[Bioaccumulation of sediment heavy metals in Bellamya aeruginosa and its relations with the metals geochemical fractions].

A 28-day sediment bioaccumulation test was conducted to study the bioaccumulation of river sediment heavy metals in Bellamya aeruginosa, and its relations with the geochemical fractions of the metals. A higher bioaccumulation of Cd, Pb, Cu, Cr, Zn, and Mn was found in the hepatopancreas of B. aeruginosa, with the greatest accumulation of Zn (84.

[The signaling pathways of plant defense response and their interaction].

A series of events occur in plant following herbivore and pathogen attack, which includes changes in ion fluxes changing through plasma membrane, rapid increasing in cytoplasmic Ca(2+) concentration, production of active oxygen species, and protein phosphorylation. These early signaling events may trigger a number of responses through salicylate, jasmonate, and ethylene signaling pathways, activating the defense responsive genes, such as PR1, BFL2. The products of these defensive genes could act on the herbivore insects.

Preliminary studies on differential defense responses induced during plant communication.

We compared the expression patterns of three representative genes in undamaged tomato and tobacco plants in response to exposure to either tomato or tobacco fed on by Helicoverpa armigera (cotton bollworm). When tomato and tobacco, two species of one family, were incubated in the chambers with the tomato plants damaged by the cotton bollworm, the expression of the PR1, BGL2, and PAL genes was up-regulated in leaves of both plants. However, the levels of gene expression were significantly higher in the tomato than that in the tobacco.