Genotypic Variation in Transpiration Efficiency, Carbon-Isotype Discrimination and Carbon Allocation During Early Growth in Sunflower

1990 ◽  
Vol 17 (2) ◽  
pp. 207 ◽  
Author(s):  
JM Virgona ◽  
KT Hubick ◽  
HM Rawson ◽  
GD Farquhar ◽  
RW Downes

Transpiration efficiency of dry matter production (W), carbon-isotope discrimination (�) and dry matter partitioning were measured on six sunflower (Helianthus annuus L.) genotypes grown for 32 days in a glasshouse. Two watering regimes, one well watered (HW) and the other delivering half the water used by the HW plants (LW), were imposed. Four major results emerged from this study. (1) There was significant genotypic variation in W in sunflower and this was closely reflected in Δ for both watering treatments. (2) The low watering regime caused a decrease in Δ but no change in W; nonetheless the genotypic ranking for either Δ or W was not significantly altered by water stress. (3) A positive correlation between W and biomass accumulation occurred among genotypes of HW plants. (4) Q, the ratio of total plant carbon content to leaf area, was positively correlated with W and negatively correlated with Δ. These results are discussed with reference to the connection between transpiration efficiency and plant growth. In short, Δ can be used to select for W among young vegetative sunflower plants. However, selection for W may be accompanied by changes in other important plant growth characteristics such as Q.

1986 ◽  
Vol 107 (2) ◽  
pp. 285-297 ◽  
Author(s):  
C. F. Green ◽  
L. V. Vaidyanathan ◽  
J. D. Ivins

SummaryObservations are presented from a crop of sugar beet grown in Cambridgeshire during 1978, and a field trial at Sutton Bonington during 1985 in which the influence of synthetic plant growth regulators (PGRs) daminozide, chlormequat, GA4+7 and ethephon were compared.Several distinct patterns of growth were evident, being similar for both growing seasons and described by two intersecting straight lines. Early development was characterized by a slow rate of biomass accumulation, a dominance of foliage production with a constant but small root fraction (around 40%), a low specific leaf area and a slow but conservative rate of sucrose fractionation. Later in the season the rate of stand growth was both constant and maximal, the root fraction doubled, specific leaf area increased and the rate of sucrose accumulation rose markedly.Transitions between developmental phases occurred at various times dependent on variate under consideration. The onset of the main growth period began at the end of June, followed by an increase in the rate of sucrose accumulation about 2 weeks later. Finally, near the end of July, partition of assimilate into the root assumed a faster rate. Changes in the partitioning into both roots and sucrose are discussed in relation to the development of the secondary cambium.Generally there were no effects of PGRs on biomass accumulation, dry-matter partitioning, specific leaf area and sucrose accumulation. However, daminozide increased early canopy expansion and early dry-matter production but failed to influence biomass or sugar yield.


1994 ◽  
Vol 45 (5) ◽  
pp. 985 ◽  
Author(s):  
M Cooper ◽  
DE Byth ◽  
DR Woodruff

The objective of this study was to use classification methodology to characterize the genotypic variation and line by environment (L x E) interaction for grain yield of a sample of advanced CIMMYT wheat lines and three local check cultivars tested over six Queensland environments. The environments were managed to differ in the magnitude of water stress they imposed on the lines at the critical developmental stage of anthesis. The grouping of lines was based on grain yield. The yield differences among the groups were investigated in terms of yield components and dry matter production and partitioning attributes. Groups of CIMMYT lines which outyielded the two groups which contained the three Queensland cultivars were identified. The yield advantage of the groups of CIMMYT lines decreased with increasing severity of water stress at anthesis and in the environment where the most severe stress was characterized there were no yield differences among the groups of lines. The yield advantage of the groups of CIMMYT lines was generally associated with a higher number of grains per unit area and in some cases a higher grain size. While phenology variation could account for some of the yield differences among the line groups there was considerable yield variation among line groups with similar phenology patterns across the environments. Additional measurements taken on the lines to characterize differences in dry matter production and the partitioning of the dry matter to yield components were not effective in explaining the yield variation among the groups of lines after the effects of phenology were taken into account. While the incidence of the large L x (water-stress) interactions encountered in this study would complicate selection for yield, the identification of groups of advanced CIMMYT lines which outyielded the Queensland cultivars in five of the six environments suggests that the L x (water stress) interactions do not preclude scope for further improvement of grain yield of wheat in Queensland.


Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 751-757 ◽  
Author(s):  
David T. Patterson ◽  
Maxine T. Highsmith ◽  
Elizabeth P. Flint

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.


1990 ◽  
Vol 17 (1) ◽  
pp. 9 ◽  
Author(s):  
AG Condon ◽  
GD Farquhar ◽  
RA Richards

The relationship between carbon isotope discrimination, Δ, measured in plant dry matter and the ratio of intercellular to atmospheric partial pressures of CO2, pi/pa, in leaves was examined in two glasshouse experiments using 14 wheat genotypes selected on the basis of variation in Δ of dry matter. Genotypic variation in Δ was similar in both experiments, with an average range of 1.8 x 10-3. Variation in pi/pa was significant but the range in pi/pa was relatively small, averaging 0.075. In both experiments, Δ measured in dry matter and pi/pa measured in flag leaves were positively correlated. Variation among genotypes in pi/pa was attributed, approximately equally, to variation in leaf conductance and in photosynthetic capacity. The relationship between plant transpiration efficiency, W* (the amount of above-ground dry matter produced per unit water transpired) and � was also examined. There was a negative correlation between W * and Δ; under well watered conditions and under gradually increasing terminal water stress. The relationship between W* of stressed plants and Δ measured in well watered plants was also negative. These results indicate that genotypic variation in Δ measured in dry matter should provide a reasonable measure of genotypic variation in long-term mean leaf pi/pa in wheat. Further, selection for improved plant transpiration efficiency in wheat under both well watered and terminally water- stressed conditions should be possible based on Δ measured in well watered plants. The extent to which such selection will be effective in improving transpiration efficiency at the field canopy level may depend on the influence of boundary layer resistance on transpirationsal water loss. Under well watered conditions and at full canopy closure, the influence of boundary layer resistance on canopy water loss may be relatively large and stomatal control of water loss may be limited. Under water stress, stomatal control of canopy water loss will be greater.


1982 ◽  
Vol 22 (115) ◽  
pp. 76 ◽  
Author(s):  
KA Boundy ◽  
TG Reeves ◽  
HD Brooke

The effect of serial planting on dry matter production, leaf area, grain yield and yield components cf Lupinus angustifoiius (cvv. Uniwhite, Uniharvest and Unicrop) and L. albus (cv. Ultra) was investigated in field plots at Rutherglen in 1973 and 1974. Delayed planting reduced dry matter production of all cultivars, and leaf area for Ultra. Differences in dry matter partitioning were observed between the late flowering Uniharvest, and the early flowering Unicrop and Ultra. In Uniharvest, delayed plantings resulted in a greater proportion of total dry matter being produced during the flowering phase, whereas the reverse was true for Unicrop and Ultra. The later flowering cultivars showed marked grain yield and yield component reduction with later sowing. Yields were reduced by 160.6 kg/ha and 222.5 kg/ha for each week's delay in sowing Uniharvest and Uniwhite, respectively. This effect was offset in the early flowering cultivars by greater development of lateral branches. In addition, when Unicrop and Ultra were planted in April, pod and flower abortion on the main stem resulted from low temperatures at flowering time. Optimum sowing time was early April for Uniwhite and Uniharvest, and early May for Unicrop and Ultra. Excellent vegetative growth under ideal moisture conditions highlighted the poor harvest indices of lupins and the scope for genetic improvement in the genus.


