scholarly journals Differences in Near Isohydric and Anisohydric Behavior of Contrasting Poplar Hybrids (I-101 (Populus alba L.) × 84K (Populus alba L. × Populus glandulosa Uyeki)) under Drought-Rehydration Treatments

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 402 ◽  
Author(s):  
Li Zhang ◽  
Li Liu ◽  
Han Zhao ◽  
Zaimin Jiang ◽  
Jing Cai
Keyword(s):  
Tree Mortality ◽  
Slow Growth ◽  
Threshold Value ◽  
Carbon Starvation ◽  
Populus Alba ◽  
Growth Strategies ◽  
Fast Growing ◽  
Hydraulic Failure ◽  
Hydraulic Safety ◽  
Slow Growing

Carbon starvation and hydraulic failure are considered important factors in determining the mechanisms associated with tree mortality. In this study, iso/anisohydric classification was used to assess drought resistance and mortality mechanisms in two contrasting poplar species, as it is generally believed that isohydric species are more susceptible to carbon starvation, while anisohydric species are more susceptible to hydraulic failure. However, these assumptions are rarely tested in poplar genotypes with contrasting growth strategies. Thus, we subjected potted poplar genotypes (I-101 (Populus alba L.) × 84K (Populus alba L. × Populus glandulosa Uyeki)) with fast and slow growth rates to drought–rehydration treatments. The slow-growing genotype maintained higher stomatal conductance and lower predawn leaf water potential than the fast-growing genotype, thus exhibiting a near-anisohydric stomatal behavior throughout the treatment period. The nonstructural carbohydrate (NSC) content indicated that the two genotypes had the same trend of carbon change (e.g., the NSC content in the leaves increased with drought and then decreased). However, when NSC content data were combined with the growth and photosynthetic data, it was observed that the slow-growing genotype mobilized carbon to maintain hydraulic safety, while the NSC content of the fast-growing genotype among tissues was static. The percent loss of hydraulic conductivity in the branches during treatments indicated that the fast-growing genotype could recover more quickly from xylem embolism than the slow-growing genotype. The slow-growing genotype with a slow growth recovery after rehydration showed a significant increase in carbon consumption, combined with a significant increase in the hydraulic safety threshold value, indicating that there may be drought tolerance. In comparison, the fast-growing genotype showed a faster hydraulic recovery ability that had no effect on the NSC content in the leaves and roots. Our findings demonstrate intraspecific isohydric behavior in poplar; however, the trade-off between carbon distribution and stomatal regulation should be considered separately within genotypes of the same species. In addition, NSC plays an important role in water–carbon balance in the drought–rehydration cycle.

scholarly journals Carbon starvation during drought-induced tree mortality – are we chasing a myth?

2015 ◽  
Vol 2 ◽  
pp. e005 ◽  
Author(s):  
Henrik Hartmann
Keyword(s):  
Tree Mortality ◽  
Stomatal Closure ◽  
Carbon Starvation ◽  
Carbon Limitation ◽  
Functional Roles ◽  
C Storage ◽  
Hydraulic Failure ◽  
Lethal Level ◽  
Potential Link ◽  
C Assimilation

Drought-induced tree mortality has received much attention in the recent past. McDowell et al.’s (2008) hydraulic framework links tree hydraulics with carbon dynamics and proposes two non-exclusive mortality mechanisms: carbon starvation (CS) and hydraulic failure (HF). CS is often referred to as the (partial) depletion of non-structural carbohydrates (NSC) in response to stomatal closure, reduced C assimilation and sustained C storage dependency during longer droughts. HF describes a lethal level of xylem dysfunction from runaway embolism during severe droughts. While HF can be readily inferred from the percentage loss of conductivity in vascular tissues at the time of death, CS is much more difficult to assess.Starvation is usually defined as a lack of food leading to suffering or death. In plants photosynthetic sugars play many functional roles, not only as a source of catabolic energy. For example, sugars are important for osmotic regulation of cell pressure and recent studies suggest a potential link between xylem parenchyma sugars and embolism repair following drought. Hence, carbon limitation could have a direct impact on tree hydraulics and HF; however, empirical evidence for such a mechanism is still inconclusive.Although HF appears to be predominant during drought mortality, our limited understanding of the roles of NSC in hydraulic function precludes any premature refutation of CS as a mechanism in drought-induced tree mortality.

