Aims Cyperaceae are common on nutrient-poor soils, including in western Japan. We examined the ability of the native Cyperaceae from western Japan to form dauciform roots and assessed the potential resulting contribution to soil phosphorus (P) dynamics. Methods We assessed dauciform roots for 28 native Cyperaceae. Shoots, roots (including dauciform roots), and bulk and rhizosheath soils of Carex lenta were collected in Seto Inland Sea district (western Japan). The number of dauciform roots, shoot P and nitrogen (N) concentration, and soil P status and fractions were analyzed. Results We confirmed dauciform-root formation in many Cyperaceae including the genus Carex . The number of dauciform roots of C. lenta showed a negative correlation with total and available soil P concentrations and with shoot P concentration. In the rhizosheath of C. lenta with many mature dauciform roots, we found an increase of readily-available inorganic P (Pi) and a decrease of readily-soluble organic P and sparingly soluble Pi fractions, indicating that the dauciform roots contributed to the acquisition of poorly-available soil P. Conclusions Our results show negative correlations of the number of dauciform roots with both soil and plant P status. Regosols with a low P availability are common in Seto Inland Sea district; thus the formation of dauciform roots and their exudates induced by low P status are important for the distribution of C. lenta in this region.

中文翻译：

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日本本土莎草科植物根的形成及其对土壤磷动态的贡献

目的 莎草科在营养贫乏的土壤中很常见，包括在日本西部。我们检查了来自日本西部的本地莎草科形成紫苏根的能力，并评估了对土壤磷 (P) 动态的潜在贡献。方法我们评估了 28 种本地莎草科植物的紫苏根。在濑户内海地区（日本西部）收集了 Carex lenta 的芽、根（包括紫薯根）以及块状和根鞘土壤。分析了紫薯根的数量、地上部 P 和氮 (N) 浓度以及土壤 P 状态和分数。结果我们在包括苔草属在内的许多莎草科植物中证实了紫苏形根的形成。C. lenta 的根茎数量与土壤总磷和有效磷浓度以及地上部磷浓度呈负相关。在 C 的根鞘中。在具有许多成熟紫苏根的 lenta 中，我们发现易利用的无机磷 (Pi) 增加，易溶有机磷和微溶 Pi 部分减少，表明紫苏根有助于获取贫瘠土壤中的磷. 结论 我们的研究结果表明，萝卜状根的数量与土壤和植物磷状态呈负相关。在濑户内海地区，具有低磷可用性的 Regosols 很常见；因此，低磷状态诱导的梨状根的形成及其渗出物对 C. lenta 在该地区的分布很重要。表明紫苏根有助于获得低效土壤磷。结论我们的结果显示紫苏根的数量与土壤和植物磷状态呈负相关。在濑户内海地区，具有低磷可用性的 Regosols 很常见；因此，低磷状态诱导的梨状根的形成及其渗出物对 C. lenta 在该地区的分布很重要。表明紫苏根有助于获得低效土壤磷。结论我们的结果显示紫苏根的数量与土壤和植物磷状态呈负相关。在濑户内海地区，具有低磷可用性的 Regosols 很常见；因此，低磷状态诱导的梨状根的形成及其渗出物对 C. lenta 在该地区的分布很重要。