scholarly journals Growth and chlorophyll fluorescence under salinity stress in sugar beet (Beta vulgaris L.)

2014 ◽  
Vol 3 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Fadi Abbas ◽  
Entessar Al-Jbawi ◽  
Mohammed Ibrahim

This study was carried out in the General Commission for Scientific Agricultural Research (GCSAR), Syria, at Der EzZour Agricultural Research Center, from 2008-2010, to examine the effect of salt conditions on some growth attributes and chlorophyll fluorescence in 10 Sugar Beet (Beta vulgaris L.) genotypes under salinity stress. Sugar beet plants were irrigated with saline water, having electrical conductivity ranged from 8.6-10 dS.m-1during first year and 8.4-10.4 dS.m-1 during second year. A randomized completely block design with three replicates was used. The results showed that all studied growth attributes, leaf area, leaf number, relative growth rate, and net assimilation rate were decreased in salinity stress conditions compared to the controlled state. The findings indicated that salinity caused a decrement of light utilizing through increased values of fluorescence origin (fo), decreased values of fluorescence maximum (fm), and maximum yield of quantum in photosystem-II (fv/fm). Genotypes differed significantly in all studied attributes except in leaf number. Under salt conditions, Brigitta (monogerm) achieved an increase in net assimilation rate, while Kawimera (multigerm) achieved the lowest decrement in quantum yield in photosystem-II. Further studies are necessary to correlate the yield with yield components under similar conditions to determine the most tolerant genotype.International Journal of Environment Vol.3(1) 2014: 1-9 DOI: http://dx.doi.org/10.3126/ije.v3i1.9937

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.


1987 ◽  
Vol 108 (1) ◽  
pp. 245-247 ◽  
Author(s):  
S. Singh ◽  
P. N. Gururaja Rao

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.


2015 ◽  
Vol 28 (2) ◽  
pp. 155-175
Author(s):  
Witold Drezner

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.


1974 ◽  
Vol 25 (3) ◽  
pp. 425 ◽  
Author(s):  
MM Ludlow ◽  
GL Wilson ◽  
MR Heslehurst

Two grasses and two legumes were grown at three illuminances: one grass and one legume in a growth cabinet (100, 50 and 34% relative illuminance) and one of each in a glasshouse (100, 30 and 10% relative illuminance). The response to shading was investigated by using classical growth analysis techniques, and the photosynthesis-respiration balance obtained by Watson and Hayashi's method. Shading caused a reduction in the proportion of root and a corresponding increase in the proportion of leaf, and an increase in the shoot/root ratio in all species except green panic. The relative growth rates of grasses (which were only clearly superior at the highest illuminance) were affected more by shading than were those of legumes, and the greater shading effect resulted from a greater decrease in net assimilation rate, and to a lesser extent, from a smaller compensatory increase in leaf area ratio in the grasses than in the legumes. The greater sensitivity of net assimilation rate of grasses to shading arose from a stronger dependence of the photosynthetic rate on illuminance. The significance of these findings for pasture production is discussed. Both tiller and runner production were dependent upon the total amount of radiant energy received by the plant, and in the growth cabinet, at least, were independent of its intensity, duration and sequence. ______________________ *Part IV, Aust. J. Agric. Res., 25: 415 (1974).


1992 ◽  
Vol 19 (2) ◽  
pp. 109 ◽  
Author(s):  
J Masle

Genotypes of wheat and barley, including modern and landrace lines, were compared in their response to soil resistance to root penetration during the early vegetative phase (up to 5 leaf stage). All genotypes exhibited reduced growth and transpiration rates at high soil resistance, but there was large variation in the magnitude and time course of these effects and in the mechanisms underlying the growth reduction (changes in net assimilation rate, carbon partitioning within the plant, relative effects of leaf primordia development, versus growth of expanding leaves). Similar wide ranges of responses were observed among landrace and modern wheats. In both wheat and barley, the genotypes with lower sensitivity to soil resistance, in terms of relative growth rate, were those with the slowest net assimilation rate and root growth rate at low soil resistance, and those for which carbon allocation to the impeded roots, relative to the shoot, was significantly increased, to the extent that root relative growth rate even became greater (in terms of mass, not of length) than on loose soil. For a number of genotypes, growth was slowed down throughout the experiment whereas for others it was reduced only during the first few days following germination. In contrast, transpiration rate was at all stages lower at high than at low soil resistance. This indicates that the effects of soil resistance to root penetration on stomatal conductance involve different controls - or different sensitivities to a common signal - from those operating on cell division and expansion.


Sign in / Sign up

Export Citation Format

Share Document