Photosynthetic and Growth Responses of Variegated Ornamental Species to Elevated CO2

1994 ◽  
Vol 21 (3) ◽  
pp. 273 ◽  
Author(s):  
WJS Downton ◽  
WJR Grant
Keyword(s):  
Leaf Area ◽  
Elevated Co2 ◽  
Dark Respiration ◽  
Photochemical Efficiency ◽  
Nerium Oleander ◽  
Growth Responses ◽  
High Co2 ◽  
Green Plants ◽  
Respiration Rates ◽  
Green Leaves

Variegated and completely green cultivars of oleander (Nerium oleander L.) and willow myrtle (Agonis flexuosa (Willd.) Sweet) were grown in controlled environment cabinets for 3 and 5 months, respectively, under either ambient levels of CO2 or with supplementary CO2 to a partial pressure of 800 μbar. Photosynthesis of entirely green leaves and the green portions of variegated leaves on both species was greatly stimulated by high CO2 and there was no evidence of downward adjustment (acclimation) of photosynthetic rates to high CO2 during the experiment. Dark respiration rates of these leaves were lowered by high CO2. The yellow portions of willow myrtle leaves showed a low level of photosynthetic activity which was stimulated by high CO2; however, dark respiration rates showed little response to elevated CO2. Green and yellow areas on variegated leaves of willow myrtle had much lower dark respiration rates than completely green leaves, but this difference was not evident for oleander. Yellow portions of oleander leaves showed little evidence of photosynthetic capacity. This was also confirmed by a low photochemical efficiency as determined by chlorophyll fluorescence. A major effect of variegation was to slow overall plant growth compared with completely green plants. The respective 3-fold and 6-7-fold differences in biomass between fully green and variegated cultivars of oleander and willow myrtle was closely related to estimated net carbon gain per day by the plant canopy. Variegation for both species averaged close to 50:50, green:yellow areas. Variegated plants developed about twice the leaf area ratio and specific leaf area compared with their completely green counterparts. The relative growth response to high CO2 was significantly greater for the variegated plants compared to the completely green plants.

scholarly journals A Quantitative-Analysis of Dark Respiration and Carbon Content as Factors in the Growth-Response of Plants to Elevated CO2

1992 ◽  
Vol 40 (5) ◽  
pp. 501 ◽  
Author(s):  
H Poorter ◽  
RM Gifford ◽  
PE Kriedemann ◽  
SC Wong
Keyword(s):  
Carbon Content ◽  
Elevated Co2 ◽  
Respiration Rate ◽  
Growth Response ◽  
Dark Respiration ◽  
Growth Responses ◽  
High Co2 ◽  
Unit Leaf ◽  
Wide Range ◽  
Few Data

An analysis of elevated CO2 effects (2-4 times ambient) on dark respiration rate and carbon content was undertaken for a wide range of plant species, using both published reports and new data. On average, leaf respiration per unit leaf area was slightly higher for plants grown at high CO2 (16%), whereas a small decrease was found when respiration was expressed on a leaf weight basis (14%). For the few data on root respiration, no significant change due to high CO2 could be detected. Carbon content of leaves and stem showed a small increase (1.2 and 1.7% respectively), whereas C-content of roots was not significantly affected. In both data sets direction of responses was variable. A sensitivity analysis of carbon budgets under elevated CO2 identified changes in respiration rate, and to a lesser extent carbon content, as important factors affecting the growth response to elevated CO2 in quite a number of cases. Any comprehensive analysis of growth responses to increased CO2 should therefore include measurements of these two variables.

scholarly journals Differential Growth Responses of Wheat Seedlings to Elevated CO2

2018 ◽  
Vol 10 (3) ◽  
pp. 400-409 ◽  
Author(s):  
Hamid Reza ESHGHIZADEH ◽  
Morteza ZAHEDI ◽  
Samaneh MOHAMMADI
Keyword(s):  
Leaf Area ◽  
Plant Height ◽  
Elevated Co2 ◽  
Co2 Concentration ◽  
Tolerance Index ◽  
Dry Matter Accumulation ◽  
Wheat Cultivars ◽  
Growth Responses ◽  
Differential Growth ◽  
Wheat Seedlings

