jackrowe at compuserve.com Sat Nov 1 13:51:50 EST 1997 I can
believe that to-us subtle changes in light frequencies can have
an effect on seed germination... what appear to be small initial
influences can often result in profound changes in outcome. This
mechanism might prevent weed seeds (which are often
impressively-long-lived) from germinating before the canopy is
opened above them or they are carried on a hog snout out into
the open and replanted. A lot of weed seeds have two dormancy
requirements. The first is a ripening or maturation stage, which
they spend underground or out of the light. The second
requirement can then be satisfied by exposure to light. This is
true of a lot of amaranthus', for instance, and Chenopdiums.
This is the reason for the common name "pigweed", historically
applied to both these genera... these plants are often
germinated by rooting pigs, who expose mature seeds to light in
the course of their rooting and so cause their germination.
These are called weeds of disturbed soil an