Phytoliths of six woody species important in the Carpathians: characteristic phytoliths in Norway spruce needles

Abstract

Phytoliths-also known as plant opals-are preserved in soils and sediments and have taxonomical relevance, therefore phytoliths can be fingerprints of the vegetation of the period from which they originated. Comparative phytolith studies are essential for finding phytolith morphotypes with taxonomic relevance. These are used to build reference collections for future palaeoecological and archaeobotanical studies. Biogenic silica extracted from the leaves of six woody species commonly occurring in temperate climate plant communities was examined using light and scanning electron microscope methods (Deciduous broad-leaved species: Corylus avellana, Fagus sylvatica, Quercus robur. Coniferous species: Abies alba, Picea abies, Pinus sylvestris). The element content of phytoliths was analysed by SEM EDX and the phytolith taxonomic diagnostic potential of element content was tested by discriminant analysis. An inventory of phytolith types with their anatomical origin was provided and type-frequencies were assessed. Three species have been systematically screened here for the first time in detail (C. avellana, F. sylvatica, Q. robur). This is the first time that a characteristic cubical phytolith morphotype ("Picea-blocky type") originating from transfusion tissue was described as a distinct layer encompassing the central cylinder of the needle. High concentrations of aluminium and magnesium in phytoliths are associated with two of three conifer species. A. alba and P. sylvestris could be differentiated statistically on the basis of elemental content. Our findings open up the possibility to identify these taxa based on their phytoliths and it is anticipated that this could be a useful tool for phytolith identification originating from soils and sediments as well. Moreover, Picea-blocky type allows comparative, in situ studies (amongst others isotopic) to provide the possibility of finding further measurable proxies.

pH-dependent silicon release from phytoliths of Norway spruce (Picea abies)

“…We collected threeyear-old or older needles from a reference tree, which was growing in a private yard in the Great Hungarian Plain (47.553296°N, 21.599187°E). This tree was selected because it was the subject of earlier studies (Lisztes-Szabó et al 2019).…”

“…Phytolith extraction from treated needles (TNs) was accomplished using the dry-ashing technique (Albert and Weiner 2001;Mercader et al 2010;Lisztes-Szabó et al 2019). Samples were dried at 105°C overnight and weighed.…”

“…A characteristic phytolith type was recently recognized in the transfusion tissue of Norway spruce (Picea abies [L.] Karst.) needles (Lisztes-Szabó et al 2019). This may be a potential keystone in future paleoecological studies for several reasons: (1) Norway spruce was an important species in the northern hemisphere during the early Holocene (Latałowa and van der Knaap 2006;Magyari et al 2014;Molnár and Végvári 2017); (2) spruce needles are often present and well preserved in sediment cores of glacial lakes and peat bogs; (3) phytoliths may be obtained from fossil needles, making it unnecessary to separate discrete phytoliths from the sediment by difficult and timeconsuming microfossil preparation protocols; (4) needle fossils preserve phytoliths in the tissues in situ, and can be further investigated with microchemical techniques (SEM-EDX, LA-ICP-MS); and (5) this special blocky form (Picea-blocky type), which develops in the needle, is a characteristic and recognizable silica body in phytolith assemblages from sediments.…”

Phytoliths in selected broad-leaved trees in China

“…To date, no especially diagnostic types of phytoliths have been identified for broad-leaved trees in general or a certain family. After reviewing other phytolith studies of species belonging to the broad-leaved trees 12,15,[46][47][48][49][50][51][52]55,56 (also see Table 4, we here propose several phytolith types that have the potential to be diagnostic to broad-leaved trees: Elongate brachiate geniculate ( Fig. 1-3), Polygonal tabular ( Fig.…”

“…Silicified epidermal cell 46 , anticlinal epidermal phytolith 7 , anticlinal 4,45 , anticlinal epidermal cell 48 , silicified tissue of the leaf epidermis composed of puzzle-piece-shaped cells 52 , jigsaw epidermal cell 50,51 , broad-leaf-types 9 ; jigsaw-shaped epidermal phytolith 5 ; epidermal jig-saw 12 , anticlinal epidermal cell 49 , stellate 55 , tabular sinuate 56 , irregular psilate sinuate 15 This type of phytoliths have been frequently reported to be observed in broad-leaved trees, however, they have also been reported to be observed in ferns, thus it might of low potential in being a diagnostic type for broad-leaved trees Polygonal tabula (Fig. 1-5)…”