Physiological responses of semiarid grasses. IV.* Photosynthetic rates of Thyridolepis mitchelliana and Cenchrus ciliaris leaves

1975 ◽  
Vol 26 (3) ◽  
pp. 459 ◽  
Author(s):  
EK Christie
Keyword(s):  
Leaf Surface ◽  
Physiological Responses ◽  
Carbon Dioxide Concentration ◽  
Assimilation Rate ◽  
Chloroplast Structure ◽  
Response Curves ◽  
The Poor ◽  
C4 Species ◽  
Net Assimilation ◽  
Photosynthetic Responses

Photosynthesis response curves of mulga and buffel grasses to irradiance and to carbon dioxide concentration, together with studies of leaf anatomy and chloroplast structure, showed that the former was a C3 and the latter a C4 species. This is held to account for the large differences in growth rate between the two species. Although Mitchell grass has the anatomy of a C4 species, its photosynthetic responses were not examined. As its net assimilation rate is high at high temperatures, its generally low growth rates are associated with the poor development of its leaf surface. *Part III, Aust. J. Aguic. Res., 26: 447 (1975).

Growth and physiological responses of aspen and jack pine to intermittent SO2 fumigation episodes

1986 ◽  
Vol 64 (11) ◽  
pp. 2421-2427 ◽  
Author(s):  
S. J. L'Hirondelle ◽  
P. A. Addison ◽  
D. B. Huebert
Keyword(s):  
Aboveground Biomass ◽  
Physiological Responses ◽  
Jack Pine ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Pine Seedlings ◽  
Leaf Resistance ◽  
Maximum Decrease ◽  
Increased Sensitivity ◽  
Net Assimilation

Five-week-old aspen seedlings and 8-week-old jack pine seedlings were exposed to a 3-h SO2 fumigation episode (peak = 0.78 μL L−1; mean = 0.30 μL L−1) 0, 2, or 5 times per week. Intermittent fumigation of both species for up to 8 weeks had no consistent, significant effect on aboveground biomass or on net assimilation rate and leaf resistance. A significant decrease (as much as 47%) in biomass of fumigated jack pine seedlings was found after 6 weeks of SO2 exposure, but after 7 weeks the decrease was not significant. In contrast, a significant increase in biomass of fumigated aspen seedlings was found, but only at 6 weeks, and apparently related to increased leaf retention. Fumigation caused transient decreases in net assimilation rate of both species. The maximum decrease in net assimilation rate measured just after an SO2 episode was 13% for aspen and 35% for jack pine, with a mean decrease for both of 12%. During SO2 fumigation, aspen net assimilation rate decreased as much as 38% and leaf resistance increased up to 47%. Both aspen and pine seedlings recovered from these transient SO2 effects, and there was no evidence for increased sensitivity to fumigation with time. After exposure to a single SO2 episode in the laboratory, field-collected branches of mature aspen showed a 30% decrease in net assimilation rate and a 50% increase in leaf resistance, from initial values similar to those of the greenhouse seedlings.

Australian Journal of Plant Physiology: Editorial Report

2000 ◽  
Vol 27 (1) ◽  
pp. I
Author(s):  
Laurie Martinelli ◽  
Jennifer McCutchan
Keyword(s):  
Electron Transport ◽  
Elevated Co2 ◽  
Dry Mass ◽  
Co2 Assimilation ◽  
Assimilation Rate ◽  
Response Curves ◽  
Co2 Assimilation Rate ◽  
Acacia Species ◽  
Net Assimilation ◽  
Co2 Treatment

