scholarly journals Temporal dynamics of nonstructural carbohydrates and xylem growth in Pinus sylvestris exposed to drought

2011 ◽  
Vol 41 (8) ◽  
pp. 1590-1597 ◽  
Author(s):  
Walter Oberhuber ◽  
Irene Swidrak ◽  
Daniela Pirkebner ◽  
Andreas Gruber
Keyword(s):  
Pinus Sylvestris ◽  
Temporal Dynamics ◽  
Growing Season ◽  
Cambial Activity ◽  
Wood Formation ◽  
Nonstructural Carbohydrates ◽  
Late Wood ◽  
Structural Growth ◽  
Xylem Growth ◽  
Soil Dryness

Wood formation requires a continuous supply of carbohydrates for structural growth and metabolism. In the montane belt of the central Austrian Alps, we monitored the temporal dynamics of xylem growth and nonstructural carbohydrates (NSC) in stem sapwood of Scots pine ( Pinus sylvestris L.) during the growing season of 2009, which was characterized by exceptional soil dryness within the study area. Soil water content dropped below 10% at the time of maximum xylem growth at the end of May. Histological analyses have been used to describe cambial activity and xylem growth. Determination of NSC was performed using specific enzymatic assays revealing that total NSC ranged from 0.8% to 1.7% dry matter throughout the year. Significant variations (P < 0.05) of the size of the NSC pool were observed during the growing season. Starch showed persistent abundance throughout the year, reaching a maximum shortly before onset of late wood formation in mid-July. Seasonal dynamics of NSC and xylem growth suggest that (i) high sink activity occurred at the start of the growing season in spring and during late wood formation in summer and (ii) there was no particular shortage in NSC, which caused P. sylvestris to draw upon stem reserves more heavily during the drought in 2009.

Blocking phloem transport triggers bimodal radial growth in Pinus sylvestris at a xeric site

2021 ◽  
Author(s):  
Walter Oberhuber ◽  
Anton Landlinger-Weilbold ◽  
Andreas Gruber ◽  
Gerhard Wieser
Keyword(s):  
Cell Wall ◽  
Pinus Sylvestris ◽  
Radial Growth ◽  
Experimental Studies ◽  
Growing Season ◽  
Phloem Transport ◽  
Cambial Activity ◽  
Wall Thickening ◽  
Summer Drought ◽  
The Impact

&lt;p&gt;A bimodal radial grow pattern, i.e. growth peaks in spring and autumn, was repeatedly found in trees in Mediterranean regions, where summer drought causes reduction or cessation of cambial activity. In a dry inner Alpine valley of the Eastern Alps (Tyrol, Austria, &lt;em&gt;c&lt;/em&gt;. 750 m asl), which is characterized by drought periods at the start of the growing season in spring and more favorable conditions during summer, &lt;em&gt;Pinus sylvestris&lt;/em&gt; shows an unimodal growth pattern with onset and cessation of cambial activity in early April and late June, respectively. Although xylem cell differentiation (cell wall thickening) may last until end of August, a resumption of cambial activity after intense summer rainfall was not observed in this region. In a field experiment we therefore tested the hypothesis that early cessation of cambial activity under drought is an adaptation to limited water availability during the growing season (April through June), leading to an early and irreversible switch of carbon (C) allocation to belowground. To accomplish this, the C status of &lt;em&gt;c&lt;/em&gt;. 20 year old &lt;em&gt;Pinus sylvestris&lt;/em&gt; saplings (mean stem height 1.5 m) was manipulated at a xeric site by physical blockage of phloem transport (girdling) in mid-July (doy 199), i.e. &lt;em&gt;c&lt;/em&gt;. four weeks after cessation of cambial cell division. The influence of manipulated C availability on radial growth was continuously recorded by stem dendrometers, which were mounted 5 cm above girdling. In response to blockage of phloem flow, resumption of radial growth was detected above the girdling zone after about 2 weeks, i.e., bimodal growth could be triggered above girdling by increasing C availability. Although the experimentally induced second growth surge lasted for the same period as in spring (i.e., &lt;em&gt;c&lt;/em&gt;. 2 months), the increment was more than twice as large. Below girdling radial growth was not affected (i.e., no reactivation of cambial activity occurred), but cell wall thickness of last latewood cells was significantly reduced indicating lack of C after girdling. Intense radial growth resumption in &lt;em&gt;Pinus sylvestris&lt;/em&gt; saplings after girdling indicates that cessation of stem cambial activity can be reversed by manipulating the C status of the stem suggesting a high belowground C demand on the drought-prone, nutrient deficient site. This work highlights the need of in-depth experimental studies in order to understand the impact of endogenous and exogenous factors on cambial activity more clearly.&lt;/p&gt;&lt;p&gt;The research was funded by the Austrian Science Fund (FWF; project number P25643-B16).&lt;/p&gt;

scholarly journals Impact of drought on the temporal dynamics of wood formation in Pinus sylvestris

