Effects of Nitrogen Deficiency on Leaf Chlorophyll Fluorescence Parameters in Two Olive Tree Cultivars ‘Meski’ and ‘Koroneiki’

• Published in: Journal of plant nutrition 2015-12, Vol.38 (14), p.2230-2246
• Main Authors: Boussadia, O, Steppe, K, Van Labeke, M.-C, Lemeur, R, Braham, M
• Format: Article
• Language: English
• Subjects: adenosine triphosphate; Calvin cycle; Carbon dioxide; carboxylation; Chlorophyll; Cultivars; electron transfer; energy; fluorescence; greenhouses; leaf chlorophyll fluorescence, olive tree, nitrogen deficiency, nitrogen nutrition index, photosynthesis; leaves; NADP (coenzyme); Nitrogen; Nutrition; nutritional status; olives; Photochemistry; photoinhibition; photosystem II; Trees
• ISSN: 1532-4087; 0190-4167; 1532-4087
• DOI: 10.1080/01904167.2015.1069339

Effects of nitrogen (N) deficiency on photosynthetic carbon dioxide (CO ₂) assimilation, photosystem II (PSII) photochemistry and photoinhibition were investigated in young trees of two olive cultivars ‘Meski’ and ‘Koroneiki’ grown in a greenhouse under controlled conditions. The trees were subjected to four different levels of N supply. N deficient trees had a significantly smaller CO ₂ assimilatory capacity, but showed little changes in maximum quantum efficiency of PSII photochemistry. However, modifications in PSII photochemistry induced by N deficiency were observed. This was reflected in decreases in quantum yield of PSII electron transport (Φ PSII) and efficiency of excitation energy capture by open PSII reaction centres (F ᵥ’/F ₘ’) and in an increase in non-photochemical quenching (NPQ). These results suggest that modifications in PSII photochemistry might be a mechanism to down-regulate photosynthetic electron transport so that production of adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH). would be in equilibrium with the decreased demand in the Calvin cycle in the N deficient trees. Therefore, both CO ₂ assimilation rate and total electron flow (J ₜ) with its compound electron flows devoted to either carboxylation (J c) or oxygenation (J ₒ) can be considered as useful tools to assess the N nutrition status of the trees. Clear relationships were found between A ₘₐₓ and the nitrogen nutrition index (NNI) on the one hand, and between J ₜ and NNI on the other hand. The results demonstrate that ‘Meski’ is more efficient than ‘Koroneiki’ when subjected to N deficiency.