Ten contrasting Acacia species were grown in glasshouses with normal ambient CO2 or ele-vated to 700 µL L–1. Plants were grown in sand with a complete nutrient solution, including 5 mМ nitrate. Our objective was to determine the degree to which photosynthesis, and the efficiency of nitrogen and water use, were affected by growth under elevated CO2 in contrasting plant species that differ in specific foliage area (foliage area per unit foliage dry mass). Photosynthetic characteristics were measured at several stages. Growth and measurement of gas exchange under 700 mL L–1 CO2 resulted in enhanced rates of CO2 assimilation per unit foliage area in nine of the species. The degree of enhancement was independent of specific foliage area. The exception was the slow-growing A. aneura, which had lower rates of CO2 assimilation when grown and measured at 700 µL L–1 CO2 compared to plants grown and measured at 350 µL L–1 CO2, at 50, 78 and 93 d after transplanting. Leaf conductance was reduced by growth in elevated CO2 in only six of the species. Overall, elevated CO2 improved the ratio of CO2 assimi-lation to conductance by 78% and increased CO2 assimilation per unit of foliage nitrogen by 30% at a given specific foliage area. Detailed study of A. saligna and A. aneura revealed that the effects of the CO2 treatment were similarly evident on all fully expanded phyllodes, regardless of their age. Intercellular CO2 response curves were analysed on four species and revealed no change in the ratio of electron transport to Rubisco activities. However, for A. aneura and A. melanoxylon, both electron transport and Rubisco activities were reduced per unit foliage nitrogen, by growth under elevated CO2 . For A. saligna and A. implexa, these activities per unit nitrogen, were not altered by the elevated CO2 treatment. To relate CO2 assimilation rates to net assimilation rates (dry matter increment per unit foliage area per day) derived from growth analysis, between 30 and 50% of daily photosynthesis appeared to be consumed in respiration. This proportion was not altered by CO2 treatment for seven of the Acacia species, but appeared to be reduced in the other three. The increase in CO2 assimilation rate by growth under 700 com-pared to 350 µL L–1 CO2 that was measured (26%, mean of all species from two surveys), matched the increase in net assimilation rate that had been derived from destructive sampling (30%). We conclude that the increase in CO2 assimilation rate in the selected Acacia species was independent of species, growth rate and foliage area per unit foliage dry mass.

Physiological ecology of lodgepole pine (Pinuscontorta) in an enriched CO2 environment

1985 ◽  
Vol 15 (2) ◽  
pp. 417-421 ◽  
Author(s):  
K. O. Higginbotham ◽  
J. M. Mayo ◽  
S. L'Hirondelle ◽  
D. K. Krystofiak
Keyword(s):  
Surface Area ◽  
Leaf Surface ◽  
Lodgepole Pine ◽  
Stomatal Closure ◽  
Light Response ◽  
Net Photosynthesis ◽  
Response Curves ◽  
Light Response Curves ◽  
Leaf Surface Area ◽  
Photosynthetic Responses

Relatively little work has been done to evaluate the effects of chronically high levels of carbon dioxide on growth and physiology of woody plants. In this study, seedlings of lodgepole pine (Pinuscontorta Dougl. var. latifoliaEngelm.) were grown for 5-month periods at 330, 1000, or 2000 μL CO2•L−1. Height growth; leaf area production; biomass of leaves, stems, and roots; and photosynthetic responses to changing light, moisture, and CO2 concentration were measured. Significant differences between treatments were found in mean seedling height on all measurement dates. Seedlings grown at 1000 μL CO2•L−1 were tallest, with seedlings grown in 2000 μL•L−1 intermediate between the control (330 μL•L−1) and 1000 μL•L−1 treatments. The same relationship was found in production of total leaf surface area. Increased leaf surface area yields a productive advantage to seedlings grown at concentrations of CO2 up to 2000 μL•L−1 even if no increase in net photosynthesis is assumed. Biomass of stems, roots, and secondary leaves was increased in both elevated CO2 conditions, with root biomass approximately 15 times greater in seedlings grown at 1000 μL•L−1 than in those grown at 330 μL•CO2•L−1. Stomatal resistances were essentially the same for all treatments, indicating no CO2-induced stomatal closure to at least 2000 μL•L−1. Photosynthetic Vmax (milligrams per square decimetre per hour) for light response curves varied with CO2 concentration. If results are extrapolated beyond a 5-month period and into field conditions, it appears that size of trees, interactions with competitors, and ecological role of the species might be altered.

