scholarly journals The Regulation of Cambial Division and Secondary Xylem Differentiation in Xanthium by Auxins and Gibberellin

1971 ◽  
Vol 47 (3) ◽  
pp. 417-422 ◽  
Author(s):  
Terry L. Shininger
Keyword(s):  
Secondary Xylem ◽  
Xylem Differentiation

scholarly journals Analysis of xylem formation in pine by cDNA sequencing

1998 ◽  
Vol 95 (16) ◽  
pp. 9693-9698 ◽  
Author(s):  
Isabel Allona ◽  
Michelle Quinn ◽  
Elizabeth Shoop ◽  
Kristi Swope ◽  
Sheila St. Cyr ◽  
...  
Keyword(s):  
Cell Wall ◽  
Loblolly Pine ◽  
Secondary Xylem ◽  
Expression Patterns ◽  
Wood Formation ◽  
Xylem Differentiation ◽  
Cell Wall Proteins ◽  
Powerful Means ◽  
Xylem Formation ◽  
Enzymes Of Carbohydrate Metabolism

Secondary xylem (wood) formation is likely to involve some genes expressed rarely or not at all in herbaceous plants. Moreover, environmental and developmental stimuli influence secondary xylem differentiation, producing morphological and chemical changes in wood. To increase our understanding of xylem formation, and to provide material for comparative analysis of gymnosperm and angiosperm sequences, ESTs were obtained from immature xylem of loblolly pine (Pinus taeda L.). A total of 1,097 single-pass sequences were obtained from 5′ ends of cDNAs made from gravistimulated tissue from bent trees. Cluster analysis detected 107 groups of similar sequences, ranging in size from 2 to 20 sequences. A total of 361 sequences fell into these groups, whereas 736 sequences were unique. About 55% of the pine EST sequences show similarity to previously described sequences in public databases. About 10% of the recognized genes encode factors involved in cell wall formation. Sequences similar to cell wall proteins, most known lignin biosynthetic enzymes, and several enzymes of carbohydrate metabolism were found. A number of putative regulatory proteins also are represented. Expression patterns of several of these genes were studied in various tissues and organs of pine. Sequencing novel genes expressed during xylem formation will provide a powerful means of identifying mechanisms controlling this important differentiation pathway.

Surgical studies on growth and xylem differentiation in the cotyledonary shoots of flax

1978 ◽  
Vol 56 (5) ◽  
pp. 476-482 ◽  
Author(s):  
M. V. S. Raju ◽  
W. N. Marchuk ◽  
Patricia L. Polowick
Keyword(s):  
Linum Usitatissimum ◽  
Secondary Xylem ◽  
Xylem Differentiation ◽  
Primary Xylem ◽  
The Third ◽  
Lateral Shoots

Growth and xylem differentiation in cotyledonary shoots were studied by partially isolating one shoot surgically in nondecapitated and decapitated flax plants (Linum usitatissimum var. noralta). Three types of cuts were made. The first type separated the shoot from the hypocotyl and the second from the epicotyl. The third type of cut was made at the node separating the two shoots, which, however, remained independently connected with the hypocotyl and epicotyl. In nondecapitated plants, the lateral shoots were inhibited. They had at their bases primary xylem strands, some of which were connected with the hypocotylary stele; the strands contained predominantly tracheids. In decapitated plants, the separated shoot grew vigorously when it was connected with both hypocotyl and epicotyl or hypocotyl alone. Such shoots contained at their bases abundant secondary xylem strands which were connected with the hypocotylary stele; the strands included predominantly vessels. The shoot that was isolated from the hypocotyl but connected with the epicotyl was inhibited even though it had abundant secondary xylem strands at its base. Results of this study suggest that growth of the cotyledonary shoot is dependent on the prior development of adequate xylem connections with the hypocotylary stele.

