Journal Article

Spatial distribution of leaf dry weight per area and leaf nitrogen concentration in relation to local radiation regime within an isolated tree crown

X. Le Roux, H. Sinoquet and M. Vandame

in Tree Physiology

Volume 19, issue 3, pages 181-188
Published in print March 1999 | ISSN: 0829-318X
Published online March 1999 | e-ISSN: 1758-4469 | DOI: http://dx.doi.org/10.1093/treephys/19.3.181
Spatial distribution of leaf dry weight per area and leaf nitrogen concentration in relation to local radiation regime within an isolated tree crown

Show Summary Details

Preview

To assess the spatial distribution of photosynthetic capacity within an isolated 20-year-old walnut tree (Juglans regia L.) crown, the distribution of relevant leaf characteristics was measured. Variations in leaf dry weight per area (Wa), and nitrogen content on a weight (Nw) and area basis (Na) were studied along two horizontal and one vertical gradients of leaf irradiance, at two dates (July 30 and September 3). In addition, the content of total nonstructural carbon on a weight (TNCw) and area basis (TNCa) was measured on July 30. Concurrently, the spatial distribution of daily integrated leaf irradiance within the crown was simulated by a three-dimensional radiation transfer model over a one week period before sampling at each date. High spatial heterogeneity was observed for Wa (from 50 to 140 g m−2), TNCa (from 4 to 17 g m−2) and Na (from 1.2 to 3.6 g m−2) among the foliage. Although TNCw and Nw were not correlated and only weakly correlated to daily leaf irradiance, respectively, Wa, TNCa and Na were strongly correlated to daily leaf irradiance. The relationship between observed Na and simulated daily leaf irradiance was used to assess the spatial distribution of Na within the crown at each date. Total leaf nitrogen in the foliage was estimated to be 339 g in late July and 317g in early September. For the whole crown (i.e., 1729 current-year shoots), Na increased strongly with basal shoot diameter (an index of “shoot vigor”), highlighting the fact that large shoots were mainly located in sunlit locations and exhibited high photosynthetic capacity.

Keywords: Juglans regia; leaf irradiance; leaf dry weight per area; starch; leaf nitrogen; non-structural carbohydrate; radiation transfer model; walnut; within crown variability

Journal Article.  0 words. 

Subjects: Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.