模拟降水变化和氮添加对红砂幼苗生物量分配的影响

Effects of rainfall change and nitrogen addition onbiomass allocation of Reaumuria soongorica seedlings

摘要:

【目的】 研究植物生长和生物量分配对不同水氮供应的响应特征，对揭示不同水氮添加之间的耦合关系和寻求最优的水肥供应模式具有重要的意义。【方法】 本研究以红砂幼苗为试验对象，测定了不同降水量（降水量减少30%、正常降水量、降水量增加30%）和氮添加[（无氮添加（纯N0 g/（m²·a），低氮添加（纯N 4. 6 g/（m²·a），中氮添加（纯N 9. 2 g/（m²·a），高氮添加（纯 N 13. 8g/（m²·a）]条件下红砂幼苗生长及各器官干物质量。【结果】 降水减少30% 时，在中、低氮添加下，红砂幼苗株高、地上地下生物量和叶重比、叶根重比、源汇重比均会随施氮量增加而增加，而在高氮添加下上述指标均受到抑制；在高氮添加下，红砂幼苗叶重比、叶根重比和源汇重比均随水分增加而增加，但根冠比呈现相反趋势。【结论】 红砂幼苗对水氮耦合效应表现出较强的可塑性，且能够通过不同的水肥供应调整株高和基径的生长以及生物量分配。

Abstract:

【Objective】 Investigation on the characteristics of plant basal height growth and biomass allocation inresponse to different water and nitrogen supplies is important for revealling the coupling relationship between differentwater and nitrogen additions and for finding the optimal water and fertilizer supply pattern.【Method】 In this study，Reaumuria soongorica seedlings were subjected to different precipitation （30% reduction in precipitation ，normalnatural precipitation，30% increase in precipitation） and N additions no N （0 g/（m²·a），low N （4. 6 g/m²·a），me-dium N（9. 2 g/（m²·a），high N（ 13. 8 g/（m2·a））.【Result】 The results showed that the height，above-ground and be-low-ground biomass， leaf weight ratio，leaf-root weight ratio and source-sink weight ratio of R. soongorica seedlingsincreased with increasing drought stress and were all suppressed with high N additions， while the basal diameter de-creased overall with increasing N additions. The basal diameter，plant height and above-and below-ground biomass ofR. soongorica seedlings increased with increasing water at low and medium N additions. Under high N addition， theleaf weight ratio， leaf root weight ratio and source-sink weight ratio of R. soongorica seedlings increased with increas-ing water， but excessive water addition inhibited their growth，while the root-to-crown ratio showed the oppositetrend.【Conclusion】 R. soongorica seedlings showed strong plasticity to the coupling effect of water and N，and wereable to adjust the growth of plant height and basal diameter as well as biomass distribution through different water andfertilizer supply.