Histologische Untersuchungen an Weinbeeren

Die Histologie der Weinbeere war schon mehrfach Gegenstand wissenschaftlicher Untersuchungen. Neben dem Aufbau der Gesamtbeere wurde in verschiedenen Arbeiten der Beerenhaut besondere Aufmerksamkeit geschenkt. Sie besitzt hohe mechanische Schutzeigenschaften. Einerseits wirkt sie dem Aufplatzen der Beere entgegen (MEYNHARDT 1964), andererseits bildet sie einen Schutz gegen pilzliche Infektionen im Laufe der Beerenentwicklung (BERNARD 1976, 1977 a und b). Die Tatsache, daß der Aufbau der Beerenhaut sortenspezifische Unterschiede aufweist (PRATT 1971), läßt eine Ergänzung der Untersuchungen im Hinblick auf mögliche Beziehungen zur Pilzresistenz der Beeren gerechtfertigt erscheinen.Histological investigations with grapevine berriesComparative histological investigations have been carried out with berries of the grapevine varieties Aris, Bacchus, Pollux, Morio-Muskat, Müller-Thurgau, Portugieser, Riesling and Vitis labrusca. Thickness of cuticle ranges from 1.6 ftm (Morio-Muskat, Portugieser) to 3.8 µm (Aris) and decreases slightly with increasing ripeness.Epidermis is between 6.5 µm (Portugieser) and 10.0 µm (Aris) in thickness.Thickness of hypodermis ranges from 107 µm (Portugieser) to 246 µm (V. labrusca).The number of the subepidermal cell layers varies between 9.3 (Portugieser) and 11.1 (Müller-Thurgau).The distance of the vascular bundles to the berry surface ranges from 200 µm to 300 µm. Only for V. labrusca a distance of 500 to 550 µm has been measured.The results are discussed with regard to possible correlations with resistance to Botrytis (gray rot) and to cracking of berries

Stable carbon Isotope evidence for neolithic and bronze age crop water management in the eastern mediterranean and southwest asia

In a large study on early crop water management, stable carbon isotope discrimination was determined for 275 charred grain samples from nine archaeological sites, dating primarily to the Neolithic and Bronze Age, from the Eastern Mediterranean and Western Asia. This has revealed that wheat (Triticum spp.) was regularly grown in wetter conditions than barley (Hordeum sp.), indicating systematic preferential treatment of wheat that may reflect a cultural preference for wheat over barley. Isotopic analysis of pulse crops (Lens culinaris, Pisum sativum and Vicia ervilia) indicates cultivation in highly varied water conditions at some sites, possibly as a result of opportunistic watering practices. The results have also provided evidence for local land-use and changing agricultural practices

Late Oligocene-Miocene mantle upwelling and interaction inferred from mantle signatures in gabbroic to granitic rocks from the Urumieh-Dokhtar arc, south Ardestan, Iran

The south Ardestan plutonic rocks constitute major outcrops in the central part of Iran’s Cenozoic magmatic belt and encompass a wide compositional spectrum from gabbro to granodiorite. U–Pb laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) dating of zircon three granodiorites yielded ages of 24.6 ± 0.1, 24.6 ± 0.1, and 24.5 ± 0.1 Ma. For tonalitic rocks, internal Rb–Sr isochron ages (biotite, feldspars) indicate cooling ages of 20.4 ± 0.1, 20.5 ± 0.1, and 22.3 ± 0.1 Ma, which are slightly younger than the zircons’ ages. The limited variations in their Sr–Nd isotope ratios indicate derivation from an asthenospheric mantle source. A geodynamic model is presented in which late Oligocene–Miocene rollback of the Neotethyan subducting slab triggered asthenospheric upwelling and partial melting in the south Ardestan. These melts were subsequently modified through fractional crystallization and minor crustal contamination en-route to the surface. Plagioclase + orthopyroxene-dominated fractional crystallization accounts for differentiation of gabbro to gabbroic diorite, whereas fractionation of clinopyroxene, titanomagnetite, and orthopyroxene led to differentiation of gabbroic diorite to diorite. Amphibole fractionation at deeper levels led to the development of tonalites

Petrogenesis of Neogene plutonic rocks from south Ardestan, Iran; mantle-derived arc magmatism

The south Ardestan region in the Urumieh-Dokhtar arc covers an area of about 250 km2 that is characterized by plutonic rocks with a compositional spectrum ranging from gabbro, gabbro-norite, gabbroic diorite, diorite, tonalite to granodiorite. Gabbroic rocks are mainly tholeiitic in character, whereas the diorites, tonalites and granodiorites show increasingly stronger calc-alkaline affinity. Gradual compositional variation and limited variation in radiogenic isotopic ratios indicate that these different rock types are petrogenetically related and most probably are derived from a common primitive source. U-Pb LA-ICP-MS dating of zircon from four granitoids yielded ages that range from 25 to 24 Ma. For tonalitic rocks, internal Rb-Sr isochron ages (biotite, feldspars) indicate cooling ages that lie in the range 20.4 +/- 0.1 to 22.1 +/- 0.5 Ma, slightly younger than the zircons’ ages. Their uniform initial Sr-Nd isotopic values imply that the major source component has probably been an asthenospheric mantle domain. This is further supported by the mantle-derived geochemical affinity of the plutonic rocks. A geodynamic model is presented in which the asthenospheric upwelling and partial melting in the south Ardestan has been triggered by Late Oligocene-Miocene rollback of the Neotethyan subducting slab. These melts were subsequently slightly modified through assimilation, fractional crystallization (AFC) en-route to the surface (A less than 6%). The trace element rich and high radiogenic Sr signature of some gabbros, this is the likely perturbation and then mobilization of Sr in the rock system during alteration. 43% fractional crystallization dominated by plagioclase and orthopyroxene is found responsible for magmatic evolution from gabbro to gabbroic diorite. Whereas, 44% fractional crystallization of a plagioclase-dominated mineral assemblage that also include clinopyroxene, titanomagnetite and orthopyroxene is found responsible for the evolutionary path from the gabbroic diorite to diorite. 22% fractional crystallization of amphibole and plagioclase is calculated as responsible for the differentiation path from diorite to tonalite. Assuming 6% crustal contamination effect inferred from isotopic trace elemental modelling by Cadomian crust, the major elemental crustal contamination effect on AFC product is found to be trivial. That is for K2O it is 10% and for other major elements less than 5%. M-REE abundances of the tonalites likely imply that a parental melts of these rocks have experienced significant amphibole differentiation due to a greater depth of magma chamber formation. We do not claim that our petrogenetic model for the south Ardestan plutonic rocks is representative for the whole UDMA. However, the new isotopic age and bulk rock data along with the mantle-dominated geochemical characteristics of the studied plutonic rocks open a new window for geodynamic interpretation and support a model suggesting that subduction still affected the UDMA in Miocene time