scholarly journals Distribution of Assimilate During Stem Elongation in Wheat

1972 ◽  
Vol 25 (3) ◽  
pp. 455 ◽  
Author(s):  
JW Patrick
Keyword(s):  
Triticum Aestivum ◽  
Vascular System ◽  
Stem Elongation ◽  
Flag Leaf ◽  
Dry Weight ◽  
Triticum Aestivum L ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Stem Extension

During the phase of stem extension in plants of Triticum aestivum L. cv. Stewart, the distribution of assimilated 14C appeared to be related to sink size, proximity to the source, and a canalizing effect imposed by the vascular system on the movement between leaves. Evidence was found of a greater resistance to export from a leaf in the upward than in the downward direction and this is consistent with the observed arrangement of the sieve elements linking the bundles at the nodes. The cross� sectional area of the phloem did not appear to impose a limitation on the amount of material transported to the apex. The bulk of carbon imported by a growing leaf was consistently transported from the second lamina below. Import from other leaves continued after the emergence of a lamina and accounted for some 80% of its final dry weight and 50% of that in the attached sheath. The elongating inter-nodes 81ther side of the leaf formed large sinks for its photosynthate. Ear growth, prior to its emergence, was supported by the upper three leaves. After emergence the flag leaf was the main supplier.

Reduced cellular cross-sectional area in the leaf elongation zone of wheat causes a decrease in dry weight deposition under saline conditions

2001 ◽  
Vol 28 (2) ◽  
pp. 165 ◽  
Author(s):  
Yuncai Hu ◽  
Urs Schmidhalter
Keyword(s):  
Spatial Distribution ◽  
Leaf Growth ◽  
Dry Weight ◽  
Triticum Aestivum L ◽  
Leaf Length ◽  
Cross Sectional Area ◽  
Elongation Zone ◽  
Sectional Area ◽  
Leaf Base ◽  
Cross Sectional

Expansion and dry weight (DW) of wheat leaves are spatially distributed along the axis and affected by salinity. The objective of this study was to evaluate the effect of salinity on the spatial distribution of cellular cross-sectional area and DW in the elongating and mature leaf zones of leaf 4 of the main stem of spring wheat (Triticum aestivum L. cv. Lona) during its linear growth phase. Plants were grown in illitic–chloritic silt loam with 0 and 120 mM NaCl in a growth chamber. Cellular cross-sectional area and DW contents of leaves were determined on the 5–20-mm scale along the leaf axis. Spatial distribution of cellular cross-sectional area changed slightly with distance within the elongation zone in both treatments. The cellular cross-sectional area of the leaf at 120 mM NaCl was reduced by 32% at 5 mm, as compared with about 36% averaged from the region between 5 and 30 mm from the leaf base, indicating that the reduction in the cellular cross-sectional area by salinity occurred mainly at the leaf base when the leaf initiates. A slight decrease in the DW per leaf length at a given location in the elongation zone may be due to the strongly decreased cellular cross-sectional area by salinity. This suggests that the limitation of leaf growth by salinity may be due mainly to the effect of salinity on leaf expansion, but not due to the effect on the synthesis of dry matter.

scholarly journals Controlled Drought Affects Morphology and Anatomy of Salvia splendens

2005 ◽  
Vol 130 (5) ◽  
pp. 775-781 ◽  
Author(s):  
Stephanie E. Burnett ◽  
Svoboda V. Pennisi ◽  
Paul A. Thomas ◽  
Marc W. van Iersel
Keyword(s):  
Polyethylene Glycol ◽  
Morphological Changes ◽  
Stem Elongation ◽  
Cross Sectional Area ◽  
Vessel Element ◽  
Sectional Area ◽  
Cross Sectional ◽  
Salvia Splendens ◽  
Growing Medium ◽  
Peg 8000

Polyethylene glycol 8000 (PEG-8000) was applied to a soilless growing medium at the concentrations of 0, 15, 20, 30, 42, or 50 g·L-1 to impose controlled drought. Salvia (Salvia splendens F. Sellow. ex Roem & Shult.) seeds were planted in the growing medium to determine if controlled drought affects morphology and anatomy of salvia. Polyethylene glycol decreased emergence percentage and delayed emergence up to 5 days. Stem elongation of salvia treated with the five lowest concentrations was reduced up to 35% (21 days after seeding), and salvia were a maximum of 53% shorter and the canopy was 20% more narrow compared to nontreated seedlings 70 days after seeding. These morphological changes were attributed to PEG-8000 mediated reduction in leaf water potential (Ψw). The growing medium Ψw ranged from -0.29 to -0.85 MPa in PEG-8000 treated plants, and plant height was positively correlated with Ψw 21 days after seeding. Stem diameter of PEG-treated seedlings was reduced up to 0.4 mm mainly due to reductions in vascular cross-sectional area. Xylem cross-sectional area decreased more than stem and phloem cross-sectional area. Polyethylene glycol 8000 reduced vessel element number, but not diameter.

