scholarly journals Shearing force of alfalfa stems: effects of cultivar and shearing site

1999 ◽  
Vol 79 (1) ◽  
pp. 49-55 ◽  
Author(s):  
A. D. Iwaasa ◽  
K. A. Beauchemin ◽  
S. N. Acharya ◽  
J. G. Buchanan-Smith
Keyword(s):  
Cell Wall ◽  
Chemical Constituents ◽  
Sampling Site ◽  
Stem Diameter ◽  
Measuring System ◽  
Cultivar Differences ◽  
Stem Segment ◽  
Shearing Force ◽  
Force Characteristics ◽  
Stem Segments

A 3-yr study was conducted to investigate the effect of shearing position on shearing force characteristics in alfalfa (Medicago sativa L.) stems and to evaluate the relationship between cell wall (CW) chemical constituents and stem shearing force. Stems from plots of 24 alfalfa cultivars were harvested from the second, third and fourth production years. Each stem was divided into three 16-cm segments: top, middle and bottom, and the force required to shear each segment was measured using a modified Ottawa Texture Measuring System. Cultivar by stem segment interactions were significant (P < 0.05) for stem diameter, weight and shearing force. The middle and bottom stem segments were the best sampling site to detect cultivar differences for shearing force. Stem diameter and weight were generally the variables most associated with shearing force for all three stem segments. However, shearing force characteristics for certain cultivars could not be entirely explained by stem diameter or weight and may be affected by CW chemical constituents and/or structural tissues. The ADL concentrations were not consistently correlated to shearing force at the top and bottom segments over the 3 yr. For the bottom stem segment a negative relationship (r = −0.42, P < 0.001) resulted between shearing force and hemicellulose, while a positive relationship (r = 0.40, P < 0.001) resulted between shearing force and cellulose. Key words: Cultivar, environment, shearing force, cell wall chemical constituents

Effect of stage of maturity and growth cycle on shearing force and cell wall chemical constituents of alfalfa stems

1996 ◽  
Vol 76 (3) ◽  
pp. 321-328 ◽  
Author(s):  
A. D. Iwaasa ◽  
K. A. Beauchemin ◽  
S. N. Acharya ◽  
J. G. Buchanan-Smith
Keyword(s):  
Cell Wall ◽  
Chemical Constituents ◽  
Growth Cycle ◽  
Stem Diameter ◽  
Stem Segment ◽  
Cellulose Content ◽  
Shearing Force ◽  
Significant Stage ◽  
Early Flower ◽  
Stem Segments

Two experiments were conducted to assess whether stage of maturity and growth cycle affected shearing force of alfalfa (Medicago sativa L.) stems. In both experiments, stem shearing force, diameter and weight were measured at several segments on the stem. In exp. 1, Anchor, Barrier and Vernal alfalfa, at the second and third regrowth were harvested at the early bud stage. Stem weight and diameter were larger at the second regrowth for all stem segments. A numeric trend for lower stem diameter in Vernal compared to Anchor and Barrier was observed. For all stem segments, shearing forces for Anchor and Barrier were lower than for Vernal and shearing force was highest for second regrowth. Vernal had higher NDF, ADF, hemicellulose and cellulose content than other cultivars and ADL was highest at the second regrowth (P < 0.01). In exp. 2, Anchor, Barrier and Vernal alfalfa, in the second production year, were harvested at four stages of maturity, early bud, early flower, late flower and early seed pod. A significant stage of maturity × stem segment effect was observed for shearing force, diameter, and weight. Shearing force, stem diameter and weight measurements generally increased as the plants aged for all stem segments. Quadratic relationships (P < 0.0001) for shearing force stem diameter and weight were observed with increasing stage of maturity for all stem segments. Generally, hemicellulose and lignin contents increased as the plants matured, while cellulose concentrations were variable. Both stage of maturity and growth cycle affected shearing force of alfalfa stems and this was associated with changes in stem diameter, weight and its cell wall chemical constituents. Key words: Alfalfa, stage of maturity, growth cycle, shearing force, cell wall chemical constituents

