Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan.
J Plant Physiol. 2013 Apr 15;170(6):577-82. doi: 10.1016/j.jplph.2012.11.015. Epub 2012 Dec 31.
The fern Gleichenia japonica is one of the most widely distributed fern and occurs throughout East to South Asia. The species often dominates plant communities by forming large monospecific colonies. However, the potential mechanism for this domination has not yet been described. The objective of this study was to test the hypothesis that allelochemicals are involved in the formation of G. japonica colonies. An aqueous methanol extract of G. japonica inhibited the growth of seedlings of garden cress (Lepidium sativum), lettuce (Lactuca sativa), ryegrass (Lolium multiflorum) and timothy (Phleum pratense). Increasing extract concentration increased the inhibition. These results suggest that G. japonica contain allelopathic substances. The extract was then purified by several chromatographies with monitoring the inhibitory activity and two growth inhibitory substances causing the allelopathic effect were isolated. The chemical structures of the two substances were determined by spectral data to be a novel compound 3-O-β-allopyranosyl-13-O-β-fucopyranosyl-3β-hydroxymanool (1) and 18-O-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl-13-epitorreferol (2). These compounds inhibited the shoot and root growth of garden cress, lettuce, alfalfa (Medicago sativa), timothy, ryegrass and barnyardgrass (Echinochloa crus-galli) at concentrations greater than 0.1-1.0mM. The concentrations required for 50% growth inhibition of root and shoot growth of these test plants ranged from 0.72 to 3.49mM and 0.79 to 3.51mM for compounds 1 and 2, respectively. Concentration of compounds 1 and 2 in soil under the pure colony of G. japonica was 4.9 and 5.7mM, respectively, indicating concentrations over those required for 50% growth inhibition are potentially available under monocultural stands of these ferns. Therefore, these compounds may contribute to the allelopathic effects caused by presence of G. japonica and may thus contribute to the establishment of monocultural stands by this fern.
蕨类植物日本金星蕨是分布最广的蕨类之一，广泛分布于东亚至南亚地区。该物种通常通过形成大型单种聚居地来主导植物群落。然而，这种主导地位的潜在机制尚未被描述。本研究的目的是检验以下假设：化感物质参与了日本金星蕨群落的形成。日本金星蕨的水甲醇提取物抑制了荠（Lepidium sativum）、生菜（Lactuca sativa）、黑麦草（Lolium multiflorum）和梯牧草（Phleum pratense）幼苗的生长。随着提取物浓度的增加，抑制作用增强。这些结果表明日本金星蕨含有化感物质。然后，通过几种色谱法对提取物进行纯化，并监测抑制活性，分离出两种导致化感作用的生长抑制物质。通过光谱数据确定这两种物质的化学结构分别为一种新型化合物 3-O-β-吡喃阿拉伯糖基-13-O-β-岩藻糖基-3β-羟基曼诺醇（1）和 18-O-α-l-鼠李吡喃糖基-（1→2）-β-d-吡喃葡萄糖基-13-epitorreferol（2）。这些化合物在浓度大于 0.1-1.0mM 时抑制荠、生菜、紫花苜蓿（Medicago sativa）、梯牧草、黑麦草和稗草（Echinochloa crus-galli）的茎和根生长。这两种化合物对这些测试植物的根和茎生长抑制 50%所需的浓度范围分别为 0.72-3.49mM 和 0.79-3.51mM。在日本金星蕨纯种群下的土壤中，化合物 1 和 2 的浓度分别为 4.9 和 5.7mM，表明在这些蕨类植物的单种群落下，可能存在浓度超过抑制 50%生长所需的化合物。因此，这些化合物可能有助于日本金星蕨引起的化感作用，并可能有助于该蕨类植物建立单种群落。
