Time Course of Steroid Biosynthesis and Metabolism in Haplopappus heterophyllus

Abstract

Summiiiiiary. A single dose of mevalonic acid-2-14C was administered simultaneously to 6 Haplopapppus heterophyllu(s plants. They were harvested at intervals ranging from 3 days to 6 months. Four groups of biosynthetically related sterols were found to be radioactive in each plant, and the changes in radioactivity with time were studied. The most striking finding was a radioactive phenolic material present only in the 6-month plant, which had flowered. The solvent was evaporated in vacuum, and the residue was then refluxed with a mixture of 25 ml of benzene, 55 ml of water, and 20 ml of concentrated hydrochloric acid for 3 hours. The benzene layer was separated, and the aqueouis layer was extracted with 2 25-ml portions of dichloromethane. The organic layers were washed with 15 ml of water, filtered, combined, an-d evaporated. The residue was taken up in 25 ml of benzene and extracted with 2 15-ml portions of 2 % sodium bicarbonate solution and 15 ml of watcr. The extracts were passed through 10 ml of benzene and discarded. The original benzene layer was then extracted with 2 15-ml portions of 0.5 N sodium hydroxide and 15 ml of water. The extracts were passed through the same 10 ml of benzene as above, filtered, combined, and immediately acidified with concentrated hydrochloric aciid. The mixture was then extracted with 2 25-ml portions of dichloromethane, and the extracts were passecd through 10 ml of water, filtered, comibined, and evaporated (Phenolic Fraction).The original benzene layer from above was combined with that used for washing the aqueous extracts, filtered, and evaporated. The residue was 973 www.plantphysiol.org on May 11, 2018 -Published by Downloaded from

OESTROGENS IN THE LONG‐DAY PLANTS HYOSCYAMUS NIGER AND SALVIA SPLENDENS GROWN UNDER INDUCTIVE AND NON‐INDUCTIVE LIGHT CONDITIONS

“…The results in the present paper reveal that an increase of oestrogen-like substances occurs only in plants grown in inductive conditions at the period of flowering. These results confirm those obtained previously (Kopcewicz,196id) and those of Bennett, Lieber and Heftmann (1967) who treated Haplopappus heterophyllus plants with mevalonic acid-2-^*C and showed that radioactive phenolic steroids were present only in flowering plants. These data, together with the known effects of inhibitors of steroid biosynthesis on flowering, support the hypothesis that, in order for the flowering to take place, a suitable level of steroidal hormones is necessary (Kopcewicz,197id).…”

Steroidal Oestrogens and Plant Growth and Development

“…However, all the oestrogen determinations were made by the Kober colour test following TLC in two systems, and as the Kober test is subject to interference by artefacts of acid hydrolysis and flavonoids also give a positive colour reaction these results must be viewed with caution. On the other hand, similar findings were obtained when Haplopappus heterophyllus was supplied with i*C-mevalonic acid (MVA): the phenolic fraction from flowering plants contained *C, but the radioactivity was not associated with any identifiable oestrogens (Bennett, Lieber and Heftmann, 1967). SK&F 7997 Ag, which inhibits the conversion of lanosterol to cholesterol in steroid biosynthesis in animals, was found to inhibit floral induction in the short day plants Pharbitis nil and Xanthium strumarium when applied to leaves.…”

Transcriptomic Analysis of Flower Blooming in Jasminum sambac through De Novo RNA Sequencing

“…KEGG enrichment analysis indicated significant differences in the DEGs between the two stages in “steroid biosynthesis”, “glycosphingolipid biosynthesis-globo series”, “plant hormone signal transduction” and “pentose and glucuronate interconversions”. The pathways associated with flower development, such as “steroid biosynthesis”, “plant hormone signal transduction” and “pentose and glucuronate interconversions”, had also been found in other plants [21,22,23,24]. However, previous studies have not reported the involvement of “glycosphingolipid biosynthesis-globo series” in flower development.…”