Nickel Hyperaccumulation in the Serpentine Flora of Albania
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© by PSP Volume 22 – No 6. 2013 Fresenius Environmental Bulletin NICKEL HYPERACCUMULATION IN THE SERPENTINE FLORA OF ALBANIA Aida Bani1, *, Alma Imeri2, Guillaume Echevarria3, 4 5 3 1 Dolja Pavlova , Roger D. Reeves , Jean Louis Morel and Sulejman Sulçe 1Agro-Environmental Department, Faculty of Agronomy and Environment, Agricultural University of Tirana, Koder-Kamez, Tirana, Albania 2Department of Plant Production, Faculty of Agronomy and Environment, Agricultural University of Tirana, Koder-Kamez, Tirana, Albania 3Laboratoire Sols et Environnement, Nancy-Université, INRA, 2 avenue de la Forêt de Haye, B.P. 172 F-54505, Vandoeuvre-lès-Nancy, France 4Department of Botany, Faculty of Biology, University of Sofia, blvd. Dragan Tzankov 8, 1164 Sofia, Bulgaria 5School of Botany, University of Melbourne, Parkville, VIC 3010, Australia ABSTRACT They are characterized by low calcium-to-magnesium ratios with Ca at significantly lower concentrations rela- Serpentine soils are widespread in Albania, they host tive than in surrounding areas. Serpentine soils are often some widespread species and several nickel hyperaccu- deficient in essential plant nutrients such as nitrogen, potas- mulating species. The objectives of the study were the sium, and phosphorus [1-3] and their physical conditions identification and collection of new and rare species, the also are inhospitable for many plants. These characteris- discovery of new instances of Ni hyperaccumulation, in tics support a unique serpentine flora, a flora which pre- which plant species can accumulate Ni to concentrations sents taxonomical, phytogeographical and ecological phe- exceeding 0.1% of the plant dry weight. In Albania, there nomena of great interest. Brady et al. (2005) [4] empha- has already been special interest in Ni accumulation by sized that plant adaptation to different soil types is evidence Alyssum murale in Pojska (Pogradec). We now report in- of the strong natural selection imposed by ecological dis- stances of hyperaccumulation of Ni (reaching shoot con- continuities. The influence of ultramafic soils on the speci- centrations of 0.5-1.26% d.w.) in plants of some serpentine ation process and species richness has been the subject of soils i.e. in Kukës, Qafë Shtamë, Gramsh and Librazhd. much investigation [1, 3, 5, 6]. The high number of endem- Most plants from these soils showed slightly elevated Ni ics indicates the importance of serpentine habitats as cen- concentrations in comparison with those from other soil ters for floristic differentiation and speciation, and this types: about 11-100 mg kg-1, rather than 0.5-10 mg kg-1. endemism ranges from strictly local (a single outcrop) to In some species Ni content ranged between 145-275 mg regional and widespread occurrences [5, 7, 8]. Serpentine kg-1, while the same species from the non-serpentine areas also appear to be important refuges for many non- substrata contained very low Ni concentrations as ex- endemic native species, since they are limitedly invaded by pected. Full knowledge of Albanian Ni hyperaccumulator other plant communities. Serpentine soils account for 10% plants and their properties is of interest because of their of the land area of Albania, on which some plant taxa are possible use in phytomining. This study was undertaken serpentine endemic. The species on serpentine soils can be in the framework of the need for further exploration of the serpentine-tolerant (ST) or serpentine-facultative (SF) plants, natural resources and the associated conservation issues. which are able to survive on serpentine but grow better else- where and serpentine-endemic or serpentine-obligate (SO) plants, which are not found on other substrata [9]. Early KEYWORDS: work on the serpentine flora of the region has been sum- Ni hyperaccumulation; flora; endemic plants; high altitude marized by Brooks (1987) [1], and other notable contribu- tions are those of Babalonas et al. (1984) [10], Pavlova, Shuka and Hallaçi (2010) [11-13]. According to Stevano- 1 INTRODUCTION vić et al. (2003) [8] there are 335 Balkan endemic vascu- lar plant taxa growing on serpentine substrates, of which Due to their physical and chemical composition, ser- 123 are obligate serpentinophytes. Confirmation of the pentine soils are known for their distinctive flora and hyperaccumulation by a number of Albanian serpentine vegetation, as compared to adjacent non-serpentine areas. species has been subject of some studies [14-17], but it is Serpentine soils frequently contain elevated levels of still insufficiently investigated. Serpentine outcrops can be heavy metals, such as iron, manganese, nickel, chromium, regarded as inland formations in mainland environments and cobalt, some of which are toxic to most plants. and biogeographic theory may help understand their spe- cies richness and species distribution [18-20]. Species of * Corresponding author particular interest include a number of endemics, suben- 1792 © by PSP Volume 22 – No 6. 