Effect of Mid-day Shading on Stem Diameter, Xylem Pressure Potential, Leaf Surface Resistance, and Net Assimilation Rate in a White Oak Sapling

1974 ◽  
Vol 4 (3) ◽  
pp. 296-300 ◽  
Author(s):  
T. M. Hinckley ◽  
J. L. Chambers ◽  
D. N. Bruckerhoff ◽  
J. E. Roberts ◽  
J. Turner
Keyword(s):  
Surface Resistance ◽  
Leaf Surface ◽  
Stem Diameter ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
White Oak ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Xylem Pressure Potential ◽  
Net Assimilation

The diurnal relationship between xylem pressure potential and stem diameter in white oak (Quercusalba L.) resulted in a hysteresis loop on clear days where, for a given level of xylem pressure potential, the stem was thinner upon rehydration than during dehydration. Cloudy days complicated this pattern by forming a loop within the main loop. This additional loop was caused by the same factor which caused the main loop, the delayed reaction or lag between changes in stem diameter and xylem pressure potential. Both net assimilation rate and leaf surface resistance were closely linked and responded rapidly to changes in radiation. Hydroactive increases in leaf surface resistance were observed as xylem pressure potential decreased below −23 bars. A discussion of the relationship between stem diameter, radiation, leaf surface resistance, and xylem pressure potential is presented.

scholarly journals Morphological bases of phytoplankton energy management and physiological responses unveiled by 3D subcellular imaging

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Clarisse Uwizeye ◽  
Johan Decelle ◽  
Pierre-Henri Jouneau ◽  
Serena Flori ◽  
Benoit Gallet ◽  
...  
Keyword(s):  
Energy Management ◽  
Morphometric Analysis ◽  
Physiological Responses ◽  
High Light ◽  
Phytoplankton Diversity ◽  
Eukaryotic Phytoplankton ◽  
Evolutionarily Conserved ◽  
Photosynthetic Responses ◽  
Photosynthesis And Respiration ◽  
Subcellular Imaging

AbstractEukaryotic phytoplankton have a small global biomass but play major roles in primary production and climate. Despite improved understanding of phytoplankton diversity and evolution, we largely ignore the cellular bases of their environmental plasticity. By comparative 3D morphometric analysis across seven distant phytoplankton taxa, we observe constant volume occupancy by the main organelles and preserved volumetric ratios between plastids and mitochondria. We hypothesise that phytoplankton subcellular topology is modulated by energy-management constraints. Consistent with this, shifting the diatom Phaeodactylum from low to high light enhances photosynthesis and respiration, increases cell-volume occupancy by mitochondria and the plastid CO2-fixing pyrenoid, and boosts plastid-mitochondria contacts. Changes in organelle architectures and interactions also accompany Nannochloropsis acclimation to different trophic lifestyles, along with respiratory and photosynthetic responses. By revealing evolutionarily-conserved topologies of energy-managing organelles, and their role in phytoplankton acclimation, this work deciphers phytoplankton responses at subcellular scales.

Effects of Temperature and CO2Concentration on the Growth of Cotton (Gossypium hirsutum), Spurred Anoda (Anoda cristata), and Velvetleaf (Abutilon theophrasti)

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 751-757 ◽  
Author(s):  
David T. Patterson ◽  
Maxine T. Highsmith ◽  
Elizabeth P. Flint
Keyword(s):  
Dry Matter ◽  
Dry Weight ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Short Term ◽  
Leaf Weight ◽  
Matter Production ◽  
Total Plant ◽  
Net Assimilation ◽  
Total Dry Weight

Cotton, spurred anoda, and velvetleaf were grown in controlled-environment chambers at day/night temperatures of 32/23 or 26/17 C and CO2concentrations of 350 or 700 ppm. After 5 weeks, CO2enrichment to 700 ppm increased dry matter accumulation by 38, 26, and 29% in cotton, spurred anoda, and velvetleaf, respectively, at 26/17 C and by 61, 41, and 29% at 32/23 C. Increases in leaf weight accounted for over 80% of the increase in total plant weight in cotton and spurred anoda in both temperature regimes. Leaf area was not increased by CO2enrichment. The observed increases in dry matter production with CO2enrichment were caused by increased net assimilation rate. In a second experiment, plants were grown at 350 ppm CO2and 29/23 C day/night for 17 days before exposure to 700 ppm CO2at 26/17 C for 1 week. Short-term exposure to high CO2significantly increased net assimilation rate, dry matter production, total dry weight, leaf dry weight, and specific leaf weight in comparison with plants maintained at 350 ppm CO2at 26/17 C. Increases in leaf weight in response to short-term CO2enrichment accounted for 100, 87, and 68% of the observed increase in total plant dry weight of cotton, spurred anoda, and velvetleaf, respectively. Comparisons among the species showed that CO2enrichment decreased the weed/crop ratio for total dry weight, possibly indicating a potential competitive advantage for cotton under elevated CO2, even at suboptimum temperatures.

