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Growth of Excised Roots of the Tomato

1938; University of Chicago Press; Volume: 99; Issue: 4 Linguagem: Inglês

10.1086/334743

1940-1205

William J. Rôbbins, Mary Bartley Schmidt,

Microbial Metabolites in Food Biotechnology

1. The possibility of unlimited growth of excised tomato roots in White's solution composed of mineral salts, sugar, and yeast extract was confirmed. 2. Each of the three parts of this medium was essential. 3. The essential nature of the yeast extract was because of its vitamin B1 or vitamin thiazole content. 4. Unlimited growth of excised tomato roots appeared possible in a solution of mineral salts, cane sugar, and vitamin B1 or thiazole. 5. The following compounds in the amounts used did not substitute for vitamin B1 or the vitamin thiazole in the growth of excised tomato roots: indole(3)acetic acid, yeast ash, vitamin C, pantothenic acid, vitamin G (B2), asparagine, cysteine hydrochloride, inositol, urea, pimelic acid, hydrolyzed nucleic acid. 6. Neo-peptone, malt flour, and certain samples of maltose at suitable concentrations substituted for yeast, probably because of their vitamin B1 or thiazole content. 7. The growth of excised tomato roots was affected by extremely small amounts of vitamin B1. The effect of 0.000000001 mg. (1 part in 40,000,000,000,000 parts of culture solution) was observed. It is believed, however, that the presence of 0.1 gamma or more is necessary for unlimited growth. 8. Tomato roots grown in a solution supplemented with thiazole alone synthesized the pyrimidine intermediate of vitamin B1. 9. Vitamin B1 did not replace inorganic nitrogen nor inorganic sulphur for tomato roots. 10. Excised tomato roots apparently required no other source of nitrogen than nitrates for unlimited growth. 11. Cane sugar, glucose, levulose, maltose, or cellobiose were available carbon sources for excised tomato roots. 12. The contaminants in "pure" sugars markedly affected the growth of excised tomato roots. 13. White's mineral solution was not adequate for best growth of tomato roots. 14. The addition of boron and zinc improved White's mineral solution. 15. Certain samples of filter paper and of filter paper ash improved White's solution. 16. A modified Pfeffer's solution with 2.5 p.p.m. of Fe2(SO4)3 instead of 0.8 p.p.m. FeCl3 was superior to White's mineral solution when yeast extract was replaced by vitamin B1. 17. Excised tomato roots did not require light for unlimited growth. 18. Variability in the growth of individual roots under the same conditions may have been associated with differences in the composition of the fragments used as inoculum.