| Autor: |
Carpita, N. C., Skaria, A., Barnett, J. P., Dunlap, J. R. |
| Předmět: |
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| Zdroj: |
Physiologia Plantarum; Dec83, Vol. 59 Issue 4, p601-606, 6p |
| Abstrakt: |
The mechanism of germination enhancement by cold stratification was examined in seeds of loblolly pine (Pinus taeda L.), Removal of the seed coat permitted elongation of radicles from unstratified embryos, but both rates of germination and radicle elongation were increased by stratification. Radicles of both stratified and unstratified embryos excised from the megagamethophyte elongated only when in contact with solid incubation media supplemented with sucrose. Stratification of embryos either in the presence or absence of the megagametophyte resulted in similar enhancement of radicle elongation. Elongation rates of radicles were increased after stratification independent of sucrose concentration, and changes in sucrose content in the megagamethophyte during stratification or incubations subsequent to stratification were insufficient to regulate radicle growth. Our results support the hypothesis that the embryos of pine seeds perceive the low temperature stimulus directly and this stimulus results in a growth potential increase in the embryonic axes. We propose that this growth potential increase enables the embryos to overcome the mechanical restraint of the seeds coats and to germinate. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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