Funkcionalna diferencijacija provenijencija hrasta crnike na istočnoj obali jadranskoga mora : [Functional differentiation of holm oak provenances in the east Adriatic coast]

Holm oak (Quercus ilex L.) is an evergreen tree species with natural distribution within the Mediterranean, from Portugal and Morocco on the west to the western coast of Turkey on the east part of its range. On the eastern coast of the Adriatic Sea, it occupies warmer localities on the coast of Istria and northern Adriatic islands while on the southern Adriatic islands as well as on the narrower coastal area south of Zadar it has a more continuous distribution. Given the size of the area of distribution, holm oak shows a big morphological and functional variability so certain populations differ according to the climate conditions in their area. This fact has been very well researched in the western and central part of its range, while the data for the eastern part, and thus for the eastern coast of the Adriatic Sea, are scarce. The great morphological and functional variability of holm oak reflects its great phenotypic plasticity. Although phenotypic plasticity is conditioned by the environment, it can also have a genetic basis through local adaptation to the established environmental conditions in different parts of the species’ area of distribution. The aim of this study was to determine whether there is a differentiation of holm oak down the climatic gradient of the eastern Adriatic coast with respect to the functional characteristics of its leaves. The research was conducted on three provenances of holm oak from the area of Pula and Zadar in the Republic of Croatia and Bar in Montenegro. During the winter of 2019, 12 leaves were sampled per 12 trees in each provenance in order to determine the specific leaf area (SLA). Additionally, acorns were collected beneath those trees with which an greenhouse experiment was established. In the experiment, a total of 64 plants were grown, of which 22 plants from the provenances of Pula and Zadar, and 20 plants from the provenance of Bar. In the second part of the vegetation period in 2020, one leaf was sampled from each pla
Hrast crnika (Quercus ilex L.) je sredozemna vazdazelena vrsta drveća, koja na svom području pridolaska pokazuje veliku morfološku i funkcionalnu varijabilnost. Cilj ovoga rada bio je utvrditi postoji li diferencijacija hrasta crnike na klimatskom gradijentu istočne obale Jadranskoga mora (opisanom s prosječnom godišnjom količinom oborina, prosječnom količinom oborina tijekom ljetnog perioda i klimatskim deficitom vlage) s obzirom na funkcionalne značajke lišća (opisane sa specifičnom lisnom površinom, indeksom relativnog sadržaja ukupnih klorofila u lišću i stopom neto fotosinteze mjerene u lišću). Specifična lisna površina mjerena je na lišću uzorkovanom u tri provenijencije na prirodnom staništu te lišću uzorkovanom u pokusnom nasadu na mladim biljkama porijeklom iz tih istih provenijencija. U pokusnom nasadu mjeren je i indeks relativnog sadržaja ukupnih klorofila i stopa neto fotosinteze. Provenijencija Pula u odnosu na provenijencije Zadar i Bar ima veću specifičnu lisnu površinu te manji indeks relativnog sadržaja ukupnih klorofila i stopu neto fotosinteze. To potvrđuje prilagodbu provenijencije Pula na vlažnije stanište, a provenijencija Zadar i Bar na suše stanište te ujedno ukazuje na funkcionalnu diferencijaciju provenijencija hrasta crnike na istočnoj obali Jadranskoga mora s obzirom na klimatske prilike. Isti obrazac diferencijacije prema specifičnoj lisnoj površini u prirodnim sastojinama i pokusnom nasadu ukazuje na ekotipsku diferencijaciju istraživanih provenijencija. Prema tomu, hrast crnika mogao bi imati značajnu mogućnost funkcionalne prilagodbe na promijenjene klimatske uvjete.