Some aspects of Late Iron Age agriculture based on the first results of an archaeobotanical investigation at Corvin tér, Budapest, Hungary

Until now, very little was known about the agriculture of the Late Iron Age in Hungary. This paper describes the first results of an archaeobotanical examination of a late Iron Age, Celtic settlement in Budapest. It is the first systematically sampled and representatively investigated site of this time period in Hungary. Most of the samples come from different types of pits, which were subjectively sampled. The macrofossils were carbonised and, apart from many seeds and fruit stones, consisted mostly of charcoal. Among the seed remains both cultivated and wild species were present. The spectrum of cultivated plants was marked by a large number of cereals. The dominant cereals were Triticum spelta L. (spelt wheat) and Panicum millaceum L. (broomcorn millet), but also common were Avena sativa L., Avena sp. (oats), Triticum monococcum L. (einkorn), Hordeum vulgare L. (barley); Triticum aestivum/durum/turgidum L./Desf./L., incl. T. compactum Host. (bread wheat, including club wheat). Secale cereale L. (rye) and Triticum dicoccum (Schrank) Schübl. (emmer) were rare and seemed to be less important. The weeds and synanthropic vegetation, including ruderals, were represented by many taxa, and some of them also occurred in large amounts. The main cereals were sown as winter crops, judging from the rarely occurring of plants accompanying the cereals. Wild fruits contributed to the daily diet, too – as seen from the stones of Cornus mas (cornelian cherry), Crataegus sp. (hawthorn) and Prunus spinos (sloe, blackthorn). There were no finds of cultivated fruits. Received October 19, 2001 / Accepted January 30, 2002     

Optimized somatic embryogenesis in Pinus strobus L.

Summary Somatic embryogenesis (SE) initiation in Pinus strobus was optimized by the manipulation of plant growth regulator (PGR) concentrations in the culture medium. Modified Litvay medium (MLV) of Litvay et al. (1985) supplemented with lower than routinely used PGR concentration increased initiation of established embryogenic cultures from approximately 20 to 53%. The original developmental stage of zygotic embryos had a pronounced effect on the SE response. The optimum stage was the pre- to shortly post-cleavage stage. A substantial genetic influence on initiation of SE was indicated by a significant variance component due to families. Genotype X collection date and genotype X media interactions had large effects on initiation of SE. The PGR levels in the culture medium prior to maturation had a significant effect on subsequent production of mature somatic embryos. Embryogenic tissue initiated and proliferated on medium with a low level of PGR consistently produced a high number of somatic embryos, indicating that optimized initiation protocol also enhanced somatic embryo production. Somatic embryos of 93 embryogenic lines (representing five families) that were initiated on media with different PGR concentrations were converted to plants at an overall frequency of 76%, and grown in the greenhouse. With these improved protocols, application of P. strobus SE in commercial clonal forestry is feasible as an alternative to traditional breeding and reforestation.     

Demographic studies of three indigenous stand-forming plant taxa (Scalesia, Opuntia, and Bursera) in the Galápagos Islands, Ecuador

Mortality and turnover of some of the most characteristic woody plants of Galápagos have been studied during 25 to 32 years on the islands of Santa Cruz, Santa Fe and Pinta. Scalesia pedunculata, S. helleri subsp. helleri and S. baurii subsp. hopkinsii display comparable patterns of high mortality, rapid turnover and relatively short life expectancy, but occur in different habitats and islands in the archipelago. In contrast, Opuntia echios var. gigantea, O. echios var. barringtonensis, O. galapageia var. galapageia, and Bursera graveolens display low mortality (especially of adults), slow turnover and long life expectancies, and occur in similar habitats on different islands. Conditions that favour one taxon may at the same time negatively affect another taxon, and adults, juveniles and seedlings within the taxa may react differently to the same environmental factors. In the humid zone species S. pedunculata, diebacks may be triggered by strong El Niño events, and mass seedling events are associated with El Niños and a subsequent year of drought. In the other taxa investigated, which are arid zone species, the response to strong El Niño events is less pronounced and, in some respects, also different. The differences in mortality, turnover and life expectancy of the species of Scalesia on the one hand and the Opuntia taxa and Bursera on the other, suggest that both humid and arid vegetation types containing species of Scalesia should get higher conservation priority than arid vegetation types without species of Scalesia.     

