Ida Noriyuki, Iwasaki Arihiro, Teruya Toshiaki, Suenaga Kiyotake, Kato-Noguchi Hisashi
Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan.
Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama 223-8522, Japan.
Plants (Basel). 2019 Dec 28;9(1):46. doi: 10.3390/plants9010046.
Cyatheaceae (tree ferns) appeared during the Jurassic period and some of the species still remain. Those species may have some morphological and/or physiological characteristics for survival. A tree fern was observed to suppress the growth of other ligneous plants in a tropical forest. It was assumed that the fern may release toxic substances into the forest floor, but those toxic substances have not yet been identified. Therefore, we investigated the phytotoxicity and phytotoxic substances of (J. Sm. ex Hook.) Copel. An aqueous methanol extract of fronds inhibited the growth of roots and shoots of dicotyledonous garden cress ( L.), lettuce ( L.), and alfalfa ( L.), and monocotyledonous ryegrass ( Lam.), timothy ( L.), and barnyardgrass ( (L.) P. Beauv.). The results suggest that fronds may have phytotoxicity and contain some phytotoxic substances. The extract was purified through several chromatographic steps during which inhibitory activity was monitored, and -coumaric acid and (-)-3-hydroxy--ionone were isolated. Those compounds showed phytotoxic activity and may contribute to the phytotoxic effects caused by the fronds. The fronds fall and accumulate on the forest floor through defoliation, and the compounds may be released into the forest soils through the decomposition process of the fronds. The phytotoxic activities of the compounds may be partly responsible for the fern's survival.
桫椤科（树蕨）出现在侏罗纪时期，其中一些物种至今仍然存在。这些物种可能具有一些用于生存的形态和/或生理特征。有人观察到一种树蕨会抑制热带森林中其他木本植物的生长。据推测，这种蕨类植物可能会向森林地面释放有毒物质，但这些有毒物质尚未被鉴定出来。因此，我们研究了黑桫椤（J. Sm. ex Hook.）Copel.的植物毒性和植物毒性物质。黑桫椤叶片的甲醇水提取物抑制了双子叶植物水芹（L.）、生菜（L.）和苜蓿（L.）以及单子叶植物黑麦草（Lam.）、梯牧草（L.）和稗草（(L.) P. Beauv.）的根和芽的生长。结果表明，黑桫椤叶片可能具有植物毒性并含有一些植物毒性物质。提取物通过几个色谱步骤进行纯化，在此过程中监测抑制活性，并分离出对香豆酸和（-）-3-羟基-β-紫罗兰酮。这些化合物表现出植物毒性活性，可能是导致黑桫椤叶片产生植物毒性作用的原因。叶片通过落叶落在森林地面上并积累，这些化合物可能通过叶片的分解过程释放到森林土壤中。这些化合物的植物毒性活性可能部分解释了这种蕨类植物的生存能力。
