Carbon Production and Utilization in Cotton: Inferences From a Carbon Budget

1980 ◽  
Vol 7 (5) ◽  
pp. 539 ◽  
Author(s):  
GA Constable ◽  
HM Rawson

A carbon budget for cotton plants at the single leaf, node and whole plant level was constructed using data from four glasshouse experiments. Data were collected on leaf expansion and dry weight growth, net photosynthesis, dark respiration of leaves and stems and on responses of photosynthesis to light in tissues of different age. The potential export of carbon by leaves was calculated as daily net photosynthesis less requirements for growth and dark respiration. The carbon budget for the single leaf showed that the leaf's maximum requirement occurred 7-8 days after unfolding, at the same time as it became a net carbon exporter. Dark respiration used most carbon at days 12-15 but even then the amount was only about 10% of the carbon fixation by the leaf during the day. Potential carbon export reached a peak in 22-day-old leaves, approximating 1 mg C cm-2 day -1 on a sunny day. The main finding from the budget was that carbon production and its utilization by bolls is out of phase both at the node and whole plant level which necessitates considerable movement of carbon among nodes and into and out of storage. This finding was confirmed in a study using 14CO2 which, while supporting the general hypothesis that the plant's carbon is fed into a pool available to all organs, indicated that there are preferred links between node positions in vertical alignment.

1974 ◽  
Vol 1 (2) ◽  
pp. 283 ◽  
Author(s):  
PJM Sale

The carbon balance of potato crops has been studied by measuring canopy net photosynthesis and dark respiration losses with a field assimilation chamber and semi-closed gas analysis system. Results are given for the latter part of growth in both a spring-planted and a summer-planted crop. Net CO2 uptake increased with solar input to reach 35–40mg dm-2 (ground area) h-1 at 400–450 W m-2, but light saturation then occurred and little or no further uptake resulted from increases in solar input up to 1000 W m-2. This supports the previous conclusion that net photosynthesis in the potato is determined by the size of the 'sink' provided by the developing tubers. The imposed experimental variables of reduced solar input (21 and 34% shade) and soil moisture were found not to affect the relation between solar input and CO2 uptake, and the effect of chamber temperature was also very small. Dark respiration rates of the canopy were markedly sensitive to temperature, and also to the solar input prior to measurement. Respiration from the below-ground plant parts accounted for a considerable part of the total plant respiration. In all, 15–20 % of the net assimilation during daylight hours was lost by night respiration. There was little variation in CO2 efflux from uncropped soil during the experiments. Dry weight changes calculated from the gasometric measurements were in accordance with those found from previous growth analysis. * Part II, Aust. J. Agric. Res., 1973, 24, 751–62.


1991 ◽  
Vol 71 (1) ◽  
pp. 235-243 ◽  
Author(s):  
J. Jiao ◽  
M. J. Tsujita ◽  
B. Grodzinski

The effect of temperature on net CO2 exchange of source and sink tissues of the flowering shoots and of whole plants was examined using single-stemmed Samantha roses. At all stages of shoot development, the optimal temperature range for whole-plant carbon (C) gain at saturating irradiance and ambient CO2 level was between 20° and 25 °C, narrower than the temperature range for optimal leaf net photosynthesis. Dark respiration increased more dramatically than photosynthesis with temperatures between 15 and 35 °C. At 25 °C, C loss due to respiration from the flower bud at colour bud stage accounted for 45% of the C loss of the flowering shoot. At low irradiance levels (e.g. 200 μmol m−2 s−1) whole-plant net photosynthesis was greater at 16° than at 22 °C because of a greater reduction in respiration. Lowering the night temperature from 27 to 17 °C also increased daily C gain due to a reduction in the C lost at night. Whole-plant net photosynthesis of plants grown and measured at enriched (1000 ± 100 μL L−1) CO2 was greater than that of plants grown and measured at ambient (350 ± 50 μL L−1) level at temperatures between 15° and 35 °C. Furthermore, the optimal temperatures for whole-plant net photosynthesis in CO2 enrichment was higher than at ambient CO2 level. Key words: Dark respiration, net photosynthesis, Rosa hybrida, temperature


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1165g-1166
Author(s):  
Keith Birkhold ◽  
Rebecca Darnell ◽  
Karen Koch

Carbon exchange and content of blueberry (Vaccinium ashei) fruit were measured from anthesis through fruit ripening in order to determine the amount of imported carbon required for fruit development. Net photosynthesis occurred in blueberry fruit from petal fall through color break. During this time, gross photosynthesis of fruit decreased from 30.1 μmol CO2·g fw-1·hr-1 to 4.8 μmol CO2·g fw-1·hr-1, and dark respiration decreased from 14.3 μmol CO2·g fw-1·hr-1 to 4.6 μmol CO2·g fw-1·hr-1. After color break, the photosynthetic rate fell to zero, and the respiration rate increased to 8.0 μmol CO2·g fw-1·hr-1, before decreasing. Preliminary data suggest that fruit photosynthesis contributes 11% of the total carbon required (dry weight gain + respiratory loss) during fruit development however, it supplies 50% of the total carbon required during the first 5 days after petal fall. This contribution of carbon from fruit photosynthesis may be critical in initial fruit development since the current season's vegetative growth is not yet providing carbohydrates.