AtCyclinD enhances secondary xylem differentiation and evaluation of mitotic activity in cambium using Cyclin-GUS fusion protein constructed from poplar

2010 ◽  
Vol 150 ◽  
pp. 506-507
Author(s):  
Takeo Fujii ◽  
Kanna Sato ◽  
Nobuyuki Nishikubo ◽  
Noriko Matsui ◽  
Takayuki Furuichi ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Mitotic Activity ◽  
Secondary Xylem ◽  
Xylem Differentiation

scholarly journals Proteolytic activity in the stem cambial region of Pinus sylvestris L. - A contribution to the specific differentiation of secondary xylem and phloem

2014 ◽  
Vol 63 (3-4) ◽  
pp. 247-253 ◽  
Author(s):  
Krzysztof J. Rakowski ◽  
Tomasz J. Wodzicki
Keyword(s):  
Pinus Sylvestris ◽  
Protease Inhibitor ◽  
Electrophoretic Mobility ◽  
Proteolytic Activity ◽  
Secondary Xylem ◽  
Cambial Activity ◽  
The Other ◽  
Xylem Differentiation ◽  
Phloem Tissue ◽  
Ph Optimum

Proteolytic activity was studied in the differentiating xylem and phloem of Scots pine (<i>Pinus sylvestris</i> L.) to determine the specificity of xylem and phloem differentiation. The activity of autolytic proteases was demonstrated in the differentiating xylem during spring, summer and autumn and it was not detectable during winter. It was initiated with the onset of cambial activity in spring and unchanged during subsequent stages of xylem differentiation. The same proteolytic activity was not detectable in the extract of fresh phloem tissue. It could be detected in phloem after removal of the inhibitor found in the extract. The same pH optimum was determined for proteases extracted from xylem and phloem. However, their identity remains uncertain because of different electrophoretic mobility. On the other hand the presence of protease inhibitor in phloem tissue can be an important factor im determining the specificity of xylem an phloem differentiation.

scholarly journals Brassinosteroids Promote Parenchyma Cell and Secondary Xylem Development in Sugar Beet (Beta vulgaris L.) Root

2020 ◽  
Author(s):  
Wei Wang ◽  
Yaqing Sun ◽  
Guolong Li ◽  
Shaoying Zhang
Keyword(s):  
Sugar Beet ◽  
Beta Vulgaris ◽  
Secondary Xylem ◽  
Parenchyma Cell ◽  
Root Diameter ◽  
Vascular Bundles ◽  
Xylem Differentiation ◽  
Root Structure ◽  
Growth Promoting ◽  
Cambial Cells

AbstractIncreasing crop yield has always been an important goal in agriculture. Brassinosteroids (BRs) are growth-promoting steroid hormones with vital roles in many root developmental processes. Sugar beet (Beta vulgaris L.) is a root crop with a tertiary root structure. The differentiation of vascular bundles and division of cambial cells increases root diameter. However, little is known about how BRs regulate the transverse growth of beetroot. Therefore, sugar beet with eight leaves was grown in medium containing epibrassinolide or brassinazole, an inhibitor of brassinosteroid biosynthesis. BRs increased the spacing between the cambial rings by increasing the size of parenchyma cells between the rings and ultimately increasing root diameter. BRs also promoted secondary xylem differentiation. These findings indicate that brassinosteroids function in transverse development in beetroot.

scholarly journals Functional Characterisation of the Poplar Atypical Aspartic Protease Gene PtAP66 in Wood Secondary Cell Wall Deposition

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1002
Author(s):  
Shenquan Cao ◽  
Cong Wang ◽  
Huanhuan Ji ◽  
Mengjie Guo ◽  
Jiyao Cheng ◽  
...  
Keyword(s):  
Cell Wall ◽  
Secondary Cell Wall ◽  
Fluorescent Protein ◽  
Secondary Xylem ◽  
Populus Trichocarpa ◽  
Wood Formation ◽  
Protease Gene ◽  
Cellulose Content ◽  
Transcription Analysis ◽  
Functional Characterisation

