scholarly journals Sink-source and sink-sink relations during reproductive development in Lolium perenne L

1997 ◽  
Vol 45 (4) ◽  
pp. 505-520
Author(s):  
J.W. Warringa ◽  
M.J. Marinissen
Keyword(s):  
Dry Mass ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Sink Strength ◽  
Seed Formation ◽  
Seed Filling ◽  
Pot Trials ◽  
Stem Reserves ◽  
Source And Sink ◽  
Final Cutting

In greenhouse pot trials, L. perenne cv. Barlet plants were labelled with 13C at regular intervals from main spike emergence onwards in order to identify and measure the activity of source and sink organs during seed formation. The source activity of the various tiller groups within the plant roughly reflected the relative contributions of these groups to total plant dry mass. After anthesis there was little net exchange of 13C-label between the older and younger tiller groups. From main spike emergence onwards the source activity of the leaves of the reproductive tiller declined sharply, from 95% of total tiller photosynthesis to 16% at final cutting. The spike became the main assimilating organ on the flowering tiller as the leaves aged. During anthesis the stem was a stronger sink than the seeds. At final cutting 70% of the label was located in the stem, when fixed during anthesis. Water-soluble carbohydrates accumulated in the stem, forming up to 25% of dry matter. After anthesis the sink strength of the developing seeds increased and that of the stem decreased and the stem remained a net sink organ up to about mid-seed filling. Pre-anthesis assimilates contributed 14% to final seed and spikelet carbon, when correcting for the palea and lemma that are present before anthesis. These results show that the stem is a temporary storage organ that can support seed filling. However, only a small amount of the stem reserves was used by the seeds. In contrast to carbon, nitrogen was largely redistributed from the stem and leaves to the seeds. At final harvest 59% of the nitrogen in the flowering tiller was located in the seeds.

Carbohydrate Storage and Mobilisation by the Culm of Wheat Between Heading and Grain Maturity: the Relation to Sucrose Synthase and Sucrose-Phosphate Synthase

1994 ◽  
Vol 21 (3) ◽  
pp. 255 ◽  
Author(s):  
IF Wardlaw ◽  
J Willenbrink
Keyword(s):  
Sucrose Synthase ◽  
Flag Leaf ◽  
Sucrose Phosphate Synthase ◽  
Leaf Sheath ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Carbohydrate Storage ◽  
Stem Reserves ◽  
Sucrose Phosphate ◽  
Phosphate Synthase

Wheat plants grown under non-stress conditions at a dayhight temperature of 18/13�C under glasshouse conditions from head emergence to maturity showed a maximum accumulation of water-soluble, non-structural carbohydrates 20-25 days after anthesis. This storage was largely as fructans with the timing and amount of storage and mobilisation varying between cultivars, although the maximum concentration (fructose equivalents per unit stem fresh weight) was similar in all cultivars. The main storage in the culm was located in the lower part of the peduncle enclosed by the flag leaf sheath, in the penultimate internode and for one cultivar also in the flag leaf sheath. 14CO2 pulse-chase studies showed that there was a considerable delay in the incorporation of flag leaf assimilates into stem fructans, a delay probably associated with transfer and metabolic processes in the stem itself. At anthesis, when soluble carbohydrates were rapidly accumulating in the culm, the level of activity of sucrose synthase (SS) in the penultimate internode was much greater than that of sucrose phosphate synthase (SPS). The activity of SS declined rapidly as active storage ceased. This pattern was the reverse of that found in the leaf where SPS, rather than SS, was initially high and declined towards maturity. These changes are discussed in relation to the possible role of sucrose synthesising enzymes, particularly SS, in the accumulation and mobilisation of stem reserves in wheat.

