The effect of kinetin on the growth of diploid and autotetraploid root tips of rye in vitro

Abstract

Both diploid and autotetraploid root tips of rye, Secale cereale var. Petkus, responded similarly when kinetin and indoleacetic acid (IAA) were added separately to the media in which they were growing. Kinetin retarded the linear growth of the main roots at 1 mg/1 and caused complete inhibition of the initiation of lateral roots; while at 0.1 mg/1, kinetin inhibited the elongation of lateral roots. IAA at 0.1 mg/1 retarded the elongation of main roots, and the initiation and the linear growth of lateral roots. When kinetin and IAA were applied in combination, kinetin was antagonistic to the inhibition caused by a high concentration of IAA in the growth of main roots of tetraploids, but not in the diploid roots.The differential response is considered to be a reflection of their genotypical difference, which may affect the endogenous content or metabolism of these phytohormones of the roots.