2013 Fresenius Environmental Bulletin demics, and Ni hyperaccumulators such as Bornmuellera ranean climate. The annual average temperature was 13 ºC baldaccii (Degen) Heywood subsp. markgrafii O.E. with maximum from 25º-30ºC (from June to August), and Schulz, Alyssum markgrafii O.E. Schulz ex Markgraf, A. minimum 0 and 2.5ºC. The average annual precipitation bertolonii Desv., and the most widespread A. murale was 1600 mm. In the first sampling station (site 1) we Waldst. & Kit. Geographic isolation by altitude in high collected the Ni hyperaccumulator Alyssum bertoloni Desv. mountains and edaphic differentiation by soil types may subsp. scutarinum (silicula 2.8-5.5 mm wide, seed-wing underlie plant endemism in such regions [21]. Moreover, 0.5 mm wide) and plant taxa that accompanied Ni-hyper- some serpentine endemics of the Balkans, including hyper- accumulator present on the site. In site 2 we opened a accumulator species (e.g. B. baldaccii), are only reported at profile and sampled soil and plant. Ni hyperaccumulator high elevation in literature [15]. Alyssum bertoloni Desv. was collected also in site 3 at an Metal hyperaccumulators have recently gained con- altitude of 1044 m. siderable interest because of their potential use in phy- The third region was Kukës near the tunnel of Kali- toremediation [22, 23], phytomining [24, 25] and food crop mash along the road for Surroj village. The region is part biofortification [26, 27]. They also constitute an excep- of the north Albanian mountain climatic region, with Medi- tional biological material and gene reservoir that can be terranean influence. The average temperature of January exploited to understand metal homoeostasis and adapta- throughout the entire site reaches low values. Average tion to extremely hostile environments. temperature oscillate from a minimum -2º to -3ºC (January) to maximum 19º-21ºC (from June to August), and annual This concentration of Ni hyperaccumulators in Alba- average between 9º and 12ºC. The average annual precipi- nia led us to investigate their distribution and behavior tation ranges from 1300 up to 1600 mm, with rainfall more closely, especially at some sites that are know for occurring mainly from the end of October to the end of hyperaccumulators [14-16, 28, 29]. The objectives of the May. Ni hyperaccumulator Alyssum markgrafii O.E. Schulz study were the identification and the collection of rare and all accompanying plants taxa were sampled on site to taxa in serpentine habitats and the scanning for potential study the Ni hiperacumulation. Ni hyperaccumulation in relation to the soil characteris- tics and to these environments. The study region Librazhd belongs to the hilly Medi- terranean climate sub zone (up to 1100 m) where mean January temperature is 5.6 °C, mean July temperature 22 °C, annual average 11.5 °C and total annual rainfall 1360 mm. 2 MATERIALS AND METHODS Up to 2% Ni has been recorded in the iron-type laterites of 2.1 Study area the Librazhd-Pogradec region. There are also Cr mines that are still mining for chromite in this area. Ni hyperaccumu- Four serpentine regions in Albania: Gramsh, Qafë lator Alyssum markgrafii O.E. Schulz and all accompany- Shtamë, Kukës and Librazhd were investigated. The study ing plants were sampled only in site 1 of this region. area belongs mainly to two climate sub zones: the pre- mountainous Mediterranean and mountainous Mediterra- 2.2 Herbarium specimens investigated for Ni hyperaccumula- nean climate in the highest peaks. tion Gramsh (Grabovë e Sipërme) is situated in the Eastern Plant samples for Brassicaceae species reported as Ni mountain climatic region of Albania, within the Mediterra- hyperaccumulators from each of the four selected regions nean mountain Climatic Zone at an elevation of 1594 m were taken from the specimens of the National Herbarium (40°47 824’N, 20°25 864"E). This mountain region dis- of Albania at the University of Tirana to investigate Ni plays cold winter and fresh summer temperature. Average and to compare them with our collected samples. The spe- temperature is 14.3ºC, with minimum 4.6 ºC in January cies were: A. bertolonii subsp. scutarinum, A. markgrafii, and maximum 26.4 ºC in July. The average annual pre- A. murale and B. baldaccii subsp. Markgrafii. cipitation attains 1350 mm. Three sites were studied for Ni hyperaccumulators. In site 1 together with Ni hyperac- 2.3 Soil and plant analyses cumulators Bornmuellera baldaccii subsp. markgrafii (Bras- The plant identification and nomenclature follows sicaceae) and Alyssum markgrafii O.E. Schulz all plant taxa Tutin et al. (1993) [30]. Voucher specimens of the plants that accompanied already known Ni-hyperaccumulators collected were deposited in the Herbarium of the Univer- were also collected. This site was a pasture with low pro- sity of Tirana, Albania. One to three specimens for each ductivity which was currently being grazed. The other Ni plant were collected from each site. Specimens were pooled hyperaccumulator, Alyssum murale Waldst. & Kit was to make a composite sample when there was more than sampled in site 2 (i.e. a rocky area) and in site 3 (i.e.