Bicellular Trichomes of Johnsongrass (Sorghum halepense) Leaves: Morphology, Histochemistry, and Function

Weed Science ◽  
1995 ◽  
Vol 43 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Chester G. McWhorter ◽  
Rex N. Paul ◽  
J. Clark Ouzts
Keyword(s):  
Leaf Surface ◽  
Unit Area ◽  
Grain Sorghum ◽  
Sorghum Halepense ◽  
Structural Factors ◽  
Soil Mixture ◽  
Low Concentrations ◽  
And Function ◽  
Wax Crystals ◽  
Surface Microroughness

Studies were conducted of one of the structural factors that influences microroughness on johnsongrass leaves. Bicellular trichomes, 47 ± 5 μm long, represented 4 to 5% of all epidermal cells. They secreted a mucilagenous material that covered 8 ± 4% of the leaf surface. Bicellular trichomes occurred in longitudinal rows, intermixed with intercostal cork-silica cells, between rows of stomata. Numbers of bicellular trichomes present per unit area were inversely related to numbers of intercostal cork-silica cells. The trichomes were the panicoid type that are reported not to secrete salts. Johnsongrass trichomes, however, could be induced to discharge salt in the mucilage-type secretions when plants were grown in a soil mixture that was high in lime. Not all secretory constituents were identified, but carbohydrates and callose were found in addition to possible low concentrations of protein. The apical or cap cell of the trichomes stained positively for lipid, protein, and polysaccharide and negatively for pectin, polyphenols, steroids, and alkaloids. The presence of trichomes increases leaf surface microroughness, but the secretion covers wax crystals, decreasing leaf microroughness and likely providing another barrier to herbicide entry through the cuticle. Bicellular trichomes on grain sorghum were similar to those on johnsongrass and also discharged secretions on the leaf surface.

Micromorphology of Johnsongrass (Sorghum halepense) Leaves

Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 583-589 ◽  
Author(s):  
Chester G. Mcwhorter ◽  
Clark Ouzts ◽  
Rex N. Paul
Keyword(s):  
Leaf Surface ◽  
Epicuticular Wax ◽  
Epidermal Cells ◽  
Sorghum Halepense ◽  
Single Type ◽  
Cork Cell ◽  
Silica Cell ◽  
Stomatal Complexes ◽  
Epicuticular Wax Crystals ◽  
Wax Crystals

Adaxial and abaxial epidermal surfaces of johnsongrass leaves were studied to determine which cells contribute to leaf microroughness. Cork-silica cell (CSC) pairs, three types of prickles, macrohairs, bicellular trichomes, stomata, and ordinary short and long epidermal cells were found and described. CSC pairs made up about 22% of all cells and probably contribute more to microroughness than any other single type because each cork cell produces 11 ± 3 wax filaments that are up to 100 μm long. Bicellular trichomes represented 4 to 5% of the total cells but decreased leaf roughness by secreting a type of mucilage that covers microscopic wax crystals. Stomatal complexes comprised 15 to 18% of all cells and contributed to leaf roughness because they are slightly recessed below the leaf surface. Long prickles occur primarily over veins and represent less than 1% of all cells. Small prickles were present primarily on adaxial surfaces and represent only 3% of all cells. Macrohairs were the largest appendages, 237 ± 104 μm, but they represent far less than 1% of all cells and occur primarily over veins. Ordinary short cells comprised 6 to 13% of all cells. Long cells were most common (41%) of all cells. Short and long cells contribute to leaf roughness because the surface is often convex. A typical johnsongrass leaf may contain more than 25 million appendages on each surface that increase the roughness already caused by epicuticular wax crystals.

Epicuticular Wax on Johnsongrass (Sorghum halepense) Leaves

Weed Science ◽  
1993 ◽  
Vol 41 (3) ◽  
pp. 475-482 ◽  
Author(s):  
Chester G. Mcwhorter
Keyword(s):  
Drought Stress ◽  
Relative Humidity ◽  
Leaf Blade ◽  
Unit Area ◽  
Grain Sorghum ◽  
Epicuticular Wax ◽  
Sorghum Halepense ◽  
Wax Deposition ◽  
Narrow Side ◽  
Leaf Surfaces

Studies were conducted to investigate the uniformity of epicuticular wax deposition on leaf blades of johnsongrass. Johnsongrass leaves grown under drought stress had greatly increased epicuticular wax weights compared to leaves from plants with adequate moisture, but relative humidity (95% vs. 40 ± 5%) had little effect on wax deposition. Wax weights decreased as leaves matured. Sections of lower leaf surfaces of young johnsongrass leaves tended to have more wax than sections of upper leaf surfaces, but weights were nearly equal on upper vs. lower leaf surfaces of older leaves. The narrow side of asymmetrical johnsongrass leaf blades often had more wax per unit area than the wide side. The area over the midvein contained more wax per unit area than either the narrow or wide side of the leaf blade. Greatest wax concentrations on individual leaves were over the midvein area near the leaf apex. Leaf blades of johnsongrass had more wax per unit area than leaves of corn or grain sorghum.

