Altitudinal Variation in Leaf Gas Exchange, Nitrogen and Phosphorus Concentrations, and Leaf Mass per Area in Populations of Frasera speciosa

1999 ◽  
Vol 31 (2) ◽  
pp. 191 ◽  
Author(s):  
William D. Bowman ◽  
Amy Keller ◽  
Mardy Nelson
Keyword(s):  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Leaf Mass Per Area ◽  
Nitrogen And Phosphorus ◽  
Altitudinal Variation ◽  
Leaf Mass

Reexamining the empirical relation between plant growth and leaf photosynthesis

2006 ◽  
Vol 33 (5) ◽  
pp. 421 ◽  
Author(s):  
Eric L. Kruger ◽  
John C. Volin
Keyword(s):  
Gas Exchange ◽  
Plant Growth ◽  
Leaf Area ◽  
Leaf Gas Exchange ◽  
Empirical Relation ◽  
Leaf Photosynthesis ◽  
Unit Leaf Area ◽  
Leaf Mass ◽  
Unit Leaf ◽  
Growth Variation

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.

Diel patterns of leaf carbohydrate concentrations differ between seedlings and mature trees of two sympatric oak species

Botany ◽  
2014 ◽  
Vol 92 (7) ◽  
pp. 535-540 ◽  
Author(s):  
Ori Baber ◽  
Martijn Slot ◽  
Gerardo Celis ◽  
Kaoru Kitajima
Keyword(s):  
Gas Exchange ◽  
Carbon Balance ◽  
Leaf Gas Exchange ◽  
Sun Exposure ◽  
Fundamental Aspect ◽  
Sink Strength ◽  
Mature Trees ◽  
Leaf Mass ◽  
Diel Patterns ◽  
Unit Leaf

A fundamental aspect of the carbon cycle is the exchange of carbon between plants and the atmosphere. It is, therefore, important to understand factors that affect differences in gas exchange and carbon balance within and among species. Concentrations of nonstructural carbohydrates are often used as a proxy for carbon balance. We determined diel patterns of leaf carbohydrate concentrations in relation to irradiance (sun vs. shade) in seedlings and mature trees of two sympatric oak species (Quercus virginiana Mill. and Quercus hemisphaerica Bartram ex Willd.). For seedlings, we also measured leaf gas exchange. Higher sun exposure significantly increased photosynthesis and carbohydrate concentrations in both species. Carbohydrate concentrations of seedling leaves showed strong diel fluctuations, whereas concentrations in mature tree leaves did not. This contrast might be attributed to faster carbohydrate export from leaves of mature trees. The difference in sink strength between seedlings and adults may be related to the decreasing ratio of leaf mass to plant mass with ontogeny, increasing the demand for carbohydrates per unit leaf mass. Seedlings and mature trees are clearly functionally different and care must be taken when extrapolating results from seedling experiments to mature trees.

Phosphorus deficiency alters scaling relationships between leaf gas exchange and associated traits in a wide range of contrasting Eucalyptus species

2018 ◽  
Vol 45 (8) ◽  
pp. 813 ◽  
Author(s):  
Nur H. A. Bahar ◽  
Paul P. G. Gauthier ◽  
Odhran S. O'Sullivan ◽  
Thomas Brereton ◽  
John R. Evans ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Phosphorus Deficiency ◽  
Leaf Traits ◽  
Leaf Mass Per Area ◽  
Eucalyptus Species ◽  
P Deficiency ◽  
Scaling Relationships ◽  
Wide Range ◽  
Leaf Metabolism

Phosphorus (P) limitation is known to have substantial impacts on leaf metabolism. However, uncertainty remains around whether P deficiency alters scaling functions linking leaf metabolism to associated traits. We investigated the effect of P deficiency on leaf gas exchange and related leaf traits in 17 contrasting Eucalyptus species that exhibit inherent differences in leaf traits. Saplings were grown under controlled-environment conditions in a glasshouse, where they were subjected to minus and plus P treatments for 15 weeks. P deficiency decreased P concentrations and increased leaf mass per area (LMA) of newly-developed leaves. Rates of photosynthesis (A) and respiration (R) were also reduced in P-deficient plants compared with P-fertilised plants. By contrast, P deficiency had little effect on the temperature sensitivity of R. Irrespective of P treatment, on a log-log basis A and R scaled positively with increasing leaf nitrogen concentration [N] and negatively with increasing LMA. Although P deficiency had limited impact on A-R-LMA relationships, rates of CO2 exchange per unit N were consistently lower in P-deficient plants. Our results highlight the importance of P supply for leaf carbon metabolism and show how P deficiencies (i.e. when excluding confounding genotypic and environmental effects) can have a direct effect on commonly used leaf trait scaling relationships.

The Effects of Drought on Leaf Gas Exchange and Growth of Three Species of Herbaceous Perennials

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 540a-540
Author(s):  
K.J. Prevete ◽  
R.T. Fernandez
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Drought Tolerance ◽  
Transpiration Rate ◽  
Leaf Gas Exchange ◽  
Gas Analysis ◽  
Herbaceous Perennials ◽  
Effects Of Drought ◽  
Analysis System

Three species of herbaceous perennials were tested on their ability to withstand and recover from drought stress periods of 2, 4, and 6 days. Eupatorium rugosum and Boltonia asteroides `Snowbank' were chosen because of their reported drought intolerance, while Rudbeckia triloba was chosen based on its reported drought tolerance. Drought stress began on 19 Sept. 1997. Plants were transplanted into the field the day following the end of each stress period. The effects of drought on transpiration rate, stomatal conductance, and net photosynthetic rate were measured during the stress and throughout recovery using an infrared gas analysis system. Leaf gas exchange measurements were taken through recovery until there were no differences between the stressed plants and the control plants. Transpiration, stomatal conductance, and photosynthesis of Rudbeckia and Boltonia were not affected until 4 days after the start of stress. Transpiration of Eupatorium decreased after 3 days of stress. After rewatering, leaf gas exchange of Boltonia and Rudbeckia returned to non-stressed levels quicker than Eupatorium. Growth measurements were taken every other day during stress, and then weekly following transplanting. Measurements were taken until a killing frost that occurred on 3 Nov. There were no differences in the growth between the stressed and non-stressed plants in any of the species. Plants will be monitored throughout the winter, spring, and summer to determine the effects of drought on overwintering capability and regrowth.

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