Experiment Station Record, Volume 92, January-June, 1945 Page: 185
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1945] AGRICULTURAL BOTANY 185
probable that materials which had already escaped somewhat from the normal
morphogenetic bonds might prove more satisfactory than excised roots for preliminary
studies along these lines. Such materials presented themselves first in
the rapid-growing disorganized galls, regularly appearing on plants of the hybrid
Nicotiana langsdorfii X N. glauca. Another suitable material was found in the
secondary galls-not containing bacteria and thus indirectly induced by the presence
of bateria elsewhere in the host-arising on sunflower inoculated with Phytomonas
tumefaciens. Finally, the author presents one set of evidence indicating the feasibility
of evoking new or restoring lost patterns in these experimental materials. When
the Nicotiana galls were grown at the surface layer between nutrient and air, tissue
growth was disorganized; when grown deep in the nutrient liquid they rapidly developed
green pigment, and their surface layers became organized by well-oriented
sequences of cell divisions into numerous typical growing points developing into
typical plantules. These reactions were completely reversible, depending on the
position with respect to the interface; strong evidence points to the conclusion that
this morphosis is an aerogenous one. Here, then, is a well-defined morphosis which
can be controlled and manipulated at will as an experimental tool in the study of
such phenomena; it is believed that many other such manipulable morphoses will be
found which will lead to a much sounder insight into the causes of the multitudinous,
variations in form and function characterizing living organisms.
The investigation of plant nutrition by artificial culture methods, D. I. ARNON
and D. R. HOAGLAND. (Univ. Calif.). (Biol. Rev. Cambridge Phil. Soc., 19'
(1944), No. 2, pp. 55-67).-This review (126 references) presents a general survey
of the subject. Several types of culture are described, including liquid culture
methods and those depending on a solid inert medium. The advantages of artificial
culture procedures for growing plants are pointed out, as one means of studying soilplant
interrelations, as well as various questions in the physiology and biochemistry
of plants. These technics have proved indispensable in investigating the chemical
elements essential to growth in the higher plants, especially those needed in only
minute amounts. These methods are also highly valuable for studying the absorption
of ions by roots, and they serve for inquiries into the interreactions of climatic conditions
and mineral nutrients. Among other topics considered are the applications of
these methods to researches on the functions of inorganic nutrients in plant
metabolism, the role of colloids in ion absorption, horticultural and agronomic
problems, and commercial production of crops (e. g., hydroponics).
The behavior of excised roots of heterotic hybrids and their inbred parents
in culture, W. G. WHALEY and A. L. LONG (Bul. Torrey Bot. Club, 71 (1944),
No. 3, pp. 267-275, illus. 3).-Excised roots of tomato and corn were grown in
Pfeffer's solution containing separately thiamine; thiamine and pyridoxine; and
thiamine, pyridoxine, and nicotinamide. In cultures containing thiamine the roots
of one inbred strain of tomato-Pritchard-responded better to added pyridoxine;
those of the other-Red Rover-to added nicotinamide. The hybrid roots were
better than those of either of the inbreds in all media used. Excised corn roots
showed progressive growth diminution in successive passages in all media. The
hybrids showed more growth in each of six passages, as well as greater average
growth, than the inbreds. In cultures containing thiamine the parents and hybrids
of one cross exhibited increased growth in presence of pyridoxine but decreased
growth in presence of pyridoxine and nicotinamide in the concentration used; the
roots of the other cross reacted in like manner but less consistently. It is suggested
that the hybrid advantage originated in its more efficient metabolism,
giving the hybrid roots greater ability to synthesize and/or utilize certain substances.
Calcium and other polyvalent cations as accelerators of ion accumulation by
excised barley roots, F. G. VIETS, JR. (Univ. Calif.). (Plant Physiol., 19 (1944),
No. 3, pp. 466-480, illus. 11).-A systematic study of K and Br absorption as
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U.S. Department of Agriculture. Agricultural Research Administration. Office of Experiment Stations. Experiment Station Record, Volume 92, January-June, 1945, book, 1947; Washington D.C.. (digital.library.unt.edu/ark:/67531/metadc5064/m1/198/: accessed October 16, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.