FEATURES OF THE PRODUCTION PROCESS OF ANCIENT AND MODERN VARIETIES OF WINTER RYE

1970 ◽  
pp. 15-19
Author(s):  
A. A. Torop ◽  
V. V. Chaykin ◽  
E. A. Torop ◽  
I. S. Brailova ◽  
S. A. Kuzmenko
Keyword(s):  
Production Process ◽  
Dry Matter ◽  
Leaf Surface ◽  
Unit Area ◽  
Biomass Accumulation ◽  
Vegetation Period ◽  
Winter Rye ◽  
Total Chlorophyll ◽  
Potential Productivity ◽  
Productivity Potential

We compared peculiarities of the production process of the older and modern(created 80 years after) sorts of winter rye. It is determined that the specific coenotic productivity of a modern sort is 60.6% higher.This increase is due to higher number of productive sprouts per unit area and higher sprout weight. The coenosis of modern sorts is highly resistant to lodging. The modern sort has a 33.5% higher leaf surface index and a 17.7% higher share of the leaves in the upper tier, differing in their erectile orientation in space. As for the content of total chlorophyll in the dry matter of leaves and vagina, the modern sort is inferior to the older by 30.2%during theearing period, and by 17.5%during the milky-wax ripeness period.As for the content of total chlorophyll in the sowing area, the compared sorts were practically the same, but the ratio between chlorophyll a and c was noticeably different. As for the chlorophyll content in stems, in dry matter and in the area of ​​sowing, the modern sort is inferior by1.5 times and more to the older in both observation terms. The sorts differed in the biomass accumulation and its distribution between the parts during the vegetation period. To establish the ear productivity, the older sort used only the current photosynthesis products.In conditions of an unfavorable growth year, the modern sort used previously accumulated by leaves and re-utilized assimilates. The actual and potential productivity of an ear in a modern sort is higher by 77.4 and 68.0%, respectively, but the degree of its vegetative mass supply is lower by 48.6%.Only due to the higher, by 77.4%, utilization of the mass of the sprout, the modern sort binds a greater number of grains in the ear with a higherseparate mass.Since the sharp increase in the ear productivity potential was not accompanied by the same growth of the sprout vegetative mass, the modern sort, in unfavorable conditions for growth, has tensions in the relation system between the sprout vegetative mass and pouring grain. This may be the reason of the unstable achievedyield level.

Weed Control in a Conservation Tillage Rotation in the Texas Blacklands

Weed Science ◽  
1987 ◽  
Vol 35 (5) ◽  
pp. 695-699 ◽  
Author(s):  
Steven M. Brown ◽  
James M. Chandler ◽  
John E. Morrison
Keyword(s):  
Control Systems ◽  
Weed Control ◽  
Conservation Tillage ◽  
Grain Sorghum ◽  
Control Measures ◽  
Sorghum Halepense ◽  
Low Intensity ◽  
No Till ◽  
Primary Tillage ◽  
And Control

A field experiment was conducted to evaluate weed control systems in a conservation tillage rotation of grain sorghum [Sorghum bicolor(L.) Moench.] – cotton (Gossypium hirsutumL.) – wheat (Triticum aestivumL.). Herbicide systems included fall and spring/summer inputs of high and low intensity. Tillage regimes were no-till (NT) and reduced-till (RT) systems; the latter included fall primary tillage followed by spring stale seedbed planting. Both tillage systems utilized controlled traffic lanes and wide, raised beds. Effective johnsongrass [Sorghum halepense(L.) Pers. # SORHA] control required intense herbicide inputs at one or both application periods, i.e., in the fall and/or spring/summer. Grain sorghum and cotton yields for the most intense weed control system, which included high inputs in both the fall and spring/summer, were not superior to systems that included high inputs in only one of the two application periods. Seedling johnsongrass emergence occurred before spring planting in RT (but not in NT) in 2 of 3 yr, and control measures were ineffective. After 3 yr, the predominant weeds were johnsongrass and browntop panicum (Panicum fasciculatumSw. # PANFA).

scholarly journals Greenhouse Evaluation of Insecticides for Control of Yellow Sugarcane Aphid and Greenbug on Sorghum Seedlings, 1994

