The role of senescence‐associated gene101 ( PagSAG101a ) in the regulation of secondary xylem formation in poplar

2021 ◽  
Author(s):  
Hui He ◽  
Xue‐Qin Song ◽  
Cheng Jiang ◽  
Ying‐Li Liu ◽  
Dian Wang ◽  
...  
Keyword(s):  
Secondary Xylem ◽  
Xylem Formation

Regeneration of vascular tissue through redifferentiation of interxylary phloem after complete girdling in Aquilaria sinensis

IAWA Journal ◽  
2021 ◽  
pp. 1-16
Author(s):  
Bei Luo ◽  
Arata Yoshinaga ◽  
Tatsuya Awano ◽  
Keiji Takabe ◽  
Takao Itoh
Keyword(s):  
Time Course ◽  
Potential Role ◽  
Vascular Tissue ◽  
Secondary Xylem ◽  
Vascular Cambium ◽  
Aquilaria Sinensis ◽  
Phloem Fibers ◽  
Interxylary Phloem ◽  
Time Course Study

Abstract We studied the time-course of stem response for six months following complete girdling in branches of Aquilaria sinensis to determine the potential role of interxylary phloem (IP) in this response. It was found that the vascular cambium, as well as its derivative secondary xylem and phloem, regenerated fully through redifferentiation of IP. We confirmed that vascular cambium regenerated within one month after girdling based on observation of new vessels, IP, and secondary phloem fibers. The time-course study showed that IPs made connections with each other, merged, and became larger through the proliferation of IPs parenchyma cells and the cleaving of secondary xylem in a narrow zone 400 to 1000 μm deep inside the girdled edge. This led to the formation of a complete circular sheath of vascular cambium, followed by the regeneration of vascular tissue. It is worth noting that the secondary xylem is regenerated always following the formation of a thick belt of wound xylem.

Eucalyptus gunnii CCR and CAD2 promoters are active in lignifying cells during primary and secondary xylem formation in Arabidopsis thaliana

2006 ◽  
Vol 44 (11-12) ◽  
pp. 674-683 ◽  
Author(s):  
A. Baghdady ◽  
A.-S. Blervacq ◽  
L. Jouanin ◽  
J. Grima-Pettenati ◽  
P. Sivadon ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Secondary Xylem ◽  
Xylem Formation

Characters and origin of vessels with heterogenous structure in leaf and flower abscission zones

1999 ◽  
Vol 77 (2) ◽  
pp. 253-261 ◽  
Author(s):  
JP André ◽  
A M Catesson ◽  
M Liberman
Keyword(s):  
Cell Differentiation ◽  
Lycopersicon Esculentum ◽  
Secondary Xylem ◽  
Abscission Zone ◽  
Leaf Abscission ◽  
Cell Maturation ◽  
Casting Method ◽  
Plant Organs ◽  
Flower Abscission

The lifetime of many plant organs does not exceed a few weeks or a few months. These organs separate from the plant at the level of specialized abscission zones. The observation of xylem vasculature in abscission zones, a largely neglected subject, revealed original features when a vessel casting method was used. In all species of dicotyledons examined so far, flower and leaf abscission zones possessed heterogenous metaxylem vessels adjoining protoxylem and secondary xylem vessels with homogenous patterns of lignified thickenings. Heterogenous metaxylem vessel thickenings were helical, reticulate, or scalariform elements when in the abscission zone and pitted elements on the proximal and the distal sides. The origin and possible role of these vessels are considered. Data obtained on the flower abscission zone of tomato (Lycopersicon esculentum Mill.) suggest that formation of heterogenous vessels results from localized changes in the rhythm of cell differentiation and cell maturation inside the procambium-cambium continuum.Key words: abscission zone, cambium, differentiation, heterogenous vessels, procambium, vessel cast.

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.

Laticifers of Ficus Carica and Their Potential Role in Plant Defense

IAWA Journal ◽  
2014 ◽  
Vol 35 (2) ◽  
pp. 109-115 ◽  
Author(s):  
C. Kajii ◽  
T. Morita ◽  
K. Kuroda
Keyword(s):  
Potential Role ◽  
Secondary Xylem ◽  
Nile Blue ◽  
Ficus Carica ◽  
Secondary Phloem ◽  
Fast Green ◽  
Cambial Zone ◽  
A Current ◽  
Latex Production

The distribution and structure of laticifers in Ficus carica L. were investigated in a current-year branch and an 8-year-old trunk, using serial sections stained with safranin-fast green or nile blue. In the 8-year-old trunk, laticifers were found not only in the cortex, secondary phloem, and pith, but also in the secondary xylem. The laticifers in the phloem and xylem were of the branched, non-articulated type. In addition, horizontal laticifers extending from the phloem through the cambium to the xylem were found in some rays. Laticifers penetrating the cambial initial layer elongated in the cambial zone without cell division. Activation of latex production occurred after wounding of cortex and phloem, and the latex exuded from the cut site of laticifers into the surrounding wounded tissue and broken cells. The potential role of laticifers in defense of F. carica against certain pathogens is discussed.

