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半日花（Helianthemum songaricum）根系生态适应特征

来源：花匠小妙招时间：2025-05-18 03:26

摘要： 珍稀濒危灌木半日花（Helianthemum songaricum）是古老的第三纪孑遗植物，其群落是荒漠植被的主要类型之一。采用全根挖掘法研究西鄂尔多斯半日花的根系形态特征, 调查群落内土壤机械组成和有效降雨后土壤水分的垂直分布格局。结果表明：半日花根系分布深度在100 cm左右，根幅为冠幅的30倍以上，根冠比为2～3；其根系生物量和根长密度主要集中在0～30 cm土层，分别占根系总量和总根长密度的94.53%和90.61%；细根（直径＜1 mm）、小根（直径为1～2 mm）、中根（直径为2～5 mm）的生物量和根长密度的垂直分布，均表现为随土壤深度加深先增加后降低的趋势，且在10～20 cm土层最高；细根的生物量和根长密度与土壤含水量具有显著的正相关性，与土壤各粒级没有显著的正相关性，但与石块含量的正相关性最高；土壤水分与土壤各粒径含量也没有显著正相关性，但与石块含量的正相关性最高。研究表明，半日花根系的形态特征是半日花长期适应干旱、砾石质生境的结果。

关键词: 半日花（Helianthemum songaricum）, 根系, 土壤含水量, 土壤机械组成, 生态适应性, 鄂尔多斯

Abstract: Helianthemum songaricum, a rare and endangered shrub species in west Ordos, is tertiary relic plant, and its community is one of the major types of desert vegetation. The species plays the important roles in maintaining the stability of desert vegetation and researches for environmental evolution, flora, biological evolution and biodiversity. In this study, the roots of H. songaricum in west Ordos were excavated in growth season to investigate its morphological characteristics. Moreover, the soil mechanical composition and vertical distribution pattern of soil moisture content after effective rainfall in H. songaricum community were also investigated. The results show that the depth of the roots could reach down to about 100 cm, and the root range was more than 30 times larger than that of canopy; the root biomass and length density were mainly distributed in soil layers of 0-30 cm, which accounted for 94.51% and 90.61% of the total root biomass and total root length density, respectively. Vertically, the biomass and root length density of fine roots (＜1 mm in diameter), small roots (1-2 mm in diameter) and medium roots (2-5 mm in diameter) were all increased at first and then decreased with the increase of soil depth, and the maximum values occurred all in soil layer of 10-20 cm. Fine root biomass and root length density had a significantly positive correlation with soil water content, but not with soil mechanical composition. Compared with the contents of other soil particles, stone content was more correlated with fine root biomass, root length density and soil moisture content. Our results suggested that the formation of root morphological characteristics of H. songaricum is a result of adaptation to drought and gravel habitat.

Key words: Helianthemum songaricum, root, soil moisture content, soil mechanical composition, ecological adaptability, Ordos

中图分类号:

Q948