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U ovome radu prikazani su rezultati rasta bukovih sadnica pod utjecajem suboptimalne ishrane s dušikom (N), fosforom (P), magnezijem (Mg) i željezom (Fe). Cilj rada bio je približiti ovu problematiku šumarskoj praksi kroz raspravu dobivenih rezultata u kontekstu dosadašnjih spoznaja o rastu biljaka pod utjecajem suboptimalne ishrane s mineralnim hranivima. U rano proljeće 2019. godine 30 bukovih jedinki u razvojnom stadiju ponika, porijeklom iz jedne prirodne mješovite sastojine hrasta kitnjaka i obične bukve, presađeno je u sterilni supstrat (agroperlit). Nakon presadnje tijekom sljedeće tri godine po šest presađenih biljaka redovito je zalijevano (tretirano) s kompletnom hranjivom otopinom (KO tretman), odnosno hranivim otopinama u kojima su izostavljeni dušik (-N tretman), fosfor (-P tretman), magnezij (-Mg tretman) ili željezo (-Fe tretman). Prema tomu, na šest biljaka unutar svakog od pet prethodno opisanih tretmana bilježeni su početak i trajanje razvoja lišća (2020. i 2021. godine), broj listova te prosječna i ukupna površina lišća (2019., 2020. i 2021. godina). Promjer stabljike na vratu korijena i visina stabljike mjereni su u proljeće 2019. i jesen 2021. godine, na temelju čega je izračunat debjinski i visinski prirast bukovih sadnica, te njihova vitkost na početku i na kraju pokusa. Uz to, tretiranim sadnicama utvrđena je masa suhe tvari lišća, stabljike i korijenja te ukupna dužina krupnog i sitnog korijenja, kao i broj račvanja i vrhova sitnog korijenja, što je obavljeno u jesen 2021. godine nakon njihova vađenja iz agroperlita. Na temelju usporedbe dobivenih rezultata između biljaka u kontrolnom i ostalim tretmanima bilo je moguće zaključiti da je pod utjecajem suboptimalne ishrane bukovih sadnica s P došlo je do odgode proljetnog otvaranja pupova i početka razvoja lišća. Najsporiji razvoj lišća zabilježen je pod utjecajem suboptimalne ishranjenosti s N i Mg. Prosječna površina lišća nije bila značajnije utjecana suboptimalnom ishranjenošću niti s jednim hranivom. Smanjenje broja listova i njihove ukupne površine pod utjecajem suboptimalne ishranjenosti sa svim hranivima zabilježeno je tek u posljednjoj godini provedbe pokusa. Debljinski i visinski prirast stabljike također su bili negativno utjecani suboptimalnom ishranjenošću sa svim hranivima, a smanjena vitkosti sadnica zabilježena je samo pod utjecajem suboptimalne ishranjenosti s Fe. Ukupna, duljina krupnog i sitnog korijenja također je bila negativno utjecana suboptimalnom ishranjenošću sa svim hranivima, izuzev N. Pod utjecajem suboptimalne ishranjenosti s N došlo je do povećanja ukupne dužine sitnoga korijenja, kao i do povećanja broja račvanja i vrhova sitnog korijenja. Unatoč tomu, na masu suhe tvari krupnog i sitnog korijenja suboptimalna ishranjenost sa svim hranivima imala je negativan utjecaj, uključujući i N.

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., 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 plant with the aim of determining the specific leaf area (SLA). In addition, the rate of net photosynthesis (A) and the relative total chlorophyll content index (CCI) were measured in the greenhouse experiment. Measurements were performed in July and September of 2020. A was measured using a portable gas exchange measuring device LCpro + (ADC BioScentific, 2007), while the CCI was measured using the CCM-200 (Opti-Sciences, Tyngsboro, MA).Analysis of the variance revealed a statistically significant difference among the studied provenances for most of the measured characteristics both on the leaves sampled in the natural habitat and on the young plants in the experimental plantation. Previous research on holm oak indicates that there is a functional differentiation of provenances on different climatic gradients in the central and western Mediterranean, with our results confirming this on the eastern coast of the Adriatic Sea. Young plants in the experimental plantation retain the same pattern of differentiation with respect to SLA as their mother trees in natural stands (Figure 1c). Such a result indicates that the differentiation of holm oak provenances is at least partly the result of genetic adaptation to local habitat conditions, i.e. that the holm oak on the eastern Adriatic coast as well as in other parts of its range could distinguish ecotypes. The sclerophilicity of the leaves described by SLA (Figure 1c) does not coincide with the average annual rainfall (Figure 1a), but with the amount of precipitation in the summer (Figure 1b) and the climate deficit of moisture (Figure 2a). The established pattern of provenance differentiation with respect to SLA and climatic conditions is followed by A measured on young plants in the experimental plantation. Therefore, Pula, which has the highest SLA and comes in the least arid climatic conditions, has the lowest A, while Zadar, which has the lowest SLA and comes in the most arid conditions, shows the highest values of A (Figures 1 and 2). This is in line with the literature that shows that the intensity of photosynthesis per unit leaf area in holm oak decreases with increasing SLA (Niinemets 2015, Peguero-Pina et al. 2017). Namely, the anatomical structure of holm oak leaves is adapted in such a way that those leaves that have a lower SLA also have better conductivity of CO2 through the mesophilic leaves and contain more nitrogen per unit area. Accordingly, the provenances of Zadar and Bar compared to the provenance of Pula had a lower SLA (Figure 1c) and a higher CCI (Figure 2b) which has a positive correlation with the nitrogen content in the leaves.Holm oak could have a significant ability to functionally adapt to different climatic conditions. Accordingly, when considering the impact of climate change on natural populations of holm oak, its phenotypic plasticity should be considered, as well as the observed functional ecotypic differentiation.

