Anatomical variation in juvenile eucalypt leaves accounts for differences in specific leaf area and CO2 assimilation rates

2002 ◽  
Vol 50 (3) ◽  
pp. 301 ◽  
Author(s):  
Christine A. Sefton ◽  
Kelvin Montagu ◽  
Brian J. Atwell ◽  
Jann P. Conroy
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Anatomical Variation ◽  
Chlorophyll Concentration ◽  
Dry Mass ◽  
Co2 Assimilation ◽  
Leaf Structure ◽  
High Investment ◽  
Use Efficiency ◽  
Palisade Cells

Specific leaf area (SLA) is an important leaf attribute representing a compromise between the capture of light and CO2 and the limitations imposed by leaf structure, herbivore resistance and the mitigation of water loss. We examined three Eucalyptus L'Her. species to determine whether variation in CO2 assimilation rate was related to SLA and leaf anatomy. Seedlings were grown in a naturally illuminated glasshouse with adequate water and nutrients. Light-saturated rates of photosynthesis were measured on the youngest fully expanded leaves. Mesophyll characteristics were measured from sections thick of the interveinal leaf lamina. Significant interspecies variation in SLA corresponded to clear trends in anatomy and photosynthesis. Low-SLA leaves were thicker, having increased thickness of palisade mesophyll because of a greater number of palisade layers. E. occidentalis, E.camaldulensis and E. grandis had 3.7, 2.0 and 1.0 layers of palisade cells which corresponded to an SLA of 14.8, 17.6 and 21.8 m2 kg-1, respectively. High investment of dry mass in photosynthetic tissue was associated with higher leaf N (area and mass) concentration, chlorophyll concentration and photosynthetic capacity per leaf area. Leaf morphology affected use of the resources N, water and CO2. In contrast to the thin leaves of E. grandis, thick leaves of E. occidentalis had low N-use efficiency and high instantaneous water-use efficiency. Differences in leaf structure of these species appear to reflect the most limiting resource experienced in the environments to which they have adapted.

Foliage height influences specific leaf area of three conifer species

2003 ◽  
Vol 33 (1) ◽  
pp. 164-170 ◽  
Author(s):  
John D Marshall ◽  
Robert A Monserud
Keyword(s):  
Water Potential ◽  
Leaf Area ◽  
Pinus Ponderosa ◽  
Specific Leaf Area ◽  
Ponderosa Pine ◽  
Branch Length ◽  
Dry Mass ◽  
Process Models ◽  
Pinus Monticola ◽  
Northern Idaho

Specific leaf area (SLA), the ratio of projected leaf area to leaf dry mass, is a critical parameter in many forest process models. SLA describes the efficiency with which the leaf captures light relative to the biomass invested in the leaf. It increases from top to bottom of a canopy, but it is unclear why. We sampled stands with low and elevated canopies (young and old stands) to determine whether SLA is related to water potential, as inferred from branch height and length, or shade, as inferred from branch position relative to the rest of the canopy, or both. We studied western white pine (Pinus monticola Dougl. ex D. Don), ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.), and interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca) in northern Idaho. SLA decreased with branch height (P < 0.0001) at rates that varied among species (P < 0.0001). Branch length had no influence on SLA (P = 0.85). We detected no differences with canopy elevation (P = 0.90), but the slopes of lines relating SLA to branch height may have differed between the canopy elevation classes (P = 0.039). The results are consistent with predictions based on the hypothesis that SLA decreases as the gravitational component of water potential falls. The lack of a strong shading effect simplifies the estimation of canopy SLA for process models, requiring only species and branch heights.

scholarly journals Concentration and periods of application of prohexadione calcium in the growth of strawberry seedlings

2018 ◽  
Vol 39 (5) ◽  
pp. 1937 ◽  
Author(s):  
Caroline Farias Barreto ◽  
Leticia Vanni Ferreira ◽  
Savana Irribarem Costa ◽  
Andressa Vighi Schiavon ◽  
Tais Barbosa Becker ◽  
...  
Keyword(s):  
Leaf Area ◽  
Chlorophyll Concentration ◽  
Growth Control ◽  
Dry Mass ◽  
Energy Costs ◽  
Petiole Length ◽  
Total Leaf Area ◽  
Total Leaf ◽  
Control Growth ◽  
Prohexadione Calcium

