Endogenous Gibberellins of Pine Pollen

Abstract

Thie endogenous gibberellins (GAs) of pollen of Pinus attenuata, P. coulteri, and P. ponderosa were bioassayed at hour 0, 3, 13, 24, 48 and 72 of germination. Dormant pollen showed relatively high GA activity throughout the elution spectrum (i.e. ranging from relatively nonpolar to highly polar). The maximum GA activity was obtained at hour 13 in more polar regions and especially in the zone corresponding to GA3 (for P. attenuata estimated as 230 micrograms of GA3/kilogram pollen). It is probable that the "nonpolar"GAs present in high quantities in dormant pollen and in early stages of germination were converted to "more polar"GAs as germination progressed. The amount of all GAs decreased after hour 13 of germination and by hour 72 no GAs could be detected. Among the species tested P. attenuata showed the highest over-all GA activity.

Gibberellins and Heterosis in Maize

“…Parental pollen tube growth rates of germinating maize pollen are positively correlated with seedling dry weight, ear weight, and grain yield of the resultant hybrids (15). Pollen tube growth is promoted through exogenous application of GA (3,11), and increases in endogenous GA of untreated pollen is positively correlated with increased pollen germination and rapid pollen tube growth (1,10). Thus, the correlation between rapidity of pollen tube growth and hybrid vigor of the progeny (15) also appears interrelated with GA physiology.…”

La culturein vitrodes organes reproducteurs chez les arbres

“…La restitution du mouvement enregistré, en l'accélérant ou en le ralentissant, a permis également d'identifier et d'analyser divers types de mouvements, comme la migration des noyaux libres et de la cellule spermatogène ainsi que les mouvements de cyclose dans la cellule du tube (Duhoux et Vieuxgué, 1979;Duhoux et Wauquier, 1980). De plus, la technique des cultures in vitro conduit à une approche biochimique du développement des gamétophytes, par 1 'analyse de leur contenu, qu'il s'agisse de substances minérales (Barbier, 1970), d'acides aminés (Duhoux et Phamthi, 1980 ou de phythormones (Michalski, 1967 ;Sweet et Lewis, 1971 ;Kamienska et Pharis, 1975).…”