{"id":2619,"date":"2017-12-18T14:27:53","date_gmt":"2017-12-18T13:27:53","guid":{"rendered":"http:\/\/ist.blogs.inra.fr\/afs\/?p=2619"},"modified":"2017-12-20T11:27:44","modified_gmt":"2017-12-20T10:27:44","slug":"photosynthesis-and-growth-responses-of-fraxinus-mandshurica-rupr-seedlings-to-a-gradient-of-simulated-nitrogen-deposition","status":"publish","type":"post","link":"https:\/\/ist.blogs.inrae.fr\/afs\/2017\/12\/18\/photosynthesis-and-growth-responses-of-fraxinus-mandshurica-rupr-seedlings-to-a-gradient-of-simulated-nitrogen-deposition\/","title":{"rendered":"Photosynthesis and growth responses of Fraxinus mandshurica Rupr. seedlings to a gradient of simulated nitrogen deposition"},"content":{"rendered":"<script type='text\/javascript' src='https:\/\/d1bxh8uas1mnw7.cloudfront.net\/assets\/embed.js'><\/script><p>During an N-deposition simulation experiment, we showed that low to medium addition of N had beneficial effects on growth and photosynthetic rates of <em>Fraxinus mandshurica<\/em> Rupr. seedlings, while beyond a threshold of 80 kg N ha\u22121 year\u22121, performance plateaued and even declined at higher immissions.<\/p>\n<p><strong>Context.<\/strong> Temperate forests are shifting from naturally N-limited toward N-saturated status with increasing N deposition. Yet, our knowledge regarding how seedling growth and physiology respond to excessive N input in temperate tree species remains very limited.<br \/>\n<strong>Aims.<\/strong> The objective of this study was to examine growth and photosynthetic responses of <em>F. mandshurica<\/em> seedlings to a gradient of simulated N deposition.<br \/>\n<strong>Methods.<\/strong> We conducted a 4-year study to investigate growth and photosynthetic responses of F. mandshurica seedlings to a large gradient of simulated N deposition (0, 20, 40, 60, 80, 100, and 120 kg N ha\u22121 year\u22121). Biomass accumulation and allocation, photosynthetic gas exchange, expression, and activities of ribulose-1,5-bisphosphate carboxylase\/oxygenase (Rubisco) in leaves were determined during the fourth growing season. Soil biochemical properties were measured to link them to the alterations in growth and photosynthetic traits across the N addition gradient.<br \/>\n<strong>Results.<\/strong> Seedling growth and photosynthesis were dependent upon the rates of N deposition. The maximum rate of carboxylation (Vc,max) and the net photosynthetic rate under saturating light (Asat) reached a maximum under 60 kg N ha\u22121 year\u22121. By contrast, high-level N inputs (100 and 120 kg N ha\u22121 year\u22121) resulted in suboptimal values in biomass and photosynthetic activity. Nitrogen deposition also modulated the activity and expression of Rubisco in leaves with a maximum around 80\u2013100 kg N ha\u22121 year\u22121. Redundancy analysis (RDA) showed that the changes of seedling growth and photosynthesis along the gradient of N deposition were mostly attributed to the variations of soil pH and total N content.<br \/>\n<strong>Conclusion.<\/strong> Our data suggest that the threshold of N deposition is about 80 kg N ha\u22121 year\u22121 for <em>F. mandshurica<\/em> seedlings in this region. Excessive N input decreased performance on the seedling growth and photosynthesis.<\/p>\n<p>Keywords<br \/>\n<em>Fraxinus mandshurica<\/em>, Photosynthetic response, Nitrogen deposition, Rubisco, Biomass production<\/p>\n<div class='altmetric-embed' data-badge-type='donut' data-doi='10.1007\/s13595-017-0678-2'  style='float: right; ' ><\/div>\n<p>Publication<br \/>\nWang, M., Zhang, WW., Li, N. et al. Annals of Forest Science (2018) 75: 1.<br \/>\n<a href=\"https:\/\/doi.org\/10.1007\/s13595-017-0678-2\">https:\/\/doi.org\/10.1007\/s13595-017-0678-2<\/a><\/p>\n<p>For the read-only version of the full text: <a href=\"http:\/\/rdcu.be\/CPsB\">http:\/\/rdcu.be\/CPsB<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>During an N-deposition simulation experiment, we showed that low to medium addition of N had beneficial effects on growth and photosynthetic rates of Fraxinus mandshurica Rupr. seedlings, while beyond a threshold of 80 kg N ha\u22121 year\u22121, performance plateaued and even declined at higher immissions. Context. Temperate forests are shifting from naturally N-limited toward N-saturated [&hellip;]<\/p>\n","protected":false},"author":94,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[14,15],"tags":[],"class_list":["post-2619","post","type-post","status-publish","format-standard","hentry","category-article-type","category-research-paper","cat-14-id","cat-15-id"],"_links":{"self":[{"href":"https:\/\/ist.blogs.inrae.fr\/afs\/wp-json\/wp\/v2\/posts\/2619","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ist.blogs.inrae.fr\/afs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ist.blogs.inrae.fr\/afs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ist.blogs.inrae.fr\/afs\/wp-json\/wp\/v2\/users\/94"}],"replies":[{"embeddable":true,"href":"https:\/\/ist.blogs.inrae.fr\/afs\/wp-json\/wp\/v2\/comments?post=2619"}],"version-history":[{"count":0,"href":"https:\/\/ist.blogs.inrae.fr\/afs\/wp-json\/wp\/v2\/posts\/2619\/revisions"}],"wp:attachment":[{"href":"https:\/\/ist.blogs.inrae.fr\/afs\/wp-json\/wp\/v2\/media?parent=2619"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ist.blogs.inrae.fr\/afs\/wp-json\/wp\/v2\/categories?post=2619"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ist.blogs.inrae.fr\/afs\/wp-json\/wp\/v2\/tags?post=2619"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}