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.

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.

SEASONAL VARIATION IN WOOD FORMATION OF CEDRELA FISSILIS (MELIACEAE)

IAWA Journal ◽  
2006 ◽  
Vol 27 (2) ◽  
pp. 199-211 ◽  
Author(s):  
Carmen Regina Marcati ◽  
Veronica Angyalossy ◽  
Ray Franklin Evert
Keyword(s):  
Secondary Xylem ◽  
Cambial Activity ◽  
Wood Formation ◽  
General Term ◽  
Dry Season ◽  
Climate Data ◽  
Wet Season ◽  
Growth Rings ◽  
Dormant Period ◽  
Xylem Formation

Cambial activity and periodicity of secondary xylem formation in Cedrela fissilis, a semi-ring-porous species, were studied. Wood samples were collected periodically from 1996 to 2000. The phenology was related to climate data of the region. The cambium has one active and one dormant period per year. The active period coincides with the wet season when trees leaf-out. The dormant period coincides with the dry season when trees lose their leaves. Growth rings are marked by parenchyma bands that begin to be formed, together with the small latewood vessels, just before the cambium becomes dormant at the beginning of the dry season. These bands are added to when the cambium reactivates in the wet season. At this time, the large earlywood vessels of the growth rings are also formed. As these bands consist of both terminal and initial parenchyma, we suggest the general term marginal bands be used to describe them. The growth layers vary in width among and within the trees.

scholarly journals Effect of auxin on xylem tracheids differentiation in decapitated stems of Pinus silvestris L. and its interaction with some vitamins and growth regulators

2015 ◽  
Vol 43 (1) ◽  
pp. 129-148 ◽  
Author(s):  
T. J. Wodzicki ◽  
S. Zajączkowski
Keyword(s):  
Vitamin A ◽  
Cell Metabolism ◽  
Choline Chloride ◽  
Late Summer ◽  
Cambial Activity ◽  
Xylem Differentiation ◽  
Pinus Silvestris ◽  
Quantitative Expression ◽  
Secondary Wall Formation ◽  
Tracheid Differentiation

The effects of several vitamins and substances known as important agents in regulation of cell metabolism upon secondary xylem differentiation were studied in interaction with auxin (IAA) as applied in lanoline to decapitated stems of 5-year-old <i>Pinus silvestris</i> trees in early and late-summer. Tested substances were: gibberellic acid, kinetin, nicotinic acid, thiamine, pyridoxine, calcium panthotenate, choline chloride, riboflavin, inositol, ascorbic acid, vitamin, A (alcohol), vitamin A (ester), saponin. None of the effects of these substances appeared significant enough to indicate the involvement in the seasonal variation of the response of cambium or differentiating tracheids to auxin. However, several effects, especially those of inositol, vitamin A and pyridoxine upon cambial xylem production and further stages of tracheid differentiation were observed. Auxin (IAA) affected cambial activity and subsequent differentiation of tracheids during the earliest stages of cell ontogenesis. At these stages auxin treatment induced quantitative expression of the developmental processes involving radial growth and secondary wall formation by tracheids. In this respect, auxin did not affect cells advanced in differentiation, however, it proved to be an essential factor in the completion of the full cycle of tracheid ontogenesis.

FLUCTUATIONS IN THE ABUNDANCE OF PLANKTONIC DIATOMS IN THE PASSAMAQUODDY REGION, NEW BRUNSWICK, FROM 1924 TO 1931

1933 ◽  
Vol 8 (1) ◽  
pp. 357-407 ◽  
Author(s):  
VIOLA M. DAVIDSON
Keyword(s):  
Marked Reduction ◽  
Late Summer ◽  
Early Spring ◽  
Surface Salinity ◽  
Apparent Lack ◽  
Planktonic Diatoms ◽  
Spring Freshet ◽  
Summer Maximum ◽  
Littoral Species ◽  
Spring Maximum

Collections made during a period of seven and a half years (1924–1931) weekly at a station of 30 m. depth in the St. Croix estuary and monthly at a station of 90 m. depth in the Outer bay show three dominant species. Thalassiosira Nordenskiöldi dominates during spring at both stations, being definitely stenothermic, finding somewhat under 6 °C. most favourable, and disappearing at that temperature, which is reached earlier in the estuarine station. Chaetoceros debilis dominates in June at that station. It is most abundant at 10–12 °C., but occurs at lower as well as at higher temperatures up to the summer maximum of 15 °C. Biddulphia aurita, an early spring littoral species, reaches its maximum at about 2 °C., and disappears when the spring freshet takes place. The forms were arctic-neritic in spring (beginning with the melting of the snow), arctic and boreal in June and July, and temperate and oceanic in late summer and autumn.There is no apparent lack of nutrient salts, nitrates, phosphates and silica being reduced but never depleted. Light is an important factor, but its effect is not clearly distinguishable, the peak of diatom production being reached usually in June at the outer station and in late June or early July at the inner station, while July had the most effective light. Marked reduction in surface salinity from river discharge with consequent stability of the water precedes the spring maximum of phytoplankton, and to a less degree local rainfall of summer has a corresponding effect.