HortScience ◽  
2004 ◽  
Vol 39 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Justine E. Vanden Heuvel ◽  
John T.A. Proctor ◽  
K. Helen Fisher ◽  
J. Alan Sullivan

In order to gain an understanding of the capacity of severely shaded leaves to be productive in dense canopies, the effects of increased shading on morphology, dry-matter partitioning, and whole-plant net carbon exchange rate (NCER) were investigated on greenhouse-grown Vitis vinifera L. `Chardonnay' grapevines. Vines were subjected to whole-plant shading levels of 0%, 54%, 90%, and 99% of direct sun 3 weeks after potting. Data were collected 8 to 10 weeks after potting. Nonlinear regression was used to investigate the relationship of leaf morphological traits and organ dry weights to increased shading. Leaf size was maintained with increased shading to approximately the 90% shading level, while leaf fresh weight, volume, density, and thickness were immediately reduced with increased shading. Root dry weight was most affected by increased shading, and root to shoot ratio was reduced. When nonlinear regressions were produced for light response curves, light compensation point was reduced by approximately 49% by moderate shading, and 61% by severe shading. Shaded leaves approached the asymptote of the light response curve more quickly, and had reduced dark respiration rates, indicating that the morphological compensation responses by the vine allow shaded leaves to use available light more efficiently. However, the long-term ramifications of reduced root growth in the current year on vines with shaded leaves may be significant.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 511d-511
Author(s):  
Marc W. van Iersel ◽  
Orville M. Lindstrom

Photosynthesis and respiration temperature-response curves are useful in predicting the ability of plants to perform under different environmental conditions. Whole crop CO2 exchange of two groups of magnolia `Greenback' plants was measured over a 26 °C temperature range. Net photosynthesis (Pnet) increased from 2 to 17% C and decreased again at higher temperatures. The Q10 for Pnet decreased from ≈4 at 6 °C to 0.5 at 24 °C. The decrease in Pnet at temperatures over 17 °C was caused by a rapid increase in dark respiration (Rdark) with increasing temperature. The Q10 for Rdark was estimated by fitting an exponential curve to data, resulting in a temperature-independent Q10 of 2.8. Gross photosynthesis (Pgross), estimated as the sum of Rdark and Pnet, increased over the entire temperature range (up to 25 °C). The Q10 for Pgross decreased with increasing temperature, but remained higher than 1. The data suggest that high respiration rates may be the limiting factor for growth of magnolia exposed to high temperatures, since it may result in a net carbon loss from the plants. At temperatures below 5 °C, both Pnet and Rdark become low and the net CO2 exchange of the plants would be expected to be minimal.


Weed Science ◽  
1989 ◽  
Vol 37 (6) ◽  
pp. 825-829 ◽  
Author(s):  
S. G. Taylor ◽  
D. G. Shilling ◽  
K. H. Quesenberry ◽  
G. R. Chaudhry

Whole plant and tissue culture experiments were conducted to determine the difference in phytotoxicity of 2,4-D and its metabolite, 2,4-DCP, to red clover. At the whole plant level, the mean concentration of 2,4-DCP (10 mM) required to cause 50% growth inhibition (I50) of shoot dry weight was 24 times greater than for 2,4-D (0.42 mM). Using callus tissue, the I50value for 2,4-DCP (0.28 mM) was 22 times greater than for 2,4-D (0.013 mM) based on dry weights. The callus tissue was 36 and 32 times more sensitive to 2,4-DCP and 2,4-D than shoot tissue based on dry weights, respectively. These data indicate that 2,4-DCP was less phytotoxic than 2,4-D to red clover both in vitro and in vivo.


1972 ◽  
Vol 50 (11) ◽  
pp. 2219-2226 ◽  
Author(s):  
Ah-Sing Chia-Looi ◽  
Bruce G. Gumming

There are circadian rhythmic changes in dark respiration, net photosynthesis, chlorophyll content, and dry weight in Chenopodium rubrum, ecotype 60°47′ N, 137°32′ W. The rhythm in dark respiration has a period of about 27 h and its phasing is quite closely correlated with the rhythm in flowering response, which has a period of about 30 h. A close similarity in the periodicity (21 h) and phasing of the rhythms in net photosynthesis and chlorophyll content suggests that the photosynthetic rhythm may be partly attributed to rhythmic changes in chlorophyll content. The rhythmic changes in dry weight, with a period of 18 h, could be due to a rhythm in dark fixation of carbon dioxide. The possible relationship of rhythmicity in these processes to other circadian rhythms that occur in C. rubrum is discussed. The concurrent existence of various rhythms in biochemical and physiological processes that differ in period and phase within a single ecotype of C. rubrum clearly reflects the possible involvement of metabolic activity in circadian rhythms.


