Bu Dong Dong, Li Ang, Wang Yin Liu, Wang Chang Hui, Huang Jian Hui
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
College ofResources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
Ying Yong Sheng Tai Xue Bao. 2019 Aug;30(8):2667-2674. doi: 10.13287/j.1001-9332.201908.015.
With a greenhouse pot experiment, we investigated the effects of nitrogen (N) and plant growth promoter (brassinolide, BR) addition on the growth and competitive ability of three common plant species of typical steppe in Inner Mongolia, including Leymus chinensis, Astragalus adsurgens and Stipa krylovii. We added N at rates of 0, 0.1, 0.2, 0.4, 0.8 mg·g soil and BR at rates of 0 and 0.005 mg·g soil during plant growth in monoculture or with L. chinensis being planted in mixing with other two species, respectively. There were significant effects on biomass of L. chinensis and A. adsurgens, but not on that of S. krylovii with increase of N and BR addition. The effects of N addition on the growth of L. chinensis varied with accompanying plant species. Nitrogen addition increased aboveground biomass production of L. chinensis when growing in monoculture and mixed with A. adsurgens, but decreased its belowground biomass when growing mixed with S. krylovii. With increasing soil N availability, plant biomass allocation of L. chinensis showed significant decrease in root-shoot ratio when it was in monoculture or mixed with S. krylovii, but similar changes were not found when it was planted in mixing with A. adsurgens. The significant effects of BR addition on plant growth appeared occasionally. BR addition significantly reduced belowground biomass of A. adsurgens in its monoculture and significantly increased aboveground biomass of L. chinensis when it was planted in mixing with A. adsurgens. The results indicated that the appropria-tely combined addition of N and BR could effectively enhance biomass production of specific species combinations in grasslands, which has application prospects in the restoration of degraded grassland.
通过温室盆栽试验，我们研究了添加氮（N）和植物生长促进剂（油菜素内酯，BR）对内蒙古典型草原三种常见植物物种生长和竞争能力的影响，这三种植物包括羊草、斜茎黄芪和克氏针茅。在植物单种栽培或羊草与其他两种物种混种生长期间，我们分别以0、0.1、0.2、0.4、0.8 mg·g土壤的速率添加N，并以0和0.005 mg·g土壤的速率添加BR。随着N和BR添加量的增加，对羊草和斜茎黄芪的生物量有显著影响，但对克氏针茅的生物量没有显著影响。添加N对羊草生长的影响因伴生植物物种而异。当羊草单种栽培以及与斜茎黄芪混种时，添加氮增加了其地上生物量产量，但当与克氏针茅混种时，其地下生物量减少。随着土壤有效氮含量的增加，羊草单种栽培或与克氏针茅混种时，其植物生物量分配的根冠比显著降低，但与斜茎黄芪混种时未发现类似变化。添加BR对植物生长的显著影响偶尔出现。在斜茎黄芪单种栽培时，添加BR显著降低了其地下生物量，而当羊草与斜茎黄芪混种时，添加BR显著增加了羊草的地上生物量。结果表明，适当组合添加N和BR可以有效提高草原特定物种组合的生物量产量，这在退化草原恢复中具有应用前景。