Predictability of wheat growth and yield in light-limited conditions

2007 ◽  
Vol 145 (1) ◽  
pp. 63-79 ◽  
Author(s):  
F. D. BEED ◽  
N. D. PAVELEY ◽  
R. SYLVESTER-BRADLEY
Keyword(s):  
Solar Radiation ◽  
Grain Yield ◽  
Incident Light ◽  
Dry Weight ◽  
Water Soluble ◽  
Growth And Yield ◽  
Soluble Carbohydrates ◽  
Total Solar Radiation ◽  
Shoot Dry Weight ◽  
Source And Sink

In seeking better predictions of grain yield under light-limited conditions, shading was applied to field-grown winter wheat cv. Slejpner during each of five consecutive phases (canopy expansion, ear expansion, pre-flowering, grain expansion and grain filling). Absolute measures were taken of solar radiation and its effects on growth in three seasons, at a site where water and nutrient supplies were not limiting. Replicate mobile shades automatically occluded 0·80 of incident light when mean total solar radiation exceeded 250 J/m2 per s. Mean effects over seasons of shading on incident total solar radiation were −296, −139, −78, −157 and −357 MJ/m2 for the five phases respectively, and corresponding effects on shoot dry weight were −236, −184, −58, −122 and −105 g/m2. Estimated efficiency of radiation use after flowering was 1·2 g/MJ unshaded, tending to increase with shading. Shading in all phases reduced grain dry matter yield: mean effects over seasons were −106, −64, −61, −93 and −281 g/m2 for the five consecutive shading periods. Shading from GS31–39 increased mean maximum area of the two top leaves from 2700 to 3100 mm2 per leaf but, with fewer stems, canopy size remained unaffected. This and the next shading, from GS39–55, reduced specific leaf weight from 42 g/m2 by 4 and 3 g/m2 respectively, but effects on shoot dry weight were largely due to stem and ear. By flowering, stem weights, and especially their reserves of water-soluble carbohydrates, had partially recovered. Effects on yield of shading from GS31–39 were explained by a reduction in grains/m2 of 3070 from 26109. Shading from GS39–55 reduced grains/m2 by 4211 due to fewer grains per ear, whilst mean weight per grain increased in compensation. Shading from GS55–61 decreased grains/ear by 2·5. Shading from GS61–71 decreased ear growth and reduced stem weight, and at harvest resulted in 4·3 less grains/ear. Effects of the final shading from GS71–87 were fully explained by a reduction in mean dry weight/grain of 10·3 mg. Except for shading from GS71–87, source- and sink-based explanations of grain yield both proved feasible, within the precision of the measurements. Constraints to accurate comparison of source- and sink-based approaches are identified, and the implications for yield forecasting are discussed.

scholarly journals Truncation of grain filling in wheat (Triticum aestivum) triggered by brief heat stress during early grain filling: association with senescence responses and reductions in stem reserves

2016 ◽  
Vol 43 (10) ◽  
pp. 919 ◽  
Author(s):  
Hamid Shirdelmoghanloo ◽  
Daniel Cozzolino ◽  
Iman Lohraseb ◽  
Nicholas C. Collins
Keyword(s):  
Triticum Aestivum ◽  
Grain Size ◽  
Heat Stress ◽  
Heat Waves ◽  
Flag Leaf ◽  
Grain Filling ◽  
Water Soluble ◽  
Grain Weight ◽  
Soluble Carbohydrates ◽  
Stem Reserves

Short heat waves during grain filling can reduce grain size and consequently yield in wheat (Triticum aestivum L.). Grain weight responses to heat represent the net outcome of reduced photosynthesis, increased mobilisation of stem reserves (water-soluble carbohydrates, WSC) and accelerated senescence in the grain. To compare their relative roles in grain weight responses under heat, these characteristics were monitored in nine wheat genotypes subjected to a brief heat stress at early grain filling (37°C maximum for 3 days at 10 days after anthesis). Compared with the five tolerant varieties, the four susceptible varieties showed greater heat-triggered reductions in final grain weight, grain filling duration, flag leaf chla and chlb content, stem WSC and PSII functionality (Fv/Fm). Despite the potential for reductions in sugar supply to the developing grains, there was little effect of heat on grain filling rate, suggesting that grain size effects of heat may have instead been driven by premature senescence in the grain. Extreme senescence responses potentially masked stem WSC contributions to grain weight stability. Based on these findings, limiting heat-triggered senescence in the grain may provide an appropriate focus for improving heat tolerance in wheat.