2010 ◽  
Vol 30 (4) ◽  
pp. 490-501 ◽  
Author(s):  
A. Gruber ◽  
S. Strobl ◽  
B. Veit ◽  
W. Oberhuber
Keyword(s):  
Pinus Sylvestris ◽  
Temporal Dynamics ◽  
Wood Formation

scholarly journals Analysis of cambial activity and formation of wood in Quercus robur L. under conditions of a floodplain forest

2012 ◽  
Vol 49 (No. 9) ◽  
pp. 412-418 ◽  
Author(s):  
P. Horáček ◽  
J. Šlezingerová ◽  
L. Gandelová
Keyword(s):  
Quercus Robur ◽  
Ecological Factors ◽  
Growth Curves ◽  
Growing Season ◽  
Cambial Activity ◽  
Wood Formation ◽  
Floodplain Forest ◽  
Pedunculate Oak ◽  
Total Production ◽  
The Social

The analyses of the activity of cambium and the study of the increment of wood during one growing season of pedunculate oak (Quercus robur L.) under conditions of a floodplain forest is provided. The following parameters were studied: the beginning and end of the cambial activity, differentiation of wood fibres (libriform) and vessels and analysis of the total increment of wood during vegetation in dominant (D), co-dominant (CD) and subdominant (SD) trees in relation to ecological factors of the environment. The course of wood formation corresponds to typical growth curves which are modified by factors of the environment (mean daily temperature, precipitation, soil water supply). The rate of growth is limited by factors of the environment and under the lack of some of them it is reduced resulting in the decrease in the total production of cells. Oak is a species sensitively responding to the period of drought which is particularly manifested in wood increment in subdominant trees. Sufficient supplies of water during spring months accelerate the formation of early wood including differentiation of spring vessels as corroborated by the results. The total formation of wood is dependent not only on the characteristics of the respective growing season but particularly on the social position of trees in the stand.

scholarly journals Forward Modeling Reveals Multidecadal Trends in Cambial Kinetics and Phenology at Treeline

2021 ◽  
Vol 12 ◽  
Author(s):  
Jan Tumajer ◽  
Jakub Kašpar ◽  
Hana Kuželová ◽  
Vladimir V. Shishov ◽  
Ivan I. Tychkov ◽  
...  
Keyword(s):  
Climate Change ◽  
Growth Rates ◽  
Climatic Factors ◽  
Temporal Stability ◽  
Growing Season ◽  
Cambial Activity ◽  
Wood Formation ◽  
Spring Phenology ◽  
Season Extension ◽  
Phenological Phases

Significant alterations of cambial activity might be expected due to climate warming, leading to growing season extension and higher growth rates especially in cold-limited forests. However, assessment of climate-change-driven trends in intra-annual wood formation suffers from the lack of direct observations with a timespan exceeding a few years. We used the Vaganov-Shashkin process-based model to: (i) simulate daily resolved numbers of cambial and differentiating cells; and (ii) develop chronologies of the onset and termination of specific phases of cambial phenology during 1961–2017. We also determined the dominant climatic factor limiting cambial activity for each day. To asses intra-annual model validity, we used 8 years of direct xylogenesis monitoring from the treeline region of the Krkonoše Mts. (Czechia). The model exhibits high validity in case of spring phenological phases and a seasonal dynamics of tracheid production, but its precision declines for estimates of autumn phenological phases and growing season duration. The simulations reveal an increasing trend in the number of tracheids produced by cambium each year by 0.42 cells/year. Spring phenological phases (onset of cambial cell growth and tracheid enlargement) show significant shifts toward earlier occurrence in the year (for 0.28–0.34 days/year). In addition, there is a significant increase in simulated growth rates during entire growing season associated with the intra-annual redistribution of the dominant climatic controls over cambial activity. Results suggest that higher growth rates at treeline are driven by (i) temperature-stimulated intensification of spring cambial kinetics, and (ii) decoupling of summer growth rates from the limiting effect of low summer temperature due to higher frequency of climatically optimal days. Our results highlight that the cambial kinetics stimulation by increasing spring and summer temperatures and shifting spring phenology determine the recent growth trends of treeline ecosystems. Redistribution of individual climatic factors controlling cambial activity during the growing season questions the temporal stability of climatic signal of cold forest chronologies under ongoing climate change.

scholarly journals Different climate sensitivity for radial growth, but uniform for tree-ring stable isotopes along an aridity gradient in Polylepis tarapacana, the world’s highest elevation tree-species

2021 ◽  
Author(s):  
Milagros Rodriguez-Caton ◽  
Laia Andreu-Hayles ◽  
Mariano S Morales ◽  
Valérie Daux ◽  
Duncan A Christie ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Carbon Source ◽  
Tree Ring ◽  
Tree Growth ◽  
Carbon Sink ◽  
Growing Season ◽  
Wood Formation ◽  
Aridity Gradient ◽  
Leaf Level ◽  
Δ13c And Δ18o

Abstract Tree growth is generally considered to be temperature-limited at upper elevation treelines. Yet, climate factors controlling tree growth at semiarid treelines are poorly understood. We explored the influence of climate on stem growth and stable isotopes for Polyepis tarapacana, the world’s highest elevation tree-species found only in the South American Altiplano. We developed tree-ring width index (RWI), oxygen (δ18O) and carbon (δ13C) chronologies for the last 60 years at four P. tarapacana stands located above 4,400 meters in elevation, along a 500-km latitude-aridity gradient. Total annual precipitation decreased from 300 to 200 mm from the northern to the southern sites. We used RWI as a proxy of wood formation (carbon sink) and isotopic tree-ring signatures as proxies of leaf-level gas exchange processes (carbon source). We found distinct climatic conditions regulating carbon-sink processes along the gradient. Current-growing season temperature regulated RWI at wetter-northern sites, while prior-growing season precipitation determined RWI at arid-southern sites. This suggests that the relative importance of temperature to precipitation in regulating tree growth is driven by site-water availability. In contrast, warm and dry growing-seasons resulted in enriched tree-ring δ13C and δ18O at all study sites, suggesting that similar climate conditions control carbon-source processes. Site-level δ13C and δ18O chronologies were significantly and positively related at all sites, with the strongest relationships among the southern-drier stands. This indicates an overall regulation of intercellular carbon dioxide via stomatal conductance for the entire P. tarapacana network, with greater stomatal control when aridity increases. The manuscript also highlights a coupling and decoupling of physiological processes at leaf level versus wood formation depending on their respectively uniform and distinct sensitivity to climate. This study contributes to better understand and predict the response of high-elevation Polylepis woodlands to rapid climate changes and projected drying in the Altiplano.

CHEMICAL INDUCTION OF TRAUMATIC GUM DUCTS IN CHINESE SWEETGUM, LIQUIDAMBAR FORMOSANA

IAWA Journal ◽  
2015 ◽  
Vol 36 (1) ◽  
pp. 58-68 ◽  
Author(s):  
Yawen Zheng ◽  
Biao Pan ◽  
Takao Itohl
Keyword(s):  
Methyl Jasmonate ◽  
Tree Species ◽  
Strong Relationship ◽  
Growing Season ◽  
Cambial Activity ◽  
Response To Treatment ◽  
Chemical Induction

The effect of ethephon (Et) and methyl jasmonate (MeJA) on the induction of traumatic gum ducts (TGDs) was studied in Chinese sweetgum, Liquidambar formosana, a broad-leaved tree species. Lanolin pastes with concentrations of 1, 2 and 5% (w/w) of these chemicals were applied to the intact bark of the trees in May, July and September without any wounding. The trees did not show any response to the treatment of MeJA, but TGDs were formed in response to treatment with Et. Trees treated with Et in the active growing season (May) produced more rows of TGDs than those treated in July or September, suggesting a strong relationship between cambial activity and susceptibility to TGD induction. These results are discussed in comparison with responses of conifers and some angiosperms to MeJA and Et treatments with and without associated wounding reported in the literature.

scholarly journals Life on leaves : uncovering temporal dynamics in Arabidopsis' leaf microbiota

