Stimulation Of Growth By Alfalfa
by D. L. Hinerman, M. D.
Professor of Pathology, University of Michigan Medical School and Hospital
Beneficial effects of alfalfa on plants and animals have been suspected for many years and exponents of natural foods have claimed beneficial effects in human beings resulting from ingestion of alfalfa pills and alfalfa tea. According to Mr. E. M. Stroombeek, about 25 years ago there was a flurry of interest among nurserymen over claims of beneficial effects on plants by use of an abstract of alfalfa, but for some reason the interest subsided. More recently, Dr. Stanley K. Ries of Michigan State University published reports in Science on March 25, 1977, and in Horticulture in August 1977 of an amazing increase in growth and productivity of plants grown in close proximity to decomposing alfalfa hay. Further investigation led to the isolation and purification of at least one of the chemicals, triacontanol, which supposedly was the active growth promoting agent in alfalfa. Triacontanol is classified as along chain alcohol. This chemical occurs widely in nature as a waxy coating on many plants and it is a major component of beeswax. The mechanism of the effect of this chemical on plants or animals is unknown. In plants only trace quantities of an aqueous solution (4 mgs. per acre of crops) was sufficient to produce maximum growth and productivity and apparently if too much was used the beneficial effects were lost. Among the most mystifying aspects of this substance were the observations by Ries and his associates that growth occurred even in the dark. Ries and his co-workers speculated that triacontanol may be a metabolic regulator.
The methods used in this experiment included the selection of ten seedling plants of R. metternichii, fine Yamato form, the seeds of which were purchased from the A. R. S. Seed Exchange in 1974 (list #285) and originated from Hideo Susuki in Japan. The selected plants were approximately equal in size and their growth rates had been fairly uniform over the three year period.
The cultural methods were identical for all ten plants with the exception of the treatment of six plants with alfalfa hay and the remainder were kept as controls. All were grown in plastic containers in a medium consisting of one-third perlite, one-third Michigan Peat and one-third humus-rich, loam soil.
On July 15, 1977, to the six treated plants a mulch or top dressing was added which consisted of about 1/2 cup of shredded and chopped alfalfa hay mixed with aged hardwood bark. To the four control plants only the same aged hardwood bark was added as a mulch.
One year later, on July 15, 1978, there were obvious quantitative and qualitative differences in growth. The illustrative photograph of four plants was chosen to reveal the extremes of growth: untreated control plants are labeled A and B; two plants treated with alfalfa hay are labeled C and D.
These obvious differences in rate of growth were measured in several dimensions. The height of each plant treated with alfalfa revealed an average increase of 55.1%, the greatest diameters increased an average of 27.6%, the number of leaves increased by an average of 27.6%, the length of leaves increased by an average of 53.5% and the width of leaves increased by an average of 19.3% (see table below).
Range Average Average
Height of plants in mms. Controls 35.0-63.0 49.0 Alfalfa Rx 63.0-101.5 76.0 55.1% Greatest diameter
of plants in mms.
Controls 63.5-114.0 88.0 Alfalfa Rx 71.5-178.0 112.3 27.6% Number of leaves Controls 10.0-17.0 14.3 Alfalfa Rx 14.0-23.0 18.3 27.0% Length of leaves in mms. Controls 38.0-52.0 45.4 Alfalfa Rx 38.0-86.0 69.7 53.5% Width of leaves in mms. Controls 12.5-23.0 16.6 Alfalfa Rx 12.5-27.0 19.8 19.3%
Top view of four seedlings of R. metternichii, fine Yamato form.
A and B are untreated controls. C and D have been treated with alfalfa
Not only were there significant quantitative differences in growth, but the quality of the plant was improved as noted by increased thickness and substance of leaves, increased indumentum, increased gloss of leaves and heavier stems and branches than in the untreated plants.
There was obvious evidence that alfalfa in rather small quantity produced a remarkable amount of growth and a better quality of growth in the seedlings of R. metternichii compared to similar plants that received identical treatment except for the alfalfa. The amount of nitrogen or other known basic plant nutrients was certainly insufficient to explain the increase in growth in this small experiment. The amount of growth roughly was equivalent to that seen in experiments of Dr. Rtes and associates where the active substance was supposed to be trace quantities of triacontanol.
Investigators from the U. S. D. A. and elsewhere have tried to repeat these experiments with varied results. There is a suspicion that the maximum dose of tricontanol may be critical and may have been exceeded, thus producing negative results.
Obviously many more experiments are indicated. Many more plants should be subjected to alfalfa and triacontanol. Plants of different ages should be tested. Clones should be used instead of seedlings to better control genetic factors. Leaf analyses should be done. Abundant scientific data will be necessary before the nature of this growth stimulation is understood.
Perhaps it is wise at this point to take a broader look at this and related problems. If such a potent stimulus to normal growth exists in alfalfa what the effects of the stimulus to abnormal growths such as plant tumors or cancers? Although it is common to attempt to extrapolate test results from one species to another such as from experimental animals to man, most extrapolations between plants and animals including man are usually considered impossible. In spite of the frenzied activity of regulatory agencies and health scientists and the grave concern of our society, we remain abysmally ignorant of the nature and toxicological properties of most chemicals to which we are exposed.
A natural and inexpensive substitute for the increasingly expensive, energy wasteful, chemical fertilizers appears to be a distinct possibility which would be satisfying both to energy conservationists and to environmentalists concerned with ever increasing contamination of the world in which we live. At the same time, we should be reasonably certain that this nature of rhododendrons.
(4) Several months ago I forwarded a prospectus for such a study to the Rhododendron Research Foundation for consideration for funding. The objectives would be to attempt to gain an understanding of why there is a growth effect - and how it relates to the production of rhododendrons.
(5) It has been my experience that liner rhododendrons obtained from one nursery on the West Coast consistently become more quickly established and grow better here than plants obtained from other West Coast sources. I recently learned that the particular nursery uses alfalfa in the production of its liners.
(6) A small test is being made here by putting crushed alfalfa pellets on part of a flat of seedlings - but it is too soon to see any significant results. substitute, a growth stimulant, is not also capable of producing abnormal growth such as cancer.
There can be no doubt that in this small experiment alfalfa contained a potent growth stimulant for young seedlings of R. metternichii.
The following is an addition to this subject by George Ring, Fairfax, VA.
(1) A firm in Kansas is marketing ALFA-GROW, chopped alfalfa plus 3% nitrogen.
(2) The U. S. D. A. is studying the effect of alfalfa on the growth of vegetable crops, such as beans, etc.
(3) To my knowledge, there is currently no really organized study on the effect of alfalfa on the growth.