Intraspecific variations in wheat growth responses to elevated CO2 was evaluated using 20 Iranian bread wheat (Triticum aestivum L.) cultivars. The plants were grown in the modified Hoagland nutrient solution at a greenhouse until 35 days of age using two levels of CO2 (~380 and 700 µmol mol–1). The shoot and root dry weights of the wheat cultivars exhibited average enhancements of 17% and 36%, respectively, under elevated CO2. This increase was associated with higher levels of chlorophyll a (25%), chlorophyll b (21%), carotenoid (30%), leaf area (54%) and plant height (49.9%). The leaf area (r = 0.69**), shoot N content (r = 0.62**), plant height (r = 0.60**) and root volume (r = 0.53*) were found to have important roles in dry matter accumulation of tested wheat cultivars under elevated CO2 concentration. However, responses to elevated CO2 were considerably cultivar-dependent. Based on the stress susceptibility index (SSI) and stress tolerance index (STI), the wheat cultivars exhibiting the best response to elevated CO2 content were ‘Sistan’, ‘Navid’, ‘Shiraz’, ‘Sepahan’ and ‘Bahar’, while the ones with poor responses were ‘Omid’, ‘Marun’, ‘Sorkhtokhm’ and ‘Tajan’. The findings from the present experiment showed significant variation among the Iranian wheat cultivars in terms of their responses to elevated air CO2, providing the opportunity to select the most efficient ones for breeding purposes.

CO2 × Nitrogen Interaction on Seedling Growth of Four Species of Eucalypt.

1992 ◽  
Vol 40 (5) ◽  
pp. 457 ◽  
Author(s):  
SC Wong ◽  
PE Kriedemann ◽  
GD Farquhar
Keyword(s):  
Leaf Area ◽  
Elevated Co2 ◽  
Eucalyptus Camaldulensis ◽  
Fold Increase ◽  
Wide Distribution ◽  
Growth Responses ◽  
Seedling Vigour ◽  
Co2 Effects ◽  
Whole Plant ◽  
Large Trees

Four eucalypt species were selected to represent two ecologically disparate groups which would be expected to contrast in seedling vigour and in the nature of growth responses to CO2 × nitrogen supply. Eucalyptus camaldulensis and E. cypellocarpa were taken as examples of fast-growing species with a wide distribution, that develop into large trees. By contrast, E. pauciflora and E. pulverulenta become smaller trees, and show a more limited distribution. Seedlings were established in pots (5 L) of a loamy soil and supplied with nutrient solution containing either 1.2 or 6.0 mM NO3- in both ambient (33 Pa) and CO2-enriched (66 Pa) greenhouses. Analysis of growth response to treatments (2 × 2 factorial) was based on destructive harvest of plants sampled on four occasions over 84 days for E. carnaldulensis and E. cypellocarpa, and 100 days for E. pulverulenta and E. pauciflora. A positive CO2 × N interaction on plant dry mass and leaf area was expressed in all species throughout the study period. In E. carnaldulensis and E. cypellocarpa, plant mass was doubled by high N at 33 Pa CO2, compared with a three to four-fold increase at 66 Pa to reach 34g by final harvest. In E. pulverulenta and E. pauciflora, slower growth resulted in about 50% less mass at a given age, but relative increases due to CO2 and N were of a similar order. A distinction can be made between N and CO2 effects on growth processes as follows. When trees were grown on low N, elevated CO2 increased nitrogen-use efficiency (NUE) at both leaf and whole plant levels. On high N, leaf NUE was increased in E. camaldulensis and E. cypellocarpa, but decreased in E. pulverulenta and E. pauciflora. Whole plant NUE showed no consistent response to elevated CO2 when plants were supplied high N. Net assimilation rate (NAR) was increased by elevated CO2 in all species on either N treatment. Moreover, high N increased NAR under either CO2 treatment in all species. There was a positive N × CO2 interaction on NAR in E. carnaldulensis and E. cypellocarpa, but not in E. pulverulenta and E. pauciflora. Growth indices for E. carnaldulensis and E. cypellocarpa species, and especially E. carnaldulensis, generally exceeded those for E. pulverulenta and E. pauciflora in terms of NAR, leaf NUE, N-enhancement of CO2 effects on leaf area and biomass, and non-structural carbohydrate content of foliage.

