Requirement for particular seed-borne fungi for seed germination and seedling growth of Xyris complanata, a pioneer monocot in topsoil-Iost tropical peatland in Central Kalimantan, Indonesia

摘要

Hawaii yellow-eyed grass (Xyris complanata: Xyridaceae) inhabits infertile, acidic peat soil in the rainy tropical zone in Southeast Asia. This monocot plant produces a large number of dormant seeds in order to make a large deposit to seed bank in the soil. Under laboratory conditions, surface-sterilized X. complanata seeds are rarely able to germinate on sterilized peat moss bed; they require inoculation with either seed epiphytic or soil fungi to facilitate active seed germination. In the present study, three different genera of seed epiphytic fungi were isolated, and two common fungal genera, Fusarium sp. (strain R-1) and Penicillium sp. (strain Y-1), were found to promote seed germination of X. complanata. In sterile peat moss beds, the germination-stimulating fungi also showed growth-promoting effects on X. complanata seedlings. These results suggest that the seed germination-promoting fungi likely function as genuine partners for X. complanata in tropical open peat lands.