scholarly journals How do trees die? A test of the hydraulic failure and carbon starvation hypotheses

2013 ◽  
Vol 37 (1) ◽  
pp. 153-161 ◽  
Author(s):  
SANNA SEVANTO ◽  
NATE G. MCDOWELL ◽  
L. TURIN DICKMAN ◽  
ROBERT PANGLE ◽  
WILLIAM T. POCKMAN
Keyword(s):  
Carbon Starvation ◽  
Hydraulic Failure

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.

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 Initial hydraulic failure followed by late-stage carbon starvation leads to drought-induced death in the tree Trema orientalis

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Yuri Kono ◽  
Atsushi Ishida ◽  
Shin-Taro Saiki ◽  
Kenichi Yoshimura ◽  
Masako Dannoura ◽  
...  
Keyword(s):  
Late Stage ◽  
Carbon Starvation ◽  
Hydraulic Failure ◽  
Trema Orientalis

An allometry-based model of the survival strategies of hydraulic failure and carbon starvation

Ecohydrology ◽  
2015 ◽  
Vol 9 (3) ◽  
pp. 529-546 ◽  
Author(s):  
Pierre Gentine ◽  
Marceau Guérin ◽  
María Uriarte ◽  
Nate G. McDowell ◽  
Willam T. Pockman
Keyword(s):  
Carbon Starvation ◽  
Survival Strategies ◽  
Hydraulic Failure

scholarly journals Balancing the risks of hydraulic failure and carbon starvation: a twig scale analysis in declining Scots pine

2015 ◽  
Vol 38 (12) ◽  
pp. 2575-2588 ◽  
Author(s):  
Yann Salmon ◽  
José M. Torres-Ruiz ◽  
Rafael Poyatos ◽  
Jordi Martinez-Vilalta ◽  
Patrick Meir ◽  
...  
Keyword(s):  
Scots Pine ◽  
Carbon Starvation ◽  
Scale Analysis ◽  
Hydraulic Failure

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.

Ethanol and carbon-source starvation enhance the accumulation of HSP80 in Neurospora crassa

1988 ◽  
Vol 34 (2) ◽  
pp. 162-168 ◽  
Author(s):  
H. S. Roychowdhury ◽  
M. Kapoor
Keyword(s):  
Heat Shock ◽  
Neurospora Crassa ◽  
Carbon Catabolite Repression ◽  
Normal Growth ◽  
Carbon Starvation ◽  
High Molecular Mass ◽  
Sucrose Starvation ◽  
Shock Response ◽  
Shock Proteins ◽  
Starvation Conditions

In Neurospora crassa, heat shock results in the induction of 9 to 11 heat shock proteins (HSP), of which HSP80 is the most abundant and the first to be synthesized. The induction of HSP80 was investigated during normal growth (2% sucrose) and under sucrose starvation. Transfer of mycelium to a medium supplemented with ethanol stimulated the synthesis of HSP80, even at the normal growth temperature of 28 °C. It was also synthesized under carbon starvation conditions, where the medium was supplemented with 0.02% sucrose, 0.3% acetate, 0.2% lactate, or ethanol. A 30–35 kilodalton polypeptide was induced by heat shock in carbon-sufficient media, but in 0.02% sucrose and 0.3% acetate containing media it was synthesized at normal temperatures. While the overall heat shock response remained unaltered in these cultures, the abundance of HSP90 and HSP70, relative to HSP80, was greater. HSP80 appears to be controlled by carbon-catabolite repression as well as heat shock. Another high molecular mass protein (tentatively designated alc'80') was observed to be induced by heat shock, provided carbon starvation conditions prevailed concurrently.

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