Occurrence of UDPG: Sterol glucosyltransferase activity in some lower plants

A study was made of the sterol glucosylating ability of cell-free homogenates obtained from 16 species of photosynthesizing and nonphotosynthesizing lower plants (2 species of Chlorophyceae, 2 species of Cyanophyceae, 1 species of Phycomycetes, 3 species of Ascomycetes, 3 species of Basidomycetes, 1 species of Myxomycetes, 3 species of Musci and 1 species of Sphenopsida). Except for the blue-green and green algae, all the remaining species showed distinct in vitro synthesis of steryl monoglucosides from UDPG and cholesterol or sitosterol. Preliminary studies on the specificity of the relevant enzymes pointed to a correlation between the sterol composition of the plant and the specificity of its glucosylating enzyme. The enzyme from Ascomycetes and Basidomycetes utilized ergosterol better than cholesterol or sitosterol. Enzymic preparations from mosses utilized sitosterol the best.     

Nitrogen stable isotopic composition of leaves and soil: Tropical versus temperate forests

Several lines of evidence suggest that nitrogen in most tropical forests is relatively more available than N in most temperate forests, and even that it may function as an excess nutrient in many tropical forests. If this is correct, tropical forests should have more open N cycles than temperate forests, with both inputs and outputs of N large relative to N cycling within systems. Consequent differences in both the magnitude and the pathways of N loss imply that tropical forests should in general be more¹⁵N enriched than are most temperate forests. In order to test this hypothesis, we compared the nitrogen stable isotopic composition of tree leaves and soils from a variety of tropical and temperate forests. Foliar ¹⁵N values from tropical forests averaged 6.5 higher than from temperate forests. Within the tropics, ecosystems with relatively low N availability (montane forests, forests on sandy soils) were significantly more depleted in¹⁵N than other tropical forests. The average ¹⁵N values for tropical forest soils, either for surface or for depth samples, were almost 8 higher than temperate forest soils. These results provide another line of evidence that N is relatively abundant in many tropical forest ecosystems.     

山东沂山种子植物区系研究

沂山位于鲁中丘陵东部,有种子植物122科、463属、886种。对108科、411属、727种野生种子植物的区系研究表明:沂山种子植物区系类型多样、地理成分复杂、优势现象明显、温带特征显著、具典型的暖温带落叶阔叶林性质。与相邻种子植物区系的比较表明:沂山种子植物区系与泰山具有较高的同质性,与崂山、云台山、千山依次递减,与芦芽山和大青山则具明显差异。     

一种基于PCR技术鉴定单拷贝转基因烟草的方法

为了鉴定携带单拷贝外源基因的转基因烟草植株,以烟草核基因组上已知的单拷贝内源基因（RNR2）为内参,转基因烟草植株基因组DNA为模板,在同一PCR反应体系中扩增内源基因（RNR2）和外源目的基因（NPTⅡ）。反应产物在琼脂糖凝胶上电泳,获得了预期大小的两条特异性扩增条带。经ImageJ软件捕捉分析两条目的条带的灰度比,当T1代转基因烟草植株中外源基因与内源基因的扩增条带灰度比为1时,所检测植株即为单拷贝外源基因的转基因烟草植株。孟德尔经典遗传学方法证实了上述检测结果高度可信。     

三峡库区资源植物的现状与保护

据调查统计,三峡库区有资源植物2070种,其中药用植物1006种、纤维植物104种、油脂植物76种、观赏植物74种、野果植物54种、芳香植物54种、树脂树胶植物68种、淀粉及糖类植物52种,鞣科植物32种、珍稀植物49种、其它类型植物465种。论述了三峡库区资源植物的分类及保护现状。