[Plant-education] Re: Caffeine's effect on plants&In-Reply-To=
David R. Hershey
(by dh321 from excite.com)
Sat Jan 3 00:33:49 EST 2009
What kind of experiment was conducted? Some students water plants with
colas or coffee as a caffeine source but the other ingredients in
those may have a greater effect on plant growth, especially the sugar
in colas and the mineral nutrients in a cup of coffee.
The high sugar content in sodas can kill plants or stunt plant growth.
The high sugar concentration makes water less available to the plant.
It also promotes the growth of microbes that release toxic waste
products in the plant rootzone, and the microbes compete with the
plant roots for mineral nutrients.
Coffee is a hot water extract of seeds so contains essential mineral
nutrients that can improve plants including high concentrations of
potassium, magnesium and phosphorus. The USDA database cited below
provides information of mineral nutrient content of a cup of coffee.
There have been many scientific studies on caffeine effects on plants,
including ones examining root initiation in cuttings, seed germination
and plant cell division.
There are two main hypotheses on the role of caffeine in plants. One
is that caffeine inhibits seed germination of other plant species so
reduces competition. Another is that caffeine in leaves and shoots
discourages animals from eating the plant. (McCarthy and McCarthy,
USDA National Nutrient Database for Standard Reference
Re: Does Caffeine affect the growth of plants?
Batish, Daizy; Singh, Harminder; Kaur, Mansimran; Kohli, Ravinder; and
Yadav, Surender. 2008. Caffeine affects adventitious rooting and
causes biochemical changes in the hypocotyl cuttings of mung bean
(Phaseolus aureus Roxb.). Acta Physiologiae Plantarum 30(3): 401-405.
Chou, C. H. and Waller, G. R. 1980. Possible allelopathic constituents
of Coffea arabica. Journal of Chemical Ecology 6(3): 643-54.
Valster, A.H. and Hepler, P.K. 1997. Caffeine inhibition of
cytokinesis: effect on phragmoplast cytoskeleton in living
Tradescantia stamen hair cells. Protoplasma 196: 155166.
McCarthy, A.A. and McCarthy, J.G. 2007. The Structure of Two N-
Methyltransferases from the Caffeine Biosynthetic Pathway. Plant
Physiology 144(2): 879889.
More information about the Plant-ed