Botanical Gazette, 47(4): 341-342 (Apr 1909)
Germination and Light
William Crocker

KINZEL12 publishes another paper on the effect of light on germination of seeds, confirming the results of former papers and adding a number of species to those favored in germination by light.

In a discussion of "after-ripening" he states that the several years' delay in germination shown by the ripe seeds of Thiaspi arvense is due to the character of the embryo and not to the character of the coat, for the coat is very delicate. In an article published in 1906,13 the reviewer has shown that the very marked delay in these seeds is entirely due to the coats. The delicacy of the coat is no criterion of its effect, for certainly few seed coats are more delicate than that of the upper seed of the cocklebur, yet it generally secures a delay of a year or more.

It is surprising that experimenters are so slow to see that the proper test for dormancy of an embryo is to free it from incasing membranes with aseptic precautions and then to subject it to germinative conditions. This treatment will probably show the cause of most cases of delay to be in structures surrounding the embryo. If such treatment shows teal dormancy of the embryo, as in the radicle of the hawthorn,14 it is then necessary to find the particular process that is delinquent. This is certainly possible in the light of the great progress that is being made in studying the catalytic nature of protoplasmic activity. When cases of delayed germination are investigated in this way, we may hope for progress. But to assume dormancy is merely marking time and leaves the physiology of delayed germination, as it is now, more than ten years behind other phases of plant physiology.

  1. KINZEL, WILHELM, Lichtkeirnung. Einige bestätigende und erganzende Bemerkungen zu den vorläufigen Mitteilungen von 1907 und 1908. Ber. Deutsch. Bot. Gesells. 26a:631-645. 1908.
  2. CROCKER, WM., Rôle of seed coats in delayed germination. BOT. GAZETTE 42:282. 1906.
  3. CROCKER, WM., Longevity of seeds. BOT. GAZETTE 47:69-72.1909.

Crocker Bibliography