Investigating the Optimal Day for Nitrogen Fertilization on Piatã palisadegrass and Quênia guineagrass after Defoliation

2019 ◽  
pp. 1-11
Author(s):  
Dayana Aparecida De Faria ◽  
Anne Caroline Dallabrida Avelino ◽  
Carlos Eduardo Avelino Cabral ◽  
Joadil Gonçalves De Abreu ◽  
Lívia Vieira De Barros ◽  
...  
Keyword(s):  
Nitrogen Fertilization ◽  
Dry Mass ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Panicum Maximum ◽  
Mato Grosso ◽  
Grass Roots ◽  
Randomized Design ◽  
Water Soluble Carbohydrates ◽  
Structural Carbohydrate

Considering that nitrogen is the main macronutrient limiting pasture productivity, the aim of this study was to investigate the most appropriate day for nitrogen fertilization of the grasses Brachiaria brizantha BRS Piatã and Panicum maximum BRS Quênia. The experiment was conducted in a greenhouse in the city of Rondonópolis, located in the state of Mato Grosso, Brazil, using a completely randomized design. The treatments consisted of five nitrogen fertilization periods: 0; 2; 4; 6 and 8 days after defoliation. The dry mass of the leaf blade (DMLB), dry mass of stem + sheath (DMSS), dry mass of residue (DMRES) and root dry mass (RDM) were evaluated. The non-structural carbohydrate of the grass roots was also quantified. The later nitrogen fertilization after defoliation reduced DMLB (P< .01) and DMSS (P< .01) of the BRS Piatã palisadegrass, and DMRES of both grasses (P< .01). Higher levels of water soluble carbohydrates were observed when nitrogen fertilization was performed on grass cutting (day 0). Nitrogen fertilization of the BRS Piatã palisadegrass close the time of defoliation is recommended. For Quênia guineagrass, nitrogen can be applied between the cutting day and the eighth day after defoliation. For the root system, there is a higher content of water soluble carbohydrates in the BRS Piatã palisadegrass and greater accumulation of starch in the BRS Quênia guineagrass.

scholarly journals The soybean (Glycine max L.) cytokinin oxidase/dehydrogenase multigene family; identification of natural variations for altered cytokinin content and seed yield

2020 ◽  
Author(s):  
Hai Ngoc Nguyen ◽  
Shrikaar Kambhampati ◽  
Anna Kisiala ◽  
Mark Seegobin ◽  
RJ Neil Emery
Keyword(s):  
Glycine Max ◽  
Seed Yield ◽  
Structural Integrity ◽  
Hormonal Control ◽  
High Expression ◽  
Cytokinin Oxidase ◽  
Sink Strength ◽  
Seed Formation ◽  
Seed Filling ◽  
Natural Variations

AbstractCytokinins (CKs) play a fundamental role in regulating dynamics of organ source/sink relationships during plant development, including flowering and seed formation stages. As a result, CKs are key drivers of seed yield. The cytokinin oxidase/dehydrogenase (CKX) is one of the critical enzymes responsible for regulating plant CK levels by causing their irreversible degradation. Variation of CKX gene activity is significantly correlated with seed yield in many crop species while in soybean (Glycine max L.), the possible associations between CKX gene family members (GFMs) and yield parameters have not yet been assessed. In this study, seventeen GmCKX GFMs were identified, and natural variations among GmCKX genes were probed among soybean cultivars with varying yield characteristics. The key CKX genes responsible for regulating CK content during seed filling stages of reproductive development were highlighted using comparative phylogenetics, gene expression analysis and CK metabolite profiling. Five of the seventeen identified GmCKX GFMs, showed natural variations in the form of single nucleotide polymorphisms (SNPs). The gene GmCKX14, with high expression during critical seed filling stages, was found to have a non-synonymous mutation (H105Q), on one of the active site residues, Histidine 105, previously reported to be essential for co-factor binding to maintain structural integrity of the enzyme. Soybean lines with this mutation had higher CK content and desired yield characteristics. The potential for marker-assisted selection based on the identified natural variation within GmCKX14, is discussed in the context of hormonal control that can result in higher soybean yield.Key MessageNatural variations in soybean cytokinin oxidase/dehydrogenase gene, GmCKX14, with high expression during seed development, were linked to increased sink strength via altered cytokinin profiles in high yielding cultivars.