Secondary cell wall (SCW) deposition is an important process during wood formation. Although aspartic proteases (APs) have been reported to have regulatory roles in herbaceous plants, the involvement of atypical APs in SCW deposition in trees has not been reported. In this study, we characterised the Populus trichocarpa atypical AP gene PtAP66, which is involved in wood SCW deposition. Transcriptome data from the AspWood resource showed that in the secondary xylem of P. trichocarpa, PtAP66 transcripts increased from the vascular cambium to the xylem cell expansion region and maintained high levels in the SCW formation region. Fluorescent signals from transgenic Arabidopsis plant roots and transiently transformed P. trichocarpa leaf protoplasts strongly suggested that the PtAP66-fused fluorescent protein (PtAP66-GFP or PtAP66-YFP) localised in the plasma membrane. Compared with the wild-type plants, the Cas9/gRNA-induced PtAP66 mutants exhibited reduced SCW thickness of secondary xylem fibres, as suggested by the scanning electron microscopy (SEM) data. In addition, wood composition assays revealed that the cellulose content in the mutants decreased by 4.90–5.57%. Transcription analysis further showed that a loss of PtAP66 downregulated the expression of several SCW synthesis-related genes, including cellulose and hemicellulose synthesis enzyme-encoding genes. Altogether, these findings indicate that atypical PtAP66 plays an important role in SCW deposition during wood formation.

Wood and Bark Anatomy of Lauraceae. ii. Licaria Aublet

IAWA Journal ◽  
1985 ◽  
Vol 6 (3) ◽  
pp. 187-199 ◽  
Author(s):  
Hans Georg Richter
Keyword(s):  
Diagnostic Tool ◽  
Secondary Xylem ◽  
Secondary Phloem ◽  
Structural Profile ◽  
Quantitative Characters ◽  
Important Diagnostic Tool ◽  
Species Groups ◽  
Bark Anatomy

Qualitative features of the secondary xylem of Licaria present a rather uniform structural profile. Constant differences in primarily quantitative characters lead to the formation of speeies groups wh ich loosely correspond to infrageneric sections based on floral and vegetative morphology. This subdivision is strongly corroborated by the highly variable secondary phloem structurc revealing considerable diversity in type and distribution of sc1erenchymatic tissues. Inorganic inclusions in the secondary xylem, crystals and silica, constitute an important diagnostic tool for differentiating certain species and species groups, but are hardly of importance in the bark.

scholarly journals Effect of Exogenously Applied 24-Epibrassinolide and Brassinazole on Xylogenesis and Microdistribution of Cell Wall Polymers in Leucaena leucocephala (Lam) De Wit

2021 ◽  
Author(s):  
S. Pramod ◽  
M. Anju ◽  
H. Rajesh ◽  
A. Thulaseedharan ◽  
Karumanchi S. Rao
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Leucaena Leucocephala ◽  
Higher Plants ◽  
Lignin Content ◽  
Wood Quality ◽  
Wall Structure ◽  
Vessel Element ◽  
Xylem Differentiation ◽  
Cell Wall Polymers

AbstractPlant growth regulators play a key role in cell wall structure and chemistry of woody plants. Understanding of these regulatory signals is important in advanced research on wood quality improvement in trees. The present study is aimed to investigate the influence of exogenous application of 24-epibrassinolide (EBR) and brassinosteroid inhibitor, brassinazole (BRZ) on wood formation and spatial distribution of cell wall polymers in the xylem tissue of Leucaena leucocephala using light and immuno electron microscopy methods. Brassinazole caused a decrease in cambial activity, xylem differentiation, length and width of fibres, vessel element width and radial extent of xylem suggesting brassinosteroid inhibition has a concomitant impact on cell elongation, expansion and secondary wall deposition. Histochemical studies of 24-epibrassinolide treated plants showed an increase in syringyl lignin content in the xylem cell walls. Fluorescence microscopy and transmission electron microscopy studies revealed the inhomogenous pattern of lignin distribution in the cell corners and middle lamellae region of BRZ treated plants. Immunolocalization studies using LM10 and LM 11 antibodies have shown a drastic change in the micro-distribution pattern of less substituted and highly substituted xylans in the xylem fibres of plants treated with EBR and BRZ. In conclusion, present study demonstrates an important role of brassinosteroid in plant development through regulating xylogenesis and cell wall chemistry in higher plants.

Sign in / Sign up

Export Citation Format

Share Document