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 oí 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 stale of the endogenous boron in the caryopsis. It was found to stimulate the synthesis of RNA in the embryo and endosperm tissue, and also α‐amylase activity in both tissues, particularly the endosperm. The transiocation 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 RNA synthesis and α‐amylase activity in the caryopsis.

Uittreksel

Daar is gevind dat die rustende toesland in die vrug van Themeda triandra Forsk deur die hyvoeging van boor by die ontkiemingsmedia gebreek kan word. Hierdie ejjek is spesifiek vir boor, want sink, koper, mangaan, yster, kobalt of molihdeen in die ontkiemingsmedia het geen merkbare veranderings veroorsaak nie. Daar is aandnidings dat die rustende toestand deur die staat van die interne boor in die vrug gereguleer word. In die embrio en endosperm word die sintese van RNS en die aktiviteit van α‐amilase gestimuleer laasgenoemde veral in die endosperm. Die vervaer van suikers vanaf die endosperm na die embrio word blykbaar ook deur boor gekontrolleer. Die behandeling van vrugte met gibbcrelliensuur kan die beëindiging van die rustende toestand veroorsaak en die sintese van RNS en die aktiviteit van α‐amilase word verhoog.