Growth Substances Separated from the Fruits of Cassia fistula

Abstract

AbstractThe growth substances of the seeds of Cassia fistula were studied and the changes in the relative levels in the endosperm and embryo (plus cotyledons) with development of the seed were noted.Indoleacetic acid was found to be the major auxin component of the seed almost throughout its growth and development, while acidic inhibitors possibly belonging to β‐complex were also noted in bioassay tests.The main source of the IAA in the seed is the endosperm, although measurable amounts are also present in the embryo. While this IAA activity in the endosperm is detectable till maturity of the fruit, it decreases relatively in the embryo to fall to insignificance at maturity of the seed. However, there is indication of the binding of such IAA in the embryo or the cotyledon, which can be released by alkaline hydrolysis but not before the seeds are matured. No such bound auxin could be detected in the endosperm. The inhibitors, on the other hand, are more prominent in the embryo than in the endosperm, particularly with ageing of the fruit. The possible significance of these changes in the growth factors has been discussed in relation to the age of the seed and the development of the embryo inside it.