The content is available as a PDF (196.1 KB).
. 2001 Feb;125(2):532–538. doi: 10.1104/pp.125.2.532
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.