Lepidimoide promotes growth of the cockscomb hypocotyl. It is exuded f
rom germinating seeds of various plant species into their culture envi
ronment. The mode of exudation of lepidimoide from seeds into the cult
ure solution, using sunflower and buckwheat seeds, was studied in rela
tion to seed germination. In the dry seeds, about 75% of the lepidimoi
de was found in the seed coat and about 25% in the kernel. Upon water
imbibition it was released into the culture solution. However, the qua
ntity of lepidimoide detected in the seed exudate was more than three
times the total amount in dry and imbibed seeds, suggesting that lepid
imoide was also produced de novo in the seeds and subsequently release
d. When seed coats or kernels were imbibed separately, the quantity of
lepidimoide released from the seed coats into the culture solution wa
s much the same as that in the dry seeds, but the amount of lepidimoid
e detected in the exudate of kernels was about 16 times that in the dr
y kernels. These results suggest that lepidimoide, already present in
dry seeds, as well as that newly produced in the kernels following imb
ibition, was released into the environment.