Effects of prolonged undernutrition on structure and function of the diaphragm

1985 ◽  
Vol 58 (4) ◽  
pp. 1354-1359 ◽  
Author(s):  
S. G. Kelsen ◽  
M. Ference ◽  
S. Kapoor
Keyword(s):  
Body Weight ◽  
Isometric Force ◽  
Dry Weight ◽  
Cross Sectional Area ◽  
Diaphragm Muscle ◽  
Sectional Area ◽  
Cross Sectional ◽  
Muscle Structure ◽  
The Cross

The present study examined the effect of prolonged undernutrition on diaphragmatic structure and force-generating ability. Studies were performed on 58 Syrian hamsters in which the feed was reduced by 33% for a 4-wk period. Sixty animals fed a similar diet ad libitum served as controls. Diaphragm muscle structure was assessed from its mass (wet and dry weight), thickness, fiber composition, and fiber size. Isometric force produced in vitro by isolated muscle strips in response to electrical stimulation of the phrenic nerve was examined over a range of muscle lengths (length-tension relationship). In undernourished animals, body weight decreased 25 +/- 5%. Diaphragm wet and dry weight, muscle thickness, and the cross-sectional area of fast-glycolytic (FG) and fast-oxidative (FO) fibers were significantly less in undernourished than control animals and correlated with reductions in body weight. The cross-sectional area of slow-oxidative (SO) fibers was the same in the two groups. The percentage of FG fibers in undernourished animals was decreased slightly and the percentage of SO fibers increased. Maximum isometric tension was reduced in undernourished animals as compared with controls, but the position and shape of the length-tension relationship was the same in the two groups. Reductions in muscle force appeared to be explained by decreases in muscle mass, since tension corrected for cross-sectional area or tissue weight was the same in the two groups. Therefore muscle mechanical efficiency appeared to be unaffected by undernutrition. These data indicate that prolonged undernutrition causes deleterious changes in diaphragm muscle structure that impair its ability to generate force.

Effects of leaf shear breaking load on the feeding value of perennial ryegrass (Lolium perenne) for sheep

1994 ◽  
Vol 123 (1) ◽  
pp. 129-136 ◽  
Author(s):  
T. Inoué ◽  
I. M. Brookes ◽  
A. John ◽  
W. F. Hunt ◽  
T. N. Barry
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Dry Weight ◽  
Breaking Load ◽  
Climatic Conditions ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Feeding Value ◽  
Two Populations

SummaryTwo populations of perennial ryegrass (PRG) (Lolium perenne L.) were selected for low (LS) and high leaf shear breaking load (HS) in 1984 at DSIR, Palmerston North. Leaf shear breaking load for the LS group was c. 41% lower than for the HS group and the LS selection had significantly shorter, narrower leaves and smaller leaf cross-sectional areas than the HS selection. LS leaves were c. 27% less resistant to shear than HS leaves per unit of cross-sectional area. The lower leaf shear strength in the LS selection was associated with a significantly lower concentration of sclerenchyma tissues in the leaf cross-sectional area compared with the HS selection. The total shear load required to break down the same dry weight of leaves to 1 mm particle size (leaf index of masticatory load) was calculated and shown to be influenced by the differences in leaf morphology. LS leaves were estimated to have a 21% lower index of masticatory load than HS leaves when both were grown under optimum climatic conditions.

Identification of quantitative trait loci for traits conferring weed competitiveness in wheat (Triticum aestivum L.)

2001 ◽  
Vol 52 (12) ◽  
pp. 1235 ◽  
Author(s):  
R. K. Coleman ◽  
G. S. Gill ◽  
G. J. Rebetzke
Keyword(s):  
Triticum Aestivum ◽  
Quantitative Trait Loci ◽  
Grain Yield ◽  
Quantitative Trait ◽  
Morphological Traits ◽  
Competitive Ability ◽  
Stem Elongation ◽  
Flag Leaf ◽  
Triticum Aestivum L ◽  
Ryegrass Growth

As weeds develop resistance to a broad range of herbicides, wheat (Triticum aestivum L.) cultivars with superior weed competitive capacity are needed to complement integrated weed management strategies. In this study, agronomic and morphological traits that enable wheat to compete effectively with weeds were identified. Halberd, Cranbrook, and 161 Cranbrook x Halberd doubled haploid (DH) lines were examined in field experiments conducted over two growing seasons. The weed species Lolium rigidum L. (annual ryegrass) was sown in strips perpendicular to the direction of wheat seeding. Various traits were measured during each season with competitive ability determined by both percent loss in wheat grain yield and suppression of ryegrass growth. Width of leaf 2, canopy height, and light interception at early stem elongation (Z31), and tiller number, height at maturity, and days to anthesis were important for competitive ability in 1999. In the previous year, length of leaf 2 and size of the flag leaf contributed to competitiveness. Seasonal effects appeared to have some impact on the relative contribution of crop traits to competitive ability. The morphological traits involved in maintaining grain yield differed from those that contributed to the suppression of ryegrass growth. Development of the Cranbrook x Halberd chromosomal linkage map enabled the putative identification of quantitative trait loci (QTL) associated with competitive ability in the DH population. Many of the QTL were mapped to similar positions in both years. Further, several traits, including time to anthesis, flag leaf size, height at stem elongation, and the size of the first 2 leaves, were mapped to similar positions on chromosomes 2B and 2D. Narrow-sense heritabilities on an entry-mean basis were typically high within each year for traits associated with weed competitive ability. However, large genotype x year interactions reduced these heritabilities, making genetic gain through phenotypic selection difficult. The identification of QTL repeatable over seasons indicates the potential for marker-assisted selection in a wheat breeding program selecting for improved grain yield and weed competitiveness.

