Calcium (⁴⁵Ca²⁺) uptake via cation channels in sorghum roots after treatment with pcmbs or ruthenium red

Abstract

Increasing concentrations of calcium (Ca²⁺) channel blockers (i.e. ‐ nifedipine, verapamil, and diltiazem) in the presence of a sulfhydryl inactivator (1 mM PCMBS) were evaluated on root tips (1 cm) of sorghum [Sorghum bicolor (L.) Moench. cv GP‐10, SC574, SC283, Funk GS22DR]. Cultivar differences were found in response to all three Ca²⁺ channel blockers. Ruthenium red inhibits Ca²⁺‐ATPase and in combination with verapamil causes major differences in response by all four cultivars to verapamil + PCMBS. None of the treatments induces complete inhibition of ⁴⁵Ca²⁺ uptake, indicating multiple types of cation nutrient uptake channels.