THE GROWTH-PROMOTING ACTION OF CRUSTACEAN EYE-STALK EXTRACT

¹ From the Laboratory of General Physiology, Harvard University, Cambridge, Massachusetts

The chromatophore activator of the crustacean Palmonetes, extractable from the eye-stalks, increases the rate of elongation of decapitated coleoptiles of Avena. The analogy of this effect with that due to the growth hormone normal to the plant is extended by the fact that the eye-stalk substance, like the substance of coleoptile tip or root tip, depresses the rate of elongation of the decapitated root of Lupinus.

Data are presented on the rate of inactivation of the eye-stalk substance by aging, and on the concentration effect.

The plant growth hormone will not activate chromatophores of crustaceans as the eye-stalk extract of crustaceans does. Nor have we been able to extend the analogy between the pituitrin-like qualities of the eye-stalk hormone and the plant growth substance by finding a chromatophore-activating factor in pregnancy urine.

It is pointed out that measurements permitted by the conditions of these experiments open the way to the assay of the eye-stalk chromatophore activator, and thus to the quantitative investigation of its origin and properties. They also raise interesting possibilities for the analysis of the growth-hormone effect in plants.