U radu je predstavljena nedestruktivna procjena koncentracije fotosintetskih pigmenata (ukupnih klorofila i karotenoida) u lišću hrasta lužnjaka pomoću prijenosnog optičkog klorofilmetra CCM-200. Istraživanje je provedeno 2015. godine na biljnom materijalu izloženom različitim tretmanima vlažnosti tla. U kontrolnom tertmanu sadržaj vlage u tlu održavan je iznad poljskog vodnog kapaciteta, dok je u sušnom tretmanu biljkama voda bila uskraćena 112 dana (1. 4. – 21. 7.). U drugom dijelu vegetacijskog razdoblja (22. 7. – 22. 10.) u oba tretmana vlaga tla održavana je iznad poljskog vodnog kapaciteta. Na temelju lišća uzorkovanoga istovremeno u oba tretmana i to sredinom jeseni (27. 10.) izrađene su kalibracijske jednadžbe koje opisuju odnos indeksa relativnog sadržaja klorofila izmjerenoga pomoću klorofilmetra i stvarne koncentracije fotosintetskih pigmenata (utvrđene laboratorijski) pred sam kraj vegetacijskog razdoblja. Jednadžbe su konstruirane posebno za kontrolni, a posebno za sušni tretman. S obzirom na takav dizajn pokusa i vrijeme uzorkovanja, primarni cilj rada bio je ispitati utjecaj dugotrajnog sušnog razdoblja na homogenost parametara kalibracijskih jednadžbi (Y-odsječaka i nagiba pravaca). Na temelju dobivenih rezultata zaključeno je da parametri kalibracijskih jednadžbi nisu bili utjecani sušnim tretmanom. Prema tome, rezultati istraživanja ukazuju na to da klorofilmetar CCM-200, uz primjenu odgovarjućih kalibracijskih jednadžbi, predstavlja pouzdan alat za nedestruktivnu procjenu koncentracije ukupnih klorofila i karotenoida u lišću hrasta lužnjaka, bez obzira na različite režime vlažnosti tla kojima je biljni materijal bio izložen tijekom vegetacijskog razdoblja. Uz to, u radu je utvrđeno da bi preciznost procjene stvarne koncentracije fotosintetskih pigmenata bilo moguće i dodatno poboljšati korekcijom klorofilnog indeksa sa specifičnom lisnom masom., The concentration of photosynthetic pigments (chlorophylls and carotenoids) in leaves of forest trees is a good indicator of the photosynthetic efficiency, level of nutrition with nitrogen and autumn leaf senescence. Thus the photosynthetic pigment concentrations is one of the most significant parameters related to the physiological status of plant. Change in pigment concentrations of leaves indicate presence of environmental stress. Well-timed detection of environmental stress play a crucial role in preventing damage on seedlings and saplings in forest nurseries and wood mass production in forest cultures and plantations. Traditional methods for determining the concentrations of photosynthetic pigments represent an obstacle to continuous monitoring concentrations of photosynthetic pigment in leaves of forest trees, primarily because they are relatively expensive, long lasting and require destruction of plant material. However, portable optical chlorophyll meters such as CCM-200 (Opti-Sciences, Tyngsboro, Massachusetts, USA) and SPAD-502 (Minolta Camera Co., Osaka, Japan) is a reliable alternative to traditional laboratory methods. To use chlorophyll meters as a tool for estimating photosynthetic pigment concentrations in leaves, it is necessary to construct regression equations (calibration equations) that reliably describe the relationships between the relative index of the total chlorophyll content in leaves (CCI) and the total pigment concentrations in leaves, determined by standard laboratory methods. In the present study, we set up experiment to establish the ability of the hand-held CCM-200 chlorophyll meter to accurately estimate the content of the photosynthetic pigments in leaves of Quercus robur L. with contrast level of soil moisture. The objectives of the present work were: (i) determine whether the long-lasting drought period significantly influences the relationship between the CCI obtined by CCM-200 and the concentration of photosynthetic pigments (total chlorophyll and carotenoid); (ii) construct calibration equations for non-destructive estimation of photosynthetic pigments in Q. robur leaves; (iii) to analyse the improvement estimation of photosynthetic pigments concentration when CCI was corrected with specific leaf mass. The research was carried out during the year 2015 on 60 two-years old plants grown in the greenhouse located in the Croatian Forestry Institute Jastrebarsko. Plant material was grown in 50 liter containers previously filled with soil originating from a natural oak stand. In the spring of the 2015, at the beginning of the study the mean height of investigated plants was 23.9 ± 4.8 cm. During the study, plant material was exposure to different level of soil moisture. In control treatment soil water content was kept above field capacity, while in drought treatment plants were exposed to water reduction during 112 days (1st of April – 21st of July). In second part of growing season (22nd of July – 22nd of October) in both treatments soil water content was kept above field capacity (Figure 1). Calibration equations, that describe relationship between relative chlorophyll content index measured with chlorophyll meter and actual photosynthetic pigment concentrations in sampled leaves (laboratory determined) at the end of growing season (27th of October), were constructed for both treatments (Table 2 and 3; Figure 4 and 5). Obtined results show that parameters of calibration equations were not affected by drought treatment (Table 4). Therefore, when using appropriate calibration equations, clorophyll meter CCM-200 can be considered as reliable tool for non-destructive estimation of total chlorophylls and carotenoids in Q. robur leaves, regardless of different soil water regimes during the growing season. Additionaly, this research confirmed that it is possible to improve the estimation of actual photosynthetic pigment concentration by using chlorophyll content index corrected with specific leaf mass (Table 2 and 3; Figure 4 and 5).