1999 ◽  
Vol 133 (2) ◽  
pp. 159-166 ◽  
Author(s):  
M. BRINK

A semi-controlled environment study was conducted from May to September 1996 in Wageningen, The Netherlands, to investigate the interaction between growth and development in bambara groundnut (Vigna subterranea) and the influence of photoperiod on dry matter partitioning. The experimental design was a split-plot with four photoperiods (10·5, 11·8, 13·2 and 14·5 h/d) and two light treatments: unshaded and shaded (42% light reduction). The selection used was ‘DipC94’ from Botswana. The dates of 50% flowering and 50% podding were determined, and samples of plants were harvested at 22, 36, 50, 64, 78, 92, 106 and 120 days after sowing. Total dry matter production was 41% lower in the shaded treatment than in the unshaded treatment, but the rates of progress from sowing to flowering and flowering to podding decreased by only 3 and 12% respectively. This suggests that growth and development in bambara groundnut are largely independent. Photoperiod influenced dry matter partitioning indirectly, through its influence on the onset of podding. There were, however, no strong direct photoperiod effects on dry matter partitioning, either before or after the onset of podding.


1968 ◽  
Vol 19 (2) ◽  
pp. 221 ◽  
Author(s):  
DG Morgan

Single plants of Festuca arundinacea (cv. S170) were treated with gibberellic acid (GA) and the sequence of effects on the growth of the whole plant and of various organs followed by means of growth analysis. The first effect of GA was to change the distribution of dry matter between shoot and root and between tillers within the shoot without affecting total plant weight. Shoot growth was increased and resulted in a larger amount of photosynthetic tissue with a higher net assimilation rate; total plant weight increased as a consequence of these effects. The significance of these results in interpreting previous work on the effects of GA on dry matter production in grasses and other plants is discussed.


1976 ◽  
Vol 86 (1) ◽  
pp. 57-64 ◽  
Author(s):  
A. P. Rhodes ◽  
G. Jenkins

SUMMARYDry matter and Kjeldahl nitrogen estimations were made on the roots and shoots of the barley varieties Riso 1508, Hiproly and Maris Mink from the seedling stage to maturity under three nitrogen treatments. After heading, the shoots were further separated into ears and stems plus leaves. Total plant nitrogen uptake was greatest in the high lysine variety Riso 1508 and was associated with a greater production of dry matter. However, the proportion of total plant nitrogen and dry matter in the grain was highest in the variety Maris Mink and this effect increased with increasing nitrogen supply. The comparative efficiency of dry-matter production and nitrogen translocation of these varieties is discussed in relation to breeding barley of improved protein yield and quality.


2009 ◽  
Vol 60 (4) ◽  
pp. 316 ◽  
Author(s):  
N. G. Inman-Bamber ◽  
G. D. Bonnett ◽  
M. F. Spillman ◽  
M. L. Hewitt ◽  
Jingsheng Xu

Relatively little is known about the physiological basis for variation in sucrose content among sugarcane clones despite substantial research at the molecular and biochemical levels. We used irrigation and continuous monitoring of photosynthesis and plant extension rate to modify dry matter partitioning in four clones differing widely in sucrose content. Three pot experiments were conducted on two low sucrose content clones, KQ97-2599 and KQ97-2835, and two high sucrose content clones, Q117 and KQ97-5080, in a temperature-controlled glasshouse. As expected, sucrose content on a dry mass basis of whole stalks was greater in high (55% maximum) than in low sucrose clones (40% maximum), but sucrose content in the two clones selected for low sucrose reached 55% in some internodes. Differences between clones in whole-plant net photosynthesis and aerial biomass accumulation were small. However, biomass was distributed over fewer stalks in the high sucrose clones (4–7 stalks per pot) than in the low sucrose clones (9–11 stalks per pot). The high sucrose clones also allocated a considerably greater proportion of dry matter to the stalk (70% maximum) than the low sucrose clones (60% maximum). It is suggested that the relatively large amount of new leaf tissue produced by the high tillering, low sucrose clones placed an additional demand for structural photo-assimilate in these clones and delayed the accumulation of sucrose in the stalk. The results indicated that there is little direct genetic control on the maximum amount of sucrose that can accumulate in stalk tissue and that genetic contrasts in sucrose content reside more in the morphology of the plant and responses to ripening stimuli such as mild water stress, and how these traits influence supply and demand for photo-assimilate.


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