The occurrence of estrogens in relation to reproductive processes in flowering plants

Abstract

Estrogens, a group of steroidal sex hormones, were determined in pollen, styles or whole pistils using a highly sensitive and specific radioimmunoassay (RIA) and found to be present at levels between 10-11 and 10-lo g/g FW. In the style of Lilium davidii Duch., the levels of total estrogen decreased after self-pollination of the open flower. After bud pollination, which partly overcame incompatibility, the levels of both estradiol and total estrogen increased. The levels of estradiol and total estrogen in the pistils of Brassica pekinensis Rupr. increased after compatible pollination during the first 3 days following pollination and decreased thereafter when the data were expressed on a FW basis. These results suggest that estrogens are to some extent associated with the reproductive processes.

Estradiol distribution during the development and expression of reproductive structures in Populus tremuloides Michx.

“…Zhang et al (1991) observed large estrogen changes during sexual reproduction of Lilium and Brassica, and further suggested a potential relationship between estrogens and compatibility. A dramatic increase in E 2 content during the first 2 days after anthesis led Zhang et al (1991) to conclude that E 2 specifically plays an especially important role in Brassica. A dramatic increase in E 2 content during the first 2 days after anthesis led Zhang et al (1991) to conclude that E 2 specifically plays an especially important role in Brassica.…”

“…Abundant evidence that plants synthesize estrogens has been presented elsewhere (Bennett et al 1966;Gawienowski and Gibbs 1969;Kopcewicz 1971;Zhang et al 1991;Milanesi et al 2001), but the mode of action of plant estrogens and any similarity to estrogen activity in animals remains to be proven. Abundant evidence that plants synthesize estrogens has been presented elsewhere (Bennett et al 1966;Gawienowski and Gibbs 1969;Kopcewicz 1971;Zhang et al 1991;Milanesi et al 2001), but the mode of action of plant estrogens and any similarity to estrogen activity in animals remains to be proven.…”

“…Steroids commonly found in mammals, such as estrogens, also occur in higher plants (Simons and Grinwich 1989;Zhang et al 1991;Milanesi et al 2001). Nonetheless, Zhang et al (1991) detected changes in estrogen levels in reproductive structures that appear to be associated with flowering plant reproduction. Nonetheless, Zhang et al (1991) detected changes in estrogen levels in reproductive structures that appear to be associated with flowering plant reproduction.…”

“…Since the first report of plant production of steroids in palm kernels and female willow flowers seven decades ago (Butenandt and Jacobi 1933;Skarzynski 1933), steroidal sex hormones have been reported in a wide number of plant species (Simons and Grinwich 1989;Zhang et al 1991;Milanesi et al 2001). Steroid identification and determination have been examined using bioassays, color reactions, gas chromatographymass spectrometry (GC-MS) and radioimmunoassay (RIA).…”

“…Earlier studies of steroidal sex hormones in plants have emphasized their natural occurrence in various tissues, concentration changes during development, and the effects of exogenously applied steroidal sex hormones on developmental processes (Jones and Roddick 1988;Simons and Grinwich 1989;Zhang et al 1991). The effects of applied steroidal sex hormones on plant developmental processes have been controversial because in some cases they yielded promotive effects, whereas in other cases they were inhibitory (Bonner et al 1963;Bennet et al 1967).…”