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.

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.

scholarly journals The Influence of Compost Amendment or Straw Mulch on the Reduction of Gas Exchange in Potato by Verticillium dahliae and Pratylenchus penetrans

Plant Disease ◽  
1999 ◽  
Vol 83 (4) ◽  
pp. 371-376 ◽  
Author(s):  
M. P. N. Gent ◽  
J. A. LaMondia ◽  
F. J. Ferrandino ◽  
W. H. Elmer ◽  
K. A. Stoner
Keyword(s):  
Gas Exchange ◽  
Verticillium Dahliae ◽  
Leaf Gas Exchange ◽  
Pratylenchus Penetrans ◽  
Mushroom Compost ◽  
Spent Mushroom Compost ◽  
Straw Mulch ◽  
Potato Plants ◽  
Unit Leaf ◽  
Compost Amendment

Single potato plants (Solanum tuberosum cv. Superior) were grown in microplots in soil that was fumigated and then infested with Verticillium dahliae, Pratylenchus penetrans, or both to evaluate the effects of these pathogens and of cultural treatments with spent mushroom compost or straw mulch on gas exchange of potato leaves. Photosynthesis and transpiration of terminal leaflets of a cohort of similar-aged leaves were measured once a week from the time of expansion until they senesced. Over all measurements, gas exchange per unit leaf area was less for plants in microplots infested with V. dahliae or P. penetrans than for those in uninfested plots. For leaves that expanded in early June, gas exchange was similar immediately after leaf expansion but declined more quickly when microplots were infested with one or both pathogens compared to no infestation. Overall, leaf gas exchange was increased by compost amendment but not affected by straw mulch. Compost amendment prevented some of the decline in gas exchange due to infestation by one or both pathogens. For leaves that expanded in July, compost increased the gas exchange immediately after expansion in both infested and non-infested plots.

The influence of soil temperature and water content on belowground hydraulic conductance and leaf gas exchange in mature trees of three boreal species

2020 ◽  
Vol 43 (3) ◽  
pp. 532-547 ◽  
Author(s):  
Anna Lintunen ◽  
Teemu Paljakka ◽  
Yann Salmon ◽  
Roderick Dewar ◽  
Anu Riikonen ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Soil Temperature ◽  
Water Content ◽  
Leaf Gas Exchange ◽  
Hydraulic Conductance ◽  
Mature Trees ◽  
Boreal Species

Unexpectedly low δ 13C in leaves, branches, stems, and roots of three acacia species growing in hyper-arid environments

2020 ◽  
Author(s):  
Daphna Uni ◽  
Elli Groner ◽  
Elaine Soloway ◽  
Amgad Hjazin ◽  
Spencer Johnswick ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Growth Parameters ◽  
Leaf Gas Exchange ◽  
Arid Environments ◽  
Acacia Tortilis ◽  
Mature Trees ◽  
Acacia Species ◽  
Δ 13C ◽  
Leaf Tissues ◽  
Irrigation Levels

Abstract Aims In plant eco-physiology, less negative (enriched) carbon 13 ( 13C) in the leaves indicates conditions of reducing leaf gas exchange through stomata, e.g. under drought. In addition, 13C is expected to be less negative in non-photosynthetic tissues as compared with leaves. However, these relationships in δ 13C from leaves (photosynthetic organs) to branches, stems and roots (non- photosynthetic organs) are rarely tested across multiple closely related tree species, multiple compartments, or in trees growing under extreme heat and drought. Methods We measured leaf-to-root 13C in three closely related desert acacia species (Acacia tortilis, A. raddiana, A. pachyceras). We measured δ 13C in leaf tissues from mature trees in Southern Israel. In parallel, a 7-year irrigation experiment with 0.5, 1.0, or 4.0 L plant -1 day -1 was conducted in an experimental orchard. At the end of the experiment, growth parameters and δ 13C were measured in leaves, branches, stems, and roots. Important findings The δ 13C in leaf tissues sampled from mature trees was ca. -27 ‰, far more depleted than expected from a desert tree growing in one of the Earth’s driest and hottest environments. Across acacia species and compartments, δ 13C was not enriched at all irrigation levels (-28‰ to ca. -27‰), confirming our measurements in the mature trees. Among compartments, leaf δ 13C was unexpectedly similar to branch and root δ 13C, and surprisingly, even less negative than stem δ 13C. The highly depleted leaf δ 13C suggests that these trees have high stomatal gas exchange, despite growing in extremely dry habitats. The lack of δ 13C enrichment in non-photosynthetic tissues might be related to the seasonal coupling of growth of leaves and heterotrophic tissues.

scholarly journals The Effect of Wind on the Vegetative and Reproductive Growth of Four Primocane-fruiting Red Raspberries (Rubus idaeus L.) in the Establishment Year

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 575e-575
Author(s):  
Jean-Pierre Privé ◽  
N. Allain
Keyword(s):  
Gas Exchange ◽  
Leaf Area ◽  
Leaf Gas Exchange ◽  
Rubus Idaeus ◽  
Gas Exchange Parameters ◽  
Yield Increase ◽  
Unit Leaf ◽  
Westerly Winds ◽  
Wind Exposure ◽  
Vegetative And Reproductive Growth

Four primocane fruiting (PP) red raspberry cultivars, `Bogong', `Cascade', `Heritage', and `Dinkum', were grown in exposed or sheltered (50% permeable artificial windbreak) sites fully exposed to prevailing westerly winds. The cultivars were evaluated to determine the effects of wind stress on vegetative and reproductive development and leaf gas exchange during the establishment year. The artificial windbreak resulted in an overall 35% reduction in wind velocity, increased the number of calm days (<5.4 km·h–1) and decreased the incidence of strong breezes (>36 km·h–1). Concurrently, the artificial windbreak did not have much of an effect on altering relative humidity, air or soil temperature. All cultivars responded similarly to wind exposure Plants in exposed sites had reduced leaf areas, internode lengths, leaf, cane, and total above ground dry weights. Leaf gas exchange parameters (Pn, gs and Ci) expressed per unit leaf area did nor differ between treatments for most of the season but the sheltered plants as a whole supported a greater total leaf area and must have fixed a greater amount of carbon than the exposed plants. These larger sheltered plants produced a more extensive fruiting framework and resulted in a 2-fold yield increase. For these reasons, it is highly recommended to shelter raspberry plants from wind in the establishment year.

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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