Ella Werker

STRUCTURE OF GLANDULAR HAIRS AND IDENTIFICATION OF THE MAIN COMPONENTS OF THEIR SECRETED MATERIAL IN SOME SPECIES OF THE LABIATAE

The anatomical structure of the secretory hairs of eight species of Labiatae was studied and the main components of their secretory substances identified. Peltate and capitate hairs were found in all species, the latter consisting of three types, differing in structure and mode of secretion. The capitate hairs precede the peltate hairs in their development and secretory activity. In the capitate hairs the secreted material is extruded to the outside, while in the peltate hairs it remains in a subcuticular space. The eight species were divided into groups according to the structure of the volatile compounds they secrete.

Spatial Organization of Hominin Activities at Gesher Benot Ya’aqov, Israel

Home Is Where the Hearth Is One aspect of human intelligence is the ability to organize our living and working spaces. It was generally thought that this capability arose with modern humans in the past 100,000 years or so. However, Alperson-Afil et al. (p. 1677) found evidence of domestic organization 800,000 years ago at a Pleistocene hominin campsite in the Jordan Valley. Around patches of burnt debris, the remains of a wide range of plant and animal foodstuffs were found, including fruits and seeds, as well as remnants of turtles, elephants, and small rodents. Specific types of stone tools appear to have been made around the hearths, where there was also evidence of nut roasting and consumption of crabs and fish. In a more distant area there were signs of intensive flint knapping and food chopping. The spatial distribution of artifacts implies that living space was organized by use as early as 800,000 years ago. The spatial designation of discrete areas for different activities reflects formalized conceptualization of a living space. The results of spatial analyses of a Middle Pleistocene Acheulian archaeological horizon (about 750,000 years ago) at Gesher Benot Ya’aqov, Israel, indicate that hominins differentiated their activities (stone knapping, tool use, floral and faunal processing and consumption) across space. These were organized in two main areas, including multiple activities around a hearth. The diversity of human activities and the distinctive patterning with which they are organized implies advanced organizational skills of the Gesher Benot Ya’aqov hominins.

SEED DORMANCY AS EXPLAINED BY THE ANATOMY OF EMBRYO ENVELOPES

ABSTRACT The effects of embryo envelopes dealt with here are: impermeability to water, impermeability to oxygen, and mechanical resistance to radicle protrusion. To prevent water penetration, one or more layers of the embryo envelopes, as well as all possible openings in it such as the hilum or chalaza of the seed coat, should be watertight. This layer usually consists of compactly arranged cells, with various hydrophobic compounds impregnated into the cellulose network of the walls and/or deposited upon them. Restriction of oxygen without hindrance of water penetration may be due to a long path through which the dissolved oxygen has to diffuse in water, to a continuous layer of mucilage covering the embryo, to oxygen-consuming compounds in the envelopes, and to selective permeability of living cells. Resistance to radicle penetration is caused by any type of mechanical tissue that has a higher mechanical restraining force than the growth potential of the embryo.

The oldest ever brush hut plant remains from Ohalo II, Jordan Valley, Israel (19,000 BP)

Detailed excavation and analysis of a brush hut from Ohalo II, Jordan Valley, Israel, provides an extraordinary view of camp construction 19,000 years ago. This report offers an important contribution to studies of Palaeolithic camp sites.

Anatomical and ultrastructural changes in aleurone and myrosin cells of Sinapis alba during germination.

SummaryThe cells of the embryo of Sinapis alba L. include either aleurone or myrosin grains and all cells contain oil bodies. Aleurone grains and oil bodies are degraded during germination. The myrosin grains of each myrosin cell, on the other hand, gradually turn into one big vacuole containing the myrosin. Probably very little, if any, new myrosin is formed in the cotyledons and hypocotyl of the seedling after germination. No difference was found between aleurone and myrosin cells in the development of organelles. The cells of provascular bundles of the mature embryo contain different amounts of aleurone grains in different stages of development, and their organelles are more developed than those of all other cells.

New Dates From Submerged Late Pleistocene Sediments In The Southern Sea Of Galilee, Israel

Unusual low water levels in the Sea of Galilee (Dead Sea Fault, Israel) have caused the recent exposure of submerged Late Pleistocene prehistoric sites and lacustrine sediments along the southern shores of the lake. The Ohalo II site is a large fisher-hunter-gatherers camp with in-situ brush hut floors, hearths, and a human grave. The site is radiometrically dated by 25 charcoal dates to 19,430 BP (average, uncalibrated). The archaeological remains include quantities of excellently preserved organic remains. These would not have been preserved without a rapid rise of lake level immediately after the occupation, covering the remains with silts and sand. Recently a concentration of eight tree trunks were found about 1.5 km south of Ohalo II, of which five trunks were identified as Salix species and dated as a single accumulation at about 16,100 BP. The trunks, too, had to be submerged quickly together to ensure excellent preservation. The camp and the trunks were found at -212/ -213 m, almost 4 m below modern high water levels. We suggest that the finds represent two separate episodes of deposition during low lake levels, almost 3,000 radiocarbon years apart, each followed by an abrupt water rise. It is possible that climatic changes caused the observed fluctuations, though earthquakes (blocking or lowering the Jordan outlet, for example) cannot be ruled out.

Charred wood remains from Kebara cave, Israel: preliminary results

SummaryAn anthracological analysis of a small sample of charred wood remains from radio-metrically dated Mousterian and Upper Palaeolithic levels at Kebara cave, Israel, resulted in the identification of six plant taxa: Quercus calliprinos (an evergreen oak), Quercus ithaburensis (a deciduous oak), Pistacia cf. atlantica, Crataegus, Salix and Ulmus. The most significant result of this preliminary study is that the composition of the analysed sample, both with respect to the taxa identified and their relative frequencies, appears to resemble the composition of the present-day local vegetation. Although the picture is far from being complete, as the study is still at a very early stage, this result may be explained, at least partially, by the fact that most of the specimens originated in layers dating to the beginning of an interstadial phase, during which time climatic conditions in the Kebara region may not have been much different from those presently prevailling. A much larger sample should, however, be...

HETEROCARPY AND ITS ONTOGENY IN AELLENIA AUTRANI (POST) ZOH. LIGHT- AND ELECTRON-MICROSCOPE STUDY

Abstract Differences between the heterocarpous diaspores of Aellenia autrani (Post) Zoh., as well as their ontogeny, are described. The diaspores differ in their location on the plant, in the size, thickness and structure of the fibres of their winged perianths, in the structure of fibres of the pericarp, in cell wall thickness in the testa, in the ultrastructure of the chloroplasts and consistency and density of aleurone grains of the embryo.