scholarly journals The possible relation between cytokinins and secondary xylem formation in Pinus silvestris. I. Seasonal correlations

2015 ◽  
Vol 48 (2) ◽  
pp. 295-303 ◽  
Author(s):  
Dorota B. Kubowicz
Keyword(s):  
Annual Ring ◽  
Secondary Xylem ◽  
Late Summer ◽  
Cambial Activity ◽  
Cytokinin Activity ◽  
Endogenous Cytokinin ◽  
Pinus Silvestris ◽  
Xylem Formation ◽  
Summer Maximum ◽  
Spring Maximum

The Seasonal dynamics of changes in the endogenous cytokinin level was investigated in the tissue of the stem cambial region, The results of the soybean test and Amaranthus test show that marked variations occur. in the course of the year in cytokinin activity in five fractions obtained from tissue of the cambial region. These variations characterized by a spring maximum and late-summer maximum may be correlated in time with changes in cambial activity and the course of annual ring differentiation in the pine stem during the vegetation season.

Regulation of secondary xylem formation in young hybrid poplars by modifying the expression levels of the PtaGLIMa gene

2017 ◽  
Vol 37 (10) ◽  
Author(s):  
Shaohui Yang ◽  
Guiyuan Zhu ◽  
Caili Wang ◽  
Lincai Chen ◽  
Yingjin Song ◽  
...  
Keyword(s):  
Secondary Xylem ◽  
Expression Levels ◽  
Hybrid Poplars ◽  
Xylem Formation

Bm-miR172c-5p regulates lignin biosynthesis and secondary xylem thickness by altering Ferulate 5 hydroxylase gene in Bacopa monnieri

2021 ◽  
Author(s):  
Gajendra Singh Jeena ◽  
Ashutosh Joshi ◽  
Rakesh Kumar Shukla
Keyword(s):  
Drought Stress ◽  
Target Genes ◽  
Secondary Xylem ◽  
Lignin Biosynthesis ◽  
Small Rna Sequencing ◽  
Cleavage Sites ◽  
Environmental Condition ◽  
Cycloartenol Synthase ◽  
Root Tissues

Abstract MicroRNAs (miRNAs) are small non-coding, endogenous RNAs containing 20–24 nucleotides that regulate the expression of target genes involved in various plant processes. A total 1429 conserved miRNA belonging to 95 conserved miRNA families and 12 novel miRNAs were identified from B. monnieri using small RNA sequencing. The Bm-miRNA target transcripts related to the secondary metabolism were further selected for validation. The Bm-miRNA expression in shoot and root tissues were negatively correlated with their target transcripts. The Bm-miRNA cleavage sites were mapped within the coding or untranslated (UTR) region as depicted by the modified RLM-RACE. In the present study, we validate three miRNA targets, including Asparagine synthetase, Cycloartenol synthase, and Ferulate 5 hydroxylase and elucidate the regulatory role of Bm-miR172c-5p, which cleaves the F5H gene involved in the lignin biosynthesis. Overexpression of Bm-miR172c-5p precursor in B. monnieri suppress F5H gene, leading to reduced lignification and secondary xylem thickness under control and drought stress. In contrast, overexpression of target mimics (eTMs) showed enhanced lignification and secondary xylem thickness leading to better physiological response under drought stress. Taken together, we suggest that Bm-miRNA172c-5p might be a key player in maintaining the native phenotype of B. monnieri under control and different environmental condition.

scholarly journals Apical control of xylem formation in the pine stem. II. Responses of differentiating tracheids

2014 ◽  
Vol 51 (2) ◽  
pp. 203-214 ◽  
Author(s):  
Jarosław Porandowski ◽  
Krzysztof Rakowski ◽  
Tomasz J. Wodzicki
Keyword(s):  
Radial Growth ◽  
Inductive Effect ◽  
Secondary Xylem ◽  
Regulatory System ◽  
Continuous Control ◽  
Pinus Silvestris ◽  
Daily Rate ◽  
Xylem Formation ◽  
Tracheid Differentiation ◽  
Cell Wall Deposition

The effect of auxin supplied to the main stem of 5-year-old <em>Pinus silvestris</em> trees during various periods after decapitation upon differentiation of the secondary xylem tracheids was investigated. The results revealed the complexity of auxin involvement in the regulatory system of tracheid differentiation of secondary xylem. It is manifested both as the inductive effect to which the cells respond in the meristematic phase and in the continuous control during the consecutive stages of radial growth and maturation. A lack of auxin during the meristematic phase resulted in smaller cell diameters and reduced the daily rate of cell wall deposition even though these cells progressively grew and matured in the presence of auxin. The intensity of these two processes increased and the cells deposited thicker walls when auxin was supplied during all stages of tracheid differentiation even though the period of maturation decreased. Under these conditions tracheids of compression wood type differentiated. Continuous availability of auxin causes earlier termination of tracheid maturation while lack of auxin results in a delay of autolysis of protoplasts. In this case auxin probably functions in a system specifying information concerning the position of the cells in respect to the cambial layer.

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