High vapour pressure deficit and low soil water availability enhance shoot growth responses of a C4 grass (Panicum coloratum cv. Bambatsi) to CO2 enrichment

1998 ◽  
Vol 25 (3) ◽  
pp. 287 ◽  
Author(s):  
Saman P. Seneweera ◽  
Oula Ghannoum ◽  
Jann Conroy
Keyword(s):  
Soil Water ◽  
Elevated Co2 ◽  
Vapour Pressure ◽  
Shoot Growth ◽  
Vapour Pressure Deficit ◽  
C4 Grasses ◽  
Growth Responses ◽  
High Co2 ◽  
C4 Grass ◽  
Shoot Mass

The hypothesis that shoot growth responses of C4 grasses to elevated CO2 are dependent on shoot water relations was tested using a C4 grass, Panicum coloratum (NAD-ME subtype). Plants were grown for 35 days at CO2 concentrations of 350 or 1000 µL CO2 L-1. Shoot water relations were altered by growing plants in soil which was brought daily to 65, 80 or 100% field capacity (FC) and by maintaining the vapour pressure deficit (VPD) at 0.9 or 2.1 kPa. At 350 µL CO2 L-1, high VPD and lower soil water content depressed shoot dry mass, which declined in parallel at each VPD with decreasing soil water content. The growth depression at high VPD was associated with increased shoot transpiration, whereas at low soil water, leaf water potential was reduced. Elevated CO2 ameliorated the impact of both stresses by decreasing transpiration rates and raising leaf water potential. Consequently, high CO2 approximately doubled shoot mass and leaf length at a VPD of 2.1 kPa and soil water contents of 65 and 80% FC but had no effect on unstressed plants. Water use efficiency was enhanced by elevated CO2 under conditions of stress but this was primarily due to increases in shoot mass. High CO2 had a greater effect on leaf growth parameters than on stem mass. Elevated CO2 increased specific leaf area and leaf area ratio, the latter at high VPD only. We conclude that high CO2 increases shoot growth of C4 grasses by ameliorating the effects of stress induced by either high VPD or low soil moisture. Since these factors limit growth of field-grown C4 grasses, it is likely that their biomass will be enhanced by rising atmospheric CO2 concentrations.

Observations of the Photosynthetic Physiology of Tree Species within the C3 Monocotyledon Genus Pandanus, and Comparison with Dicotyledon C3 Tree Species

1998 ◽  
Vol 46 (1) ◽  
pp. 103 ◽  
Author(s):  
Catherine E. Lovelock
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Tree Species ◽  
Dark Respiration ◽  
Dry Weight ◽  
Weight Basis ◽  
Growth And Survival ◽  
Respiration Rates ◽  
Leaf Dark Respiration ◽  
Resource Levels

Photosynthetic characteristics of tree species from the tropical C3 monocotyledon genus Pandanus were compared with C3 dicotyledon species growing in similar environments. The Pandanus species had similar maximum photosynthetic rates (Amax) to dicotyledon tree species in leaves from both sun and shaded environments when Amax was expressed on an area basis. Because of the low specific leaf area of the schlerophyllous leaves of the Pandanus compared to the dicotyledon species, the similarity in Amax was no longer evident when Amax was expressed on a dry-weight basis. Leaf dark respiration rates of the Pandanus on a leaf area and weight basis were generally lower than the shade-intolerant dicotyledons and similar to the shade-tolerant dicotyledon species. Low dark respiration rates and low specific leaf area of the Pandanus may be important characteristics for growth and survival in environments where resource levels are low and the likelihood of tissue damage is high.

Elevated CO2 Effects on Water Use and Growth of Maize in Wet and Drying Soil

1996 ◽  
Vol 23 (1) ◽  
pp. 53 ◽  
Author(s):  
AB Samarakoon ◽  
RM Gifford
Keyword(s):  
Leaf Area ◽  
Elevated Co2 ◽  
Water Use ◽  
Dry Matter ◽  
Growth Promotion ◽  
Atmospheric Co2 ◽  
Growth Enhancement ◽  
High Co2 ◽  
Water Regimes ◽  
Reduced Water

