plants
(in)compatibility
Most
gardening books include advices on companion planting, i.e.
positioning plants together that are reput- ed to have a beneficial
effect on neighboring plants by discouraging pests and diseases or
improving growth. I don’t recall a single warning on negative or
at least unwonted effects of companion planting. And then surprise:
this spring I’ve planted together cypress vine (Ipomoea
Quamoclit pennata) and morning glory (Ipomoea purpurea),
both annuals, and I’ve also planted two cypress vine seedlings to
one bush of our perennial morning glory (Ipomoea indica). The
idea was to mix the heavenly blue flowers of morning glory with the
scarlet flowers of cypress vine. Well, through- out this spring and
summer, not a single morning glory flower appeared on the bush
accompanied by cypress vines (on the right) while unaccompanied bush (on the left) blossomed normally. Even more drastic
difference is exposed by the two annual species potted together to
climb over a metallic mash [ROLLOVER]:
while both plants are reach in leaves (cypress vine leaves are
deeply pinnatisect), only cypress vine flowers are present.
Of
course, ‘incompatibility of plants’ has many hits on the web,
probably a fertile ground for many Ph.D. thesis in botany. Wait a
moment: incompatibility by whose criteria? Look what Charles Darwin
said in The Origin of Species (Sixth ed.,1872):
"The
elder Geoffroy and Goethe propounded, at about the same time, their
law of compensation or balance- ment of growth; or, as Goethe
expressed it, ‘in order to spend on one side, nature is forced to
economise on the other side’. I think this holds true to e certain
extent with our domestic productions ... I suspect also, that some
of the cases of compensation which have been advanced, and likewise
some other facts, may be merged under a more general principle,
namely, that natural selection is continually trying to economise
every part of the organization ... Thus, as I believe, natural
selection will tend in the long run to |

reduce
any part of the organisation, as soon as it becomes, through changed
habits, superfluous, without by any means causing some other part to
be largely developed in a corresponding degree. And, conversely,
that natural selection may perfectly well succeed in largely
developing an organ without requiring as a necessary com- pensation
the reduction of some adjoining part." |