A new allelopathic substance that promoted the shoot growth of
different plant species but inhibited the root growth was isolated
as an amorphous powder from mucilage of germinated cress (Lepidium
sativum L.) seeds. This substance was identified as sodium
2-O-rhamnopyranosyl-4-deoxy-threo-hex-4-enopyranosiduronate
(designated lepidimoide) from the mass and the nuclear magnetic
resonance and infrared spectra coupled with some chemical evidence.
Lepidimoide promoted the hypocotyl growth of etiolated
Amaranthus caudatus L. at concentrations higher than 3 gM and
inhibited the root growth at concentrations higher than 100 gM.
The growth-promoting activity in hypocotyls was 20 or 30 times as
much as that of gibberellic acid.
The