1,720,978 research outputs found
La genetica di popolazioni fornisce un efficace strumento per quantificare l'impatto della frammentazione in ecosistemi forestali
No full textA simple general method to evaluate intra-specific transpiration parameters within and among seedling families
No full textA method to evaluate the genetic control of
plant response to increasing soil water deficit is proposed.
A description of single tree transpiration
behavior was obtained considering parameters independent
from air and soil conditions. We removed
environmental effects by using two approaches: the
normalization of drought data to control (watered)
plants and the fitting of a process model. We analyzed
the transpiration of 475 4-year-old European beech
seedlings, belonging to eight full-sib families.
Approximately, one-third of the seedlings were kept in
well-watered conditions while the others were exposed
to drought for 14 days. Daily plant transpiration was
estimated as the difference between two subsequent
gravimetric measurements. A mechanistic model was
fitted to transpiration data separately for each tree. In
the model, the relationship of transpiration with vapor
pressure deficit and soil water deficit of each tree is
modulated by three parameters: maximum leaf conductance
(gMl
), maximum transpiration in well-watered
soil conditions ðEM0
l Þ and a parameter describing stomatal
sensitivity to soil water deficit (c). The model
successfully fitted most single tree data and a distribution
of estimates for the three parameters (gMl
, EM0
and c) was obtained. Predicted transpiration values
were in good agreement with observed data
(R2 = 0.86). The model approach produced parameters
significantly correlated with those of the ‘‘normalization
to control’’ approach. Estimated parameters vary
considerably among trees, suggesting the presence of
individual differences in stomatal behavior and response
to drought. In spite of a large among tree
(within family) variation, the among families component
for gMl
, EM0
l and c explained 9.5, 3.3 and 0.1% of
total parameters variation suggesting a significant genetic
control of transpiration processes
Validation of the Brass Index – Blaylock Risk Assessment Screen Score – to evacuate the patients risk of problems after discharge from medical wards. Developing research in nursing, social care education and multisectorial cooperation
No full textAnalisi genetica della popolazione di abete bianco (Abies alba Miller) presente nel Parco delle Alpi Apuane
No full textVariability of stomatal conductance in a small and isolated population of Silver fir (Abies alba Mill.)
No full textWe analyzed the response to drought of 420 individuals from eight half-sib families from a small and isolated population of silver fir (Abies alba Mill.): 105 of them were kept in well-watered conditions as control while the remaining 315 were exposed to drought for 27 days. A model describing stomatal behavior derived from Monteith and developed in beech by Leonardi et al. was fitted to experimental transpiration data obtained simply from the difference between two daily pot weighings. The estimated parameters were maximum stomatal conductance, maximum transpiration in well-watered conditions and sensitivity to soil water deficit. The model worked well: convergence for all but four individuals and concordance between experimental and fitted data were good (R
2 = 0.86). Inter-individual variability for all three estimated parameters was high and two of them (maximum stomatal conductance and sensitivity to soil water deficit) were significantly different among families, suggesting genetic control. Our results validate the simplified method used to evaluate individual stomatal parameters. We also show that in the small and isolated population of our study substantial adaptive variability remains, a crucial prerequisite to endure environmental conditions determined by climatic change foreseen for the next decades
Oltre la perturbazione: la foresta di Lagdei verso un nuovo futuro
Full text linkStudi, interventi e scelte di gestione dopo le annate siccitose e gli attacchi di bostrico dell’abete ross
Microsatellite mtDNA can be used to assess the genetic variability of Norway Spruce in different management systems in the Italian Alps
No full textAnalisi dell’infestazione di Ips typographus nella foresta dell’Alta Val Parma e strategie per la ricomposizione del bosco
Full text linkAnalysis of the bark beetle outbreak in the forest “Alta Val Parma” (Corniglio, Parma, Italy) and strategies for its regeneration. Norway spruce plantations located in the Foresta Demaniale Alta Val Parma (Corniglio, province of Parma - Italy) experienced since 2004 a massive outbreak of Norway spruce bark beetle (Ips typographus). This outbreak has been triggered by the exceptionally warm and dry summer of 2003. In the following years bark beetle attacks repeated and spread, raising concern about the future of this kind of stands. A survey program has been carried out to help local administration to chose the correct managements strategies. Monitoring of Ips typographus population, carried out between 2007 and 2013, confirmed the presence of two generations per year, with values above the risk threshold in 2007 and just below though very high in 2011. In the affected area, six survey plots have been realized to test different management options with the aim of favoring a fast regeneration of the forest cover. The tested options showed the great difficulty in the establishment of natural generation either for the lack of mother plants in such pure stands or for competition with tall grasses. Sowing brought no significative results, while direct plantation of indigenous broadleaves was more effective, with almost half of the individuals still alive after three years. Our results confirm the great difficulty to rebuild the forest cover after strong ecological disturbances in these artificial forests. Hybrid management strategies and ad hoc silvicultural choices seem to be the only way to manage such kind of situations in a National park, where the priority is biodiversity conservatio
Global change e risalita della treeline: conseguenze genetiche della colonizzazione dei pascoli alpini.
No full textGenetic variability of Italian southern Scots pine (Pinus sylvestris L.) populations: the rear edge of the range
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