Effect of nitrate supply on the facilitation between two salt-marsh plants (Suaeda salsa and Scirpus planiculmis). (7th January 2020)

• Record Type: Journal Article
• Authors: Ma, Hua; Cui, Li-Juan; Pan, Xu; Li, Wei; Ning, Yu; Zhou, Jian
• Editors: Niu, Shuli
• Is Part Of: Journal of plant ecology. Volume 13:Number 2(2020:Apr.)
• Page Start: 204
• Page End: 212
• Publication Date: 2020-01-07
• Subjects: nitrate supply -- salinity gradient -- salt-marsh plants -- facilitation -- stress-gradient hypothesis; 硝酸盐浓度 -- 盐度梯度 -- 盐沼植物 -- 促进作用 -- 胁迫梯度假说; Plant ecology -- Periodicals; Phytogeography -- Periodicals; 581.705
• DOI: 10.1093/jpe/rtaa001
• Languages: English
• ISSNs: 1752-9921

Abstract

Abstract: Aims: In estuarine salt-marshes, nitrate supply and soil salinity, which are known as two main environmental drivers, simultaneously affect the interspecific interactions between plant species. However, to date, their interactive effects on interspecific interactions have not been closely examined for salt-marsh plant species. Methods: Juvenile plants of Suaeda salsa L. (Chenopodiaceae) and Scirpus planiculmis Fr. (Cyperaceae) were grown in rinsed river sand to conduct a greenhouse experiment with three treatment categories: interspecific interaction (mixed culture or monoculture), three salinity levels (1, 50 and 100 mmol L −1 ) and three nitrate levels (0.5, 5 and 10 mmol L −1 ). First, height and biomass of all plants were measured. Then, the growth data, relative interaction index and competitive important index of the two species were analyzed. Important Findings: The interspecific interactions between S. salsa and S. planiculmis were facilitation across the salinity gradients. The promotion of S. salsa growth with high nitrate supply did not enhance the facilitative effect of the species, especially at low salinity. However, high nitrate supply significantly shifted the interspecific interactions of S. planiculmis from facilitation to competition at high salinity. Our results suggest that excessive nitrate application changes the prediction of the stress-gradient hypothesis along a salinity gradient, leading to collapse of the two species coexistence in the salt-marshes. These findings make a contribution to the understanding of how S. salsa and S. planiculmis, as well as salt-marsh communities, respond to the human modification of estuarine nutritional levels.