The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mm ABA. Exogenous application of 1 μm and 1 nm ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.
|Original language||English (US)|
|Number of pages||8|
|Journal||Annals of Botany|
|State||Published - Mar 1985|
Bibliographical noteFunding Information:
This research represents a portion of a thesis submitted in partial fulfillment of the requirements for a Master of Science degree in Biology at Baylor University. We thank Prof. J. D. Smith for providing us with the vp-9 mutants and Dr Jim Barrentine for providing us with Fluridone. This research was supported by funds provided by the University Research Committee and the Department of Biology of Baylor University.
- Root growth
- Vp-9 mutant
- Zea mays