Mark Furber

Identification of Antheridiogens in Lygodium circinnatum and Lygodium flexuosum.

Antheridiogens in two species of Schizaeaceous ferns, Lygodium circinnatum and Lygodium flexuosum, were analyzed by gas chromatography-mass spectrometry. In L. circinnatum, gibberellin A73 (GA73) methyl ester (GA73-Me), which had originally been identified in L. japonicum, was identified as a principal antheridiogen, and the methyl esters of five known GAs (GA9, GA20, GA70, GA88, and 3-epi-GA88) were also identified as minor antheridiogens. In addition, four compounds corresponding to isomers of monohydroxy-GA73-Me were detected. One of these was shown to be 12[beta]-hydroxy-GA73-Me, the parent acid of which has been allocated the GA assignment GA96. The other three compounds, tentatively named X1, X2, and X3, have not been fully characterized. In L. flexuosum, GA73-Me was also identified as a major antheridiogen, with X2 being detected as a minor one. The total antheridium-formation activity in the culture medium of 7-week-old prothallia of L. circinnatum and L. flexuosum was more than 1000 times higher than that of L. japonicum. On the other hand, the response of gametophytes of the former two Lygodium ferns to GA73-Me was more than 100 times lower than that of L. japonicum.

Kaurenoids and gibberellins, including the newly characterized gibberellin A88, in developing apple seeds

The ethyl acetate-soluble acids from extracts of immature apple seeds (Malus domestica cvs Coxs Orange Pippin, Dabinett, Sunset and Tremletts Bitter) were analysed by combined gas chromatography-mass spectrometry. The following previously characterized gibberellins were identified by comparison of their mass spectra and Kovats retention indices with those of standards: GA1, GA3, GA4, GA7, GA9, GA12, GA15, GA17, GA19, GA20, GA25, GA34, GA35, GA44, GA45, GA53, GA54, GA61, GA62, GA63, GA68, GA80, GA84, and 3-epiGA54. In addition, a number of kaurenoid and gibberellin-like compounds were detected. The identity of one of the gibberellins with ent-3α,10β-dihydroxy-20-norgibberella-9(11),16-diene-7,19-dioic acid 19,10-lactone (9,11-didehydro GA4) was confirmed by partial synthesis from GA7 and is accorded the trivial name GA88.