2021 ◽  
Author(s):  
Juliana Almario ◽  
Maryam Mahmoudi ◽  
Samuel Kroll ◽  
Matthew Agler ◽  
Aleksandra Placzek ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Photosynthetic Activity ◽  
Temporal Dynamics ◽  
Growing Season ◽  
High Turnover ◽  
Microbial Network ◽  
Stabilization Phase ◽  
Time Patterns ◽  
Microbe Interactions ◽  
Compositional Changes

Leaves are primarily responsible for the plant′s photosynthetic activity. Thus, changes in the phyllosphere microbiota, which includes deleterious and beneficial microbes, can have far reaching effects on plant fitness and productivity. In this context, identifying the processes and microorganisms that drive the changes in the leaf microbiota over a plant′s lifetime is crucial. In this study we analyzed the temporal dynamics in the leaf microbiota of Arabidopsis thaliana, integrating both compositional changes and changes in microbe-microbe interactions via the study of microbial networks. Field-grown Arabidopsis were used to follow leaf bacterial, fungal and oomycete communities, throughout the plant′s growing season (extending from November to March), over three consecutive years. Our results revealed the existence of conserved time patterns, with microbial communities and networks going through a stabilization phase (decreasing diversity and variability) at the beginning of the plant′s growing season. Despite a high turnover in these communities, we identified 19 "core" taxa persisting in Arabidopsis leaves across time and plant generations. With the hypothesis these microbes could be playing key roles in the structuring of leaf microbial communities, we conducted a time-informed microbial network analysis which showed core taxa are not necessarily highly connected network "hubs" and "hubs" alternate with time. Our study shows that leaf microbial communities exhibit reproducible dynamics and patterns, suggesting it could be possible to predict and drive these microbial communities to desired states.

scholarly journals The significance of compression wood in restoration of the leader in Pinus sihestris L. damaged by moose (Alces alces). II. Structure of growth rings in regenerating stems in relation to juvenile wood formation

2015 ◽  
Vol 40 (2) ◽  
pp. 315-340 ◽  
Author(s):  
B. A. Molski
Keyword(s):  
Tree Ring ◽  
Tree Rings ◽  
Compression Wood ◽  
Juvenile Wood ◽  
Alces Alces ◽  
Wood Formation ◽  
Ring Structure ◽  
Growth Rings ◽  
Late Wood ◽  
Wood Compression

The corewood of pine ds very prone to compression wood formation, this changing the whole pattern of the tree ring structure and the siz.es of early and late wood. Compression wood always increases the formation of late wood at the expense of early wood. Tree rings with compression wood are generally wider than those without it, but there occur also tree rings wihout compression wood wider than those in which it is present, formed in the same year and in the same tree.

Combined effects of site preparation, soil properties, and sowing date on the establishment of Pinus sylvestris and Picea abies from seeds

2003 ◽  
Vol 33 (5) ◽  
pp. 931-945 ◽  
Author(s):  
Michelle de Chantal ◽  
Kari Leinonen ◽  
Hannu Ilvesniemi ◽  
Carl Johan Westman
Keyword(s):  
Soil Moisture ◽  
Picea Abies ◽  
Pinus Sylvestris ◽  
Soil Properties ◽  
Seedling Emergence ◽  
Growing Season ◽  
Sowing Date ◽  
Site Preparation ◽  
Winter Mortality ◽  
Frost Heaving

The aim of this study is to determine the effect of site preparation on soil properties and, in turn, the emergence, mortality, and establishment of Pinus sylvestris L. (Scots pine) and Picea abies (L.) Karst. (Norway spruce) seedlings sown in spring and summer along a slope with variation in soil texture and moisture. Three site preparation treatments of varying intensities were studied: exposed C horizon, mound (broken L–F–H–Ae–B horizons piled over undisturbed ground), and exposed Ae–B horizons. Seedling emergence was higher in the moist growing season than in the dry one. During a dry growing season, mounds and exposed C horizon had negative effects on soil moisture that increased mortality. Moreover, frost heaving was an important cause of winter mortality on mounds and exposed C horizon, whereas frost heaving was low on exposed Ae–B horizons, even though soil moisture and the content of fine soil particles (<0.06 mm) were high. Frost heaving mortality was higher for summer-sown than for spring-sown seedlings and for P. abies than for P. sylvestris. Growing season mortality was high following a winter with frost heaving, suggesting that roots were damaged, thereby making seedlings more susceptible to desiccation.

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