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INORGANIC NITROGEN NUTRITION OF THE SEEDLINGS OF THE ORCHID, CATTLEYA
Author(s) -
Raghavan V.,
Torrey John G.
Publication year - 1964
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.1537-2197.1964.tb06629.x
Subject(s) - kinetin , ammonium , nitrogen , seedling , biology , botany , nitrate reductase , germination , dry weight , chlorophyll , ascorbic acid , horticulture , nitrate , chemistry , tissue culture , biochemistry , in vitro , ecology , organic chemistry
When grown in vitro in a medium containing NH 4 NO 3 as the sole source of nitrogen, seeds ro the orchid, Cattleya (C. labiata ‘Wonder’ X C. labiata ‘Treasure'), germinated readily and proceeded to form small plantlets. Development of the embryos was accompanied by an increase in their total nitrogen and a decline in the percent dry weight. Growth responses of the seedlings in other ammonium salts like (NH 4 ) 2 SO 4 , (NH 4 ) 2 HPO 4 , NH 4 Cl, ammonium acetate and ammonium oxalate were similar to that in NH 4 NO 3 . However, when grown in a medium containing NaNO 3 , development of the seedlings was drastically inhibited; KNO 3 , Ca(NO 3 ) 2 , KNO 2 and NaNO 2 also were poor nitrogen sources. Attempts to grow the seedlings in NaNO 3 by changing the pH or by addition of kinetin, molybdenum or ascorbic acid as supplements were completely unsuccessful. When seedlings growing in NH 4 NO 3 for varying periods were transferred to NaNO 3 , it was found that those plants allowed to grow for 60 or more days in NH 4 NO 3 could resume normal growth thereafter in NaNO 3 . Determination of the nitrate reductase activity in seedlings of different ages grown in NaNO 3 , after NH 4 NO 3 , showed that the ability of the seedlings to assimilate inorganic nitrogen was paralleled by the appearance of the enzyme.