It is unclear from the literature as to whether growth of C4 species is responsive to elevated atmospheric CO2 concentration. Reports vary between no response to strong response. To explore the origin of this discrepancy, spaced plants of maize (Zea mays) were grown at atmospheric CO2 concentrations of 362 or 717 μL L-1 under continuously wet or drying soil regimes. The aims were to evaluate the comparative growth promotion from elevated CO2 in a C4 plant under the two contrasting water regimes and the causes of any such promotion, and also how water-use efficiency (WUE) is influenced by high CO2 under the two water regimes. In wet soil, transpiration rate was reduced on average by 29% at high CO2, but neither total dry matter nor plant height was significantly affected by CO2 level. Leaf area was not influenced significantly, so daily water use per plant was 25% lower and WUE was increased entirely due to reduced water use at high CO2. In soil that was drying from field capacity, plants in high CO2 used about 30% less water than those in ambient CO2 while the soil was still wet. This resulted in higher soil water content at high CO2. Plant growth showed a marked response, accumulating 35% more leaf area and 50% more dry matter. Young internodes elongated up to 170% more, giving taller plants. The growth enhancement was largely due to higher average net assimilation rate indicating that C4 photosynthesis responded to elevated CO2 during drought. In drying soil the increase in WUE was due to both increased dry matter and reduced water use, the contribution from each depending on the stage of soil drying. We hypothesise therefore that literature examples where maize growth responded to elevated CO2 may have involved (possibly unrecognised) minor water deficits.

scholarly journals Growth responses of light demanding and shade tolerant peat swamp forest saplings to elevated CO2

2021 ◽  
Vol 42 (3(SI)) ◽  
pp. 735-743
Author(s):  
M.N.L. Wahidah ◽  
◽  
M.S. Nizam ◽  
C.M.Z. Che Radziah ◽  
W.A. Wan Juliana ◽  
...  
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Elevated Co2 ◽  
Co2 Concentration ◽  
Growth Responses ◽  
Swamp Forest ◽  
Relative Growth ◽  
Peat Swamp Forest ◽  
Elevated Atmospheric Co2

Aim: To determine the growth responses of two peat swamp forest species, Shorea platycarpa, a shade-tolerant slow-growing species and Macaranga pruinosa, a light-demanding fast-growing species under elevated atmospheric CO2 concentration. Methodology: The saplings of both species were grown in a shade house at ambient (400±50 µmol mol-1) and in an open roof ventilation greenhouse at elevated atmospheric CO2 concentration 800±50 µmol mol-1 for seven months. The temperature in both environments ranged between 25-33°C with 55–60% sunlight transmittance and the saplings were thoroughly watered twice a day. Plants growth measurements were estimated at frequent intervals. Saplings biomass characteristics were examined using destructive methods after seven months of treatment and non-destructive method was used for determination of leaf area. Results: Elevated CO2 enhanced all the growth characteristics in M. pruinosa with a significant increase was observed particularly on both height and diameter relative growth rate and biomass characteristics. The height relative growth rate and leaf area were significantly reduced under elevated CO2 in S. platycarpa but did not affect the shoot or root diameter and biomass significantly. A positive correlation (r =0.77, p>0.05) between stem biomass and basal diameter for plants under elevated CO2 was recorded for M. pruinosa, but not in S. platycarpa. Both species showed negative correlation (S. platycarpa; r = -0.53, M. pruinosa; r = -0.46, p>0.05) between stem growth and stem biomass at elevated CO2. Interpretation: These results unveiled profound effects of elevated CO2 on the growth of light-demanding species M. pruinosa, while shade-tolerant species S. platycarpa was not relatively affected by elevated CO2. This underscored the necessity to analyse different species performance to elevated CO2, thereby improving the ability to predict tropical swamp forest ecosystem responses to rising CO2.

Relationship between visual colour rating and chlorophyll content, photosynthetic rate, and some growth characteristics in couchgrass (Cynodonspp. L.)

1983 ◽  
Vol 100 (1) ◽  
pp. 221-225 ◽  
Author(s):  
M. S. Rahman
Keyword(s):  
Leaf Area ◽  
Chlorophyll Content ◽  
Photosynthetic Rate ◽  
Unit Area ◽  
Dark Respiration ◽  
Dry Weight ◽  
Chlorophyll Contents ◽  
Respiration Rates ◽  
Unit Leaf ◽  
Visual Colour

SUMMARYChlorophyll contents per unit leaf area and unit dry weight, chlorophylla:bratio, visual colour rating, specific leaf area, and leaf fresh weight: dry weight ratios were estimated for 12 couch (bermudagrass) varieties (Cynodonspp. L.) in winter (July) and spring (October). Net photosynthetic and dark respiration rates were estimated in winter only.The chlorophyll contents per unit leaf area were higher in all varieties in spring than in winter, but per unit weight were more variable. The varieties differed substantially in the net photosynthetic and dark respiration rates. The specific leaf areas were greater in winter than in spring in five varieties: in others it changed little. The fresh: dry weight ratios of the leaves were almost constant between varieties in the spring but varied greatly during the winter. Visual colour ratings were well correlated with chlorophyll contents per unit area but not with weight. The net photosynthetic rate was closely correlated with chlorophyll content (per unit area) but not so closely with colour rating.

