Kin Selection in Plants, a bit off topic

Kin Selection and Inclusive Fitness are important and not completely
understood aspects of evolution. The general idea is that natural selection
may favor traits that help relatives of an individual to survive. The
reasoning is that relatives (kin) share some of the genes that an individual
has, and that helping kin can help perpetuate shared genes.

Inclusive Fitness is apparently not the same as Altruism, but the concepts
are similar and overlapping. Helping kin has costs, and Altruism has costs.
If an organism shares resources (nutrients, water, sunlight) there is
typically a cost. Sharing sunlight or soil nutrients can result in
production of fewer flowers and seeds, and therefore fewer offspring. Loss
of offspring is the ultimate cost.

Therefore, whenever Inclusive Fitness is observed, it is proposed that there
is some sort of evolutionary tradeoff, a mitigation of cost. An individual
might produce fewer direct offspring, but kin have nearly identical gene
sets and a benefit can be realized (in evolutionary terms) if kin are able
to propagate and so perpetuate identical (or similar) genes.

The interesting bit of news this week is that Dr. Susan Dudley and her
colleagues at McMaster University have documented that plants seem to give a
break to members of their own species in the never ending competition for
resources. The effect was observed in root growth. Typically, plants will
make extra roots if they are in proximity to other plants. The extra roots
help a plant acquire water and nutrients that might otherwise be usurped by
neighbors.

Dr. Dudley has shown that plants produce more roots (and do so more quickly)
when in proximity to unrelated plants. When grown alongside siblings (same
maternal line) the study plants produced fewer roots--the plants shared.
This is all interpreted is Kin Selection, i.e., the plants are not as
competitive with relatives as they are with strangers.

The experiments were conducted in the laboratory where plants (Cakile
edentula) were grown in groups of four. The Cakile were grown with same
species (derived from the same maternal line) or with more distantly related
plants.

The result is more than a bit of data showing the kin selection is a broad
phenomenon in Nature. The result raises really interesting questions. How
do plants recognize close relatives vs. not close relatives and how do the
modulate their root growth accordingly. The answer will be interesting to
unravel; perhaps the mechanism is related to pollen acceptance or rejection
wherein plants can recognize their own pollen and prevent
self-fertilization. Perhaps an unknown mechanism is involved such as
related plants being able to share mycorrhizal fungi and perhaps gain by
sharing.

If one plant species has Kin Selection it seems most probable that other
species will have the feature. I'm confident that some bulbs will be shown
to exhibit Kin Selection.

LINK: Dr. Dudley, Home Page, McMaster Univ.
http://science.mcmaster.ca/biology/faculty/…

LINK: Page 1, The Ecology of Kin Recognition (JSTOR)
http://www.tiny.cc/RkTDP/

Cordially,

Joe
Conroe, TX