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STUDIES ON SUBMICROSCOPIC ASPECTS OF MINERAL DEFICIENCIES. II. NITROGEN, POTASSIUM, SULFUR, PHOSPHORUS, AND MAGNESIUM DEFICIENCIES IN THE SHOOT APEX OF BARLEY
Author(s) -
Marinos Nicos G.
Publication year - 1963
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.1537-2197.1963.tb06582.x
Subject(s) - elongation , apex (geometry) , biology , potassium , magnesium , shoot , phosphorus , sulfur , cytoplasm , botany , potassium deficiency , ultrastructure , starch , biochemistry , chemistry , materials science , organic chemistry , ultimate tensile strength , metallurgy
Marinos, Nicos G. (Waite Agric. Res. Inst., Adelaide, S.A., Australia.) Studies on submicroscopic aspects of mineral deficiencies. II. Nitrogen, potassium, sulfur, phosphorus, and magnesium deficiencies in the shoot apex of barley. Amer. Jour. Bot. 50(10): 998–1005. Illus. 1903.—The elongation of the shoot apex of barley was retarded in the absence of N, P, or Mg, while the lack of S or K did not affect its growth as compared with the controls. Ultrastructural changes in cells of the terminal 100 μ of the apical dome either appeared concurrently with, or preceded, measurable effects on apical elongation. These changes included: (1) formation of many dense intramitochondrial granules and a statistically significant reduction of the length of mitochondrial tubules; (2) accumulation in the cytoplasm of dense manganophilic inclusions which appeared to be formed by the Golgi bodies (dictyosomes); (3) starch accumulation, only in P‐dcficient plants, in a region of the apex that is normally free of starch. The similarities in the symptoms induced by N, P, and Mg deficiencies reflect the metabolic interrelationships between these elements. On the basis of the time of appearance of these symptoms and their distribution in the longitudinal axis of the apical dome, it is concluded that altered mitochondrial function is an early response of cells to the lack of certain essential elements.