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KINETIN‐INDUCED PSEUDONODULES ON TOBACCO ROOTS
Author(s) -
Arora Nirmal,
Skoog F.,
Allen O. N.
Publication year - 1959
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1959.tb07060.x
Subject(s) - pericycle , kinetin , primordium , biology , botany , apex (geometry) , lateral root , meristem , amyloplast , anatomy , tissue culture , plastid , biochemistry , shoot , arabidopsis , gene , mutant , in vitro , chloroplast
A rora , N irmal , F. S koog , and O. N. A llen . (U. Wisconsin, Madison.) Kinetin‐induced pseudonodules on tobacco roots. Amer. Jour. Bot. 46(8): 610–613. Illus. 1959.—Tobacco stem segments were cultured on modified White's medium containing 0.02–0.1 mg./l. of kinetin, 2 mg./l. of IAA and 2 g./l. of casein hydrolysate. Roots grew profusely from these stem pieces. In the presence of kinetin, especially when a second supply (0.2 mg./l.) was introduced after the roots had developed, large numbers of pseudonodules were formed along the root surfaces. The protuberances were spherical in shape and were invariably associated with the axial area of lateral rootlets derived as root primordia from parent root pericycle. Development of the pseudonodules started with the division and enlargement of cortical cells. The center of each pseudonodule contained either a simple provascular strand constituting a modified rootlet with a poorly defined apex and layers of tracheids at the base, or a normal lateral root primordium capable of continued growth and eventual emergence as a rootlet. In later stages, the swellings became lobed and the mature cells showed a high starch content. Although these kinetin‐induced pseudonodules arose from cortical tissue, their anatomical structure remained undifferentiated and unspecialized and bore no resemblance to that of typical nodules caused by rhizobia.