Abstract. The radiation (3'P) induced dwarf mutant of spring barley, Hordeum vulgare L., Mut. Dornburg 576, was genetically studied by crosses with the mother variety and characterized by seedling assays and investigations on development and yield formation. In comparison to the normal mother variety (Hordeum vuigare L., cv. 'Saale') mutant plants exhibit drastically reduced culm length, intensive tillering, a prolonged life cycle and a smaller biomass and grain yield formation. These characters are controlled by one gene in a pleiotropic way. The mutant responds with normal growth and development to the application of gibberellins.
The influence of water shortage and ethylene (ethephon) application on ear fertility and tillering of barley plants were compared. In both cases, highest sensitivity was observed duringjointing and pre-anthesis (Feekes 7-9). The ear initial with the surrounding tissue was identified as the site of ethylene action. Treating this region of barley plants with AVG before wilting partly prevented drought effects. These results, in connection with rising ethylene values in ear-bearing stem segments of wilting barley plants (more obvious in increasing ACC and MACC levels), especially in the droughtsensitive stages, favors a role for ethylene in the development of cereal plants under drought.
In order to determine the significance of the C-6 carboxyl group for the biological activity gibberellin A3, 6-epigibberellin A3, 7-norgibberellin A3, 6β-methyl-7-norgibberellin A3, and 7-homogibberellin A3 were studied using dwarf pea, dwarf maize, dwarf rice, dwarf barley and α-amylase bioassays. All gibberellin A3(GA3)derivatives tested were considerably less active than GA3. In all biossays, 6-epi-GA3 showed a low activity of the same order, whereas 6β-methyl-7-nor-GA3 was inactive. Surprisingly, 7-nor-GA3 had some activity in the dwarf rice (root application), dwarf barley, and α-amylase bioassay, in contrary to its low potency in the dwarf pea, dwarf maize, and dwarf rice (micro drop) bioassay. 7-Homo-GA3 was primarily active in the dwarf maize, dwarf barley and dwarf rice bioassay. It also caused antigibberellin effects in dwarf rice. The results demonstrate that the C-6 carboxyl group is not absolutely essential for biological activity of gibberellins. The different activities of 7-nor-GA3 observed in the various test systems may indicate that the C-6 carboxyl group is a structural requirement more for uptake and/or transport processes than for receptor affinity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.