72 research outputs found

    Abnormal Cones in Cupressus Sempervirens

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    Abnormal cones found in Cupressus sempervirens include bisexual cones and double female and male cones. They are very infrequent, but there are individual trees with a tendency to produce such cones. We suggest that these cones reflect changes in normal hormonal balance

    Aggregated Cones in Pinus Halepensis

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    Aggregated female cones were found in 192 Pinus halepensis trees growing in 54 populations in Israel, in habitats of vastly differing ecological conditions. All of these trees also carried normal (1-5 in a whorl) female cones. The number of aggregates per tree varied from one to several dozen. Some of the trees formed aggregates every year, after the first year of aggregate formation, while others formed aggregates only once, or at long intervals. Not all cones in the aggregates reached maturity. The number of cones in an aggregate ranged from six to 62, and they were usually smaller than normal. Many of the trees with aggregates showed other abnormalities, e.g., individual female cone scales, proliferated dwarf shoots, three-needled dwarf shoots, shorter cone stalks, needles on cone stalks, larger terminal cones on the main axis in cones formed during the current year, proliferated female cones, and degradation of the main axis above the aggregate. The clusters probably result from replacement of dwarf shoots by ovulate cones

    Articulated cork in Calotropis procera (Asclepiadaceae)

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    The cork of the small tree. Calotropis procera, which grows in a very hot district of Israel, is remarkable for its thickness and brittleness. The cork of the stems and large branches is composed of longitudinal ridges that extend over several internodes. The cork ridges have deep fissures around the circumference at almost every node. I propose that these nodal fissures in the cork serve as joints for two functions: (1) to prevent breakage of the fragile cork layer when branches bend under wind stress, and (2) to allow thermal expansion while avoiding tissue cracking on extremely hot days, similar to the joints left between steel rails in railroads and between concrete beams in bridges

    Patterns of Dilatation Growth in Ficus Pumila and Ficus Sycomorus

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    Dilatation growth occurs in the secondary phloem rays, in the axial secondary phloem parenchyma, and in the parenchyma of the cortex of Ficus pumila (a Iiana) and Ficus sycomorus (a tree). Dilatation growth in Ficus pumila is mostly the result of meristematic activity, but in Ficus sycomorus it is the result of both meristematic activity and increase in cell size. Dilatation meristem is formed in the rays in various patterns: in the center of the ray, at one or two of the ray\u27s margins, in horizontal or diagonal strips (relative to the axis) in the ray, or in more than one pattern in a single ray

    The olive tree-ring problematic dating

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    We are glad to see that our paper has stimulated a lively debate, and we acknowledge the appreciation of our work by Bietak, Kuniholm and MacGillivray as well as that of those who oppose our hypothesis (Bruins & van der Plicht, Friedrich et al., all above). The enigma of the dating of the Santorini eruption is a long-lasting one, and because of its bearing on the dating of several eastern Mediterranean civilisations, has attracted significant attention. The potentially great importance of the Santorini olive branch used by Friedrich et al. (2006) was that it came from the site itself, and possibly belonged to the destruction layer. As such, the sincere and serious attempt to date it made by Friedrich et al. (2006) should be appreciated. Unfortunately, large olive branches may exist as dead limbs for a very long time and thus represent earlier period

    The “when”, the “where” and the “why” of the Neolithic revolution in the Levant

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    An accumulation of data concerning the domestication of plants and the refinement of research questions in the last decade have enabled us a new look at the Neolithic Revolution and Neolithization processes in the Levant. This paper raises some points concerning the “When” and “Where” of plant domestication and suggests that the origins of plant domestication were in a welldefined region in southeast Turkey and north Syria. It presents a view on the process of Neolithization in the Levant and offers some comments concerning the background and motivations behind the Neolithic Revolution.Naraščanje količine podatkov o udomačitvi rastlin in vedno bolj natančna vprašanja raziskovalcev so v zadnjem desetletju omogočili, da na novo ovrednotimo neolitsko revolucijo in proces neolitizacije v Levantu. V članku izpostavljamo nekatere vidike “časa” in “kraja” udomačitve rastlin ter menimo, da je bil izvor udomačitve rastlin na jasno omejenem območju jugovzhodne Turčije in severne Sirije. Predstavimo pogled na proces neolitizacije v Levantu in nekoliko pojasnimo družbeno okolje in motive za neolitsko revolucijo

    The olive-branch dating of the Santorini eruption

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    The date of the volcanic eruption of Santorini that caused extensive damage toMinoan Crete has been controversial since the 1980s. Some have placed the event in the late seventeenth century BC. Others have made the case for a younger date of around 1500 BC. A recent contribution to that controversy has been the dating of an olive tree branch preserved within the volcanic ash fall on Santorini. In this debate feature Paolo Cherubini and colleagues argue that the olive tree dating (which supports the older chronology) is unreliable on a number of grounds. There follows a response from the authors of that dating, and comments from other specialists, with a closing reply from Cherubini and his tea

    Distribution and Extinction of Ungulates during the Holocene of the Southern Levant

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    BACKGROUND: The southern Levant (Israel, Palestinian Authority and Jordan) has been continuously and extensively populated by succeeding phases of human cultures for the past 15,000 years. The long human impact on the ancient landscape has had great ecological consequences, and has caused continuous and accelerating damage to the natural environment. The rich zooarchaeological data gathered at the area provide a unique opportunity to reconstruct spatial and temporal changes in wild species distribution, and correlate them with human demographic changes. METHODOLOGY: Zoo-archaeological data (382 animal bone assemblages from 190 archaeological sites) from various time periods, habitats and landscapes were compared. The bone assemblages were sorted into 12 major cultural periods. Distribution maps showing the presence of each ungulate species were established for each period. CONCLUSIONS: The first major ungulate extinction occurred during the local Iron Age (1,200-586 BCE), a period characterized by significant human population growth. During that time the last of the largest wild ungulates, the hartebeest (Alcelaphus buselaphus), aurochs (Bos primigenius) and the hippopotamus (Hippopotamus amphibius) became extinct, followed by a shrinking distribution of forest-dwelling cervids. A second major wave of extinction occurred only in the 19th and 20th centuries CE. Furthermore, a negative relationship was found between the average body mass of ungulate species that became extinct during the Holocene and their extinction date. It is thus very likely that the intensified human activity through habitat destruction and uncontrolled hunting were responsible for the two major waves of ungulate extinction in the southern Levant during the late Holocene

    Defensive (anti-herbivory) Batesian mimicry in plants

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