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.

Variability of Bark Structure in Plantation-Grown Eucalyptus Globulus

IAWA Journal ◽  
1999 ◽  
Vol 20 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Teresa Quilhó ◽  
Helena Pereira ◽  
Hans Georg Richter
Keyword(s):  
Eucalyptus Globulus ◽  
Sieve Tube ◽  
Variable Number ◽  
Tree Age ◽  
Phloem Parenchyma ◽  
Age Related ◽  
Parenchyma Cells ◽  
Axial Variation ◽  
Bark Structure ◽  
Old Trees

The bark structure of Eucalyptus globulus Labill. grown in plantations in Central Portugal is described, based on specimens extracted at six height levels from ten 15-year-old trees. No significant variation of qualitative features between trees was observed. The non-collapsed phloem is characterised by multiseriate tangential rows of phloem parenchyma alternating with rows of phloem fibres, interspersed with large sieve tubes and their respective companion cells, and uniseriate rays . With the onset of sieve tube collapse (collapsed phloem ), some parenchyma cells expand and sclerify, the course of rays becomes irregular, and ray dilatation is initiated. The periderm is composed of a phellem of lignified cells with horseshoe thickening (phelloids), followed by a layer of cells with suberised tangential walls, and a phelloderm with a variable number of layers of thin-walled cells. Age-related secondary changes give rise to a specific within-tree pattern of axial variation. Both the intensity of sclerification of phloem parenchyma cells and the degree of ray dilatation increase with tree age.

Within-Tree Variation in Wood Fibre Biometry And Basic Density of the Urograndis Eucalypt Hybrid (Eucalyptus Grandis × E. Urophylla)

IAWA Journal ◽  
2006 ◽  
Vol 27 (3) ◽  
pp. 243-254 ◽  
Author(s):  
Teresa Quilhó ◽  
Isabel Miranda ◽  
Helena Pereira
Keyword(s):  
Wall Thickness ◽  
Fibre Length ◽  
Eucalyptus Grandis ◽  
Basic Density ◽  
Wood Properties ◽  
Axial Variation ◽  
Average Fibre ◽  
Length Width ◽  
Hybrid Eucalyptus ◽  
Old Trees

Within-tree variations in fibre length, width, wall thickness and wood basic density of Eucalyptus grandis × E. urophylla (urograndis) were studied in five 6.8-yr-old seedling trees and five 5.6-yr-old trees from one clone from Brazil. Samples were taken at 5%, 25%, 35%, 55%, 65% and 90% of stem height and five radial positions (10%, 30%, 50%, 70% and 90% of radius). The tree average fibre length, width and wall thickness were in seed and clone trees: 0.955 mm and 1.064 mm, 18 μm and 20 μm, 3.6 μm and 4.4 μm respectively. The axial variation of fibre dimensions was very low, while there was a consistent but small increasing trend from pith to periphery. The basic density ranged from 397–464 kg/m3 to 486–495 kg/m3 respectively in seedling and clone trees with a low variation along the stem. In comparison with other eucalypt pulpwood, e.g. E. globulus, the urograndis hybrid showed similar fibre dimensions and lower basic density. Overall the within-tree variation of these wood properties was low and age had a small impact on the variation of density and fibre dimensions.

scholarly journals Wood and bark fiber characteristics of Acacia melanoxylon and comparison to Eucalyptus globules

CERNE ◽  
2011 ◽  
Vol 17 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Fatima Tavares ◽  
Teresa Quilhó ◽  
Helena Pereira
Keyword(s):  
Cell Wall ◽  
Wall Thickness ◽  
Eucalyptus Globulus ◽  
Fiber Length ◽  
Tree Height ◽  
Specific Pattern ◽  
Cell Wall Thickness ◽  
Wood Fibers ◽  
Acacia Melanoxylon ◽  
Fiber Wall

