MONTEDISON ACQUIRES ARCO RESEARCH UNIT Montedison SpA <MONI.MI> has acquired a 70 pct stake in <Plant Cell Research Institute - PCRI> of California from Atlantic Richfield Co <ARC.N> for "several tens of millions of dollars," a senior Montedison executive said. Renato Ugo, a member of Montedison's management committee, told reporters that <Stanford Research Institute International> of Menlo Park, California, had acted as a partner in the purchase, itself acquiring a stake in PCRI of under 10 pct. PCRI, based in Dublin, California has a biotechnology research laboratory. Ugo said the price paid included outlays for the laboratory technology and staff. He said other negotiations were under way with biotechnology companies in the health care and diagnostics sectors through Montedison's health care subsidiary <Erbamont NV>, but gave no details. "We hope they will be concluded by the year end," he said. Montedison currently invests around 30 billion lire a year in biotechnology research and expects to increase this figure to around 50 billion lire in the next few years.