The Growth of Cucumis Melo Seedlings at Different Temperatures

The work of Julius Sachs (10) published in 1860, and in particular his discussion of the results, served to introduce two concepts into plant physiology, that of minimal, optimal, and maximal temperatures, and that of the grand period of seedling growth. Each of these phenomena has received the attention of numerous workers since that time but there have been relatively few attempts to combine the two fields of interest and to follow the course of growth of seedlings cultured in darkness at several constant temperatures throughout their entire growth period. The work of Sierp (11), Hamada (4), and Silberschmidt (12) on the growth of oat coleoptiles belongs in this class, as does that of Edwards, Pearl, and Gould (1) on Celosia crislata seedlings. Silberschmidt also tested pea and rice seedlings and contributed an interesting analysis of the problem. The present paper deals with the growth of Cucumis melo seedlings in darkness at seven constant temperatures between 15 ° and 40°C. inclusive. While we have accumulated in this laboratory during the past 10 years a considerable volume of unpublished observations on the effect of temperature on the growth of canteloup seedlings, so far as is known the only published work on the temperature relations of growth in this species are those of de Vries (14) who found greater growth at the end of a 48 hour period at 37.2 ° than at any of the other three temperatures he tested. Gregory (3) has made interesting temperature tests of another sort on Cucumis salivus seedlings grown in light which indicate a much lower optimal temperature range than was found in de Vries' experiments or in those presented here.