CULTIVATION OF EXCISED ROOT TIPS AND STEM TIPS 
UNDER STERILE CONDITIONS* 
WILLIAM J. ROBBINS 
(WITH FOUR FIGURES) 
The growth of higher plants under sterile conditions is a necessary 
procedure in the investigation of problems involving the direct use 
by higher plants of organic or inorganic substances which may be 
altered by bacterial action. Failure to observe sterile conditions 
throws doubt on the conclusions drawn from the results secured in 
any experiment where the direct use by plants of an organic 
compound and some inorganic substances such as ammonium salts 
or nitrates is investigated. 
As indicated by Witson (18), the methods which have been used 
to grow plants under sterile conditions have either attempted to 
grow the entire plant under sterile conditions, or to keep that part 
of the plant which is of importance in the special investigation in 
a sterile environment. Lutz, LAURENT, LEFEVRE, MOLLIARD, 
GraFE, Ravin, Knupson (11), BRANNON (4), and others have 
described methods of cultivating entire plants under sterile condi- 
tions. Maz and Perrier (12), SHULOw, Hurcuinson and 
MILLER (9), and Witson (15) have described in some detail methods 
by which higher plants may be grown with their tops exposed to 
the normal aerial environment. Mazé and WILsoN grew cor 
plants to maturity with the root systems in sterile water cultures. 
Isolated and mature plant embryos have been cultivated under 
non-sterile conditions for longer or shorter periods by Brown and 
Morris, ANDRONESCU (2), URBAIN (16), and others. KNUDSON 
cultivated corn embryos, and Buckner and Kast1e (3) bean 
embryos for short periods under sterile conditions. Isolated and 
immature embryos of species of Rhapanus and of Cochlearia danica 
have been grown with some success under sterile and non-sterile 
conditions by Hannic (8). HaBertanpt (5) attempted to grow 
* Published with the permission of the Director of the Agricultural Experiment 
Station, University of Missouri. 
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