Shearing force of alfalfa stems: Effects of genotype and year interactions

1998 ◽  
Vol 78 (4) ◽  
pp. 719-722
Author(s):  
A. D. Iwaasa ◽  
K. A. Beauchemin ◽  
S. N. Acharya ◽  
J. G. Buchanan-Smith
Keyword(s):  
Cell Wall ◽  
Medicago Sativa ◽  
Key Words ◽  
Chemical Constituents ◽  
Stem Segment ◽  
Shearing Force ◽  
Medicago Sativa L ◽  
Genotype Clustering ◽  
Force Characteristics

Shearing force of alfalfa (Medicago sativa L.) stems was measured to evaluate genotype-by-year interactions. Based on mean shearing force for each stem segment and genotype clustering criteria, several genotypes had similarly shearing forces among years. Therefore, selecting genotypes with desirable shearing force characteristics to improve digestibility or intake potential of forages may be possible. Key words: Genotype, environment, shearing force, cell wall chemical constituents

Shearing force of alfalfa stems as affected by seeding rate

1998 ◽  
Vol 78 (2) ◽  
pp. 273-280 ◽  
Author(s):  
A. D. Iwaasa ◽  
K. A. Beauchemin ◽  
S. N. Acharya ◽  
S. R. Bowley ◽  
J. G. Buchanan-Smith
Keyword(s):  
Cell Wall ◽  
Chemical Constituents ◽  
Physical Characteristics ◽  
Stem Diameter ◽  
Measuring System ◽  
Shearing Force ◽  
Seeding Rate ◽  
Simple Method ◽  
Physical Measurements ◽  
Shearing Strength

Physical properties of forages may provide a simple method of predicting animal voluntary feed intake. Physical measurements, such as shearing force, may indicate the resistance of the forage to particle breakdown during mastication. The objective of this study is to determine the effects of seeding rate on the physical characteristics and cell wall chemical constituents of alfalfa (Medicago sativa L.) stems, and to relate these characteristics to shearing strength. Stems of eight alfalfa cultivars (120, Legend, Multiking 1, OAC Minto, Saranac, Vernal, Vertus, WL320) seeded at 6, 12 and 24 kg ha−1 were harvested in the first and second production years and divided into three 16 cm segments: top, middle and bottom, and the force required to shear each segment was measured using a modified Ottawa Texture Measuring System. For both years, shearing force, segment weight and stem diameter measurements generally decreased as seeding rate increased when measured at the middle and bottom shearing segments on the stem, but this was not observed for the top shearing segment. Effect of seeding rate on differences in segment weight and stem diameter among cultivars was variable among years and stem segments. Concentrations of cell wall constituents in stems were not influenced by seeding rate, and these influenced shearing force to a lesser extent than physical characteristics. Shearing force was directly related to the diameter and weight of the stem. Because of the associations between shearing force and diameter and weight, physical characteristics of the stem may influence forage breakdown during mastication independently, and to a greater extent than cell wall chemical constituents. Key words: Alfalfa, seeding rate, shearing force, cell wall chemical constituents, diameter, weight

Studies on the Optical Measuring System for Grape Stem Diameter

2014 ◽  
Vol 568-570 ◽  
pp. 65-70
Author(s):  
Ming Jun Wang ◽  
Jun Zhou
Keyword(s):  
Continuous Measurement ◽  
High Accuracy ◽  
Stem Diameter ◽  
Experimental Results ◽  
Measuring System ◽  
Stem Segment ◽  
Physiological Disorders ◽  
Optical Measuring ◽  
Periodic Data

This study presented a novel non-contact optical measuing method for grape stem diameter in fields. The main algorithm contained 3 steps: saperation of the stem from background, determination of the stem segment, and the computation of stem diameter. The experiments conducted in field not only validated the effectiveness, but also proved the high accuracy of the optical measuring system. And our further experimental results showed that the continuous measurement of grape stem diameter can provide periodic data for the analysis of physiological disorders in grapes.

