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THE ROLE OF ROOTS IN THE NUTRITION OF AQUATIC VASCULAR PLANTS
Author(s) -
Bristow J. Michael,
Whitcombe Mark
Publication year - 1971
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1971.tb09939.x
Subject(s) - biology , shoot , phosphate , compartment (ship) , botany , myriophyllum , elodea canadensis , aquatic plant , ecology , biochemistry , macrophyte , oceanography , geology
Rooted stems of three aquatic species were cultured in a two‐compartment apparatus which allowed the upper and lower portions of the stem to be kept in different nutrient solutions. P 32 was supplied to either the upper or lower compartment. At the end of a 10‐day growth period, the specific activity of phosphate was determined in axillary shoots which developed during the course of the experiment from buds in the upper compartment. The results indicated that most of the phosphate in these shoots was not absorbed from the ambient medium but was derived from the rooted stem base in the lower compartment (over 90 % in Myriophyllum brasiliense , 59 % in M. spicatum , and 74 % in Elodea densa ). These results give a very different but probably more accurate picture of phosphate absorption in rooted aquatic vascular plants than short‐term experiments, in which phosphate is readily taken up from the ambient medium by leaves of M. spicatum and E. densa . In M. brasiliense the amount of phosphate translocated is related to the mass of roots present. Evidence is presented that normal growth of axillary shoots occurs even when all mineral ions have to be obtained by translocation from the lower compartment.