Intra-annual dynamics of cambial and xylem phenology in subalpine conifers at Deogyusan National Park in the Republic of Korea

AbstractSubalpine conifers are highly sensitive to climatic changes. In these trees, the intra-annual dynamics of cambial activity and phenological process in xylem development are closely associated with climatic conditions. However, these scientific findings have not been verified for subalpine conifers in the Republic of Korea. Therefore, we initiated such a study with four subalpine conifers, viz. Abies koreana, Pinus koraiensis, Taxus cuspidata, and Picea jezoensis, growing between 1573 and 1594 m a.s.l. at Deogyusan National Park. Microcores (Ø 2 mm) of these trees were obtained using a mini borer, called as Trephor, every week between April 7 and September 25 in 2017 to monitor their growing seasons, the intra-annual dynamics of the cambial activity, and the number of cells during phenological phases of cell enlargement and cell-wall thickening. For the study, five trees were selected for each conifer species. Results showed that the cambial activity of A. koreana, P. koraiensis, and P. jezoensis required at least 73.8 heat-sum values, whereas the T. cuspidata needed 109.6 heat-sum. The durations of cambial activity of A. koreana, P. koraiensis, T. cuspidata, and P. jezoensis were 134 (127–144), 113 (92–128), 113 (106–120), and 100 (76–128) days, respectively. The intra-annual variations of the number of cells in the cambium, during the cell enlargement phase and cell-wall thickening phase showed predominantly a bell-shaped curve, with a delay of approximately 2–4 weeks between each other. On the other hand, the number of cumulated mature cells showed an S-shaped curve. Through this study, the first fundamental data on phenological process in xylem development of subalpine conifers in the Republic of Korea have been successfully presented.

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Tick surveillance of migratory birds during 2010–2011 on Hong and Heuksan Islands, Jeollanam Province, Republic of Korea

Systematic and Applied Acarology ◽

10.11158/saa.23.11.13 ◽

2018 ◽

Vol 23 (11) ◽

pp. 2214 ◽

Cited By ~ 2

Author(s):

Sung-Tae Chong ◽

Heung Chul Kim ◽

Jong-Gil Park ◽

Chang-Yong Choi ◽

Chang-Uk Park ◽

...

Keyword(s):

Disease Surveillance ◽

National Park ◽

Migratory Birds ◽

Bird Species ◽

Republic Of Korea ◽

Surveillance Program ◽

Haemaphysalis Longicornis ◽

Haemaphysalis Concinna ◽

Park Service ◽

The Republic

Migratory birds were captured, examined, banded and then released in accordance with a bird banding protocol of the Bird Research Center, National Park Research Institute, Korea National Park Service, from January-December 2010–2011 on Hong and Heuksan Islands, Jeollanam (Jeonnam) Province, in the Republic of Korea (ROK). Concurrently, ticks were collected from captured birds as part of a tick-borne disease surveillance program. A total of 381 ticks belonging to three genera and eight species – Ixodes turdus (297 ticks), Ixodes nipponensis (16), Haemaphysalis flava (46), Haemaphysalis longicornis (9), Haemaphysalis formosensis (5), Haemaphysalis ornithophila (6), Haemaphysalis concinna (1), and Amblyomma testudinarium (1)—were collected from 32 bird species belonging to 3 families. This is the first host report of A. testudinarium (1 nymph) collected from White’s Thrush, Zoothera aurea (Aves: Passeriformes: Turdidae), in the ROK. Most ticks were collected from birds during the months of April (44.1%) and November (54.2%).

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

10.5194/egusphere-egu21-2095 ◽

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

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, c. 750 m asl), which is characterized by drought periods at the start of the growing season in spring and more favorable conditions during summer, Pinus sylvestris 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 c. 20 year old Pinus sylvestris 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. c. 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., c. 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 Pinus sylvestris 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.The research was funded by the Austrian Science Fund (FWF; project number P25643-B16).

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Effect of girdling on cambial activity in white pine

Canadian Journal of Botany ◽

10.1139/b68-024 ◽

1968 ◽

Vol 46 (2) ◽

pp. 141-146 ◽

Cited By ~ 16

Author(s):

Brayton F. Wilson

Keyword(s):

Mitotic Activity ◽

Transport System ◽

Phloem Transport ◽

Cambial Activity ◽

Cell Number ◽

Wall Thickening ◽

White Pine ◽

Cell Dimensions ◽

Cambial Zone ◽

Number Of Cells

There are no changes in cell dimensions more than 10 cm above a girdle in white pine (Pinus strobus L.), but up to 10 cm above, cell radial diameters are less, and at 2 cm cell walls may be thicker. There is an increase in number of cells produced from 2 to 310 cm above girdles, apparently because of a higher mitotic index and longer season for mitotic activity. The radial number of cells in the cambial zone does not change. From 2 to 310 cm below girdles mitotic activity and radial enlargement soon stop, cell wall thickening continues slowly, and there is no change in radial cell number in the cambial zone. These effects above and below girdles appear to be independent of time of girdling. They may be explained by the effect of girdling in blocking both the polarized auxin transport system and the non-polarized phloem transport system.

