Open AccessNitrogen assimilation and nitrate reductase activity in tomato seedlings. II. Effect of increasing calcium doses in the presence of high magnesium concentrations on nitrate reduction and protein content
Author(s) -
A. Suder-Moraw,
J. Buczek
Publication year - 2015
Publication title -
acta societatis botanicorum poloniae
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.297
H-Index - 29
eISSN - 2083-9480
pISSN - 0001-6977
DOI - 10.5586/asbp.1977.020
Subject(s) - chemistry , calcium , nitrate reductase , nitrate , nitrogen , magnesium , zoology , nutrient , nuclear chemistry , biology , organic chemistry
A 3:30 Ca:Mg ratio in the nutrient solution produces in tomato seedlings symptoms of Ca2+ deficit owing to excessive accumulation of Mg2+ ions and the depressed Ca2+ accumulation. As a result of this a decrease in dry weight increment and protein content is observed together with inhibition of nitrate reductase activity. A doubled Ca2+ dose in the nutrient solution, that is a change in the Ca:Mg ratio to 6:30 abolishes the external symptoms of Ca2+ deficit and reduces Mg2+ accumulation, that of Ca2+ ions remaining unchanged. At the same time an enhanced activity of nitrate reductase appears, reaching values close to those in control plants. Tomato seedlings grown on a 3-fold increased Ca2+ dose (Ca:Mg = 9:30) did not differ at all from the control ones. An in-crease in calcium concentration in the nutrient solution, the high magnesium dose remaining unchanged, causes enhanced K+ accumulation, and this may affect nitrate absorption and reduction. It would seem that Ca2+ deficit in plant tissues induced by excessive Mg2+ accumulation with unsuitable Ca:Mg ratio in the nutrient solution in cause of disorders in NO3 nitrogen assimilation