TRANSLATABLE RNA POPULATIONS ASSOCIATED WITH MAINTENANCE OF PRIMARY ROOT ELONGATION AND INHIBITION OF MESOCOTYL ELONGATION BY ABSCISIC-ACIDIN MAIZE SEEDLINGS AT LOW WATER POTENTIALS
In. Saab et al., TRANSLATABLE RNA POPULATIONS ASSOCIATED WITH MAINTENANCE OF PRIMARY ROOT ELONGATION AND INHIBITION OF MESOCOTYL ELONGATION BY ABSCISIC-ACIDIN MAIZE SEEDLINGS AT LOW WATER POTENTIALS, Plant physiology, 109(2), 1995, pp. 593-601
Previous work indicated that accumulation of abscisic acid (ABA) acts
differentially to maintain elongation of the primary root and inhibit
elongation of the mesocotyl of maize (Zea mays L.) seedlings at low wa
ter potentials (psi(w)). Subsequent results indicated specific locatio
ns in the elongation zones where elongation is maintained, inhibited,
or unaffected by endogenous ABA at low psi(w). This information was ut
ilized in this study to identify in vitro translation products of RNA
associated with the maintenance or inhibition of elongation in the pri
mary root and mesocotyl, respectively, by endogenous ABA at low psi(w)
. The results distinguished products associated specifically with the
elongation responses from those nonspecifically associated with ABA ac
cumulation or low psi(w), as well as normal cell development and matur
ation. In the primary root, the maintenance of elongation at low psi(w
) by ABA was associated with the maintenance of expression of three pr
oducts that were also expressed during elongation at high psi(w), the
expression of a novel product, and the suppression of two products. In
the mesocotyl, the inhibition of elongation by ABA after transplantin
g to low psi(w) was associated with the induction of a novel translati
on product. However, the induction of this product, as well as accumul
ation of ABA and inhibition of elongation, occurred without a decline
in tissue water content. The results demonstrate the necessity of exam
ining the association of gene expression with elongation responses to
low psi(w) with a high degree of spatial resolution.