scholarly journals Boreal conifer seedling responses to experimental competition removal during summer drought

Ecosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Tanvir Ahmed Shovon ◽  
Daniel Gagnon ◽  
Mark C. Vanderwel
Keyword(s):  
Summer Drought ◽  
Conifer Seedling

White clover sensitivity to UV-B radiation - biochemical relationships and interaction with drought

2003 ◽  
pp. 273-277
Author(s):  
R.W. Hofmann ◽  
B.D. Campbell ◽  
E.E. Swinny ◽  
S.J. Bloor ◽  
K.R. Markham ◽  
...  
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Ultraviolet B ◽  
Summer Drought ◽  
Stress Protection ◽  
Trade Offs ◽  
Population Comparisons ◽  
Potential Benefits ◽  
Quercetin Glycosides ◽  
Balance Trade

During summertime in New Zealand, white clover experiences high levels of ultraviolet-B (UV-B) radiation. This frequently coincides with periods of summer drought. We investigated responses to UV-B and to the combination of UV-B and drought in various white clover populations, including New Zealand cultivars and ecotypes as well as overseas germplasm. The results were obtained under controlled environmental conditions in three independent trials. Overall, white clover growth was reduced by UV-B. The population comparisons indicated that low growth rate and adaptation to other forms of stress may be related to UV-B tolerance under well-watered conditions, but not during extended periods of drought. Flavonoid pigments that are involved in stress protection were strongly increased under UV-B and were further enhanced in the combination of UV-B and drought. The responses among these flavonoids were highly specific, with more pronounced UV-B-induced increases in quercetin glycosides, compared to their closely related kaempferol counterparts. UV-B toler ance of the less productive white clover populations was linked to the accumulation of quercetin compounds. In conclusion, these studies suggest (i) that slow-growing white clover ecotypes adapted to other stresses have higher capacity for biochemical acclimation to UV-B under well-watered conditions and (ii) that these biochemical attributes may also contribute to decreased UV-B sensitivity across white clover populations under drought. The findings alert plant breeders to potential benefits of selecting productive germplasm for high levels of specific flavonoids to balance trade-offs between plant productivity and stress tolerance. Keywords: Drought, flavonoids, genetic variation, HPLC, kaempferol, quercetin, str ess, Trifolium repens L., ultraviolet-B, white clover

Soil compaction and organic matter affect conifer seedling nonmycorrhizal and ectomycorrhizal root tip abundance and diversity.

1996 ◽  
Author(s):  
Michael P. Amaranthus ◽  
Debbie Page-Dumroese ◽  
Al Harvey ◽  
Efren Cazares ◽  
Larry F. Bednar
Keyword(s):  
Organic Matter ◽  
Soil Compaction ◽  
Root Tip ◽  
Abundance And Diversity ◽  
Conifer Seedling

scholarly journals Regeneration dynamics in fragmented landscapes at the leading edge of distribution: Quercus suber woodlands as a study case

2021 ◽  
Author(s):  
Jorge Luis Montero-Muñoz ◽  
Carmen Ureña ◽  
Diego Navarro ◽  
Valentín Herrera ◽  
Pilar Alonso-Rojo ◽  
...  
Keyword(s):  
Tree Growth ◽  
Quercus Suber ◽  
Forest Recovery ◽  
Tree Cover ◽  
Distribution Area ◽  
Soil Parameters ◽  
Old Fields ◽  
Summer Drought ◽  
Regeneration Dynamics ◽  
Positive Effect

Abstract Aims We studied the regeneration dynamics of woodlands and abandoned old fields in a landscape dominated by Quercus suber in its lower limits of rainfall and temperature. Two hypotheses were established: (1) regeneration of Quercus species is strongly favored by the presence of tree cover; and (2) growth of Q. suber is driven by the climatic variables that represent the lower ecological limit of its leading distribution edge. Methods We selected woodlands and old fields with and without tree remnants (n = 3 per type), and analyzed stand structure, soil parameters and tree growth. Results Succession was arrested in old fields without tree remnants. By contrast, remnant trees were accelerators of forest recovery in old fields. Tree cover played a fundamental role in Quercus recruitment throughout seed dispersal and facilitation that mitigate the effects of summer drought on seedlings. Also, tree cover improved soil parameters (e.g., organic matter) that are important factors for understanding differences in regeneration. Winter/spring precipitation exerted a positive effect on tree growth, as well as temperatures during winter/spring and September. Conclusions Regeneration dynamics are modeled by the density of tree cover in the cold and dry edge of the distribution area of Q. suber where Q. ilex is increasing in abundance. Although temperature has a positive effect on the tree growth of Q. suber, when demographic processes are considered, decreases in water availability likely play a critical role in Q. ilex recruitment. This in turn changes dominance hierarchies, especially in abandoned areas with little or no tree cover.

