Open AccessA System for Measuring Penetration of Radioactive Ions Across Roots of Intact Plants
Author(s) -
Fred H. Emmert
Publication year - 1966
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.41.2.244
Subject(s) - xylem , transpiration stream , transpiration , penetration (warfare) , phaseolus , botany , isotope , biology , chemistry , horticulture , photosynthesis , physics , operations research , quantum mechanics , engineering
A technique was developed for estimating penetration of P(32) across roots of intact plants (Phaseolus vulgaris) by measuring the level of isotope in the xylem stream. Penetration was defined as movement from the root surface to the xylem sap. The xylem sap measurement for P(32) was made in the stem as the material ascended the plant in the transpiration stream. Stems were held near 0 degrees to arrest metabolic concentration of isotope adjacent to the xylem column. A 3 layer environment control system was constructed to allow stem chilling in a manner that would not interfere with the environments of the roots or foliage. Despite these precautions, some extra-xylary build-up of (32)P occurred in the chilled stem. The mathematical function of the extra-xylary fraction was derived, and the difference between this value and total P(32) in the stem represented xylem sap isotope.