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MOVEMENT OF CALCIUM ACROSS TIPS OF PRIMARY AND LATERAL ROOTS OF PHASEOLUS VULGARIS
Author(s) -
Moore Randy
Publication year - 1985
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.1537-2197.1985.tb08340.x
Subject(s) - phaseolus , biology , primary (astronomy) , calcium , botany , medicine , physics , astronomy
Calcium (Ca) movement across tips of primary and lateral roots of Phaseolus vulgaris was determined by applying 45 Ca 2+ to one side of the root and collecting radioactivity in an agar receiver block on the opposite side of the root. The ratios of cpm in receiver blocks on the bottom of primary roots : cpm in receiver blocks on the top of primary roots were 1.87 and 2.47 after 1 and 2 hr, respectively. This polar transport of Ca across tips of primary roots correlated positively with a gravicurvature of 43° after 2 hr. The ratio of cpm in receiver blocks on the bottom of lateral roots : cpm in receiver blocks on the top of lateral roots was 1.20 after 2 hr. The decreased polar movement of Ca across tips of lateral roots correlated positively with lateral roots being nongraviresponsive. These data 1) support the suggestion that gravistimulation induces polar movement of Ca toward the lower side of tips of primary roots, and 2) suggest that the reduced polar movement of Ca across tips of lateral roots may be involved in uncoupling gravistimulation from gravicurvature in lateral roots.