Contrasting physiological responsiveness of establishing trees and a C4 grass to rainfall events, intensified summer drought, and warming in oak savanna

2009 ◽  
Vol 16 (12) ◽  
pp. 3349-3362 ◽  
Author(s):  
ASTRID VOLDER ◽  
MARK G. TJOELKER ◽  
DAVID D. BRISKE
Keyword(s):  
Oak Savanna ◽  
Summer Drought ◽  
Rainfall Events ◽  
C4 Grass

Microsite patterns of conifer seedling establishment and growth in a mixed stand in the southern Alps

2005 ◽  
Vol 210 (1-3) ◽  
pp. 67-79 ◽  
Author(s):  
Urs Hunziker ◽  
Peter Brang
Keyword(s):  
Seedling Establishment ◽  
Southern Alps ◽  
Mixed Stand ◽  
Conifer Seedling

Two different strategies of Mediterranean macchia plants to avoid photoinhibitory damage by excessive radiation levels during summer drought

1999 ◽  
Vol 20 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Christiane Werner ◽  
Otilia Correia ◽  
Wolfram Beyschlag
Keyword(s):  
Summer Drought

scholarly journals Flowering phenology in alpine grassland strongly responds to shifts in snowmelt but weakly to summer drought

Alpine Botany ◽  
2021 ◽  
Author(s):  
Maria Vorkauf ◽  
Ansgar Kahmen ◽  
Christian Körner ◽  
Erika Hiltbrunner
Keyword(s):  
Biotic Interactions ◽  
Flowering Phenology ◽  
Alpine Plants ◽  
Alpine Grassland ◽  
Summer Drought ◽  
Phenological Cycle ◽  
The Alps ◽  
Delayed Flowering ◽  
Photoperiod Sensitive ◽  
Species Specific

AbstractAlpine plants complete their seasonal phenological cycle during two to three snow-free months. Under climate change, snowmelt advances and the risk of summer droughts increases. Yet, photoperiodism may prevent alpine plants from benefiting from an earlier start of the growing season. To identify the drivers of flowering phenology in the seven main species of an alpine grassland, we experimentally shifted the snowmelt date through snow manipulations, and excluded precipitation during summer. With “time-to-event” models, we analysed the beginning of main flowering with respect to temperature sums, time after snowmelt, and calendar day (photoperiod). We identified two phenology types: four species tracking snowmelt dates directly or with a certain lag set by temperature sums, including the dominant sedge Carex curvula, Anthoxanthum alpinum Helictotrichon versicolor, and Trifolium alpinum, and three species tracking photoperiod: Geum montanum, Leontodon helveticus and Potentilla aurea. Photoperiodism did not act as daylength threshold but rather modulated the thermal sums at flowering. Hence, photoperiod delayed flowering after earlier snowmelt. The grass A. alpinum was the only one of seven species that clearly responded to drought by earlier and longer flowering. The remarkably high importance of snowmelt dates for both phenology types suggests an earlier onset of flowering in a warmer climate, particularly for non-photoperiod-sensitive species, with an increasing risk for freezing damages and potential disruptions of biotic interactions in the most frequent type of alpine grassland across the Alps. Consequentially, the distinct microclimate and species-specific responses to photoperiod challenge temperature-only based projections of climate warming effects on alpine plant species.

scholarly journals Representation of Soil Moisture Feedbacks during Drought in NASA Unified WRF (NU-WRF)

2013 ◽  
Vol 14 (1) ◽  
pp. 360-367 ◽  
Author(s):  
Benjamin F. Zaitchik ◽  
Joseph A. Santanello ◽  
Sujay V. Kumar ◽  
Christa D. Peters-Lidard
Keyword(s):  
Soil Moisture ◽  
Great Plains ◽  
Climate Models ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Summer Drought ◽  
Dynamic Surface ◽  
Seasonal Drought ◽  
Weather Forecasts ◽  
Local Soil

Abstract Positive soil moisture–precipitation feedbacks can intensify heat and prolong drought under conditions of precipitation deficit. Adequate representation of these processes in regional climate models is, therefore, important for extended weather forecasts, seasonal drought analysis, and downscaled climate change projections. This paper presents the first application of the NASA Unified Weather Research and Forecasting Model (NU-WRF) to simulation of seasonal drought. Simulations of the 2006 southern Great Plains drought performed with and without soil moisture memory indicate that local soil moisture feedbacks had the potential to concentrate precipitation in wet areas relative to dry areas in summer drought months. Introduction of a simple dynamic surface albedo scheme that models albedo as a function of soil moisture intensified the simulated feedback pattern at local scale—dry, brighter areas received even less precipitation while wet, whereas darker areas received more—but did not significantly change the total amount of precipitation simulated across the drought-affected region. This soil-moisture-mediated albedo land–atmosphere coupling pathway is structurally excluded from standard versions of WRF.

scholarly journals Impact of summer drought on isoprenoid emissions and carbon sink of three Scots pine provenances

2016 ◽  
Author(s):  
M. Lüpke ◽  
M. Leuchner ◽  
R. Steinbrecher ◽  
A. Menzel
Keyword(s):  
Scots Pine ◽  
Carbon Sink ◽  
Summer Drought ◽  
Isoprenoid Emissions

Parasitism of Tylenchus Emarginatus On Conifer Seedling Roots and Some Observations On the Biology of the Nematode

Nematologica ◽  
1967 ◽  
Vol 13 (2) ◽  
pp. 191-196 ◽  
Author(s):  
Jack R. Sutherland
Keyword(s):  
Seedling Roots ◽  
Conifer Seedling
Sign in / Sign up

Export Citation Format

Share Document