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Origin of Intra-annual Density Fluctuations in a Semi-arid Area of Northwestern China

Frontiers in Plant Science ◽

10.3389/fpls.2021.777753 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jiani Gao ◽

Sergio Rossi ◽

Bao Yang

Keyword(s):

Cambial Activity ◽

Wood Formation ◽

Density Fluctuations ◽

Arid Ecosystems ◽

Wall Thickening ◽

Drought Event ◽

Cell Enlargement ◽

Xylem Formation ◽

June July ◽

Semi Arid

Intra-annual density fluctuation (IADF) is a structural modification of the tree ring in response to fluctuations in the weather. The expected changes in monsoon flow would lead to heterogeneous moisture conditions during the growing season and increase the occurrence of IADF in trees of the arid ecosystems of continental Asia. To reveal the timings and physiological mechanisms behind IADF formation, we monitored cambial activity and wood formation in Chinese pine (Pinus tabuliformis) during 2017–2019 at three sites in semi-arid China. We compared the dynamics of xylem formation under a drought event, testing the hypothesis that drought affects the process of cell enlargement and thus induces the production of IADF. Wood microcores collected weekly from April to October were used for anatomical analyses to estimate the timings of cambial activity, and the phases of enlargement, wall thickening, and lignification of the xylem. The first cells started enlargement from late April to early May. The last latewood cells completed differentiation in mid-September. Trees produced IADF in 2018. During that year, a drought in June limited cell production in the cambium, only 36% of the xylem cells being formed in IADF trees, compared to 68% in normal tree rings. IADF cells enlarged under drought in early July and started wall thickening during the rainfall events of late July. The drought restricted cell enlargement and affected wall thickening, resulting in narrow cells with wide walls. Cambium and cell enlargement recovered from the abundant rainfall, producing a new layer with large earlywood tracheids. IADF is a specific adaptation of trees to cope with water deficit events occurring during xylem formation. Our findings confirmed the hypothesis that the June-July drought induces latewood-like IADFs by limiting the process of cell enlargement in the xylem. Our finding suggests a higher occurrence of IADF in trees of arid and semi-arid climates of continental Asia if the changes to monsoon flows result in more frequent drought events during the earlywood formation in June.

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Climatic and physiological regulation of the bimodal xylem formation pattern in Pinus pinaster saplings

Tree Physiology ◽

10.1093/treephys/tpz099 ◽

2019 ◽

Vol 39 (12) ◽

pp. 2008-2018 ◽

Cited By ~ 2

Author(s):

Núria Garcia-Forner ◽

Joana Vieira ◽

Cristina Nabais ◽

Ana Carvalho ◽

Jordi Martínez-Vilalta ◽

...

Keyword(s):

Water Availability ◽

Growth Pattern ◽

Pinus Pinaster ◽

Cambial Activity ◽

Fine Tuning ◽

Wall Thickening ◽

Physiological Variables ◽

Second Growth ◽

Xylem Formation ◽

Number Of Cells

Abstract Seasonality in tree cambial activity and xylem formation encompass large variation in environmental conditions. Abiotic stressors such as warming or drought also modulate plant behavior at species and individual level. Despite xylem formation susceptibility to carbon (C) and water availability, it is still unknown which are the key physiological variables that regulate xylogenesis, and to what extent plant performance contributes to further explain the number of cells in the different phases of xylem development. Xylogenesis and physiological behavior was monitored in saplings of Pinus pinaster Aiton, a bimodal growth pattern species, distributed in different irrigation regimes. Xylogenesis and plant physiological behavior were compared between treatments and the relationship between climate, physiology and the number of cells in the cambium, enlargement and cell-wall thickening phases was evaluated. Xylogenesis regulation shifted from physiological to climatic control as cell differentiation advanced to mature tracheids. The number of cells in the cambium increased with assimilation rates and decreased with the water potential gradient through the plant. Enlargement was the most susceptible phase to plant relative water content, whereas no physiological variable contributed to explain the number of cells in the wall thickening phase, which declined as temperatures increased. All treatments showed a bimodal growth pattern with a second growth period starting when primary growth was completed and after plants had experienced the highest summer hydraulic losses. Our study demonstrates the importance of including physiological responses and not only climate to fully understand xylogenesis, with special attention to the enlargement phase. This is critical when studying species with a bimodal growth pattern because the second growth peak responds to internal shifts of C allocation and may strongly depend on plant hydraulic responses and not on a fine tuning of cambial activity with soil water availability.

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