Accumulation of Persistent Pollutants in Normal and Dwarfed Arctic Char (Salvelinus alpinus sp. complex)

1993 ◽  
Vol 50 (12) ◽  
pp. 2574-2580 ◽  
Author(s):  
Johan Hammar ◽  
Per Larsson ◽  
Maris Klavins
Keyword(s):  
Growth Rate ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Individual Growth ◽  
The Arctic ◽  
Growth Strategies ◽  
Sympatric Populations ◽  
Fast Growing ◽  
Persistent Pollutants ◽  
Slow Growing

Two extreme growth fractions of introgressed sympatric populations of the Arctic char (Salvelinus alpinus) species complex from Lake Blåsjön, northern Sweden, were sampled for individual concentrations of persistent pollutants originating from atmospheric deposition. Slow growing char (dwarfs) had significantly higher levels of SPCB (sum of PCB congeners found) and p,p-DDE (dominating DDT-compound) than fast growing char (normals). Besides demonstrating a highly divergent growth pattern the introgressed populations also inhabit a great range of depths, and the seasonal food consumption rates may differ between extreme growth fractions, although the same major invertebrates (introduced Mysis relicta and Pallasea quadrispinosa) are consumed over the year. However, of the life history parameters differing in late spring, individual growth rate was the most important factor explaining the variation in the levels of the pollutants studied. The results support the hypothesis of a biomass "dilution" of pollutants in fish, illustrated by lower levels in fast growing char and higher levels in the slow-growing dwarfs. Individuals with alternative growth strategies in sympatric conspecific communities thus provide unique opportunities to study growth rate as a variable influencing levels of persistent pollutants in fish.

scholarly journals Tree Mortality Risks Under Climate Change in Europe: Assessment of Silviculture Practices and Genetic Conservation Networks

2021 ◽  
Vol 9 ◽  
Author(s):  
Cathleen Petit-Cailleux ◽  
Hendrik Davi ◽  
François Lefèvre ◽  
Pieter Johannes Verkerk ◽  
Bruno Fady ◽  
...  
Keyword(s):  
Climate Change ◽  
Forest Management ◽  
Mortality Risk ◽  
Tree Mortality ◽  
Frost Damage ◽  
Carbon Starvation ◽  
Genetic Conservation ◽  
Future Climate ◽  
Extreme Climatic Events ◽  
Hydraulic Failure

General Context: Climate change can positively or negatively affect abiotic and biotic drivers of tree mortality. Process-based models integrating these climatic effects are only seldom used at species distribution scale.Objective: The main objective of this study was to investigate the multi-causal mortality risk of five major European forest tree species across their distribution range from an ecophysiological perspective, to quantify the impact of forest management practices on this risk and to identify threats on the genetic conservation network.Methods: We used the process-based ecophysiological model CASTANEA to simulate the mortality risk of Fagus sylvatica, Quercus petraea, Pinus sylvestris, Pinus pinaster, and Picea abies under current and future climate conditions, while considering local silviculture practices. The mortality risk was assessed by a composite risk index (CRIM) integrating the risks of carbon starvation, hydraulic failure and frost damage. We took into account extreme climatic events with the CRIMmax, computed as the maximum annual value of the CRIM.Results: The physiological processes' contributions to CRIM differed among species: it was mainly driven by hydraulic failure for P. sylvestris and Q. petraea, by frost damage for P. abies, by carbon starvation for P. pinaster, and by a combination of hydraulic failure and frost damage for F. sylvatica. Under future climate, projections showed an increase of CRIM for P. pinaster but a decrease for P. abies, Q. petraea, and F. sylvatica, and little variation for P. sylvestris. Under the harshest future climatic scenario, forest management decreased the mean CRIM of P. sylvestris, increased it for P. abies and P. pinaster and had no major impact for the two broadleaved species. By the year 2100, 38–90% of the European network of gene conservation units are at extinction risk (CRIMmax=1), depending on the species.Conclusions: Using a process-based ecophysiological model allowed us to disentangle the multiple drivers of tree mortality under current and future climates. Taking into account the positive effect of increased CO2 on fertilization and water use efficiency, average mortality risk may increase or decrease in the future depending on species and sites. However, under extreme climatic events, our process-based projections are as pessimistic as those obtained using bioclimatic niche models.

scholarly journals Genotypic traits and tradeoffs of fast growth in silver birch, a pioneer tree

