Lateral movement out of the sieve tubes and its effect on the 14C translocation profile in Helianthus seedlings

Planta ◽  
1970 ◽  
Vol 95 (3) ◽  
pp. 247-263 ◽  
Author(s):  
Catherine M. Whittle
Keyword(s):  
Lateral Movement ◽  
Sieve Tubes

Heat-induced callose and lateral movement of assimilates from phloem

1968 ◽  
Vol 46 (10) ◽  
pp. 1215-1220 ◽  
Author(s):  
D. H. Webster ◽  
H. B. Currier
Keyword(s):  
Dark Period ◽  
Lateral Movement ◽  
Localized Heating ◽  
Sieve Tubes ◽  
Cotyledonary Petioles

Brief localized heating of cotton cotyledonary petioles increased phloem callose and decreased lateral movement of 14C-assimilates. There was little or no increase in phloem callose when plants were heated directly after a dark period of 16 or more hours. Such heated low-callose petioles had more lateral movement than heated high-callose petioles. Phloem callose and lateral movement returned to normal within 1 day after heating. These results suggest that phloem callose caused part of the decrease of lateral movement in heated high-callose petioles. Excessive phloem callose would be expected to restrict lateral movement, if movement from sieve tubes were via plasmodesmata.

scholarly journals Evaluation of dsRNA delivery methods for targeting macrophage migration inhibitory factor MIF in RNAi-based aphid control

2021 ◽  
Author(s):  
Shaoshuai Liu ◽  
Maria Jose Ladera-Carmona ◽  
Minna M. Poranen ◽  
Aart J. E. van Bel ◽  
Karl-Heinz Kogel ◽  
...  
Keyword(s):  
Immune Responses ◽  
Artificial Diet ◽  
Sieve Tube ◽  
Feeding Strategies ◽  
Macrophage Migration ◽  
Delivery Methods ◽  
Host Immune Responses ◽  
Aphid Control ◽  
Barley Leaves ◽  
Sieve Tubes

AbstractMacrophage migration inhibitory factors (MIFs) are multifunctional proteins regulating major processes in mammals, including activation of innate immune responses. In invertebrates, MIF proteins participate in the modulation of host immune responses when secreted by parasitic organisms, such as aphids. In this study, we assessed the possibility to use MIF genes as targets for RNA interference (RNAi)-based control of the grain aphid Sitobion avenae (Sa) on barley (Hordeum vulgare). When nymphs were fed on artificial diet containing double-stranded (ds)RNAs (SaMIF-dsRNAs) that target sequences of the three MIF genes SaMIF1, SaMIF2 and SaMIF3, they showed higher mortality rates and these rates correlated with reduced MIF transcript levels as compared to the aphids feeding on artificial diet containing a control dsRNA (GFP-dsRNA). Comparison of different feeding strategies showed that nymphs’ survival was not altered when they fed from barley seedlings sprayed with naked SaMIF-dsRNAs, suggesting they did not effectively take up dsRNA from the sieve tubes of these plants. Furthermore, aphids’ survival was also not affected when the nymphs fed on leaves supplied with dsRNA via basal cut ends of barley leaves. Consistent with this finding, the use of sieve tube-specific YFP-labeled Arabidopsis reporter lines confirmed that fluorescent 21 nt dsRNACy3, when supplied via petioles or spraying, co-localized with xylem structures, but not with phloem tissue. Our results suggest that MIF genes are a potential target for insect control and also imply that application of naked dsRNA to plants for aphid control is inefficient. More efforts should be put into the development of effective dsRNA formulations.

Uncovering Lateral Movement using Authentication Logs

2021 ◽  
pp. 1-1
Author(s):  
Haibo Bian ◽  
Tim Bai ◽  
Mohammad A. Salahuddin ◽  
Noura Limam ◽  
Abbas Abou Daya ◽  
...  
Keyword(s):  
Lateral Movement

scholarly journals Redistribution of ground subtracks for aircraft noise calculations

Noise Mapping ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 146-153
Author(s):  
Olivier Schwab
Keyword(s):  
Lower Number ◽  
Aircraft Noise ◽  
Lateral Movement ◽  
Limited Information ◽  
Geometric Matching ◽  
Final Output

AbstractFor aircraft noise calculations, lateral flight dispersion is commonly represented by means of subtracks – a backbone track and side-tracks to each side of the backbone track – where each subtrack is assigned a movement percentage. Aircraft noise calculations impose quality demands on these subtracks, while the latter are often created based on limited information.This paper presents a method to increase flexibility when designing subtracks. The method allows to redistribute subtracks geometrically, allowing for the design of simplified track representations, for instance through a lower number of subtracks and very basic indications of movement allocations. The method is based on the geometric matching of the initial subtracks and on the estimation of the lateral movement distributions for both input and final output subtracks. No restrictions on the number of sub-tracks or on the shape of the distributions are needed, neither for the input nor for the output. A number of examples of the redistribution and its effect on aircraft noise calculations are discussed.

