Pollen morphology in Saxifraga(Saxifragaceae) from Ny-Alesund, Svalbard, Arctic, and its taxonomic significance

Pollen morphology of eight species of Saxifraga, i.e.S, cespitosa, S. oppositifolia, S. cernua, S. nivalis, S. aizoides, S. rivularis, S. hieraciifolia, and S. hirculus, collected from Ny-Alesund, Svalbard, Arctic was examined using light and scanning electron microscopy. Pollen grains of Saxifraga species are subprolate or prolate, 3-colpate, 15.4-44.4 μm in the polar axis, 11.4 34.6 μm in the equatorial axis, and show a P/E ratio 1.19-1.40. On the basis of exine ornamentation, four pollen types, viz., the S. oppositifolia type （striate without scabrae on the muff）, S. cernua type （striate with scabrae on the muri）, S. nivalis type （microreticulate and operculum absent）, and S. cespitosa type （microechinate and operculum present）, were recognized. Hierarchical cluster analysis of the pollen morphological characters indicated that pollen morphology supports the infrageneric classification of the genus Saxifraga.

Pollen morphology of selected tundra plants from the highArctic of Ny-lesund, Svalbard

Documenting morphological features of modem pollen is fundamental for the identification of fossil pollen, which will assist researchers to reconstruct the vegetation and climate of a particular geologic period. This paper presents the pollen morphol- ogy of 20 species of tundra plants from the high Arctic of Ny-Alesund, Svalbard, using light and scanning electron microscopy. The plants used in this study belong to 12 families： Brassicaceae, Caryophyllaceae, Cyperaceae, Ericaceae, Juncaceae, Papav- eraceae, Poaceae, Polygonaceae, Ranunculaceae, Rosaceae, Salicaceae, and Scrophulariaceae. Pollen grain shapes included： spher- oidal, subprolate, and prolate. Variable apertural patterns ranged from 2-syncolpate, 3-colpate, 3-（-4）-colpate, 3-（-5）-colpate, 3-colporate, 5-poroid, ulcerate, ulcus to pantoporate. Exine ornamentations comprised psilate, striate-perforate, reticulate, mi- croechinate, microechinate-perforate, scabrate, granulate, and granulate-perforate. This study provided a useful reference for com- parative studies of fossil pollen and for the reconstruction of paleovegetation and paleoclimate in Svalbard region of Arctic.

Natural traps of spores and pollen grains from the region surrounding Wenbi Reservoir, Yunnan, China

We did a comparative analysis of pollen and spores from five kinds of natural pollen traps at Wenbi Reservoir, northwest Yunnan, China. The natural traps were the surface soil, ground inhabiting mosses, spider webs, tree bark and moss/lichen on trees. These traps showed qualitative and quantitative variations in the pollen and spore spectra. The palynomorphs recovered from the soil samples of trees and shrubs ranged from 90.54% to 95.98% of the total counts. These counts were higher than counts from ground mosses(53.13%–81.66%), spider webs(61.71%), bark samples(53.8%) and moss/lichen on trees(50%–53.6%). The result of pollen/spore analysis showed that surface soil, ground mosses and spider webs better reflect the local vegetation compared with tree bark or moss/lichen on trees.

Man-environment interaction and its impact since ca. 3600 years BP in West Bengal, India: A multiproxy approach

Climatic variability during the Holocene and corresponding anthropogenic response have gained considerable attention in different parts of India, but surprisingly very little is known on climate-human interrelationship from eastern India especially from the Gangetic plains of West Bengal. As climate has played significant role behind the collapse of many of the ancient human civilizations hence, to explore the reason behind the abandonment of any archaeological site, understanding of the climate of the contemporaneous past is a prerequisite. Agricultural development, subsistence strategies and dynamic behavior of climate in the Lower Gangetic plains of West Bengal since ca. 3600 cal a BP(Chalcolithic period) and post-Chalcolithic period(ca. 2350–2120 cal a BP to recent) were explored using multiproxy approach including plant-animal macro remains, wood charcoals and pollen and non-pollen palynomorphs from an archaeological site at Pakhanna, district Bankura in West Bengal, India. Evidences from palynological and phytolith data suggest that a warm-moist tropical climate during ca. 3600 cal a BP supported the spread of a village farming community in this part of lower Gangetic plains of West Bengal who practiced double-cropping as evidenced by the recovery of cereals(rice) and pulses(black gram) from the cultural deposits of Chalcolithic and Early Historic periods. In addition, a plenty of animal remains(opercula of carp fishes, fragments of plastron of Indian Soft Shelled Turtle, Indian Flap Shelled Turtle, ramus of mandible with teeth of Indian Boar) from similar cultural deposits indicate their probable inclusion in dietary list. The climate started changing during the onset of Early Historic period ca. 2350 cal a BP as revealed by pollen and phytolith proxies and became warmer and drier than that in earlier phase which is continuing till recent. The observations of palynological and phytolith data were also corroborated by the results of correspondence analysis(CA) and canonical correspondence analysis(CCA) respectively. Recovery of rice and mustard from Early Historic deposits suggests their continued cultivation at a later phase. Rich assemblages of animal macro remains from the post-Chalcolithic deposits(ca. 2350–2120 cal a BP) indicate their use as food resources in later phase too. Considering the database obtained from all the proxies it can be concluded that a moist-tropical climatic condition was prevailing during Chalcolithic period(ca. 3600 cal a BP) and later gradually shifted to a slight drier condition in lower Gangetic West Bengal.