Oecologia ◽  
2021 ◽  
Author(s):  
Juha Mikola ◽  
Katariina Koikkalainen ◽  
Mira Rasehorn ◽  
Tarja Silfver ◽  
Ulla Paaso ◽  
...  
Keyword(s):  
Resource Competition ◽  
Leaf Growth ◽  
N Uptake ◽  
Insect Herbivory ◽  
Fast Growth ◽  
Grass Cover ◽  
Soil N ◽  
Fast Growing ◽  
Slow Growing ◽  
Leaf N

AbstractFast-growing and slow-growing plant species are suggested to show integrated economics spectrums and the tradeoffs of fast growth are predicted to emerge as susceptibility to herbivory and resource competition. We tested if these predictions also hold for fast-growing and slow-growing genotypes within a silver birch, Betula pendula population. We exposed cloned saplings of 17 genotypes with slow, medium or fast height growth to reduced insect herbivory, using an insecticide, and to increasing resource competition, using naturally varying field plot grass cover. We measured shoot and root growth, ectomycorrhizal (EM) fungal production using ergosterol analysis and soil N transfer to leaves using 15N-labelled pulse of NH4+. We found that fast-growing genotypes grew on average 78% faster, produced 56% and 16% more leaf mass and ergosterol, and showed 78% higher leaf N uptake than slow-growing genotypes. The insecticide decreased leaf damage by 83% and increased shoot growth, leaf growth and leaf N uptake by 38%, 52% and 76%, without differences between the responses of fast-growing and slow-growing genotypes, whereas root mass decreased with increasing grass cover. Shoot and leaf growth of fast-growing genotypes decreased and EM fungal production of slow-growing genotypes increased with increasing grass cover. Our results suggest that fast growth is genotypically associated with higher allocation to EM fungi, better soil N capture and greater leaf production, and that the tradeoff of fast growth is sensitivity to competition, but not to insect herbivory. EM fungi may have a dual role: to support growth of fast-growing genotypes under low grass competition and to maintain growth of slow-growing genotypes under intensifying competition.

scholarly journals Studies on the Regulation of Algal Growth by Gibberellin

1971 ◽  
Vol 24 (4) ◽  
pp. 1115 ◽  
Author(s):  
RC Jennings
Keyword(s):  
Red Algae ◽  
Algal Growth ◽  
Red Alga ◽  
General Phenomenon ◽  
Hypnea Musciformis ◽  
Fast Growing ◽  
High Concentrations ◽  
Amo 1618 ◽  
Slow Growing

CCC and Amo.1618, at relatively high concentrations only, inhibited the growth of excised branch apices of the red alga Hypnea musciformis. Neither GA3 nor GA7 stimulated growth of the alga in the presence or absence of these compounds, and gibberellin-like material extracted from H. musciformis also failed to stimulate growth. However, both gibberellins stimulated the growth of slow-growing, but not fast-growing, branch apices of the related red alga Gracilaria verucosa. It is concluded that endogenous gibberellins may not regulate the growth of H. musciformis, but this is likely to be a peculiarity of this species and not a general phenomenon in red algae.

scholarly journals The Role of Cell Motility in Metastatic Cell Dominance Phenomenon: Analysis by a Mathematical Model

2000 ◽  
Vol 3 (1) ◽  
pp. 63-77 ◽  
Author(s):  
A. V. Kolobov ◽  
A. A. Polezhaev ◽  
G. I. Solyanik
Keyword(s):  
Mathematical Model ◽  
Cell Motility ◽  
Threshold Value ◽  
Experimental Investigations ◽  
Metastatic Cell ◽  
Metastatic Cells ◽  
Motile Cells ◽  
Cell Subpopulations ◽  
Cell Motion ◽  
Slow Growing

Metastasis is the outcome of several selective sequential steps where one of the first and necessary steps is the progressive overgrowth or dominance of a small number of metastatic cells in a tumour. In spite of numerous experimental investigations concerning the growth advantage of metastatic cells, the mechanisms resulting in their dominance are still unknown. Metastatic cell overgrowth occurs even if doubling time of the metastatic subpopulation is shorter than that of all others subpopulations in a heterogeneous tumour. In order to examine the hypothesis that under conditions of competition of cell subpopulations for common substrata cell motility of the slow-growing subpopulation can result in its dominance in a heterogeneous tumour, a mathematical model of heterogeneous tumour growth is suggested. The model describes two cell subpopulations which can grow with different rates and transform into the resting state depending on the concentration of the substrate consumed by both subpopulations. The slow-growing subpopulation is assumed to be motile. In numerical simulations it is shown that this subpopulation is able to overgrow the other one. The dominance phenomenon (resulting from random cell motion) depends on the motility coefficient in a threshold manner: in a heterogeneous tumour the slow-dividing motile subpopulation is able to overgrow its non-motile counterparts if its motility coefficient exceeds a certain threshold value. Computations demonstrate independence of the motile cells overgrowth from the initial tumour composition.

