Possible Membrane-Associated Effects in Gibberellic Acid and Phenylalanine-Induced Rose Coloration Enhancement

Abstract

When combined with GA. phenylalanine produced marked enhancement of red colouration of rose (cv Baccara) petals, this effect significantly exceeding that ofGA applied alone, while phenylalanine when administered alone was virtually ineffective in this respect. Parallel assays of phenyl-ammonialyase (PAL) activity indicated essentially similar endogenous levels of enzyme irrespective of treatment. These results are interpreted as indicating that mode of GA action in this system is probably not by direct PAL activation but rather via GA-inducedenhancement of membrane permeability thus providing more phenylalanine precursor for anthocyanidin pigment synthesis. This hypothesis is substantiated by the results of plasmolysis studies executed on rose petal epidermal strips in hypertonic solutions where GA significantly cut down time required to achieve a given degree of plasymolysis.

Anatomical Characterization of Flower-bud Blasting and Suppression Following Hormone Application in Eustoma grandiflorum (Raf.) Shinn.

“…They also promote the expression of the flower meristem identity gene LEAFY, which directly activates genes including stamen and carpel identity genes (Blazquez and Weigel, 2000;Busch et al, 1999;Parcy et al, 1998). In addition, exogenous GA modulates flower development in various plants (Demunk and Gijzenberg, 1977;Ohno, 1991;Zhang et al, 2008;Zieslin et al, 1977). In light of these findings and our analysis, GA-mediated promotion of flower development appears to be conserved in Eustoma.…”

Perturbation of Phospholipid Membranes by Gibberellins

“…Release of compartmentalized ions, proteins, peptides and hydrolytic enzymes has also been observed following treatment of barley aleurone cells and subcellular fractions from barley aleurone tissue with GAg (Jones, 1971;Melcher and Varner, 1971;Jones, 1973;Gibson and Paleg, 1977;Jelsema et al, 1977). In a different system, Zieslin et al (1977) have attributed the enhanced coloration of rose petals following gibberellin treatment to a hormonally induced enhancement of membrane permeability to a precursor for anthocyanin synthesis.…”