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.

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.

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 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.

scholarly journals Preliminary Findings on the Correlation between Water-soluble Carbohydrate Content in Stolons and First Year Green-up of Seeded Bermudagrass Cultivars

2010 ◽  
Vol 20 (4) ◽  
pp. 758-763 ◽  
Author(s):  
Stefano Macolino ◽  
Matteo Serena ◽  
Bernd Leinauer ◽  
Umberto Ziliotto
Keyword(s):  
Cynodon Dactylon ◽  
Warm Season ◽  
Dry Weight ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
First Year ◽  
Green Cover ◽  
Mediterranean Countries ◽  
The University ◽  
Water Soluble Carbohydrate

Warm-season grasses are not widely accepted in Mediterranean countries because they lose color during the winter months. A study was conducted at the University of Padova (Padova, Italy) to determine whether fall and spring water-soluble carbohydrate (WSC) content in stolons of seeded bermudagrass cultivars (Cynodon dactylon) influenced spring green-up in the first year of establishment. Nine bermudagrass cultivars (La Paloma, Mohawk, NuMex Sahara, Princess 77, Riviera, SR 9554, Barbados, Contessa, and Yukon) were seeded in July 2005, and dry weight and WSC content in stolons were measured in Fall 2005 and again in Spring 2006. The percentage of green cover and days needed to achieve 80% green cover (D80) were regressed against November and March values of stolon dry weight and WSC content to determine if they were good predictors of D80. ‘Yukon’ showed earliest spring green-up by end of April, and ‘Princess 77’ and ‘Riviera’ were slowest, needing 43 to 46 days more than ‘Yukon’ to reach D80. There was a significant inverse relationship between November (r2 = 0.57) and March (r2 = 0.77) WSC content in stolons and D80 for all nine bermudagrass cultivars. These results suggest that bermudagrass cultivars with high WSC in stolons recover more rapidly from dormancy during establishment than those with low WSC content.

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).

Effects of water stress on photosynthesis in relation to diurnal accumulation of carbohydrates in source leaves

1982 ◽  
Vol 60 (3) ◽  
pp. 195-200 ◽  
Author(s):  
James A. Bunce
Keyword(s):  
Water Stress ◽  
Dry Weight ◽  
Light Period ◽  
Carbohydrate Content ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Nonstructural Carbohydrates ◽  
Photosynthetic Rates ◽  
Total Nonstructural Carbohydrates ◽  
Water Soluble Carbohydrate

Net photosynthetic rates, stomatal and mesophyll conductances to CO2 uptake, water soluble and total nonstructural carbohydrates contents, specific leaf weights of fully expanded source leaves, and elongation rates of rapidly expanding leaves were measured on 2 days during a period of water stress in soybean and sunflower plants in a controlled environment. Compared with control plants, elongation rates of expanding leaves and translocation rates of dry weight from source leaves in the light were more reduced by stress than were net photosynthetic rates of source leaves. Over the 8-h light period, the dry weight increase of source leaves was up to 23 mg dm−2 (1.5 × control) higher in stressed plants, but was not in all cases higher in stressed than control plants. In stressed plants a smaller fraction of the increase in dry weight in source leaves in the light was in nonstructural carbohydrates. At the end of the light period, water soluble and total nonstructural carbohydrates were up to 9 mg dm−2 higher in stressed than control leaves in sunflower, but were not higher in soybean. No differences in carbohydrate contents at the end of the light period were found in sunflower between the 2 days of stress, although stress became more severe in terms of lower rates of photosynthesis, translocation, and leaf elongation. The approximately threefold reductions in net photosynthetic rates in stressed leaves were related to both lower stomatal and lower mesophyll conductances. Mesophyll conductances of stressed leaves were not significantly correlated with water soluble carbohydrate content, total nonstructural carbohydrate content, or specific leaf weight in either species.

Increased Kernel Number in Norin 10-Derived Dwarf Wheat: Evaluation of the Cause

1986 ◽  
Vol 13 (6) ◽  
pp. 767 ◽  
Author(s):  
RA Fischer ◽  
YM Stockman
Keyword(s):  
Spring Wheat ◽  
Dry Matter ◽  
Dry Weight ◽  
Field Studies ◽  
Water Soluble ◽  
Growth Potential ◽  
Soluble Carbohydrate ◽  
Floral Initiation ◽  
Kernel Number ◽  
Shoot Dry Weight

This study of the effect of major Norin 10 dwarfing genes (Rht1, Rht2) on kernel number in spring wheat emphasised three near-isogenic pairs of spring wheat, differing in the presence or absence of both genes. Plants were grown under controlled environment conditions with equal light intensities at their tops and were restricted to main stems by repeated tiller trimming. The dwarf wheats had a higher proportion of shoot dry weight in the spike at anthesis, an effect which field studies suggest is closely associated with their production of more kernels per unit land area. Stems of dwarf genotypes were somewhat shorter as early as 50 days before anthesis (i.e. before floral initiation) but relative differences became especially great commencing at 35 days before anthesis. Apex and spike lengths were never very different. A greater proportion of dry matter was distributed to leaf lamina from 50 days before anthesis until the end of lamina growth in dwarf wheats, while partitioning to stems was lower from 50 days before anthesis onwards. Partitioning to spikes was only higher in the 15 days preceding anthesis. Stem water-soluble carbohydrate (WSC) contents at anthesis were greater in dwarf wheats but maximum spike WSC contents reached at about 15 days before anthesis were lower. Spike morphogenesis including floret production and grain setting did not differ generally, except for a tendency with dwarf wheats for a longer floral initiation to anthesis interval and for more kernels per unit of spike weight at anthesis. The major unique feature of dwarf genotypes, the higher proportion of dry matter partitioned to the spike, appeared to be due to reduced competition from growing stems in dwarf wheats rather than intrinsic differences in the growth potential of their spikes.

Effects of season, maturity and rate of nitrogen fertilizer on ensilage of Setaria sphacelata

1968 ◽  
Vol 8 (34) ◽  
pp. 569 ◽  
Author(s):  
VR Catchpoole
Keyword(s):  
Nitrogen Fertilizer ◽  
Dry Matter ◽  
Dry Weight ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Moderate Amount ◽  
Ph Values ◽  
Silage Fermentation ◽  
Setaria Sphacelata ◽  
Water Soluble Carbohydrate

A study was made of the chemical composition and silage fermentation of Setaria sphacelata CV. Nandi. The grass was ensiled at three periods of the growing season, with two maturities at harvest, and grown with two levels of nitrogen fertilizer. On each harvest day cuts were taken in the morning, at noon, and in the afternoon. The object was to measure the variation that occurred under field conditions in south-eastern Queensland. The water soluble carbohydrate content of the grass was always below 6 per cent of its dry weight, and the silage had very low contents of lactic acid, high contents of volatile acids and high pH values. Volatile base contents were usually well below 20 per cent of the total nitrogen, showing that degradation of protein was not extensive. By traditional standards of silage quality the S. sphacelata was poorly preserved. On the other hand a degree of preservation was achieved as shown by the moderate amount of protein breakdown and small losses of dry matter and nitrogen during storage. Variation in the extent of fermentation changes, and of losses during ensilage, demonstrated that grass cut at five weeks was more effectively preserved than grass cut at eight weeks. Also, on any one harvest day, grass cut during the morning had lower dry matter contents, and was not as well preserved as cuts made later during the day.

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