Assimilate Supply and Floret Development Within the Spike of Wheat (Triticum aestivum L.)

1983 ◽  
Vol 10 (6) ◽  
pp. 585 ◽  
Author(s):  
YM Stockman ◽  
RA Fischer ◽  
EG Brittain
Keyword(s):  
Flag Leaf ◽  
Dry Weight ◽  
Triticum Aestivum L ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Controlled Environment ◽  
Lower Priority ◽  
Carbohydrate Concentration ◽  
Leaf Emergence ◽  
Water Soluble Carbohydrate

The effect of increased as well as reduced assimilate on floret growth and development in wheat (cv. Yecora) was investigated in a controlled environment. Plants from which all tillers were removed were grown at 21/10°C with a 14 h photoperiod. At flag leaf emergence, an additional light (15% above control) and two shading treatments (40 and 70% below control) were applied to the plants for an 8-day period, ending 6 days before anthesis. The additional light and the 70% shade treatments had significant effects (+37%, -43% respectively), on the number of competent florets (as judged by anther appearance at anthesis) and subsequently similar effects on the number of kernels per spike at maturity. The changes in competent floret numbers were closely related to changes in spike dry weight at anthesis and in turn, during the treatment period. The heavy shading decreased grain yield significantly. Within the spike, treatment effects on floret and kernel number were greater in basal spikelets than in distal and especially central spikelets, in both an absolute as well as relative sense. These effects were paralleled by greater changes in basal spikelet dry weight and water-soluble carbohydrate concentration. They may be related to the smaller size or later development of basal spikelets at the onset of treatment, and suggest that the base of the spike is normally a lower priority sink for assimilate at that time.

Drought Stress Induces Changes in the Non-Structural Carbohydrate Composition of Wheat Stems

1991 ◽  
Vol 18 (3) ◽  
pp. 239 ◽  
Author(s):  
JM Virgona ◽  
EWR Barlow
Keyword(s):  
Molecular Weight ◽  
Drought Stress ◽  
Flag Leaf ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Structural Carbohydrate ◽  
Water Soluble Carbohydrate ◽  
Hydrolysis Of

The effect of drought stress on the non-structural carbohydrate (NSC) composition and water relations of the wheat (Triticum aestivum L.) stem has been investigated. Five separate parts of the stem were sampled: the unsheathed portion of the peduncle (Stem 1a), the sheathed portion of the peduncle (Stem 1b), the penultimate internode (Stem 2), the lower internodes (Stem 3+4) and the flag-leaf-pulvinus (pulvinus). The NSC was analysed as two fractions, an ethanol-soluble carbohydrate (ESC) fraction containing mono- and di-saccharides and some low molecular weight oligosaccharides, and a water-soluble carbohydrate (WSC) fraction containing mostly fructans and some high molecular weight oligosaccharides. In Stems 1b, 2 and 3 +4, the imposition of drought midway through grain filling resulted in a shift in soluble carbohydrate from the WSC to the ESC fraction indicating hydrolysis of fructans. In Stem 2 on day 29 of grain filling, the WSC/ESC ratio was 7.6 � 1.5 in well watered plants in contrast to 0.5 � 0.1 in droughted plants on day 30, even though NSC concentration did not differ. The NSC content of Stem la and the pulvinus increased threefold under drought, although levels were significantly lower than in the rest of the stem. The WSC/ESC ratio in these tissues was low com- pared to the rest of the stem but still declined noticeably under drought stress. Turgor (P) was fully maintained in Stem 2 and the pulvinus of droughted plants. Under drought, P in the pulvinus was maintained at higher levels (1.9-2.4 MPa) than in Stem 2 (0.8-1.2 MPa).

Kernel Number Per Spike in Wheat (Triticum aestivum L.): Responses to Preanthesis Shading

1980 ◽  
Vol 7 (2) ◽  
pp. 169 ◽  
Author(s):  
RA Fischer ◽  
YM Stockman
Keyword(s):  
Dry Weight ◽  
Triticum Aestivum L ◽  
Water Soluble ◽  
Sensitive Period ◽  
Soluble Carbohydrate ◽  
Kernel Number ◽  
Maximum Water ◽  
Total Dry Weight ◽  
Water Soluble Carbohydrate ◽  
Unit Spike