scholarly journals Cambial Activity of Moringa peregrina (Forssk.) Fiori in Arid Environments

2021 ◽  
Vol 12 ◽  
Author(s):  
Holger Gärtner ◽  
Emad Farahat
Keyword(s):  
Photosynthetic Activity ◽  
Storage Capacity ◽  
Cambial Activity ◽  
Ring Formation ◽  
Arid Environments ◽  
Dry Tropics ◽  
Xylem Formation ◽  
Moringa Peregrina ◽  
Desert Regions ◽  
Environmental Adaptability

Moringa peregrina (Forssk.) Fiori, one of 13 species of the Moringaceae family widely distributed throughout the dry tropics, has the potential to become one of the most economically important medicinal plants in Egypt. However, despite its tolerance for drought and heat, it is also threatened by increasing temperatures and decreasing precipitation. Although the phenophase of this species is well documented, almost nothing is known about its period of cambial activity in desert regions. Ring formation and the general environmental adaptability of trees are affected by the timing of cambial activation. In our study site, we observe a distinct coupling of the development of new green leaves at the onset of vegetative growth in October and the phase of cambial activity (November–January). The onset of cambial activity seems to be related to a drop in temperature in October and the onset of torrential rains in the region. There might even be a short phase between the end of cambial activity and the onset of bud formation without xylem formation, but with photosynthetic activity. If so, we assume that all assimilates are stored as non-structural carbohydrates (NSC) in the parenchyma of the new ring. This potential gap opens new questions regarding the correlation between NSC storage capacity and the timing of remobilization for subsequent ring formation.

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

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.

The effects of artificial soil frost on cambial activity and xylem formation in Norway spruce

Trees ◽  
2011 ◽  
Vol 26 (2) ◽  
pp. 405-419 ◽  
Author(s):  
Tuula Jyske ◽  
Markku Manner ◽  
Harri Mäkinen ◽  
Pekka Nöjd ◽  
Heli Peltola ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Cambial Activity ◽  
Artificial Soil ◽  
Soil Frost ◽  
Xylem Formation

Seasonal cambial activity and wood formation in trees and lianas of Leguminosae growing in the Atlantic Forest: a comparative study

Botany ◽  
2015 ◽  
Vol 93 (4) ◽  
pp. 211-220 ◽  
Author(s):  
Arno Fritz das Neves Brandes ◽  
Claudio Sergio Lisi ◽  
Leonardo Davi S.A.B. da Silva ◽  
Kishore S. Rajput ◽  
Cláudia Franca Barros
Keyword(s):  
Tree Species ◽  
Secondary Xylem ◽  
Cambial Activity ◽  
Wood Formation ◽  
Montane Forest ◽  
Vascular Cambium ◽  
Growth Rings ◽  
Indirect Methods ◽  
Annual Growth Rings ◽  
Direct And Indirect Methods

Cambial activity and the formation of secondary xylem were investigated in the main stem of three arboreal leguminous species and one liana. To compare the seasonal vascular cambium behavior of these species, two methods were concurrently applied: induction of injury in the vascular cambium and anatomical analysis of the vascular cambium and adjacent zones (differentiation zone). One tree species, Pseudopiptadenia contorta (DC.) G.P.Lewis & M.P.Lima, was sampled in three forest formations: alluvial, submontane, and montane. Two more tree species, Apuleia leiocarpa (Vogel) J.F.Macbr. and Pseudopiptadenia leptostachya (Benth.) Rauschert, were sampled in submontane and montane forest, respectively. Dalbergia frutescens (Vell.) Britton var. frutescens, a liana, was sampled in montane forest. All species investigated showed distinctive formation of annual growth rings. Reactivation of the vascular cambium was observed at the end of spring, and it remained active during the summer. Thereafter, cambial activity either ceased or declined dramatically at the end of autumn. Similar to the tree species studied, cambial activity in D. frutescens var. frutescens showed similar seasonal cambial activity throughout the year. Based on both direct and indirect methods, our results showed that cambial activity and wood formation only occurred during the rainy season, suggesting the potential of these species for use in dendrochronological studies.

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