Wood and bark fibers of Acacia melanoxylon were characterized and compared to Eucalyptus globulus which is a major quality source of pulp fibers. In 20 trees from four sites, fiber length and wall thickness were measured at 5, 35 and 65% of total tree height and at 10, 30, 50, 70 and 90% of the distance from pith. Maceration were prepared in a 1:1 glacial acetic acid:hydrogen peroxide solution. Wood and bark fiber length varied between 0.90 - 0.96 mm and 1.33 - 1.59 mm respectively. The cell wall thickness varied between 3.45 - 3.89 µm in wood and 5.01 - 5.40 µm in bark. Wood and bark fiber length decreased from the bottom to the top of the tree and cell wall thickness had no specific pattern for axial variation. Fiber length and wall thickness increased from the pith to the bark, but the wall thickness increased slightly with some fluctuations. In Acacia melanoxylon significant site differences were found in relation to bark fiber length and to wood wall thickness. The fibers of Acacia melanoxylon were similar to those of Eucalyptus globulus but the wood fibers were thinner and the bark fibers thicker. The radial variation was similar in both species. In wood of Eucalyptus globulus, fiber wall thickness increases from the base to the middle of tree height and decreases to the top; in the bark decreases from the base to the top. In Eucalyptus globulus fibers bark are higher in the top.

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.

Studies on the Feeding and Nutrition of Tuberolachnus Salignus (Gmelin) (Homoptera, Aphididae):

1957 ◽  
Vol 34 (3) ◽  
pp. 334-341
Author(s):  
T. E. MITTLER
Keyword(s):  
Host Plant ◽  
Sieve Tube ◽  
Normal Rate ◽  
Phloem Sap ◽  
Food Canal ◽  
Tuberolachnus Salignus ◽  
Normal Feeding ◽  
Sieve Tubes ◽  
Considerable Pressure ◽  
Salix Spp

1. A study has been made of the factors involved in the uptake of phloem sap by Tuberolachnus salignus (Gmelin) feeding on the stems of various Salix spp. 2. A method has been developed for maintaining the parthenogenetic viviparous forms of T. salignus in culture throughout the year. 3. It has been established that during normal feeding T. salignus have the tips of their stylets inserted into the phloem sieve-tubes of the host plant. 4. The phloem sieve-tube sap of intact and turgid willow stems is under considerable pressure. This pressure forces the sieve-tube mp up the stylet food canal of feeding aphids, and also causes the sieve-tube sap to exude for many hours from the cut end of embedded stylet bundles. 5. Intact and feeding T. salignus rely almost entirely on this pressure to maintain their normal rate of eieve-tube sap uptake. The aphids must, however, swallow actively in order to ingest.

ANATOMICAL CHARACTERISATION AND VARIABILITY OF THE THISTLE CYNARA CARDUNCULUS IN VIEW OF PULPING POTENTIAL

IAWA Journal ◽  
2004 ◽  
Vol 25 (2) ◽  
pp. 217-230 ◽  
Author(s):  
Teresa Quilhó ◽  
Jorge Gominho ◽  
Helena Pereira
Keyword(s):  
Wall Thickness ◽  
Anatomical Variation ◽  
Fibre Length ◽  
Vessel Element ◽  
Slight Variation ◽  
Vascular Bundles ◽  
Cynara Cardunculus ◽  
Fibrous Sheath ◽  
Fibre Wall ◽  
Fibre Width

The thistle Cynara cardunculus L. is an herbaceous perennial with high productivity that is harvested annually and is a potential fibre crop for paper pulp production. The anatomical variation within stalks was studied (base, middle and top) and compared in C. cardunculus plants at different development phases. The stalk of C. cardunculus includes an epidermis, cortex and a central cylinder with fibro-vascular bundles with phloem, xylem and a fibrous sheath that is variable in arrangement and size within and between plants.At harvest, the pith represents 37% of the stalk transectional area and 7% of the total weight. There was a slight variation in quantitative features of, respectively, the three development groups studied; mean fibre length was 1.04 mm, 0.95 mm and 1.05 mm; mean fibre width was 15 μm, 16 μm and 21 μm; mean fibre wall thickness was 3.2 μm, 3.4 μm and 4.9 μm. Fibre length and width decreased within the stem from base to top, while fibre wall thickness increased. Mean vessel diameter was 22 μm and mean vessel element length 220–483 μm. In mature plants, parenchyma represents 39% of the total transectional area and fibres 25%. The proportion of fibres increases during plant development and in mature plants is highest at the stalk base.As regards anatomical features, Cynara stalks compare favourably to other annual plants and fibre biometry indicates good potential for paper sheet forming and strength properties.