1973 ◽  
Vol 51 (6) ◽  
pp. 1161-1168 ◽  
Author(s):  
K. Loach ◽  
C. H. A. Little

Rates of net photosynthesis and dark respiration of 1-year-old and currently developing foliage were measured in the uppermost (i.e. 1-year-old) whorl of branches of 6-year-old balsam fir trees (Abies balsamea (L.) Mill.) during the period of extension growth of the current shoot. The rates were integrated to estimate net dry matter production by the two ages of foliage, and compared with dry matter requirements for growth of the new shoot (estimated from a regression equation of length over dry weight), and with cambial growth in the 1-year-old shoot (estimated from periodic harvests). The surplus of production over use in these two sinks was stored temporarily in the 1-year-old foliage or exported from the branch, the latter predominating. Two periods in which a large proportion of the photosynthetic production was exported (corresponding roughly to the months of May and July) were separated by a period when export was relatively low. At this intermediate time, current photosynthetic production was minimal and local growth demands were at their highest. Photosynthates stored in the 1-year-old foliage before budbreak supplemented current photosynthesis and permitted export to continue, except for a few days at the end of June. The contribution from stores in the old foliage, however, never exceeded one-third of current photosynthetic production. When extension growth terminated, a second transient storage peak occurred in the 1-year-old foliage for about 2 weeks. These observations explain the commonly observed reduction in root growth during current shoot extension, and corroborate results from studies made by other investigators using radioactive tracers.


2021 ◽  
Vol 83 (2) ◽  
Author(s):  
Nicola Wannicke ◽  
Achim Herrmann ◽  
Michelle M. Gehringer

AbstractHeterocystous Cyanobacteria of the genus Nodularia form major blooms in brackish waters, while terrestrial Nostoc species occur worldwide, often associated in biological soil crusts. Both genera, by virtue of their ability to fix N2 and conduct oxygenic photosynthesis, contribute significantly to global primary productivity. Select Nostoc and Nodularia species produce the hepatotoxin nodularin and whether its production will change under climate change conditions needs to be assessed. In light of this, the effects of elevated atmospheric CO2 availability on growth, carbon and N2 fixation as well as nodularin production were investigated in toxin and non-toxin producing species of both genera. Results highlighted the following: Biomass and volume specific biological nitrogen fixation (BNF) rates were respectively almost six and 17 fold higher in the aquatic Nodularia species compared to the terrestrial Nostoc species tested, under elevated CO2 conditions. There was a direct correlation between elevated CO2 and decreased dry weight specific cellular nodularin content in a diazotrophically grown terrestrial Nostoc species, and the aquatic Nodularia species, regardless of nitrogen availability. Elevated atmospheric CO2 levels were correlated to a reduction in biomass specific BNF rates in non-toxic Nodularia species. Nodularin producers exhibited stronger stimulation of net photosynthesis rates (NP) and growth (more positive Cohen’s d) and less stimulation of dark respiration and BNF per volume compared to non-nodularin producers under elevated CO2 levels. This study is the first to provide information on NP and nodularin production under elevated atmospheric CO2 levels for Nodularia and Nostoc species under nitrogen replete and diazotrophic conditions.


2002 ◽  
Vol 127 (3) ◽  
pp. 423-429 ◽  
Author(s):  
Marc W. van Iersel ◽  
Jong-Goo Kang

To determine the effect of fertilizer concentration on plant growth and physiology, whole-plant C exchange rates of pansies (Viola ×wittrockiana Gams.) subirrigated with one of four fertilizer concentrations were measured over 30 days. Plants were watered with fertilizer solutions with an electrical conductivity (EC) of 0.15, 1.0, 2.0, or 3.0 dS·m-1 (N at 0, 135, 290, or 440 mg·L-1, respectively). Plants watered with a fertilizer solution with an EC of 2 dS·m-1 had the highest shoot dry weight (DW), shoot to root ratio, leaf area, leaf area ratio (LAR), and cumulative C gain at the end of the experiment compared to those watered with a solution with a higher or lower EC. Shoot tissue concentrations of N, P, K, S, Ca, Fe, Na, and Zn increased linearly with increasing fertilizer concentration. A close correlation between final DW of the plants and the measured cumulative C gain (CCG) (r2 = 0.98) indicated that the C exchange rates were good indicators of plant growth. There were quadratic relationships between fertilizer EC and gross photosynthesis, net photosynthesis, and dark respiration, starting at 13, 12, and 6 days after transplanting, respectively. Although plants fertilized with a fertilizer solution with an EC of 2 dS·m-1 had the highest C exchange rates, the final differences in shoot DW and CCG among ECs of 1.0, 2.0, and 3.0 dS·m-1 were small and it appears that pansies can be grown successfully with a wide range of fertilizer concentrations. Plants with a high LAR also had higher DW, suggesting that increased growth was caused largely by increased light interception. A detrimental effect of high fertilizer concentrations was that it resulted in a decrease in root DW and a large increase in shoot to root ratio.


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