Several cultivars of wheat, grown in pots in a controlled environment, were subject to single shading periods of 8-11 days within the interval from 36 days before anthesis until anthesis. The aim was to confirm sensitivity of kernel number to reduced irradiance as observed in the field and to investigate its causes. Shading periods centred 10-13 days before anthesis had biggest effects on kernel number per spike through effects on kernels per spikelet. This was associated with greatest reductions in the spike dry weight at anthesis and with reductions in the number of competent florets (florets with full anther development) per unit spike dry weight; floret fertility (kernels per competent floret) was unaffected. Approximately 30% of the total dry weight increment of the plant was being allocated to the spike at the stage of greatest sensitivity to shading, but shading did not alter this partitioning. Maximum water soluble carbohydrate (WSC) content of the spike (30-40% on a dry basis in unshaded plants) occurred at 15 days before anthesis. Shading at the most sensitive period reduced temporarily WSC concentration in the spike, reduced stainable starch in carpels of florets of central spikelets, and reduced floret survival by increasing degeneration of distal florets. Shading before or after this period reduced kernel number less, reducing spike dry weight but not competent florets per unit spike dry weight. Reduced assimilate supply is probably the cause of these responses in the spike.

Canopy morphology and nutritional quality traits as potential grazing value indicators for Lolium perenne varieties

2002 ◽  
Vol 139 (3) ◽  
pp. 257-273 ◽  
Author(s):  
T. J. GILLILAND ◽  
P. D. BARRETT ◽  
R. L. MANN ◽  
R. E. AGNEW ◽  
A. M. FEARON
Keyword(s):  
Lolium Perenne ◽  
Nutritive Value ◽  
Canopy Structure ◽  
Total Lipid Content ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Carbohydrate Concentration ◽  
Harvest Year ◽  
Water Soluble Carbohydrate ◽  
Testing Protocols

Twelve perennial ryegrass (Lolium perenne L.) varieties of different ploidy and maturity classifications were compared under a frequent cutting management in their second harvest year, equivalent to the simulated rotational grazing system employed in UK testing protocols. Varietal differences in canopy structure (proportion of lamina, green leaf mass, sward surface height, extended tiller height, bulk density) and in herbage nutritive value factors (water-soluble carbohydrate content and proportion of linoleic and α-linolenic fatty acids) were assessed and their importance evaluated with reference to total herbage production. Significant variety variation (P<0·001) was recorded in the annual means of all the canopy structure characteristics. Significant differences associated with ploidy were also recorded, with tetraploid varieties having significantly higher values than diploids in most plant characters, indicating better intake characteristics for these grasses. Temporal patterns of variation associated with maturity were also observed in several characters, thus making it impossible to designate a single assessment that would be representative of the annual ranking of varieties. Water-soluble carbohydrate concentration differed significantly (P<0·001) between varieties and although the tetraploids tended to have high contents, the highest value of all was recorded in a diploid variety, which had been selectively bred for this trait. The varieties did not differ in total lipid content but there were significant differences in the proportion of linoleic acid between varieties (P<0·001) while the proportion of α-linolenic acid differed between varieties (P<0·001), ploidy (P<0·001) and maturity (P<0·05) classes.Overall evaluation of the extensive variety variation highlighted the need for better quantification of animal responses to differences of these magnitudes, before the high workload of including them in routine variety testing protocols could be justified. Potential for breeding improvement in these factors was also indicated and the future prospects for their use in farmer decision support systems was considered.

Genotypic variation in water-soluble carbohydrate accumulation in wheat

2006 ◽  
Vol 33 (9) ◽  
pp. 799 ◽  
Author(s):  
Sari A. Ruuska ◽  
Greg J. Rebetzke ◽  
Anthony F. van Herwaarden ◽  
Richard A. Richards ◽  
Neil A. Fettell ◽  
...  
Keyword(s):  
Genotypic Variation ◽  
Dry Weight ◽  
Grain Filling ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Soluble Carbohydrate ◽  
Broad Sense Heritability ◽  
Carbohydrate Accumulation ◽  
Sequential Mechanism ◽  
Water Soluble Carbohydrate

The water-soluble carbohydrate (WSC) that accumulates in the stems of wheat during growth can be an important contributor to grain filling, particularly under conditions when assimilation is limited, such as during end-of-season drought. WSC concentration was measured at anthesis across a diverse set of wheat genotypes over multiple environments. Environmental differences in WSC concentration were large (means for the set ranging between 108 and 203 mg g–1 dry weight), and there were significant and repeatable differences in WSC accumulation among genotypes (means ranging from 112 to 213 mg g–1 dry weight averaged across environments), associated with large broad-sense heritability (H = 0.90 ± 0.12). These results suggest that breeding for high WSC should be possible in wheat. The composition of the WSC, examined in selected genotypes, indicated that the variation in total WSC was attributed mainly to variation in the fructan component, with the other major soluble carbohydrates, sucrose and hexose, varying less. The degree of polymerisation (DP) of fructo-oligosaccharides was up to ~13 in samples where higher levels of WSC were accumulated, owing either to genotype or environment, but the higher DP components (DP > 6) were decreased in samples of lower total WSC. The results are consistent with fructan biosynthesis occurring via a sequential mechanism that is dependent on the availability of sucrose, and differences in WSC contents of genotypes are unlikely to be due to major mechanistic differences.

