Principles of Nutrient Uptake from Fertilizer Bands. VII. P32 Uptake by Brace Roots of Maize and Its Distribution Within the Leaves¹

Abstract

The influence on phosphorus uptake of area of roots in the fertilized soil and the rate of fertilization was investigated using aerial brace roots of maize. Either 1 or 2 brace roots were directed into soil containing 0.62 or 3.10 g of phosphorus labeled with P32. The radioactivity of the tip and/or basal portions of all leaves was measured by wrapping one thickness of leaf around a long G–M tube. The distribution of P32 in several leaves was mapped with an end window G–M tube. The P32 accumulation measured by the in‐situ technique was highly correlated with that of the standard briquet method. Phosphorus uptake varied with the rate of fertilization and the number of fed brace roots. The proportion of total phosphorus derived from the fertilizer ranged from 1–37%. The P32 distribution in the leaves depended upon their position relative to the fertilized brace roots. The leaves on the brace root side had higher P32 activity in their tip portions than in their basal portions. This distribution is explained by limited connections between vascular bundles of the stem and the diverging of the leaf veins from the midrib.

Nonuniform Transport of Phosphorus from Single Roots to the Leaves of Zea mays

“…Nonetheless, the relative position of the single roots utilized in these experiments would appear to be the factor determining whether a given leaf margin would result in high or low accumulation (Figures 4, 5 and 7). A similar notion has been advanced by Robertson et al (1966) in explaining the distribution of P uptake by a single adventitious root. In their work, differences in leaf P distribution occurred in basal vs. apical portions of the leaves as well as between opposite margins.…”

Nitrogen, Phosphorus, and Potassium Fertilization of Non‐Tilled Maize1

“…B ECAUSE plowing for corn (Zea mays L.) has been customary, most fertilizer placement studies made with corn have been concerned with the effects of various kinds of row placement or methods of incorporating surface applied fertilizer by plowing or disking (3,5,8,16,17). Very little data is available to indicate the effectiveness of surface applied fertilizer in continuous no-tillage systems of corn production.…”

Plastic film mulching stimulates brace root emergence and soil nutrient absorption of maize in an arid environment

“…where RSA is root surface area per plant (m 2 ); RSA LC is summed RSA in 0-120 cm soil depth between drip lateral and crop row; RSA 0-10 , RSA [10][11][12][13][14][15][16][17][18][19][20] , and RSA [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] are summed RSA in 0-120 cm soil depth at horizontal distances 0-10, 10-20, and 20-35 cm away from the crop row, respectively.…”

“…Brace roots are responsible for physical stability. However, Robertson et al 34 and Hoppe et al 35 found that brace roots of maize also play an important role in soil water and nutrient acquisition. In this study, mulching stimulated growth of brace roots, and resulted in high soil P consumption in surface soil, and may have led to extremely low (< 10 mg/kg) SOPCs.…”