Studies on the Relationship between Gibberellin Metabolism and Daylength in Normal and Non-flowering Red Clover ( Trifolium pratense L.)
1966; Oxford University Press; Volume: 17; Issue: 1 Linguagem: Inglês
10.1093/jxb/17.1.96
ISSN1460-2431
Autores Tópico(s)Horticultural and Viticultural Research
ResumoFeeding experiments on tillers of a non-flowering red clover segregate indicated that the promotive effect of gibberellin upon stem extension and flowering occured only under inductive long days (LD). Furthermore, floral initiation took place in LD only when free gibberellin exceeded an unspecified critical level. Various intermediates in fungal gibberellin synthesis were fed in a similar fashion but none exerted any effect upon reproductive growth. Studies using 3H-gibberellin A3 (GA3) showed that in normal (flowering) material GA3 was more rapidly metabolized in short days than in long days. Qualitative differences in gibberellin metabolism between normal and non-flowering genotypes were revealed by radio-isotope studies. Non-flowering material rapidly degraded GA3 under LD conditions to a biologically inactive compound chromatographically indentical with allo-gibberic acid, whereas normal plants metabolized GA3 more slowly producing a compund similar to gibberellenic acid. The implications of these results are discussed in terms of the mechanism of stem elongation and floral initiation.
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