Vicia faba seedlings, subjected to a 10 microT 50 Hz square wave magnetic field for 40 min together with a radioactive pulse, showed a marked increase in amino acid uptake into intact roots. A more modest increase was observed with a 100 microT 50 Hz square wave. An increase in media conductivity at low field intensities from 10 microT 50 Hz square wave, 100 microT 50 Hz sine wave, and 100 microT 60 Hz square wave fields, indicated an alteration in the movement of ions across the plasma membrane, most likely due to an increase in net outflow of ions from the root cells. Similarly, marked elevation in media pH, indicating increased alkalinity, was observed at 10 and 100 microT for both square and sine waves at both 50 and 60 Hz. Our data would indicate that low magnetic field intensities of 10 and 100 microT at 50 or 60 Hz can alter membrane transport processes in root tips.

Tiller axis observations for perennial ryegrass (Lolium perenne) and tall fescue (Festuca arundinacea): Number of active phytomers, probability of tiller appearance, and frequency of root appearance per phytomer for three cutting heights, Abstract Counts of phytomers in various developmental stages from formation at the apical meristem to senescence following root formation and death are presented for perennial ryegrass and tall fescue. Total number of active phytomers on tiller axes averaged 18.7 for perennial ryegrass and 16.3 for tall fescue (P < 0.05) and decreased with increasing cutting height (P < 0.05). Ryegrass maintained more primordia than tall fescue between the apical meristem and the emerging leaf, but had fewer fully emerged live leaves per tiller. Numbers of tillers and roots formed per phytomer are reported as nodal probabilities and nodal frequencies, respectively. The nodal probability of daughter tiller formation T n varied over time from 0 to 0.7, and was highest when swards had a low leaf area index shortly after establishment. Nodal frequency of root formation R n was relatively constant at around 1.5 per phytomer for both ryegrass and tall fescue. The A 97076 first root was most commonly found at the phytomer immediately below the last live leaf. The number of phytomers on the tiller axis bearing live roots is approximately double the number bearing live leaves, indicating slower turnover rate of roots than leaves.

Plastid DNA (ptDNA) probes were used in RFLP analysis to determine ptDNA inheritance in interspecific hybrids in Zantedeschia. Biparental and maternal ptDNA inheritance was found in albino hybrids between the evergreen species Z. aethiopica and several winter-dormant species. From two albino hybrids, different types of ptDNA were detected in shoots derived from different parts of an embryo. This result indicates that plastids were sorted out during embryo development. Only maternal ptDNA was detected in the hybrids of Z. aethiopica × Z. odorata (a summer-dormant species) but paternal, biparental, and maternal ptDNA were found in the hybrids of the reciprocal cross. Z. odorata × Z. aethiopica. By correlating these ptDNA inheritance patterns with the leaf colour (albino, pale-green, and green) of the hybrids, it is suggested that the Z. odorata plastome is incompatible with the Z. aethiopica genome. The Z. aethiopica plastome is partially compatible with the Z. odorata genome but the development of Z. aethiopica plastids appears to be blocked by the presence of the Z. odorata plastids.

No abstract

A questionnaire concerning the coat colour and sex of cats being vaccinated or neutered was sent to 2585 veterinary practices; 393 (15.2 per cent) were returned and information was obtained about 9816 cats. Of 4598 males, 20 were recorded as tortoiseshell (0.43 per cent). The frequency of the orange gene was 19.7 per cent assuming that male tortoiseshell cats had two X chromosomes. The chromosome complement and/or gonadal histology of 14 male tortoiseshell cats is described. Cytogenetic analysis of 11 animals revealed six with a 38,XX/38,XY complement, two with 39,XXY, two with 38,XX, and one with a 38,XY complement.