scholarly journals 583 Field performance of Grafted Chestnut Cultivars and their Seedlings

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 547B-547
Author(s):  
Rachel Byard ◽  
Ian A. Merwin
Keyword(s):  
Mortality Rate ◽  
Interspecific Hybrid ◽  
Field Performance ◽  
Dry Weight ◽  
Cross Sectional Area ◽  
First Year ◽  
Sectional Area ◽  
Cross Sectional ◽  
Yield Efficiency ◽  
The Third

We planted grafted and seedling chestnuts of six cultivars in Lansing, N.Y., in April 1995 to evaluate performance of the different cultivars in our region and to compare grafted and seedling trees. We used the following cultivars: the Chinese chestnut cultivar Mossbarger (Castanea mollissima) and five interspecific hybrid cultivars [Douglas 1A (C. mollissima × C. dentata), Eaton [C. mollissima × (C. crenata × C. dentata)[, Skioka (C. mollissima × C. sativa), Layeroka (open-pollinated daughter of `Skioka'), and Grimo 142Q (an open pollinated daughter of `Layeroka')]. Growth was not significantly different between cultivars. There were no notable correlations between trunk cross-sectional area at planting and any measurement after the first year. Significant differences between cultivars were found for mortality, yield, and yield efficiency. `Eaton' had the lowest mortality rate (2%) of all cultivars. `Grimo 142Q' and `Layeroka' had the highest dry weight yields and the greatest yield efficiencies, although `Grimo 142Q' had significantly larger nuts than `Layeroka'. In 1998, the largest nuts (5.2 g) were harvested from `Mossbarger' and `Eaton trees'. `Skioka' had the highest mortality (48%), lowest yield, lowest yield efficiency, and smallest nut size. In the first 2 years, most grafted trees showed significantly higher yields and greater yield efficiency than seedling trees. By the third year, differences in yield between grafted and seedling trees were no longer significant for most cultivars. Over the 3 years most grafted trees revealed higher mortality and slower growth than seedlings of the same cultivar. Seedlings did not show more variability in measurements than grafted trees of the same cultivar.

Effects of sowing method on survival, ion uptake and yield of wheat (Triticum aestivum L.) in sodic soils

2000 ◽  
Vol 134 (4) ◽  
pp. 369-378 ◽  
Author(s):  
I. RAJPAR ◽  
D. WRIGHT
Keyword(s):  
Triticum Aestivum ◽  
Grain Yield ◽  
Flag Leaf ◽  
Dry Weight ◽  
Triticum Aestivum L ◽  
Economic Feasibility ◽  
Ion Uptake ◽  
Loamy Sand ◽  
Clay Loam ◽  
Sodic Soils

Two separate experiments, in clay loam and loamy sand (prepared by mixing the clay loam with washed sand), were performed to determine the effects of sowing method and sodicity on the survival, ion uptake, grain yield and yield components of spring wheat (Triticum aestivum L.) cv. Kharchia- 65. Three sodicity levels (control, exchangeable sodium percentage (ESP) 5–7; low (ESP 18–20); high (ESP 39–40)) and four sowing methods (sowing dry and pre-germinated seed and transplanting of 16 and 21-day-old seedlings) were tested. In the control and at low sodicity, sowing method had no effect on plant survival, grain and straw dry weight per plant. However at high sodicity, these variables were lower in plants established from pre-germinated seed than in plants established from dry seed, the farmers' normal practice. In contrast, transplanted seedlings showed increased survival and had significantly higher grain and straw dry weight than plants established by sowing dry seed. Differences in grain yield between sowing method and sodicity treatments were mainly due to differences in the number of grains per plant. Although increasing sodicity was associated with higher concentration of Na+, and lower concentrations of K+, Ca2+, Mg2+ and lower K+/Na+ ratio in flag leaf sap, ion concentrations were unaffected by sowing method.It is suggested that the increased survival and yield of transplanted seedlings is due to the fact that they are not exposed to sodicity during the sensitive stages of germination and emergence. In addition, their already established roots and shoots may be better able to capture the resources required to support their subsequent growth. The decreases in grain and straw dry weight per plant, and the increases in these parameters achieved by transplanting seedlings instead of sowing dry seed, were greater in clay loam than in loamy sand. Further studies are required to determine whether the responses to transplanting observed here also occur in sodic soils under field conditions, and to investigate the technical and economic feasibility of adopting this technique in commercial agriculture.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

DETERMINATION OF THE FUNCTION OF THE ROD’S CROSS-SECTIONAL AREA USING VIBRATION EIGENFREQUENCIES

2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Variable Cross ◽  
Sectional Area ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Method Error ◽  
Various Boundary Conditions ◽  
Elastic Fixation ◽  
Crosssectional Area

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

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