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比根长反映了植物对不同生境的适应特征,密度制约下比根长的变化可能是植物对地上和地下资源投资权衡的结果。在祁连山建立禾本科牧草燕麦(Avena sativa L.)与豆科毛苕子(Vicia villosa Roth)混播草地,按燕麦与毛苕子的密度比例设置CK1(1∶0)、A1(8∶2)、A2(6∶4)、A3(5∶5)、A4(4∶6)、A5(2∶8)和CK2(0∶1)7个密度组,研究了混播草地密度制约下燕麦与毛苕子根系比根长的空间分布格局。结果表明:各混播组燕麦根长和比根长均大于毛苕子(P<0.05),二者地下生物量无明显差异;随着混播草地中燕麦密度的减小和毛苕子密度的增大,燕麦和毛苕子的根长逐渐增加(P<0.05),根系生物量先减小后增大(P<0.05),比根长先增加后减小(P<0.05);5个混播组中燕麦和毛苕子比根长随土层加深持续减小,且燕麦细根表层化程度大于毛苕子。1年生牧草根系在空间上的分层分布改变了混播草地的资源分配策略,逐渐优化了资源利用格局,实现了土壤资源利用的最大化。
The specific root length reflects the adaptive characteristics of plants to different habitats. The change of specific root length under density control may be the result of the plant’s trade-off between investment in above-ground and underground resources. According to the density ratio of oats to hairy millet, CK1 (1: 0), A1 (8: 2) and A2 (6) were set up in a mixed grassland of Avena sativa L. and Vicia villosa Roth in the Qilian Mountains. The results showed that the root length ratio of root and shoot of oat and hairy millet was higher than that of the control The spatial distribution pattern. The results showed that the root length and specific root length of oat in each mixed-sowing group were greater than that of hairy (P0.05). There was no significant difference in the underground biomass between the two groups. With the decrease of oat density and the increase of the density of 毛苕 seeds, (P <0.05). Root biomass decreased firstly and then increased (P <0.05), and then root length increased first and then decreased (P <0.05). In the five mixed-sowing groups, the ratio of oat and hairsporum Root length deepened with the deepening of soil continued to decrease, and oat fine root surface degree is greater than hairy seed. Spatial stratification of 1-year-old pasture roots changed the resource allocation strategy of mixed-sown grassland and gradually optimized the pattern of resource utilization, maximizing the utilization of soil resources.