increased with growth irradiance. Ribulosebisphosphate carboxylase activity per unit leaf area increased markedly with irradiance. Photosystem II, cytochrome f and latent ATPase activity per unit chlorophyll increased to a lesser extent. While the chlorophyll a/chlorophyll b ratio increased substantially with growth irradiance, the chlorophyll content per unit leaf area declined slightly. Our results show that coordinated changes in the structure of leaf tissue, and the organisation and composition of chloroplast components are responsible for Alocasia being capable of acclimation to high as well as low irradiance.


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