1995 ◽  
Vol 20 (1) ◽  
pp. 230-230
Author(s):  
R. M. Anderson ◽  
G. L. Teetes
Keyword(s):  
Grain Sorghum ◽  
Hollow Cone ◽  
Soil Mixture ◽  
Insecticide Application ◽  
Sugarcane Aphid ◽  
Greenhouse Evaluation ◽  
Seedling Plant ◽  
Plant Emergence ◽  
Spray Volume ◽  
Pre Treatment

Abstract Foliar treatments of 2 organophosphates and imidachloprid (Confidor) were evaluated for yellow sugarcane aphid (YSA) and greenbug (GB) control in a research greenhouse at Texas A&M University. Hybrid grain sorghum seedlings (ATx399 × RTx430) were grown in 110-mm germination pots containing a prepared soil mixture composed of peat, vermiculite, and periite in a 2:1:1 ratio, respectively. Four days after plant emergence and 3 d prior to insecticide applications, each seedling plant was infested with 10-20 YSA or GB. There were 5 singleseedling replications for each treatment. Insecticides were applied by using a CO2-pressurized backpack sprayer, through TX-3 hollow-cone nozzles at 35 psi, producing a finished spray volume of 5.6 gpa. Pre-treatment counts of YSA and GB were made the day of insecticide application; post-treatment counts of aphids were made 1, 2, and 3 DAT. Percent control was calculated by using Abbott’s (1925) formula. Data were statistically analyzed by using ANOVA and LSD.

scholarly journals Microbial Diversity and Function in Shallow Subsurface Sediment and Oceanic Lithosphere of the Atlantis Massif

mBio ◽  
2021 ◽  
Author(s):  
J. Goordial ◽  
T. D’Angelo ◽  
J. M. Labonté ◽  
N. J. Poulton ◽  
J. M. Brown ◽  
...  
Keyword(s):  
Microbial Diversity ◽  
Oceanic Lithosphere ◽  
Global Scale ◽  
Nutrient Cycles ◽  
Subsurface Sediment ◽  
Shallow Subsurface ◽  
Low Concentrations ◽  
Atlantis Massif ◽  
And Function

The subsurface rock beneath the ocean is one of the largest biospheres on Earth, and microorganisms within influence global-scale nutrient cycles. This biosphere is difficult to study, in part due to the low concentrations of microorganisms that inhabit the vast volume of the marine lithosphere.

scholarly journals Physiological framework for adaptation of stomata to CO 2 from glacial to future concentrations

2012 ◽  
Vol 367 (1588) ◽  
pp. 537-546 ◽  
Author(s):  
Peter J. Franks ◽  
Ilia J. Leitch ◽  
Elizabeth M. Ruszala ◽  
Alistair M. Hetherington ◽  
David J. Beerling
Keyword(s):  
Leaf Surface ◽  
Unit Area ◽  
Leaf Gas Exchange ◽  
Feedback Regulation ◽  
Cell Nuclei ◽  
Short Term ◽  
Dna Amount ◽  
Taxonomic Range ◽  
Operational Range

In response to short-term fluctuations in atmospheric CO 2 concentration, c a , plants adjust leaf diffusive conductance to CO 2 , g c , via feedback regulation of stomatal aperture as part of a mechanism for optimizing CO 2 uptake with respect to water loss. The operational range of this elaborate control mechanism is determined by the maximum diffusive conductance to CO 2 , g c(max) , which is set by the size ( S ) and density (number per unit area, D ) of stomata on the leaf surface. Here, we show that, in response to long-term exposure to elevated or subambient c a , plants alter g c(max) in the direction of the short-term feedback response of g c to c a via adjustment of S and D . This adaptive feedback response to c a , consistent with long-term optimization of leaf gas exchange, was observed in four species spanning a diverse taxonomic range (the lycophyte Selaginella uncinata , the fern Osmunda regalis and the angiosperms Commelina communis and Vicia faba ). Furthermore, using direct observation as well as flow cytometry, we observed correlated increases in S , guard cell nucleus size and average apparent 1C DNA amount in epidermal cell nuclei with increasing c a , suggesting that stomatal and leaf adaptation to c a is linked to genome scaling.