SENSITIVITY AND ADAPTATION OF SELECTED RHIZOBIA AND AGROBACTERIA TO PARAQUAT

1985 ◽  
Vol 65 (3) ◽  
pp. 555-562 ◽  
Author(s):  
E. B. ROSLYCKY
Keyword(s):  
Key Words ◽  
Genetic Effect ◽  
Agrobacterium Radiobacter ◽  
Plant Weight ◽  
Fast Growing ◽  
Plant Symbiont ◽  
Paraquat Resistance ◽  
Rhizobium Lupini ◽  
The Relationship ◽  
Slow Growing

Sensitivity to paraquat as function of growth varied considerably among 15 rhizobia from seven cross-inoculation groups and 13 agrobacteria from five different species. No relationship was evident between the sensitivity and the "fast-growing" or the "slow-growing" characteristics among the rhizobia. The agrobacteria were uniformly less sensitive. Maximum stabilized paraquat resistance induced by the adptations ranged from 200 μg paraquat∙mL−1 in Rhizobium lupini 112, to 20 000 μg paraquat∙mL−1 in Agrobacterium radiobacter R-590 and A. tumefaciens A6-K1. No relationship was found between the sensitivity and the adaptability. Identical lytic patterns with six bacteriophages confirmed the relationship between the adapted and parent cultures suggesting no genetic effect of paraquat on susceptibility to lysis. The bacteria-plant symbiont interaction, including nodulation, plant weight, vigor and color, was unaffected by the adaptations to paraquat resistance. Similarly, the adaptations exerted no effect on tumorigenicity of A. tumefaciens A6-K1. Key words: Rhizobia, agrobacteria, adaptation, herbicides, paraquat, N2-fixation

scholarly journals Current state of Donetsk dendroflora

2016 ◽  
Vol 5 (2) ◽  
pp. 20-24
Author(s):  
Alexandr Zakharovych Glukhov ◽  
Lyudmila Valerievna Kharkhota ◽  
Georgy Alexandrovych Pasternak ◽  
Elena Nikolaevna Likhatskaya
Keyword(s):  
Age Structure ◽  
Steppe Zone ◽  
Age Group ◽  
Fast Growing ◽  
Industrial City ◽  
Current State ◽  
Study Results ◽  
Slow Growing ◽  
Trees And Shrubs ◽  
Fast Growing Species

We present the study results of modern dendroflora of Donetsk (a large industrial city of the south steppe zone). We have determined the species composition, analyzed the age structure of plantations, estimated the life condition of trees and shrubs. Plantations compose 76 species and 32 forms, types, sorts of trees, including 11 species and 9 sorts of the coniferous, as well as 79 species and 35 forms, sorts of shrubs, including 7 species and 19 sorts of the coniferous. Trees and shrubs belong to 78 genera, which are included into 38 families. The most represented family among the deciduous is Rosaceae Juss. - 46 species and 13 sorts, among the coniferous - Pinaceae Lindl. (9 species and 6 sorts), Cupressaceae Rich. ex Bartl. (7 species and 22 sorts). Tree species dominating in plantations are Populus bolleana Lauche (14,6% of the total number of trees), dominating shrubs are the sorts of Rosa hybrida (44,0% of the total number of shrubs). In the plantations studied we have indicated 33 species of trees and shrubs of the aboriginal fraction of local flora. Analysis of the age structure of plantations revealed that the majority of trees compose the age group of 20-29 years, the majority of shrubs - up to 10 years. Fast-growing species prevail in plantations (73% of the total number). Viability of the most part of trees of fast-growing and slow-growing species is estimated by 4 points, viability of moderate-growing species - by 6 points. The number of trees being in unsatisfactory condition (0 or 1-3 points) prevails among fast-growing species.

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