The effect of micronutrients and gibberellic acid on the germination and metabolism of seedlings of Themeda triandra Forsk

Abstract

Dormancy of the caryopsis of Themeda triandra Forsk was shown to be broken by the addition of boron to the germination media. This effect was specific to boron, as no response was observed with zinc, copper, manganese, iron, cobalt and molybdenum in the germinating media. Evidence is put forward suggesting that dormancy is regulated by the state of the endogenous boron in the caryopsis. It was found to stimulate the synthesis of ribonucleic acid in the embryo and endosperm tissue, and also alpha-amylase activity in both tissues, particularly the endosperm. The translocation of the sugars from the endosperm to the embryo appears also to be regulated by boron. Gibberellic acid was also found to break dormancy, and to stimulate ribonucleic acid synthesis and alpha-amylase activity in the caryopsis.

Keywords: micronutrients|acid|gibberellic acid|germination|metabolism|seedlings|dormancies|caryopsis|boron|chemicals|zinc|copper|manganese|iron|cobalt|molybdenum|germinating seedlings|embryos|endosperms