关键词: 滞尘量, 城市绿化, 常绿阔叶树, 综合滞尘能力

Abstract: The specific root length (SRL) reflects the feature of plants’ adaptation to different environments. In this study, the mixedsowing grassland of gramineous grass Avena sativa and leguminous grass Vicia vilosa with the density ratio of CK₁ (1∶0), A₁ (8∶2), A₂ (6∶4), A₃ (5∶5), A₄ (4∶6), A₅ (2∶8) and CK₂ (0∶1) was established in the upper reaches of Qilian Mountains, Gansu Province, Northwest China in 2013, aimed to study the spatial distribution patterns of SRLs of the two mixedsowing grasses. The results showed that the total root length and SRL of all mixed sowing groups of A. sativa were greater than those of V. villosa (P<0.05), but both species had no significant difference in underground biomass. With the decrease of A. sativa density and the increase of V. vilosa density in mixedsowing grassland, the root lengths of both grasses increased gradually (P<0.05), the root biomass decreased first and then increased (P<0.05), the SRLs increased first and then decreased (P<0.05). The SRLs of both species in the five mixed sowing groups gradually decreased with soil layers, and the superficial degree in fine roots of A. sativa was higher than that of V. villosa. The layering distribution of roots of currentyear grass changed the resource allocation strategy, gradually optimized the utilization structure of resources, and maximized the utilization of soil resources.

Key words: comprehensive dust absorption ability, evergreen broad-leaved plant, dust absorption amount, urban greening