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Elevated CO 2 and limited nitrogen nutrition can restrict excitation energy dissipation in photosystem II of Japanese white birch ( Betula platyphylla var. japonica ) leaves
Author(s) -
Kitao Mitsutoshi,
Koike Takayoshi,
Tobita Hiroyuki,
Maruyama Yutaka
Publication year - 2005
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2005.00540.x
Subject(s) - photoinhibition , photosystem ii , photosynthesis , chemistry , chlorophyll fluorescence , japonica , nitrogen , chlorophyll , horticulture , botany , photosynthetic pigment , photochemistry , biology , organic chemistry
Elevated atmospheric CO 2 concentration [CO 2 ] and different levels of nitrogen (N) nutrition can influence the amount of excess excitation energy in photosystem (PS) II and related photosynthetic properties. The interactive effect of two [CO 2 ] levels (ambient: 360 µ M M −1 and elevated: 720 µ M M −1 ) and two N levels (high: 700 mg N plant −1 and low: 100 mg N plant −1 ) on these properties was examined in seedlings of Japanese white birch ( Betula platyphylla var. japonica ) using simultaneous measurements of gas exchange and chlorophyll fluorescence. Photosynthetic acclimation to elevated [CO 2 ], as indicated by a decline in carboxylation efficiency (CE), was observed in plants grown at elevated [CO 2 ] especially under low N. Elevated [CO 2 ] resulted in a decrease in area‐based leaf N content (N area ) irrespective of N treatment. The adverse effect of elevated [CO 2 ] and low N on CE may have been exacerbated by a greater accumulation of leaf sugar and starch contents in these plants leading to a lower electron transport rate (ETR). While these plants also showed higher non‐photochemical quenching (Nq P ) that could offset the reduction in energy dissipation through ETR to some extent, they still have a higher risk of photoinhibition from excessive excitation energy in PSII as indicated by a decrease in photochemical quenching (q P ). However, chronic photoinhibition was not observed in plant grown at elevated [CO 2 ] and low N because they showed no difference in F v /F m (the maximum photochemical efficiency of PSII) from those grown at ambient [CO 2 ] and low N after an overnight dark adaptation. High levels of Nq P in plants grown at elevated [CO 2 ] and low N reflect a near saturation of thermal energy dissipation. This impaired capacity of photoprotection would render these plants more vulnerable to photoinhibition in the event of additional environmental stresses such as drought, low or high temperature.