Expression and function of KCNH2 (HERG) in the human jejunum

2003 ◽  
Vol 284 (6) ◽  
pp. G883-G895 ◽  
Author(s):  
A. M. Farrelly ◽  
S. Ro ◽  
B. P. Callaghan ◽  
M. A. Khoyi ◽  
N. Fleming ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Interstitial Cells Of Cajal ◽  
Circular Muscle ◽  
Slow Waves ◽  
Enteric Neurons ◽  
Longitudinal Smooth Muscle ◽  
Low Concentrations ◽  
Pair Sequence ◽  
And Function ◽  
Cells Of Cajal

Previous studies suggest that ether-a-go-go related gene (ERG) KCNH2 potassium channels contribute to the control of motility patterns in the gastrointestinal tract of animal models. The present study examines whether these results can be translated into a role in human gastrointestinal muscles. Messages for two different variants of the KCNH2 gene were detected: KCNH2 V1 human ERG (HERG) (28) and KCNH2 V2 (HERGUSO) (13). The amount of V2 message was greater than V1 in both human jejunum and brain. The base-pair sequence that gives rise to domains S3– S5 of the channel was identical to that previously published for human KCNH2 V1 and V2. KCNH2 protein was detected immunohistochemically in circular and longitudinal smooth muscle and enteric neurons but not in interstitial cells of Cajal. In the presence of TTX (10−6 M), atropine (10−6M). and l-nitroarginine (10−4 M) human jejunal circular muscle strips contracted phasically (9 cycles/min) and generated slow waves with superimposed spikes. Low concentrations of the KCNH2 blockers E-4031 (10−8 M) and MK-499 (3 × 10−8 M) increased phasic contractile amplitude and the number of spikes per slow wave. The highest concentration of E-4031 (10−6 M) produced a 10–20 mV depolarization, eliminated slow waves, and replaced phasic contractions with a small tonic contracture. E-4031 (10−6 M) did not affect [14C]ACh release from enteric neurons. We conclude that KCNH2 channels play a fundamental role in the control of motility patterns in human jejunum through their ability to modulate the electrical behavior of smooth muscle cells.

scholarly journals The Frequency of BDCA3-Positive Dendritic Cells Is Increased in the Peripheral Circulation of Kenyan Children with Severe Malaria

2006 ◽  
Vol 74 (12) ◽  
pp. 6700-6706 ◽  
Author(s):  
Britta C. Urban ◽  
Damien Cordery ◽  
Mohammed J. Shafi ◽  
Peter C. Bull ◽  
Christopher I. Newbold ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Severe Malaria ◽  
Peripheral Blood ◽  
Plasma Concentrations ◽  
Peripheral Circulation ◽  
Interleukin 10 ◽  
Low Concentrations ◽  
High Concentrations ◽  
And Function ◽  
Antigen Presenting

ABSTRACT The ability of Plasmodium falciparum-infected erythrocytes to adhere to host endothelial cells via receptor molecules such as ICAM-1 and CD36 is considered a hallmark for the development of severe malaria syndromes. These molecules are also expressed on leukocytes such as dendritic cells. Dendritic cells are antigen-presenting cells that are crucial for the initiation of adaptive immune responses. In many human diseases, their frequency and function is perturbed. We analyzed the frequency of peripheral blood dendritic cell subsets and the plasma concentrations of interleukin-10 (IL-10) and IL-12 in Kenyan children with severe malaria and during convalescence and related these parameters to the adhesion phenotype of the acute parasite isolates. The frequency of CD1c+ dendritic cells in children with acute malaria was comparable to that in healthy controls, but the frequency of BDCA3+ dendritic cells was significantly increased. Analysis of the adhesion phenotypes of parasite isolates revealed that adhesion to ICAM-1 was associated with the frequency of peripheral blood CD1c+ dendritic cells, whereas the adhesion of infected erythrocytes to CD36 correlated with high concentrations of IL-10 and low concentrations of IL-12 in plasma.

scholarly journals Transpiration and The Waxy Bloom in Brassica Oleracea L.

1970 ◽  
Vol 23 (1) ◽  
pp. 27 ◽  
Author(s):  
DW Denna
Keyword(s):  
Brassica Oleracea ◽  
Leaf Surface ◽  
Unit Area ◽  
Cuticular Waxes ◽  
Cuticular Transpiration ◽  
Wax Deposits ◽  
Brassica Oleracea L

The stomatal and cuticular transpiration rates and quantity of wax per unit area of leaf surface were determined for seven glaucous and non-glaucous sibling lines of B. oleracea. There were no statistically significant differences in the stomatal transpiration rates of the glaucous and non-glaucous lines, but there were highly statistically significant differences between the two classes of lines in terms of cuticular transpiration. Rubbing the surfaces of the leaves to remove lightly adhering wax deposits, such as the waxy bloom, significantly increased the cuticular but not the stomatal transpiration rates of both glaucous and non-glaucous plants. There was no appreciable correlation between the quantity of wax per unit area of leaf surface and the loss of water through cuticular transpiration among either the glaucous or nonglaucous lines. It was concluded that the function of cuticular waxes in limiting cuticular transpiration is a product of the architecture of the deposits and the quantity of wax per unit area of leaf surface.

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