Assessment of stem shearing force for three alfalfa cultivars grown under dryland and irrigated conditions

1995 ◽  
Vol 75 (1) ◽  
pp. 177-179 ◽  
Author(s):  
A. D. Iwaasa ◽  
K. A. Beauchemin ◽  
S. N. Acharya ◽  
J. G. Buchanan-Smith
Keyword(s):  
Key Words ◽  
Positive Relationship ◽  
Physical Property ◽  
Stem Diameter ◽  
Measuring System ◽  
Shearing Force ◽  
Physiological Maturity ◽  
Significant Positive Relationship ◽  
Growing Conditions

The Ottawa Texture Measuring System was used to assess the shearing force of three alfalfa cultivars at similar physiological maturity. Shearing force of stems varied among growing conditions and shearing locations. A significant positive relationship was observed between shearing force and stem diameter. Shearing force may indicate stem fragility and provide a rationale for differences in forage breakdown during mastication. Key words: Alfalfa, Ottawa Texture Measuring System, Warner-Bratzler blade, physical property, shearing force

scholarly journals Regulation of Cell Wall Synthesis in Avena Stem Segments by Gibberellic Acid

1975 ◽  
Vol 55 (6) ◽  
pp. 1043-1047 ◽  
Author(s):  
Michael J. Montague ◽  
Hiroshi Ikuma
Keyword(s):  
Cell Wall ◽  
Gibberellic Acid ◽  
Cell Wall Synthesis ◽  
Stem Segments

scholarly journals The Dynamics of the Cell Wall Proteome of Developing Alfalfa Stems

Biology ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 60 ◽  
Author(s):  
Sergeant ◽  
Printz ◽  
Guerriero ◽  
Renaut ◽  
Lutts ◽  
...  
Keyword(s):  
Cell Wall ◽  
Apical Region ◽  
Stem Segment ◽  
Burp Domain ◽  
Composition And Structure ◽  
Striking Change ◽  
Stem Development ◽  
Cell Wall Proteome ◽  
Beta Galactosidase

In this study, the cell-wall-enriched subproteomes at three different heights of alfalfa stems were compared. Since these three heights correspond to different states in stem development, a view on the dynamics of the cell wall proteome during cell maturation is obtained. This study of cell wall protein-enriched fractions forms the basis for a description of the development process of the cell wall and the linking cell wall localized proteins with the evolution of cell wall composition and structure. The sequential extraction of cell wall proteins with CaCl2, EGTA, and LiCl-complemented buffers was combined with a gel-based proteome approach and multivariate analysis. Although the highest similarities were observed between the apical and intermediate stem regions, the proteome patterns are characteristic for each region. Proteins that bind carbohydrates and have proteolytic activity, as well as enzymes involved in glycan remobilization, accumulate in the basal stem region. Beta-amylase and ferritin likewise accumulate more in the basal stem segment. Therefore, remobilization of nutrients appears to be an important process in the oldest stem segment. The intermediate and apical regions are sites of cell wall polymer remodeling, as suggested by the high abundance of proteins involved in the remodeling of the cell wall, such as xyloglucan endoglucosylase, beta-galactosidase, or the BURP-domain containing polygalacturonase non-catalytic subunit. However, the most striking change between the different stem parts is the strong accumulation of a DUF642-conserved domain containing protein in the apical region of the stem, which suggests a particular role of this protein during the early development of stem tissues.

scholarly journals Callus induction and regeneration of Alkanna orientalis var. Orientalis and A. sieheana

2019 ◽  
Vol 48 (3) ◽  
pp. 633-640 ◽  
Author(s):  
Cenney Yaman ◽  
Serkan Uranbey ◽  
Hussein Abdullah Ahmed ◽  
Sabahattin Özcan ◽  
Osman Tugay ◽  
...  
Keyword(s):  
Shoot Regeneration ◽  
Callus Induction ◽  
High Frequency ◽  
Stem Segment ◽  
Leaf Base ◽  
Cotyledonary Leaf ◽  
Frequency Variations ◽  
Alkanna Orientalis ◽  
Stem Segments