Genotypic variation of wheat (Triticum aestivum L.) in grain filling and contribution of culm reserves to yield

2021 ◽  
Vol 50 (1) ◽  
pp. 51-59
Author(s):  
Md Amirul Islam ◽  
Md Soaliman Ali Fakir ◽  
Md Alamgir Hossain ◽  
Maria Akter Sathi
Keyword(s):  
Grain Yield ◽  
Genotypic Variation ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Dry Mass ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
The Mean ◽  
Ripe Stage ◽  
Different Parts

To study the genotypic variation in the rate of grain filling and contribution of culm reserves to yield in wheat, an experiment was conducted consisting 12 popular cultivars of Bangladesh, viz., BARI Gom21 (Shatabdi), BARI Gom22 (Shufi), BARI Gom23 (Bijoy), BARI Gom24 (Prodip), BARI Gom25, BARI Gom26, Akbar (BAW 43), BARI Gom18 (Protiva), BARI Gom19 (Sourav), BARI Gom20 (Gourab), Agrani (BAW38), and Kanchan (BAW28). Tillers were sampled from anthesis to maturity to determine the changes in dry weights of different parts to examine the contribution of culm reserves to grain yield. The results in the experiment revealed that the grain yield varied from 2.61 to 5.35 ton/ha with the mean of 4.18 ton/ha. Among the cultivars BARI Gom24, BARI Gom26, BARI Gom19, and BARI Gom23 appeared as high yielders while Kanchan, Agrani, BARI Gom20, BARI Gom22 as the low yielders. Generally, high yielding cultivars showed higher total dry mass accumulation compared to low yielding ones. Moreover, high yielding cultivars also showed higher water soluble carbohydrates (WSCs) contents in culm at milk ripe stage than the low yielders. In general, contribution of culm WSCs to grain yield was more in high yielders than low yielders and it ranged from 2 to 29% of total grain weight. So, higher contribution of culm reserves resulted in higher grain yield of wheat.

scholarly journals Evaluation of the Tolerance Ability of Wheat Genotypes to Drought Stress: Dissection through Culm-Reserves Contribution and Grain Filling Physiology

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1252
Author(s):  
Md. Amirul Islam ◽  
Rajib Kumar De ◽  
Md. Alamgir Hossain ◽  
Md. Sabibul Haque ◽  
Md. Nesar Uddin ◽  
...  
Keyword(s):  
Drought Stress ◽  
Grain Yield ◽  
Grain Filling ◽  
Dry Mass ◽  
Water Soluble ◽  
Limiting Factors ◽  
Soluble Carbohydrates ◽  
Matter Production ◽  
Grain Filling Period ◽  
Ripe Stage

Drought stress is one of the limiting factors for grain filling and yield in wheat. The grain filling and determinants of individual grain weight depend on current assimilation and extent of remobilization of culm reserves to grains. A pot experiment was conducted with eight wheat cultivars at the Pot House to study the grain filling and the contributions of reserves in culm, including the sheath to grain yield under drought stress. Drought stress was enforced by restricting irrigation during the grain-filling period. The plants (tillers) were harvested at anthesis, milk-ripe, and maturity. The changes in dry weights of leaves, culm with sheath, spikes, and grains; and the contribution of culm reserves to grain yield were determined. Results revealed that drought stress considerably decreased the grain filling duration by 15–24% and grain yield by 11–34%. Further, drought-induced early leaf senescence and reduced total dry matter production indicate the minimum contribution of current assimilation to grain yield. The stress reduced the contribution of culm reserves, the water-soluble carbohydrates (WSCs), to the grains. The accumulation of culm WSCs reached peak at milk ripe stage in control, varied from 28.6 to 84 mg culm−1 and that significantly reduced in the range from 14.9 to 40.6 mg culm−1 in stressed plants. The residual culm WSCs in control and stressed plants varied from 1.23 to 8.12 and 1.00 to 3.40 mg g−1 culm dry mass, respectively. BARI Gom 24 exhibited a higher contribution of culm WSCs to grain yield under drought, while the lowest contribution was found in Kanchan. Considering culm reserves WSCs and their remobilization along with other studied traits, BARI Gom 24 showed greater drought tolerance and revealed potential to grow under water deficit conditions in comparison to other cultivars.

