Leaf anatomical characteristics are less important than leaf biochemical properties in determining photosynthesis responses to nitrogen top-dressing. (22nd May 2021)

• Record Type: Journal Article
• Authors: Xiong, Dongliang; Flexas, Jaume
• Editors: Sharwood, Robert
• Is Part Of: Journal of experimental botany. Volume 72:Number 15(2021)
• Page Start: 5709
• Page End: 5720
• Publication Date: 2021-05-22
• Subjects: Leaf anatomy -- mesophyll conductance -- nitrogen -- photosynthesis -- Rubisco -- top dressing; Botany -- Periodicals; Botany, Experimental -- Periodicals; Plant physiology -- Periodicals; 580
• DOI: 10.1093/jxb/erab230
• Languages: English
• ISSNs: 0022-0957

Abstract

Abstract : Mesophyll conductance ( g m ) responds rapidly to nitrogen top-dressing; however, leaf anatomical traits can only partly explain the rapid response of g m to nitrogen top-dressing. Abstract: The photosynthetic capacity of leaves is dramatically influenced by nitrogen (N) availability in the soil, as CO2 concentration in chloroplasts and photosynthetic biochemical capacity are related to leaf N content. The relationship between mesophyll conductance ( g m ) and leaf N content was expected to be shaped by leaf anatomical traits. However, the increased g m in mature leaves achieved by N top-dressing is unlikely to be caused by changes in leaf anatomy. Here, we assessed the impacts of N supply on leaf anatomical, biochemical, and photosynthetic features, specifically, the dynamic responses of leaf anatomy, biochemistry, and photosynthesis to N top-dressing in tobacco. Plant performance was substantially affected by soil N status. In comparison with the leaves of plants subjected to low N treatment, leaves of plants with high N treatment photosynthesized significantly more, due to higher CO2 diffusion conductance and photosynthetic biochemical capacity. The high g m in high N-treated leaves apparently related to modifications in the leaf anatomy; however, the rapid response of g m to N top-dressing cannot be fully explained by leaf anatomical modifications.