Uptake, transport and metabolism of phosphate by individual roots of Zea mays L.
1995
Mistrik, I. | Mistrikova, I. (Slovenska Akademia Vied, Bratislava (Slovakia). Botanicky Ustav)
The root system of 21 day old maize plants is formed by three different types of roots. The seminal root system, primary seminal (PS) and seminal adventitious roots (SA) represent 52.48 %, and nodal roots (N) represent 47.52 %, of the total root mass. Phosphate absorption and participation of individual roots in the total phosphate uptake increase in the following order: PS less than SA less than N. More than half of the total phosphate taken up by individual roots was found in the fraction of inorganic phosphate. Incorporation of sup(32)P into organic low molecular weight phosphate compounds and free nucleotides increased in the order of PS less than SA less than N, and decreased in the same order in the macromolecular phosphate compounds. Phosphate taken up by seminal roots was quickly transported to the shoot. The amount of phosphate transported from seminal roots was two times higher than from the nodal ones. In primary seminal and seminal adventitious roots the water movement occurred in the protoxylem and early and late metaxylem vessels. In the nodal roots only a small amount of late metaxylem vessels were involved in water transport.
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