scholarly journals Quality of re-ensiled sorghum silages after prolonged periods of environmental exposure

2020 ◽  
Vol 41 (1) ◽  
pp. 357
Author(s):  
Tamires Oliveira de Lima ◽  
Adriano de Almeida Lino ◽  
Luis Aurelio Sanches ◽  
Vinícius Martins Brito ◽  
Sabrina Novaes dos Santos-Araujo ◽  
...  
Keyword(s):  
Environmental Exposure ◽  
Nutritive Value ◽  
Dry Mass ◽  
Water Soluble ◽  
Neutral Detergent Fiber ◽  
Soluble Carbohydrates ◽  
Regression Equations ◽  
Air Exposure ◽  
Total N ◽  
Fermentation Profile

The aim of this study was to evaluate the effect of re-ensiling on the fermentability coefficient (FC), chemical composition and fermentation profile of untreated whole-crop sorghum silage after prolonged periods of environmental exposure. Treatments comprised eight times of exposure to the environment (0, 6, 12, 24, 48, 72, 96, and 120 h) and two procedures for conservation (conventional and re-ensiling) in a completely randomized design with two factors and three replicates. Experimental silos made of 12-L plastic buckets were used in trials. Silage nutritive value, fermentation profile, and dry mass (DM) losses were analyzed before and 90 days after re-ensiling. Regression analyses were performed, and ANOVA was used to compare means. The FC was higher than 45 even when the silage was exposed to air for 120 h before re-ensiling (59.2±2.54). Regression equations were fitted to the data with low accuracy (R2 < 0.47). Moreover, we observed that the main effect occurred between before and after re-ensiling, decreasing the contents of DM (42 to 37 %) and water-soluble carbohydrates (7.0 to 5.8 % DM), neutral detergent fiber (60.4 to 55.4 % DM), and acid detergent fiber (49.5 to 33.5 % DM), but increasing those of lactic acid (0.52 to 0.96 % DM) and ammoniacal nitrogen (1.58 to 2.51 % total N). The DM losses were linear with increasing times of air exposure; however, silage nutritive value and fermentation profile showed no disturbing changes for silage conservation and animal feeding.

scholarly journals Agronomic Evaluation of the Results of Selection within Late-Maturing Dactylis glomerata Populations

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1362
Author(s):  
Joseph G. Robins ◽  
B. Shaun Bushman ◽  
Kevin B. Jensen
Keyword(s):  
Nutritive Value ◽  
Dactylis Glomerata ◽  
Dry Mass ◽  
Water Soluble ◽  
Neutral Detergent Fiber ◽  
Soluble Carbohydrates ◽  
Fiber Digestibility ◽  
Harvest Intervals ◽  
Dactylis Glomerata L

Selection from novel orchardgrass (Dactylis glomerata L.) germplasm sources resulted in the development of a late-maturing orchardgrass population. This population comprises 58 families that were evaluated with 5 commercial cultivars under frequent and infrequent harvest intervals at two Cache County, UT, USA field locations during 2013 and 2014. The objective of this study was to characterize the performance of individual families when compared to check cultivars Intensive and Latar. Across locations and harvest intervals, individual families produced greater herbage dry mass and nutritive value than the check cultivars did, i.e., up to 12% greater herbage dry mass than that of the highest check, Intensive, and 1% (neutral-detergent-fiber digestibility) to 14% (water soluble carbohydrates) greater forage quality than that of the corresponding highest check cultivar. However, there were substantial genotype-by-environment interactions between families and locations, but not harvest intervals. Because of this, results were analyzed across harvest intervals but within locations. Within each location, there were families that possessed similar or greater maturity, herbage dry mass, in vitro true digestibility, and neutral-detergent-fiber digestibility at both locations. Overall, on the basis of the performance of its component families, this late-maturing orchardgrass population exhibited potential for developing improved cultivars.

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