Studio della risposta adattativa alla siccità in Pinus heldreichii lungo un transetto altitudinale negli Appennini e nei Balcani

Responsabili di progetto

Giovannigiuseppe Vendramin, Jelena Lazarevic

Accordo

MONTENEGRO - MoS-not in force - Ministero della Scienza del Montenegro

Bando

CNR-MoS 2017-2018

Dipartimento

Scienze bio-agroalimentari

Area tematica

Scienze bio-agroalimentari

Stato del progetto

Rinnovo

Relazione per il rinnovo

relazione-2015-16.pdf

Proposta di ricerca

One of the most pressing research object of evolutionary ecology is the estimate of the adaptive potential of forest trees. In particular, forest tree populations at the margins of the distribution range can be useful case studies to understand the processes by which populations adapt or not to novel environmental conditions (Hampe & Petit 2005; Hampe & Jump 2011). This may be particularly true in the case of populations at the southern margins that can be adapted to climatic conditions expected in the future in more northerly central populations. Several documented events of forest tree die-off have been induced by drought (Allen et al. 2010; Martínez-Vilalta et al. 2011), suggesting that temperature is an important environmental factor, which can limit the geographical distribution and growing season of forest trees. To implement conservation strategies under global change scenario, it will be crucial to study local adaptations at the rear edge limit of tree populations. Pinus heldreichii H. Christ is an oro-Mediterreanean species mostly present in high mountain regions in the western part of Balkan peninsula and it is considered a tertiary relict. In southern Apennines it is also present with small and scattered populations at an altitude between 800-2200 m a.s.l.. At the upper forest treeline, it vegetates mainly on harsh, xerothermic and poor habitats, on soils derived from calcareous parent material, commonly vey stony or on screans, while on lower parts of its distribution in Montenegro it forms climatogenous forests on more or less flatten mountain plateaus with relatively well developed soil layer (brown soils on limestone (Lepic cambisol (eutric).
Upward migration is limited at treeline by selective pressure from unfavourable abiotic conditions on seedling establishment and growth. Low temperature severely limits tissue formation and seedling growth (Körner, 1999). During winter frozen soil strongly reduces water availability, while stems and shoots are exposed to water losses caused by high wind and intensive radiation (Baig and Tranquillini, 1980). Drought stress combined with frequent freeze-thaw events causes embolism damage in forest trees (Mayr et al., 2003). Moreover, during the last decades, frost damage has been increased by the shorter snow cover, caused in the alpine region by reduced winter precipitation (Brunetti et al., 2000). Harsh environmental conditions, increasing temperature and the marked decline of grazing make treeline colonization a unique opportunity to study the balance of the main forces (selection and gene flow) that drive tree migration. Recent research in conifers (Wachowiak et al., 2009) demonstrated that several genes are induced by environmental stress associated with dehydration. Among them a group of dehydrins, which accumulation in plant tissues in response to dehydrative stress have been shown to enhance survival of woody plants in low temperature or under drought conditions (Welling and Palva, 2006).
Therefore, this research proposal primarily aims at establishing a collaboration between CNR and Montenegro to search for patterns of selection in a group of drought-related candidate genes by analyzing the level of nucleotide variation, linkage disequilibrium, and departures of allele (haplotype) distributions from neutral expectations in comparisons between populations along altitudinal transects replicated both in the Balkans and in southern Apennines. Partially sampled populations and candidate genes primers already optimized in P. heldreichii can provide a solid starting point.

References
Allen CD, Macalady AK, Chenchouni H et al. (2010) Forest Ecology and Management, 259: 660-684
Baig MN, Tranquillini W (1980). Oecologia 47: 252-256.
Brunetti M, Maugeri M, Nanni T (2000). Theor Appl Climatol 65: 165-174.
Körner C (1999). Alpine plant life. Springer: Berlin.
Hampe A, Petit RJ (2005) Letters, 8:461-467
Hampe A, Jump AS (2011) Annual Review of Ecology, Evolution, and Systematics, 42: 313-333.
Mayr S, Schwienbacher F, Bauer H (2003). Plant Physiol 131: 780-792.
Martínez-Vilalta J, Lloret F, Breshears DD (2011) Biology Letters, rsbl20111059
Wachowiak W, Balk PA, Savolainen O(2009) Tree Genetics & Genomes 5:117-132
Welling A, Palva ET (2006) Physiol Plantarum 127:167-181

Obiettivi della ricerca

The scope of this project is to strengthen the cooperation of Montenegro and Italy developed by the previous "Tree fragmented populations from refugial areas: the anfiadriatic connection" project in the area of implementing forest trees conservation strategies under a global change scenario.
The major aims are:
1. To study local adaptation at the rear edge limit of Pinus heldreichii populations,along altitudinal transects replicated both in the Balkans and in southern Apennines.
2. To develop science-based forest management strategies for the protection of forests under ongoing climate changes
3. To develop research proposals with EU funding perspective and further consolidate the scientific cooperation between the participating countries

Ultimo aggiornamento: 06/12/2024