Polar Calcium Flux in Sunflower Hypocotyl Segments

Polar calcium flux in sunflower hypocotyl segments : I. The effect of auxin.

The flux of Ca(2+) at the apical or basal ends of short sunflower (Helianthus annuus L.) hypocotyl segments was monitored using a Ca(2+)-specific electrode. A higher Ca(2+) efflux was observed at the apical end relative to the basal end, indicating a net polar flux of Ca(2+). The extreme low mobility of Ca(2+) in the isolated segment makes it likely that the observed Ca(2+) fluxes are of locali...

Boron and calcium sites involved in indole-3-acetic Acid transport in sunflower hypocotyl segments.

Sunflower (Helianthus annuus L. cv Russian Mammoth) hypocotyl segments deficient in either B or Ca exhibited a higher rate of potassium leakage, compared to nondeficient segments. Potassium leakage, used here as an indication of membrane integrity, was completely reversed by the addition of H(3)BO(3) or Ca(NO(3))(2) to the incubation medium of the B-deficient or Ca-deficient hypocotyl segments,...

The transport of indole-3-acetic Acid in boron- and calcium-deficient sunflower hypocotyl segments.

Transfer of sunflower (Helianthus annuus L. cv Russian Mammoth) seedlings from complete nutrient solution to solutions deficient in either boron or calcium resulted in a steady decline in the rate of auxin transport, compared to seedlings that remained in the complete solution. In seedlings transferred to solutions deficient in both B and Ca, the decline in auxin transport was greater than seed...

Chemical Factors Affecting Anthocyanin Formation and Morphogenesis in Cultured Hypocotyl Segments of Impatiens balsamina.

Introduction The effects of various chemicals on anthocyanin synthesis and morphogenesis in the Impatiens hypocotyl were investigated to determine possible relationships between a specific biochemical process (anthocyanin synthesis) and morphogenetic events (the formation of roots and epidermal hairs). Cultured segments of balsam (Impatiens balsamina L.) provide excellent material for the study...

Whole - Body Calcium Flux Rates