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Potassium Influx Characteristics of Corn Roots and Interaction with N, P, Ca, and Mg Influx 1
Author(s) -
Claassen N.,
Barber S. A.
Publication year - 1977
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/agronj1977.00021962006900050034x
Subject(s) - shoot , potassium , chemistry , plant roots , zea mays , plant growth , human fertilization , cell permeability , root system , horticulture , agronomy , botany , biology , biochemistry , organic chemistry
At K levels usually found in soil solution, K influx characteristics of plant roots can be described by Michaelis‐ Menten kinetics. When only part of the roots are supplied with K, plant uptake of K may be reduced, causing a reduction in K concentration in the plant and this, in turn, may also reduce plant growth. Knowledge of how K distribution in the root zone influences K uptake by the plant is important in developing efficient practices of K fertilization. The objective of this research was to determine the K influx characteristics of corn ( Zea mays L.) roots and investigate how supplying only part of the roots with K influences both K influx and N, P, Ca, and Mg influx. Four split‐root experiments were conducted in solution culture. Corn was grown from 7 to 17 days with varying proportions of the root system supplied with K. Reducing the proportion of roots in K reduced K uptake by the plant; however, the K influx of the K‐supplied roots increased up to 2.6 times that of roots on plants where all roots were supplied with K. Presence or absence of K in the solution bathing the roots did not affect root growth in these experiments. Two additional experiments were conducted to produce plants having varying shoot K levels for use in measuring K. influx characteristics. Analysis of all six experiments showed an inverse curvilinear relation between %K in the shoot and maximum K influx into the root (R 2 = 0.74). Comparison of K influx by K‐supplied‐roots and roots originally in solution without K that were attached to the same shoot indicated the K level in the shoot had a greater effect on K influx than K level of the root. Magnesium influx increased as K concentration in the plant decreased. Magnesium influx was much greater on the K‐absent side than on the K‐present side of the split‐root system. Nitrogen influx was greater on the K‐present than on the K‐absent side.