PHYTOCHROME CONTROL OF DEGREENING OF ATTACHED COTYLEDONS and PRIMARY LEAVES OF MUSTARD (SINAPIS ALBA L.) SEEDLINGS*

Abstract— Mustard ( Sinapis alba L.) seedlings were grown on moistened vermiculite without added nutrients for 17 days in medium white light (4.6 lx). During this period cotyledons as well as primary leaves expressed signs of senescence as defined by the loss of chlorophyll(ide) a ('degreening'). While degreening was detectable 9 days after sowing in the cotyledons it was not measurable before 15 days after sowing in the primary leaves. Phytochrome retards the loss of chlorophyll(ide) a in both organs; however, it does not change the temporal pattern of greening and degreening.     

THE EFFECT OF PROLONGED LIGHT EXPOSURE ON THE EFFECTIVENESS OF PHYTOCHROME IN ANTHOCYANIN SYNTHESIS IN TOMATO SEEDLINGS*

Abstract— The hypocotyl of the tomato ( Lycopersicon esculentum ) seedling synthesizes large amounts of anthocyanin if exposed to prolonged light. Single light pulses are totally ineffective. The involvement of phytochrome can be shown by light pulse treatments following a prolonged light exposure. It is predominantly the action of blue/UV light which leads to a high responsiveness of anthocyanin synthesis towards phytochrome. Moreover, the data suggest a phytochrome-independent action of blue/UV light, in particular of UV-B, on anthocyanin synthesis.     

Reaktionen in organischen kristallen. III Trispiro-pyrroloisochinoline durch asymmetrische photodimerisierung und H-Verschiebung in kristallinen cyclohexyliden-phenyl-5(4H)oxazolonen.

Solid-state photolysis of some substituted oxazolones $\text{1}$ leads via asymmetric dimerization and H-abstraction to dimers of type $\text{2}$ as the main products.     

Microwave silicon Schottky-barrier field-effect transistor

Schottky-barrier field-effect transistors have been realised in silicon epitaxial films on high-resistivity silicon substrates. The 1 ?m wide gates are produced by projection-masking techniques. The maximum transconductances observed are 42 mA/V per mm gate length; the maximum frequency of oscillation fmax was 8 GHz.     

New diastereomeric compound with cholesteric twist inversion

The synthesis and characterization of a new diastereomeric compound are reported; this exhibits a temperature induced inversion of the cholesteric twist. Measurements of the cholesteric pitch and handedness are presented and qualitatively discussed in terms of the nature of the cholesteric twist inversion in pure compounds. Preliminary measurements of properties of the ferroelectric S*c phase of this compound are also reported.