Ethanol Tolerance and Alcohol Dehydrogenase (ADH; EC1.1.1.1) Activity in Species of the cardini Group of Drosophila

Ethanol tolerance, alcohol dehydrogenase (ADH;EC1.1.1.1) activity, and tissue-specific expression wereexamined in species of the cardini group ofDrosophila using D. melanogaster as astandard of comparison. In contrast to most fruit-breeding species, allcardini species examined, two from the cardini subgroupand five from the dunni subgroup, were ethanol sensitive(LC₅₀ 2.05%) and the mean ADH activityof males ranges from only 8 to 16% that of D.melanogaster Adh^FF. Among all sevencardini species, there were small but significantdifferences in ethanol tolerance and ADH activity.Differences in enzyme mobility were in accordance with the proposedphylogeny for the dunni-subgroup species. ADH isexpressed in the fat body and midgut. Males of D.acutilabella and of D. belladunni havesignificantly less ethanol tolerance and express less ADH activitythan females in zymograms and histologicalpreparations.     

Experiments on the effect of different intensities of desiccation on bryophyte survival,using chlorophyll fluorescence as an index of recovery

Abstract

Chlorophyll fluorescence provides a non-invasive and non-destructive method to follow various aspects of the photosynthetic function of bryophytes under relatively natural conditions, which is easy to use and can be applied to small amounts of material. Some of its potentialities (and potential pitfalls) for bryophyte desiccation physiology are outlined. Data are presented on the responses of eleven desiccation-tolerant bryophytes to drying at –41, –114, –218 and –412 MPa for periods up to ~240 days. Recovery was assessed from F_V/F_M after 20 min and 24 h re-wetting, and from the mean F_M value after 24 h. For the more desiccation-tolerant species, Grimmia pulvinata, Syntrichia ruralis, Andreaea rothii, Racomitrium lanuginosum, R. aquaticum, Leucodon sciuroides, Pleurochaete squarrosa and Ulota crispa, long-term survival (>30–120 d) was generally best at ~–100 to –200 MPa (20–45% r.h.). The moderately desiccation-tolerant Anomodon viticulosus, Porella platyphylla and P. obtusata survived best at the highest humidity used, –41 MPa (74% r.h.).