Interactions Between Rising CO2 Concentration and Nitrogen Supply in Cotton. I. Growth and Leaf Nitrogen Concentration

1996 ◽  
Vol 23 (2) ◽  
pp. 119 ◽  
Author(s):  
GS Rogers ◽  
PJ Milham ◽  
MC Thibaud ◽  
JP Conroy
Keyword(s):  
Leaf Area ◽  
Elevated Co2 ◽  
Shoot Growth ◽  
High Co2 ◽  
N Supply ◽  
Co2 Concentrations ◽  
N Concentration ◽  
Leaf N Concentration ◽  
Sink Development ◽  
Leaf N

The influence of sink development on the response of shoot growth in cotton (Gossypium hirsutum L. cv. Siokra BT1-4) was investigated by growing plants at three levels of CO2=2 concentration: 350 (ambient), 550 and 900 μL L-1 and six levels of nitrogen (N) supply ranging from deficient to excess (0-133 mg N kg-1 soil week-1). Changes in leaf N concentration were also investigated. At 59 days after sowing, there was an average 63% increase in shoot growth at 550 μL CO2 L-1 compared with ambient CO2-grown plants, with no significant growth increase at 900 μL CO2 L-1 and, this response was closely matched by sink development (flower number and stem weight). Low N supply restricted the responses of both sink development and shoot growth to high CO2. At elevated CO2, leaf N concentration was reduced by an average 27% at low to adequate N supply. The high CO2-induced reduction in leaf N concentration, however, disappeared when the N supply was increased to a high level of 133 mg N kg-1 soil week-1. These CO2 effects on leaf N concentration were smaller when N was expressed per unit leaf area, apparently due to a combination of the effects of elevated CO2 or high N supply reducing specific leaf area and, to an N uptake limitation at low to moderate levels of N supply. The critical foliar N concentrations (leaf N concentration at 90% of maximum shoot growth) were reduced from 42 to 38 and 36 mg g-1 when CO2 concentrations were increased from 350 to 550 and 900 μL L-1 respectively, indicating that changes in fertiliser management may be required under changing CO2 concentrations.

Elevated CO2 Improves the Growth of Wheat Under Salinity

1993 ◽  
Vol 20 (3) ◽  
pp. 349 ◽  
Author(s):  
ME Nicolas ◽  
R Munns ◽  
AB Samarakoon ◽  
RM Gifford
Keyword(s):  
Leaf Area ◽  
Elevated Co2 ◽  
Dry Matter ◽  
Stomatal Closure ◽  
Dry Weight ◽  
Primary Component ◽  
Dry Matter Accumulation ◽  
Salt Tolerant ◽  
High Co2 ◽  
Sodium Accumulation

Wheat plants (Triticum aestivum cv. Matong and T. durum cv. Modoc) were grown at ambient and elevated CO2 (350 cm3 m-3 above ambient) in soil with or without 150 mol m-3 NaCl for 6 weeks. The increase in dry matter, leaf area and tillering under high CO2 was relatively greater under saline than non-saline conditions for both cultivars. Tillering was the primary component of growth affected by both salinity and high CO2. Salinity greatly reduced tillering and high CO2 partly reversed the effects of salinity. High CO2 increased dry matter accumulation of the salt-sensitive Modoc to a greater extent (+104%) than that of the more salt-tolerant Matong (+73%) in the salt treatment. Transpiration rates were greatly reduced by salinity for both cultivars. Under high CO2, increased leaf areas compensated for reduced transpiration rates per unit leaf area (i.e. greater stomatal closure), and total transpiration was little affected by CO2 level within each treatment. The more salt-tolerant Matong showed greater stomatal closure and higher transpiration efficiencies than the salt-sensitive Modoc under salinity. High CO2 reduced transpiration rate (per unit dry weight) by 40 to 50%, but did not significantly change the rate of sodium accumulation (per unit dry weight), indicating that salt uptake was largely independent of water uptake, and that high CO2 did not increase growth by reducing the salt load. Our results suggest that high CO2 increased growth by stimulating the development of tiller buds that would otherwise have been inhibited.

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