Biomechanics of Arytenoid Adduction Surgery in an Ex Vivo Canine Model

1998 ◽  
Vol 107 (6) ◽  
pp. 454-461 ◽  
Author(s):  
J. Pieter Noordzij ◽  
Donald F. Perrault ◽  
Peak Woo
Keyword(s):  
Vocal Fold ◽  
Ex Vivo ◽  
Canine Model ◽  
Vocal Fold Paralysis ◽  
Lateral Movement ◽  
Arytenoid Adduction ◽  
Vocal Process ◽  
Process Procedures ◽  
Suture Tension

The biomechanics of arytenoid adduction surgery are not well understood. An excised canine larynx model was used to study the effects of variable suture tension on glottal configuration and on vocal fold tension (at the midfold and the vocal process). Arytenoid adduction both medializes the vocal fold and closes a posterior glottal chink. Vocal fold tension at the midfold did not vary significantly with suture tension. As suture tension increased to approximately 100 g, vocal fold tension at the vocal process also increased. Beyond 100 g of suture tension, vocal fold tension at the vocal process did not increase. We conclude that the effects of suture tension on the resistance to lateral movement are different at the midfold compared to the vocal process. Procedures for surgical rehabilitation of vocal fold paralysis should address the biomechanical subunits of the larynx individually in order to achieve optimum results.

WITHIN–TREE VARIATION IN PHLOEM CELL DIMENSIONS AND PROPORTIONS IN EUCALYPTUS GLOBULUS

IAWA Journal ◽  
2000 ◽  
Vol 21 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Teresa Quilhó ◽  
Helena Pereira ◽  
Hans Georg Richter
Keyword(s):  
Wall Thickness ◽  
Eucalyptus Globulus ◽  
Tree Height ◽  
Sieve Tube ◽  
Bark Thickness ◽  
Cell Type ◽  
Fibre Width ◽  
Axial Variation ◽  
Sieve Tubes ◽  
Old Trees

The axial variation of bark thickness and quantitative anatomical features of Eucalyptus globulus bark were analysed for one site based on individual measurements of ten 15-year-old trees at six height levels (DBH, 5%, 15%, 35%, 55% and 75% of total tree height). The parameters studied were: length, tangential diameter and percentage of sieve tubes; length, width, cell wall thickness and percentage of fibres; height and percentage of rays; percentage of sclereids in the secondary phloem. Bark thickness decreases from base to top of the tree. Fibre width and wall thickness decrease from base upwards. No distinct axial patterns of variation were observed for the other biometric variables studied. Parenchyma is the main cell type of the bark (50%) followed by fibres (27.9%), rays (12.1%), sieve tubes (2.7%), and sclereids (7.3%). The cell type proportions vary significantly within the tree, i.e., parenchyma, ray and sclereid proportions decrease, fibre and sieve tube proportions increase towards the top of the tree.

Localisation par autoradiographie de l'acide [5-3H]indole-3-acétique dans le bourgeon terminal du Lycopersicum esculentum

1984 ◽  
Vol 62 (6) ◽  
pp. 1149-1157 ◽  
Author(s):  
D. Driss-Ecole ◽  
G. Perbal ◽  
Y. Leroux
Keyword(s):  
Total Radioactivity ◽  
Lycopersicum Esculentum ◽  
Meristematic Cells ◽  
Differentiated Cells ◽  
Apical Bud ◽  
Ethylcarbodiimide Hydrochloride ◽  
Meristematic Activity ◽  
Sieve Tubes ◽  
Whole Plants ◽  
Label Distribution

[3H]indoleacetic acid (AIA) was applied to the shoot tip of intact young plants of Tomato (Lycopersicum esculentum Mill.) for 10, 60, or 120 min. Autoradiograms of whole plants were prepared and liquid scintillation counts of stem segments and principal root segments were performed. Chromatographic analysis showed that 66% of the radioactivity was associated with AIA after 120 min of contact with [3H]AIA. Autoradiographs of semithin and ultrathin sections were prepared after treatment by DCC (1-(3-dimethyl-aminopropyl)-3-ethylcarbodiimide hydrochloride). The quantity of label per cell and the density of label were determined for all tissues of the apical bud. The density of label was greater for meristematic cells than for differentiated cells. The observed homogeneity of label distribution in the apical meristem shows that auxin levels do not play a prominent role in distinguishing between its lateral and axial zones. The density of label was similar in the apical and in the axillary bud of leaf 4. The cells of the rib meristem, which elongate to produce pith, were more intensely labelled than the other meristematic cells. The percentage of label was calculated for each tissue in a transverse section of the stem just below the apex. The amount of auxin was greatest in the parenchyma (axial and cortical) with lesser amounts in the procambium, phloem parenchyma, and xylem parenchyma. Vessels, which had the greatest density of label, did not contain more than about 3% of total radioactivity of the stem section, while sieve tubes had only 0.5%. Pathways of auxin transport and the role of AIA in regulating meristematic activity in the apical bud are discussed.

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