Application of resistance drilling to genetic studies of growth, wood basic density and bark thickness in Eucalyptus globulus

2020 ◽  
Vol 83 (3) ◽  
pp. 172-179
Author(s):  
H. Nickolas ◽  
D. Williams ◽  
G. Downes ◽  
P. A. Harrison ◽  
R. E. Vaillancourt ◽  
...  
Keyword(s):  
Eucalyptus Globulus ◽  
Basic Density ◽  
Bark Thickness ◽  
Genetic Studies ◽  
Wood Basic Density ◽  
Resistance Drilling

Micro versus nanochannels: carbon micro-sieve tubes from biological phloem tissues for lithium–oxygen batteries

2020 ◽  
Vol 22 (2) ◽  
pp. 388-396 ◽  
Author(s):  
Zhuang Sun ◽  
Yuchen Zhang ◽  
Bin Sun ◽  
Chushu Yang ◽  
Tao Zhang
Keyword(s):  
Sieve Tube ◽  
Phloem Tissue ◽  
Sieve Tubes ◽  
Stability Issues ◽  
Lithium Oxygen Batteries

Microscale sieve-tube carbon from biological phloem tissue goes much beyond nanoscale channel carbon, avoiding clogging and alleviating stability issues.

scholarly journals The Effect of Crown Social Class on Bark Thickness and Sapwood Moisture Content in Norway Spruce

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1316
Author(s):  
Luka Krajnc ◽  
Jožica Gričar
Keyword(s):  
Social Class ◽  
Moisture Content ◽  
Norway Spruce ◽  
Research Study ◽  
Physiological State ◽  
Tree Height ◽  
Social Classes ◽  
Bark Thickness ◽  
Individual Tree ◽  
The Relationship

The research study examined the effect of tree properties (crown social class, diameter at breast height (DBH), and tree height) on bark thickness (BT) and sapwood moisture content (SMC) in Norway spruce (Picea abies (L.) H. Karst.). Both examined variables were shown to be positively affected by DBH and tree height. The relationship between DBH and SMC varied among crown social classes, while the relationship between DBH and BT was relatively constant across crown social classes. Crown social class had a relatively small effect on BT and SMC, having a more pronounced effect on SMC than on BT. The relationship between tree height and BT did not vary across crown social classes, while the relationship between SMC and tree height was found to change slightly across crown social classes. Measurements of BT and SMC in the field are affordable, fast, and easy to use. Both variables could potentially be used to improve predictions of bark beetle attacks, as they reflect the physiological state of an individual tree.

Über den Zuckergehalt der Siebröhren- bzw. Siebzellensäfte von Heracleum Mantegazzianum und Picea abies (L.) KARST.

1959 ◽  
Vol 14 (4) ◽  
pp. 278-281 ◽  
Author(s):  
Hubert Ziegler ◽  
Tom E. Mittler
Keyword(s):  
Picea Abies ◽  
Sieve Tube ◽  
Vascular Bundles ◽  
Heracleum Mantegazzianum ◽  
Sieve Tubes

Sieve-tube sap from the petioles of Heracleum Mantegazzianum and Picea abies stems was obtained by severing the proboscides of aphids tapping the sieve tubes of these plants. Sucrose was the only sugar detected in the sieve-tube sap, and occurred at concentrations of 24% (Heracleum) and 10% (w/v) (Picea). Volumes of sieve-tube sap equal to 5500 sieve-tube cells of Heracleum and 50 sievetube cells of Picea exuded from severed aphid probiscides.The mouth-parts of the aphids living within hollow Heracleum petioles normally penetrate the xylem of the vascular bundles in order to reach the phloem sieve-tubes. The aphids also tap the sievetubes of isolated phloem strands.

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