Poster: Root biology

Abs # 697: Effects of lanthanum (La3+) on corn roots

Presenter:	Liu, Min , mxl3440@louisiana.edu
Authors	Liu, Min  (A)   Hasenstein, Karl H. (A)
Affiliations:	(A): University of Louisiana at Lafayette, Lafayette LA, 70504

Lanthanum ions (La3+) and are used as a tool to study the role of Ca2+. However, the mechanism of lanthanum itself remains unknown. Root growth studies showed that La3+ induced growth inhibition is concentration and time dependent. To study La3+ uptake we used protoplasts and inductively coupled plasma optical emission spectroscopy (ICP-OES). La3+ appears to be taken up after a lag of ca. 30 min. Microtubules (MTs) and microfilaments (MFs) in maize protoplast also responded to La3+. La3+ shifted the MT array from random to parallel and caused bundling and aggregation of MFs. In an attempt to characterize responses to La3+ we used DD-RT PCR, and detected genes that were differentially expressed in both intact root cells and protoplasts with a size range of 200-1000 bp. Several of the genes that are differentially expressed are being identified. The differential display also compares the effect of cell wall removal. The data show that in addition to indirect calcium effects La3+ exerts complex molecular and intracellular effects. Supported by NASA grant NAG10-190.