Exogenously applied 24-epi brassinolide reduces lignification and alters cell wall carbohydrate biosynthesis in the secondary xylem of Liriodendron tulipifera

2014 ◽  
Vol 101 ◽  
pp. 40-51 ◽  
Author(s):  
Hyunjung Jin ◽  
Jihye Do ◽  
Soo-Jeong Shin ◽  
Joon Weon Choi ◽  
Young Im Choi ◽  
...  
Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1002
Author(s):  
Shenquan Cao ◽  
Cong Wang ◽  
Huanhuan Ji ◽  
Mengjie Guo ◽  
Jiyao Cheng ◽  
...  

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.


IAWA Journal ◽  
2014 ◽  
Vol 35 (2) ◽  
pp. 127-137 ◽  
Author(s):  
Shengcheng Zhai ◽  
Yoshiki Horikawa ◽  
Tomoya Imai ◽  
Junji Sugiyama

The cell wall organization of leaf sheath fibers in different palm species was studied with polarized light microscopy (PLM) and transmission electron microscopy (TEM). The secondary wall of the fibers consisted of only two layers, S1 and S2. The thickness of the S1 layer in leaf sheath fibers from the different palm species ranged from 0.31 to 0.90 μm, with a mean value of 0.57 μm, which was thicker than that of tracheids and fibers in secondary xylem of conifers and dicotyledons. The thickness of the S2 layer ranged from 0.44 to 3.43 μm, with a mean value of 1.86 μm. The ratio of S1 thickness to the whole cell wall thickness in palm fibers appears to be higher than in secondary xylem fibers and tracheids. The lignin in the fiber walls is very electron dense which makes it difficult to obtain high contrast of the different layers in the secondary wall. To clarify the cell wall layering with cellulose microfibrils in different orientations, the fibrovascular bundles of the windmill palm (Trachycarpus fortunei) were delignified with different reaction time intervals. The treated fibers were surveyed using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy analysis and TEM. The secondary fiber walls of windmill palm clearly showed only two layers at different reaction intervals with different lignin contents, even after almost all lignin was removed. We suggest that the two-layered structure in the secondary wall of palm leaf fibers, which presumably also applies to the homologous fibers in palm stems, is a specific character different from the fibers in other monocotyledons (such as bamboo and rattan) and dicot wood.


1998 ◽  
Vol 95 (16) ◽  
pp. 9693-9698 ◽  
Author(s):  
Isabel Allona ◽  
Michelle Quinn ◽  
Elizabeth Shoop ◽  
Kristi Swope ◽  
Sheila St. Cyr ◽  
...  

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.


1969 ◽  
Vol 47 (11) ◽  
pp. 1701-1711 ◽  
Author(s):  
P. V. Rangnekar ◽  
D. F. Forward ◽  
N. J. Nolan

The distribution of photoassimilated carbon-14 in young plantation trees was studied 6 or 10 days after supplying 14CO2 for a day to a single branch in the second, third, or fourth whorl. Both apical and cambial growth occurred during the interval, and apical growth throughout the trees was measured. Elongating terminals and products of cambial growth in the fed branch were highly labeled. In all trees some 14C was exported to the adjacent side of the tree. Movement in the trunk was bidirectional, but the position of the donor branch determined the direction of major transport. Only from whorl 2 was it upward; from whorl 3 or 4 it was downward. In both directions activity decreased with distance from the base of the donor branch, and the leader did not accumulate more, per unit weight, than the intervening internodes. Some 14C entered branches arising in the path of transport.Radioactivity was concentrated only in regions of growth, whether apical or cambial. Most of the 14C was in ethanol-insoluble compounds, largely in cell wall constituents. Autoradiographs of stem sections confirmed that 14C was deposited in currently developing tracheids of secondary xylem during most of the 10-day growth period. The ratio of activity in lignin to that in cellulose was inversely related to the total 14C in the cell wall constituents.


1973 ◽  
Vol 7 (3) ◽  
pp. 173-188 ◽  
Author(s):  
Lidija Murmanis ◽  
Irving B. Sachs

2009 ◽  
Vol 47 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Arnaud Day ◽  
Godfrey Neutelings ◽  
Frédérique Nolin ◽  
Sébastien Grec ◽  
Anouk Habrant ◽  
...  

IAWA Journal ◽  
2020 ◽  
Vol 41 (3) ◽  
pp. 356-389
Author(s):  
Nadeeshani Karannagoda ◽  
Antanas Spokevicius ◽  
Steven Hussey ◽  
Gerd Bossinger

Abstract The products of secondary xylem are of significant biological and commercial importance, and as a result, the biology of secondary growth and how intrinsic and extrinsic factors influence this process have been the subject of intense investigation. Studies into secondary xylem range in scale from the cellular to the forest stand level, with phenotypic analyses often involving the assessment of traits relating to cell morphology and cell wall chemical composition. While numerous techniques are currently available for phenotypic analyses of samples containing abundant amounts of secondary tissue, only a few of them (microanalytical techniques) are suitable when working with limiting amounts of secondary tissue or where a fine-scale resolution of morphological features or cell wall chemical composition is required. While polarised light microscopy, scanning electron microscopy, field emission-scanning electron microscopy and X-ray scattering and micro-tomography techniques serve as the most frequently used microanalytical techniques in morphotyping, techniques such as scanning ultraviolet microspectrophotometry, X-ray photoelectron spectroscopy, gas chromatography, Fourier-transform infrared spectroscopy and matrix-assisted laser desorption ionisation mass spectrometry serve as the most commonly used microanalytical techniques in chemotyping. Light microscopy, fluorescence microscopy, confocal laser scanning microscopy, transmission electron microscopy and Raman spectroscopy serve as dual micro morphotyping and chemotyping techniques. In this review, we summarise and discuss these techniques in the light of their applicability as microanalytical techniques to study secondary xylem.


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