In:
Canadian Journal of Botany, Canadian Science Publishing, Vol. 50, No. 1 ( 1972-01-01), p. 139-158
Abstract:
Decapitated 5-mm segments from stage 1 sporangiophores of Phycomyces blakesleeanus had similar regeneration capacity and polarity under room as under constant conditions. Regeneration on segments with whole apices was more frequent under room conditions despite resumption of apical elongation, but was only about half as frequent as on decapitated apical segments. Regeneration at incisions in the middle of stage 1 sporangiophores was rare unless cross walls formed at the incision. Sporangiophore halves and pairs of 5-mm segments were grafted successfully and cultured for 24 h. The protoplasts fused and a new wall rejoined the cut ends. Regeneration was rare on grafted sporangiophore halves. On grafts of decapitated, oppositely oriented segments regeneration was almost 100% and occurred mainly at the apical ends alone whether these were fused or free. On grafts of decapitated, normally oriented segments in normal or reversed order almost all anterior segments regenerated apically (as did the controls), but only half or fewer of the same segments in posterior position regenerated. Multiple regeneration and attainment of stage 4 were more frequent on anterior segments. Regeneration was less than 50% on grafts between segments with whole apices and basal segments, and on the latter was much less than on isolated controls.Movement of cytoplasm detectable by dry weight changes only occurred towards the regenerating end of segments after initiation of sporangiophores. The velocity of bidirectional protoplasmic streaming in segments increased during regeneration and was highest towards the basal non-regenerating end.The results of grafting do not support the hypothesis that an inhibitor from the apex normally suppresses regeneration (branching), but both suppression and induction of regeneration can be explained by a mechanism based on acropetal transport.
Type of Medium:
Online Resource
ISSN:
0008-4026
Language:
English
Publisher:
Canadian Science Publishing
Publication Date:
1972
detail.hit.zdb_id:
218116-2
detail.hit.zdb_id:
1481926-0
SSG:
12