scholarly journals Improving Grain Yield via Promotion of Kernel Weight in High Yielding Winter Wheat Genotypes

Biology ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 42
Author(s):  
Cong Zhang ◽  
Bangyou Zheng ◽  
Yong He
Keyword(s):  
Grain Yield ◽  
Flag Leaf ◽  
Grain Filling ◽  
Kernel Weight ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Leaf Photosynthesis ◽  
Wheat Genotypes ◽  
Water Soluble Carbohydrate ◽  
Grain Filling Stage

Improving plant net photosynthetic rates and accelerating water-soluble carbohydrate accumulation play an important role in increasing the carbon sources for yield formation of wheat (Triticum aestivum L.). Understanding and quantify the contribution of these traits to grain yield can provide a pathway towards increasing the yield potential of wheat. The objective of this study was to identify kernel weight gap for improving grain yield in 15 winter wheat genotypes grown in Shandong Province, China. A cluster analysis was conducted to classify the 15 wheat genotypes into high yielding (HY) and low yielding (LY) groups based on their performance in grain yield, harvest index, photosynthetic rate, kernels per square meter, and spikes per square meter from two years of field testing. While the grain yield was significantly higher in the HY group, its thousand kernel weight (TKW) was 8.8% lower than that of the LY group (p < 0.05). A structural equation model revealed that 83% of the total variation in grain yield for the HY group could be mainly explained by TKW, the flag leaf photosynthesis rate at the grain filling stage (Pn75), and flag leaf water-soluble carbohydrate content (WSC) at grain filling stage. Their effect values on yield were 0.579, 0.759, and 0.444, respectively. Our results suggest that increase of flag leaf photosynthesis and WSC could improve the TKW, and thus benefit for developing high yielding wheat cultivars.

scholarly journals Interactive Short-term Effects of Waterlogging and Salinity Stress on Growth and Carbohydrate, Lipid Peroxidation, and Nutrients in Two Perennial Ryegrass Cultivars

2017 ◽  
Vol 142 (2) ◽  
pp. 110-118 ◽  
Author(s):  
Xiujie Yin ◽  
Chao Zhang ◽  
Xin Song ◽  
Yiwei Jiang
Keyword(s):  
Lipid Peroxidation ◽  
Salinity Stress ◽  
Perennial Ryegrass ◽  
Dry Weight ◽  
Nutrient Content ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Fresh Weight ◽  
Short Term ◽  
Water Soluble Carbohydrate

Waterlogging can occur in salt-affected turfgrass sites. The objective of this study was to characterize growth and carbohydrate, lipid peroxidation, and nutrient levels in the leaves and roots of two perennial ryegrass (Lolium perenne) cultivars (Catalina and Inspire) to short-term simultaneous waterlogging and salinity stress. Previous research showed that ‘Catalina’ was relatively more tolerant to salinity but less tolerant to submergence than ‘Inspire’. Both cultivars were subjected to 3 and 7 days of waterlogging (W), salinity [S (300 mm NaCl)], and a combination of the two stresses (WS). Across the two cultivars, W alone had little effect on the plants, while both S and WS alone significantly decreased plant height (HT), leaf fresh weight (LFW), leaf dry weight (LDW), root fresh weight (RFW), root dry weight (RDW), leaf nitrogen (LN) and carbon (LC), and leaf and root K+ (RK+), and increased leaf water-soluble carbohydrate (LWSC) and root water-soluble carbohydrate (RWSC), malondialdehyde (MDA), and Na+ content, compared with the control. A decline in chlorophyll content (Chl) was found only at 7 days of WS. Leaf phosphorus (LP) content either decreased or remained unchanged but root phosphorus content increased under S and WS. Reductions in LFW and LDW were found at 3 days of S and WS, whereas RFW and RDW were unaffected until 7 days of S or WS. Both cultivars responded similarly to W, S, and WS with a few exceptions on RDW, LWSC, leaf MDA (LMDA), and root MDA (RMDA). Although WS caused declines in Chl and resulted in higher leaf Na+ (LNa+) and root Na+ (RNa+) than S at 7 days of treatment, S and WS had similar effects on growth, carbohydrate, MDA, N, C, and phosphorus, and K+ content across the two cultivars. The results suggested that S alone largely accounted for the negative effects of WS on plant growth and physiology including alteration of carbohydrate and nutrient content as well as induction of lipid peroxidation.

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