Callus induction and proliferation of Alkanna orientalis var. orientalis and Alkanna sieheana containing valuable alkannin/shikonin (A/S) derivates were investigated using leaf base and stem segment explants. Stem segments and cotyledonary leaf base of both species were cultured on Murashige and Skoog medium fortified with different concentrations of BAP, Kn, NAA, IAA and IBA for callus induction and shoot regeneration. High frequency reproducible, prolific and compact calli formation was obtained from the stem segments of both species in all media tested. The frequency variations of callus induction and shoot regeneration were discussed in terms of different species, plant growth regulators and explant resources. A. orientalis and A. sieheana may be considered to be alternative plants for the A/S production in vitro.

scholarly journals The acropetal effects of indole-3-acetic acid in isolated shoot segments of Acer pseudoplatanus L. II. Possible regulation by a vectorial fieid of auxin waves

2014 ◽  
Vol 60 (1-2) ◽  
pp. 51-66
Author(s):  
Jacek A. Adamczyk
Keyword(s):  
Acetic Acid ◽  
Phase Shift ◽  
Direct Action ◽  
Lateral Branch ◽  
Stem Segment ◽  
Acer Pseudoplatanus ◽  
Basipetal Transport ◽  
Indole 3 Acetic Acid ◽  
Stem Segments ◽  
Growing Shoot

The acropetal effects of auxin on elongation of axillary buds and on modulation of the wave-like pattern of basipetal efflux of natural auxin to agar from <i>Acer pseudoplatanus</i> L. shoots were studied. When synthetic IAA was applied to cut surfaces of one of two branches the elongation growth of buds situated on the opposite branch was retarded, suggesting regulation independent of the direct action of the molecules of the applied IAA. Oscillations in basipetal transport of natural auxin along the stem segments were observed corroborating the results of other authors using different tree species. Apical application of synthetic IAA for 1 hour to the lateral branch caused a phase shift of the wave-like pattern of basipetal efflux of natural auxin, when the stem segment above the treated branch was sectioned. The same effect was observed evoked by the laterally growing branch which is interpreted as an effect of natural auxin produced by the actively growing shoot. These modulations could be propagated acropetally at a rate excluding direct action of auxin molecules at the sites of measurement. The results seem to corroborate the hypothesis suggesting that auxin is involved in acropetal regulation of shoot apex growth through its effect upon modulation of the vectorial field which arises when the auxin-waves translocate in cambium.

scholarly journals The Influence of Location of Main Stem Segment Origin on Forcing and Rooting of Softwood Shoots of Betula nigra L.

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 890C-890 ◽  
Author(s):  
Laurie J. George* ◽  
John E. Preece
Keyword(s):  
Shoot Length ◽  
Main Stem ◽  
Stem Segment ◽  
Root Initiation ◽  
Native Trees ◽  
Adult Phase ◽  
Natural Photoperiod ◽  
Shoot Forcing ◽  
The Relationship ◽  
Stem Segments

The objective of this study was to investigate the effects of the position on the main stem that large stem segments were harvested from on forcing and subsequent rooting of Betula nigra L. (river birch) softwood shoots. The main trunks of eight adult-phase native trees (four trees per run of the experiment) were cut into 50-cm long segments from the ground up. The segments placed in horizontally in 52 × 25 × 6.5 cm (l × w × h) flats containing perlite and were positioned so the bottom one-third of the stem was within the medium. Shoots were forced under natural photoperiod and intermittent mist. This experiment was conducted twice. Data were collected weekly for fourteen weeks on the number of softwood shoots each segment produced, shoot length, number of rootable shoots (>6 cm long), the length of time that the stem segments produced rootable shoots, and the rootability of these shoots treated with 3000 ppm IBA in talc. The number of harvested shoots was greater in Run 1, with the basal segments producing the most harvestable shoots. However, the upper segments in Run 2 produced the most harvestable shoots. Softwood shoots that rooted were placed under intermittent mist. Out of the 540 harvested shoots for both runs, 82.4% rooted, with the majority of those from Run 1. Shoots harvested from this run began producing roots about 6 weeks after harvest, and continued until the end of the experiment. Run 2 shoots began root initiation about 3 weeks after harvest and ended about 2 weeks before the end of the experiment. Run 1 had an mean of 8.3 roots per shoot and Run 2 had an mean of 6.2 roots. The relationship between juvenility and shoot forcing and subsequent rooting will be discussed.

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