Distribution of the major cyclic spermidine in rapeseed.

<p>(<b>A</b>) Structure of the major cyclic spermidine conjugate (<b>13</b>) identified from rapeseed. (<b>B</b>) The concentration of <b>13</b> in different tissues and whole rapeseed. HR, hypocotyl and radicle; IC, inner cotyledon; OC, outer cotyledon; and SE, seed coat and endosperm. Each column shows the mean of four replicates with standard error, and *means not detectable.