Full text loading...
Abstract
Induction of oospore formation by the complementary strain occurred in both cases when A1 and A2 isolates of Phytophthora parasitica were separated by polycarbonate membranes and up to 3 mm of agarose. The number of oospores produced increased as separation distance decreased. The homothallic species P. heveae induced oospore formation in both the A1 and A2 isolates of P. parasitica. Phytophthora megasperma var. sojae stimulated oospore formation in the A2 but not the A1 isolate of P. parasitica, while P. cactorum and P. katsurae stimulated the A1 but not the A2 isolate. Sexual reproduction of homothallic species of Phytophthora may thus also be controlled by α hormones. Sixteen types of chemically regulated sexuality among the members of Phytophthora, differing in hormone production and responsiveness to hormones, are postulated.
- Received:
- Published Online: