ABSTRACT
The callus of a metal hypertolerant fern, Athyrium yokoscense, was induced from the spores generated on a small sectioned frond in vitro. The callus grew vigorously with the periodical medium change, especially in a liquid culture. When the callus and regenerated tissues were exposed to Cd, every tissue tolerated at least 1 mM Cd for >1 month. These tissues accumulated high levels of Cd (maximum 3.3 mg g(-1) dry weight in roots) in accordance with the Cd concentration of the medium, and the Cd concentrations of all parts, except roots, were at a similar level. The data suggest that the Cd tolerance of this fern is basically independent of the plant parts and the developmental stages, although the accumulation ability is higher in roots than in the other plant parts.
Subject(s)
Cadmium/pharmacology , Cadmium/pharmacokinetics , Ferns/physiology , Ferns/drug effects , Ferns/growth & development , Plant Roots/drug effects , Plant Roots/physiology , Plant Structures/drug effects , Plant Structures/physiology , Spores/drug effects , Spores/physiologyABSTRACT
Rice SPK is a calmodulin-like domain protein kinase specific to immature seeds and promotes the degradation of sucrose. Therefore, antisense SPK transformants showed a defective production of storage starch, but accumulated sucrose in watery seeds. Despite a reduced sink strength, no difference was found in the sucrose concentration in phloem sap of the transformants and wild-type plants, which increased after floral organ induction to levels greater than 500 mM. However, sucrose was detected at relatively lower levels in the watery seed sap. These results suggest that sucrose content in the phloem is regulated independently from the demand for carbon sources in the sink organs.