U radu je istražen potencijal prijenosnog optičkog klorofilmetra CCM-200 (Opti-Sciences, Tyngsboro, MA, USA) u svrhu utvrđivanja stanja ishrane hrasta lužnjaka s dušikom na temelju uzorkovanja različitih tipovia lišća (lišće proljetnih i sekundarnih izbojaka). Istraživanje je provedeno na 30 biljaka uzgajanih u pokusnom nasadu tijekom dva vegetacijska razdoblja (2009. i 2010. godine). Meteorološke prilike i gnojidbeni tretman koji je bio proveden u rano proljeće 2009. godine uvjetovali su razlike između istraživanih godina s obzirom na razvoj izbojaka tijekom tercijarnoga porasta (što predstavlja potencijalni pokretač translokacije dušika u krošnjama istraživanih biljaka). Na temelju lišća proljetnih i sekundarnih izbojaka, uzorkovanoga u srpnju i rujnu 2009. i 2010. godine konstruirano je ukupno osam kalibracijskih jednadžbi. Te jednadžbe pouzdano opisuju (p < 0,001) odnos između klorofilnoga indeksa izmjerenoga pomoću klorofilmetra i koncentracije ukupnoga dušika u lišću proljetnih i skundarnih izbojaka s obzirom na vrijeme uzorkovanja. Pomoću ANCOVA-e ispitan je utjecaj tipa uzorkovanoga lišća na homogenost parametara kalibracijskih jednadžbi (Y-odsječaka i nagiba pravaca) s obzirom na vrijeme uzorkovanja. Tip lišća nije značajno utjecao na nagibe pravaca, ali značajno je utjecao na njihove Y-odsječke u tri od ukupno četiri promatrana vremena uzorkovanja. Homogenost parametara kalibracijskih jednadžbi konstruiranih na temelju različitih tipova lišća utvrđena je samo u rujnu 2009. godine, kada je pod utjecajem produkcije tercijarnih izbojaka došlo do izjednačenja koncentracije ukupnoga dušika u oba tipa uzorkovanoga lišća. Prema tomu, jednom konstruiranu kalibracijsku jednadžbu nije moguće istovremeno koristiti za preciznu procjenu ukupne koncentracije dušika u različitim tipovima lišća. Takav rezultat dovodi u pitanje praktičnost i pouzdanost procjene stanja ishrane hrasta lužnjaka s dušikom pomoću klorofilmetra CCM-200., In this paper we investigated potential of portable chlorophyll meter CCM-200 (Opti-Sciences, Tyngsboro, MA, USA) to estimate total nitrogen concentration in different types of Pedunculate oak leaves. Research was conducted on 30 plants grown in field trial, during two vegetation periods (in years 2009 and 2010). Fertilization treatment (carried out in early spring in 2009) and meteorological conditions caused differences between investigated years regarding third-flush shoots (that can be considered as potential trigger for translocation of nitrogen in leaves and branches of investigated plants). Eight calibration curves was constructed based on spring and second-flush leaves, sampled in July and September in 2009 and 2010. These equations shown to be are reliable (p < 0,001) in describing relationship between chlorophyll content index, measured with chlorophyll meter, and total nitrogen concentration in spring and second-flush leaves, regarding moments of sampling (July and September 2009 and 2010). Influence of leaf flush type on homogeneity of equation parameters (i.e. slope and intercept), regarding moment of sampling, was tested using ANCOVA. Leaf flush type (spring or second-flush) did not have significant influence on slope, but did influenced intercepts in three moments of sampling (July 2009, and July and September 2010). Homogeneity of equation parameters was observed only for one moment of sampling, e.g. September in 2009, when third-flush shoots occurred which resulted in levelling of total nitrogen concentration in sampled leaves.