Research Article
Abstract
The present study was conducted to assess the impact of nitrogen treatment on the physiological aspects of cork oak (Quercus suber L.) seedlings from acorns collected from seven sources (Kroumiry and Cap-bon). Nitrogen fertilization increased significantly specific leaf area (SLA) and leaf mass area (LMA) of Q. suber L grown for 2 months at nitrogen concentration 1.5 g/l, respectively. Results indicate that leaf hydraulic conductance (KLeaf) increased significantly under nitrogen treatment, but no significant correlation was observed between KLeaf, A and gs. Stomatal conductance (gs), transpiration rate (E), net photosynthetic rate (A) and maximum efficiency of PSII (Fv/Fm) were investigated in seedlings of Q. suber L. This study validated that KLeaf, the stomatal conductance, transpiration rate and net photosynthetic rate of Q. suber were performed under increasing Nitrogen fertilizer. Stomatal conductance influences both photosynthesis and transpiration, thereby coupling the carbon and water cycles and affecting surface-atmosphere energy exchange. We found that the stomatal conductance, transpiration rate, net photosynthetic rate and maximum efficiency of PSII were showed variation in both photosynthetic traits due essentially to local genetic adaptation. However, the seven seedlings sources of cork oak (Q. suber L.) showed a different response of physiological aspects during nitrogen treatment. These findings suggest that nitrogen treatment affects gas exchange and the photosynthetic capacity of the cork oak. Based on the above results, we conclude that nitrogen fertilizer treatments could promote photosynthetic performance of Quercus suber by stimulating morphological and physiological responses.