The effects of microfilament and microtubule inhibitors and periodic electrical impulses on phloem transport in pea seedling

In phloem transport, whether protoplasmic activity participates in assisting sap flow in sieve element_companion cell complex has long been in debate. The present investigation assumed microfilament (MF) and microtubule (MT), the two constituents of the protoplasmic cytoskeleton, as motive force, and employed germinating pea seedling suspended in moist chamber as experimental material: the seed being the source; the elongating root, the sink. 14 C_labeled sucrose was added to the seed as indicator. The amount of sap transported from source to sink was measured by the increase in root elongation. The transport phloem was within the cylinder of the peeled root in the middle. The exposed cylinder was treated with MF inhibitor (cytochalasin B), or microtubule inhibitor (amiphos_methyl). Results showed that the sap influx into the elongating root, and the 14 C activity as well, was reduced by about one half in treatment with cytochalasin B, and much less by amiphos_methyl treatment. Similar effect was shown in electrical impulse treatment, which seems to disrupt the MF and MT configuration.

In phloem transport, whether protoplasmic activity participates in assisting sap flow in sieve element-companion cell complcx hils long been in debate. The prcsent investigation assumcd microfilament (MF) and microtubule (MT), the two constituents of the protoplasmic cytoskeleton, as motive force, and employed germinating pea seedling suspended in moist chamber as experinental material: thc seed being the source; the elongating root, the sink.14C-labeled sucrose was added to the seed as indicator. The amount of sap transported from source to sink was measured by the increase in root elongation. The transport phloem was within the cylinder of the peclcd root in thc middle. The exposed cylinder was treated with MF inhibitor (cytochalasin B), or microtubule inhibitor (amiphosmethyl). Results showed that the sap influx into the elongating root. and the14C activity as well, was reduced by abut one half in treatrrrent with cytochaliisin B, and much less by amiphos-methyl treatment. Similar effect was shown in clcctrical impulse Ireatnimt, which scems to disrupt the MF and MT configuration.