For strawberry cultivation in Brazil, producers are dependent on imported seedlings. An alternative strategy to reduce this dependence is the use of seedlings obtained from nursery plants grown in a protected environment. However, as these seedlings are produced in the summer and planted at the end of this season or the spring of the following year, it is necessary to control growth to reduce the energy costs of the plants. The objective of this study was to evaluate the effect of different concentrations and periods of application of proexadione calcium (ProCa) on growth control of strawberry seedlings. The experiment was carried out in a greenhouse with seedlings of the cultivars ‘Aromas’ and ‘Camarosa’, produced by rooting stolons and kept in polystyrene trays of 72 cells in a substrate of carbonized rice husk. The experimental design was completely randomized, with a 4 × 2 factorial scheme (4 concentrations of ProCa: 0, 100, 200, and 400 mg L-1 × 2 periods of application: at 20 and 30 days after the planting period of rooting stolon). Plant survival, crown diameter, petiole length, total leaf area, specific leaf area, chlorophyll concentration, and dry mass of the crown and shoot were evaluated. The application of ProCa at 20 days after the planting period of the rooting stolon at the concentrations of 200 and 400 mg L-1 favored the reduction of petiole length in plants of ‘Aromas’ strawberry and total leaf aerial in ‘Camarosa’ strawberry. The application of ProCa from the concentration of 100 mg L-1 reduced the vegetative growth of ‘Aromas’ and ‘Camarosa’ strawberry seedlings cultivated in substrate.

Changes in specific leaf area and photosynthetic nitrogen-use efficiency associated with physiological acclimation of two hybrid poplar clones to intraclonal competition

2011 ◽  
Vol 41 (7) ◽  
pp. 1465-1476 ◽  
Author(s):  
Lahcen Benomar ◽  
Annie DesRochers ◽  
Guy R. Larocque
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Populus Trichocarpa ◽  
Hybrid Poplar ◽  
Growing Seasons ◽  
Poplar Clones ◽  
Use Efficiency ◽  
Intraclonal Competition ◽  
Physiological Acclimation ◽  
Two Hybrid

Photosynthesis is the most important process driving productivity, and its acclimation to intraclonal competition is not well understood in hybrid poplars. The aim of this study was to examine the physiological response of the crown of two hybrid poplar clones, BT747215 ( Populus balsamifera L. × Populus trichocarpa Torr. & A. Gray) and MB915319 ( Populus maximowiczii A. Henry × P. balsamifera ), to intraclonal competition. We measured light-saturated photosynthesis (Amax), leaf N content on an area basis (Narea), specific leaf area (SLA), and photosynthetic N-use efficiency (PNUE) for three successive growing seasons on trees planted at three spacings (1 m × 1 m, 3 m × 3 m, and 5 m × 5 m). Crowns were sampled at 10 locations corresponding to vertical and horizontal subdivisions. Significant changes took place at the crown level in the closest spacing (1 m × 1 m) compared with the wider spacings (3 m × 3 m and 5 m × 5 m): (i) 30% decrease in Narea, (ii) 20% increase in SLA, and (iii) 40% increase in PNUE. The slope of the Amax–Narea curve was greatest in the closest spacing, indicating a greater change in Amax per unit change in Narea. The two hybrid poplar clones had a similar morphophysiological response to changes of spacing. Both clones showed physiological acclimation of their foliage in response to intraclonal competition through modulation of SLA and PNUE.

scholarly journals Photosynthetic Photon Flux, Photoperiod, and CO2 Concentration Affect Growth and Morphology of Lettuce Plug Transplants

HortScience ◽  
1998 ◽  
Vol 33 (6) ◽  
pp. 988-991 ◽  
Author(s):  
Yoshiaki Kitaya ◽  
Genhua Niu ◽  
Toyoki Kozai ◽  
Maki Ohashi
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Dry Mass ◽  
Leaf Length ◽  
Leaf Number ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Hypocotyl Length ◽  
R Ratio ◽  
Four Levels

Lettuce (Lactuca sativa L. cv. Summer-green) plug transplants were grown for 3 weeks under 16 combinations of four levels (100, 150, 200, and 300 μmol·m-2·s-1) of photosynthetic photon flux (PPF), two photoperiods (16 and 24 h), and two levels of CO2 (400 and 800 μmol·mol-1) in growth chambers maintained at an air temperature of 20 ±2 °C. As PPF increased, dry mass (DM), percent DM, and leaf number increased, while ratio of shoot to root dry mass (S/R), ratio of leaf length to leaf width (LL/LW), specific leaf area, and hypocotyl length decreased. At the same PPF, DM was increased by 25% to 100% and 10% to 100% with extended photoperiod and elevated CO2 concentration, respectively. Dry mass, percent DM, and leaf number increased linearly with daily light integral (DLI, the product of PPF and photoperiod), while S/R, specific leaf area, LL/LW and hypocotyl length decreased as DLI increased under each CO2 concentration. Hypocotyl length was influenced by PPF and photoperiod, but not by CO2 concentration. Leaf morphology, which can be reflected by LL/LW, was substantially influenced by PPF at 100 to 200 μmol·m-2·s-1, but not at 200 to 300 μmol·m-2·s-1. At the same DLI, the longer photoperiod promoted growth under the low CO2 concentration, but not under the high CO2 concentration. Longer photoperiod and/or higher CO2 concentration compensated for a low PPF.