Varietal differences in growth characteristics in sugar cane

1987 ◽  
Vol 108 (1) ◽  
pp. 245-247 ◽  
Author(s):  
S. Singh ◽  
P. N. Gururaja Rao
Keyword(s):  
Growth Rate ◽  
Sugar Cane ◽  
Growth Characteristics ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Area Index ◽  
Relative Growth ◽  
Varietal Differences ◽  
Net Assimilation ◽  
High Yielding Varieties

In sugar cane, investigations made earlier (Singh & Gururaja Rao, 1985) have shown that high-yielding varieties have higher net assimilation rate than low-yielding types. Similarly, differences in progeny means for relative growth rate and net assimilation rate have been reported by George (1965). In other crops also, varietal differences in leaf area index and net assimilation rate have been reported (Watson, 1947). It appears that in this crop, limited attempts have been made to study all the growth characteristics. This paper describes the differences in most of the growth characteristics in six sugar-cane varieties.

EFFECT OF SOLID AND LIQUID ORGANIC FERTILIZER ON GROWTH, YIELD AND YIELD COMPONENTS OF ROSSELLE (Hibiscus sabdariffa L.) IN THE NIGERIAN SAVANNAH

2021 ◽  
Vol 5 (2) ◽  
pp. 428-439
Author(s):  
K. M. Ladan ◽  
M. G. Abubakar ◽  
J. Suleiman
Keyword(s):  
Growth Rate ◽  
Plant Height ◽  
Seed Weight ◽  
Organic Fertilizer ◽  
Poultry Manure ◽  
Dry Weight ◽  
Assimilation Rate ◽  
Area Index ◽  
Net Assimilation ◽  
100 Seed Weight

The Study was conducted to evaluate the effect of solid and liquid organic fertilizer on growth and yield of rosselle in 2016 cropping season at Institute of Agricultural Reserve Zaria, Samaru (11011’N 07038E and 686m) and Institute of Horticultural Research Farm Bagauda (12000’N 8031”Em 488m) in Northern Guinea Savannah and Sudan Savannah Ecological Zones of above sea level Nigeria. Treatments consisted of four levels of solid poultry manure (0.0, 1.0, 2.0 and 3.0) tons/ha and five levels of liquid organic manure from Grand Total Organic Fertilizer Limited (0.0, 0.5, 1.0, 1.5 and 2.9) litres/ha, which were factorially combined in a randomized complete block design (RCBD) and replicated three times. Data on growth parameter were collected on plant height (cm), plant dry weight (g), leaf Area index crop growth rate (CGR) Relative Growth Rate (RGR) and Net assimilation rate (NAR) while data on yield parameters like number of calyx per pant, 100 seed weight (g) and  calyx yield per hectare kg/ha were collected. Results showed that plant height, plant dry weight(g), 100 seed weight(g) and calyx dry yield kg/ha had a significant increase with application of 2.0 litres/ha of liquid fertilizer than other rates. While application of solid poultry manure at 3.0ton/ha significantly increases plant height, net assimilation rate, leaf area index and calyx dry weight when compared with other rates. From the results obtained, the combination of 2.0 litres/ha liquid organic fertilizer and 3.0 ton/ha solid poultry manure produce the highest calyx yield at both location.

scholarly journals Wplyw stopnia krzewienia się roślin na akumulacje biomasy organicznej u niektórych odmian zwyczajnej pszenicy ozimej [Influence of tillering degree on the accumulation of dry matter of some winter wheat varieties]

2015 ◽  
Vol 28 (2) ◽  
pp. 155-175
Author(s):  
Witold Drezner
Keyword(s):  
Winter Wheat ◽  
Dry Matter ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Wheat Varieties ◽  
H Index ◽  
Net Assimilation ◽  
Winter Wheat Varieties

The correlation between the net assimilation rate and the degree of plant tillering are investigated for several varieties of simple winter wheat. The net assimilation rate (E, NAR, An) of the studied varieties for different degrees of tillering, individual shoots and individual plants is described according to the units mg/cm<sup>2</sup> • 24 h. Index of efficiency of assimilation surface (F, LAR, I<sub>S</sub>) is determined in units cm<sup>2</sup>/mg. The tillering ability of vegetative shoots in plaints is a very important factor which increases the total assimilate stirfaice value and the assimilation effectivity of the plant's biomass.

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