Sowing/Raising seeds questions

Jeffrey Kirby ez043438 at barney.ucdavis.edu
Mon Jun 5 11:52:20 EST 1995


Nancy Harrison (nanharrison at delphi.com) wrote:
: Pouring hot water over seeds doesn't work for all seeds!  We
: use that technique in Calif (called "scalding") for hard-coated
: seeds that are native to areas where fires occur seasonally -
: it fakes out the seeds so they think they've been burnt, and
: this triggers germination.

Scarification is the process by which one somehow treats a seed so that
the seed coat becomes permeable to gas and water exchange. Many seeds need
this to germinate (because their seedcoat doesn't let anything through).
Techniques that I know of that one can use include a short dip (30 seconds
or so) in boiling water, sandpapering one side, or a dip in acid (usually
hydrochloric, I believe). Some plants in nature also need fire to
germinate (or are at least helped out greatly) because of several possible
factors including a removal of competition, the release of nutrients into
the soil, the removal of allelopathic plants, the removal of homes for
rodents which munch munch munch, the release of the seeds (like in
closed-cone conifers), and/or the levels of light. The fire periodicity
and temperature required to sustain an ecosystem depends on the system
(e.g. Northern California foothill chaparral burns every 25 years or so at
very high temps, killing everything except some seeds - temperatures below
ground are much lower). I seem to have rambled. Apologies.

-J
-----------------------------                                      -----
        Jeffrey A. Kirby -- Jester of Xanadu -- jakirby at ucdavis.edu

"Das Material des Tones bietet"    ("The material of the tone offers" )
                    - Arnold Schoenberg from _Zusammenhang, Konfrapunkt, 
Instrumentation, Formenlehre_
 



More information about the Plantbio mailing list