Tripsacum dactyloides (L.) L. caryopses water uptake dynamics and germination responses to giberellic acid, fluctuating temperatures and pericarp scarification
Tripsacum dactyloides (L.) L. germination problems lies on the presence of a hard cupule and a deep caryopses dormancy. The objectives of this study were: i) to determine differences in caryopses water uptake as a result of cupule removal and pericarp scarification, ii) to evaluate the following variables (main effects) on germination: thermal treatment (25°C vs. 25/30°C), incubation medium (water vs. 1.44 mM GA3), pericarp condition (intact vs. scarified), seed lot and their interactions iii) to determine germination of isolated embryos and scarified dispersal units. Similar increments of water uptake (ml g−1) for dormant caryopses (scarified and intact ones) and dispersal units were recorded. So, coats were not a barrier to water uptake. ANOVA showed significant increases in germination for the four main effects: fluctuating temperatures (69.79% vs. 59.67%), GA3 (79.4% vs. 57.8%), scarification (76.25% vs. 61.19%), seed lot (71.16, 62.61, 60.41 for 2002, 2003 and 2004, respectively) and three simple interactions were highly significant: seed lot X caryopses scarification, seed lot X incubation medium and caryopses scarification X incubation medium. Germination percentages were close for intact and scarified caryopses incubated in GA3 (72.83% vs. 78.78%). In contrast, scarification highly increased germination of water incubated caryopses (36.79% vs. 70.52%). These results suggest that GA3 could antagonize some inhibitory effect in intact caryopses, but the GA3 action per se and/or highest leakage or degradation of some inhibitor, probably ABA, trigger germination of scarified ones. Isolated embryos fully germinated in distilled water after 48 h of dark incubation. Intact and scarified dispersal units showed germination of 0% and 18.28%, respectively. More than 80% remained dormant, which points out that cupule inhibits germination by a different mechanism to that related to caryopsis dormancy, most probably a physical constraint.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
Document Type: Research Article
Publication date: July 1, 2007
More about this publication?
- Seed Science and Technology (SST) is one of the leading international journals featuring original papers and review articles on seed quality and physiology as related to seed production, harvest, processing, sampling, storage, distribution and testing. This widely recognised journal is designed to meet the needs of researchers, advisers and all those involved in the improvement and technical control of seed quality.
- Editorial Board
- Information for Authors
- Subscribe to this Title
- Membership Information
- Ingenta Connect is not responsible for the content or availability of external websites