scholarly journals Combined effect of green-colored covers and shading on the growth of sisal (Furcraea hexapetala) plants

2017 ◽  
Vol 35 (3) ◽  
pp. 314-322
Author(s):  
Fánor Casierra-Posada ◽  
Fernando Portilla-Fuentes ◽  
Julián Molano-Díaz
Keyword(s):  
Leaf Area ◽  
Dry Mass ◽  
Infrared Light ◽  
Relative Growth ◽  
Light Reduction ◽  
Plant Morphogenesis ◽  
Shoot Ratio ◽  
Content Index ◽  
Use Efficiency

Plants have the ability to respond in different ways to the quality of light, its intensity, and the combination of both. In addition, chlorophyll absorbs light in the blue and red bands of the spectrum, but green and infrared light are poorly absorbed or not absorbed, yet they affect plant morphogenesis. An experiment was carried out in Tunja, Colombia, in which the influence of shading on sisal plants (Furcraea hexapetala) was evaluated. The plants were placed under green polypropylene filters that induced 55.4, 85.8 and 90.1% light reduction and were compared with open exposure plants in a greenhouse. As a consequence of shading, the values of the following variables were reduced: chlorophyll content index by between 52.2 and 55.0%, dry mass by between 80.8 and 94.0%, water uptake by between 40.9 and 44.9%, water use efficiency by between 23.0 and 53.7% and relative growth rate by between 35.1 and 58.4%, as compared to the control, while the values for the root to shoot ratio, specific leaf area and leaf area ratio were increased by ranges of 24.2 to 73.5%, 107.5 to 132.4% and 116.6 to 174.9%, respectively. The shading with green filters induced a reduction in the red/far red ratio of light. Based on these results, it was possible to infer that the sisal plants presented low plasticity for tolerating the abiotic stress induced by green-filter shading.

scholarly journals Growth, Water-Use Efficiency, Stomatal Conductance, and Nitrogen Uptake of Two Lettuce Cultivars Grown under Different Percentages of Blue and Red Light

Horticulturae ◽  
2018 ◽  
Vol 4 (3) ◽  
pp. 16 ◽  
Author(s):  
Jonathan Clavijo-Herrera ◽  
Edzard van Santen ◽  
Celina Gómez
Keyword(s):  
Stomatal Conductance ◽  
Water Use Efficiency ◽  
Leaf Area ◽  
Blue Light ◽  
Water Use ◽  
Nitrogen Uptake ◽  
Broad Spectrum ◽  
Red Light ◽  
Dry Mass ◽  
Use Efficiency

The objective of this study was to characterize growth, water-use efficiency (WUE), stomatal conductance (gs), SPAD index values, and shoot nitrogen uptake of two lettuce cultivars grown under different percentages of blue and red light. The treatments evaluated were 100% red; 7% blue + 93% red; 26% blue + 74% red; 42% blue + 58% red; 66% blue + 34% red; and 100% blue. Broad-spectrum (19% blue, 43% green, and 38% red) light was used to observe the effects of wavelength interactions. All of the treatments provided an average daily light integral (DLI) of 17.5 mol·m‒2·d‒1 (270 ± 5 µmol·m‒2·s‒1 over an 18-h photoperiod). The experiment was replicated three times over time; each terminated 21 days after treatment initiation. Leaf area, specific leaf area (SLA), and SPAD index had a similar response in that all of the parameters increased with up to 66% blue light, and slightly decreased or remained constant with 100% blue light. In contrast, leaf number, shoot dry mass, and WUE generally decreased in response to blue light. Conversely, for every 10% increase in blue light, gs increased by 10 mmol·m‒2·s‒1. Nitrogen uptake was unaffected by light quality. Our findings indicate that when grown under different blue and red photon flux ratios, the WUE of lettuce significantly decreases under higher blue light, which could be attributed to a reduction in plant growth (leaf number and dry mass), and an increase in gs. However, green light within broad-spectrum lamps might counteract blue-light mediated effects on gs and WUE in lettuce.

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