| Seed protein profiles Seed proieins were extracted from individual plants by grinding 100 mg of mature seeds with 1.0 ml cold (4C) distilled water over an ice bath. The resulting mixture was centrifuged at 10.000 g for 15 min. and the supernatant was lyophilized. The subsequent isoelectric focusing of water soluble proteins was performed by using polyacrilamide gels with carrier ampholite pH 4.0-6.5. Representative seed protein profiles are shown in Fig. 2. Although slight variability was detected both within (more) and between (less) populations, all the examined plants (23) were found to possess the same basic seed protein profile composed of 34 bands. No qualitative protein phenotypic differences were found and all the observed variation concerned the intensities of some bands among which bands numbered 5, 6, 8 and 13 manifested the most conspicuous intensity differences. The most frequent protein profiles are two, precisely number 1(observed in four out of five populations) and number 2 (detected in three populations). The profile number 3, common enough, showed mutually reverse intensities in bands 5, 6 and 13 comparatively with the profile 2. The pattern number 4 was detected only once (in the most abundant population). The observed differences in the darkness of bands suggest that the formation of certain bands in seed protein profiles are probably under control of quantitative gene systems (LADIZINSKY & HYMOWITZ 1979). The above mentioned slight variation in band intensities should be a consequence of a specific structural gene arrangment modified in activity by gene regulation (KREFT et al.1976), a feature which does not alter the consistent protein pattern, a fairly conservative characteristic of the species. Thus, the obtained data can be considered as a resolving power with regards to J1J1 genome identification, since the remarkable uniformity of the patterns is in agreement with the observed karyotype constancy. It should be added that the findings pointed by HENEEN & RUNEMARK (1972) about A. striatulum chromosomal polymorphism and by STRID (1968) and BOTHMER (1975) about other Aegean species which showed also heterogeneity of chromosomal compositions cannot be taken as markedly opposing the present data. Their sources of material coming from margin areas of an ecosystem (small isolated islands) could give the possibilities for maintaining cytological instabilities resulting in polymorphisms. Instead, our A. striatulum populations grown in abundance and checked as highly fertile are likely to represent a more balanced genomic situation. |
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