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Growth and Nitrogen Accumulation in Tobacco Plants as Affected by Nitrate Concentration, Root Temperature, and Aerial Temperature 1
Author(s) -
Osmond Deanna L.,
Raper C. David
Publication year - 1981
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1981.00021962007300030022xa
Subject(s) - nicotiana tabacum , nutrient , dns root zone , dry matter , root system , nitrogen , horticulture , dry weight , agronomy , nitrate , chemistry , botany , biology , irrigation , biochemistry , organic chemistry , gene
Early spring is a period of widely fluctuating gradients between aerial and soil temperatures. Aerial temperatures affect growth and N demand of seedlings while temperature and N availability in the root zone alter the ability of roots to supply the plant with N. The purpose of this study, in which tobacco ( Nicotiana tabacum L.) plants were grown in a temperature controlled, flowing nutrient solution system within a controlled‐environment room, was to determine the independent effects of aerial temperature, root‐zone temperature, and NO 3 ‐ concentration of nutrient solution and their interactions on growth and N accumulation. In each of nine experiments consisting of all combinations of day/night aerial temperatures of 22/18, 26/22, and 30/26 C and solution NO 3 ‐ concentrations of 3.5, 7.2, and 14.6 m M , plants were grown for 38 days at root‐zone temperatures of 16, 24, and 32 C. For analysis of variance the study was considered as a 3 3 factorial. Plants were sampled at 14, 19, 24, 31, and 38 days, dried, weighed, and analyzed for total N and soluble carbohydrates. Root‐zone temperatures had greater effects on growth than either aerial temperature or NO 3 ‐ concentration. Plant dry weight, leaf area, and stem height were less at 16 C than 24 and 32 C root temperatures. The reduction in growth at 16 C apparently was attributable to initial water stress and reduced loading of N from the root into the vascular system. Reductions in dry matter and N accumulation of plants associated with reductions in root temperature were enhanced as aerial temperature was increased and solution NO 3 ‐ concentration was decreased. This suggests an interrelated and synergistic effect of the variables.