title: Characterization of photosynthetic gas exchange in leaves under simulated adaxial and abaxial surfaces alternant irradiation.
abstract: Previous investigations on photosynthesis have been performed on leaves irradiated from the adaxial surface. However, leaves usually sway because of wind. This action results in the alternating exposure of both the adaxial and abaxial surfaces to bright sunlight. To simulate adaxial and abaxial surfaces alternant irradiation (ad-ab-alt irradiation), the adaxial or abaxial surface of leaves were exposed to light regimes that fluctuated between 100 and 1,000 μmol m(-2) s(-1). Compared with constant adaxial irradiation, simulated ad-ab-alt irradiation suppressed net photosynthetic rate (Pn) and transpiration (E) but not water use efficiency. These suppressions were aggravated by an increase in alternant frequency of the light intensity. When leaves were transferred from constant light to simulated ad-ab-alt irradiation, the maximum Pn and E during the high light period decreased, but the rate of photosynthetic induction during this period remained constant. The sensitivity of photosynthetic gas exchange to simulated ad-ab-alt irradiation was lower on abaxial surface than adaxial surface. Under simulated ad-ab-alt irradiation, higher Pn and E were measured on abaxial surface compared with adaxial surface. Therefore, bifacial leaves can fix more carbon than leaves with two "sun-leaf-like" surfaces under ad-ab-alt irradiation. Photosynthetic research should be conducted under dynamic conditions that better mimic nature.
authors.affiliation: State Key Lab of Crop Biology, Tai'an, Shandong Province, China.|College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong Province, China.|College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong Province, China.
authors.forename: Zi-Shan
authors.initials: ZS
authors.lastname: Zhang
authors.affiliation: State Key Lab of Crop Biology, Tai'an, Shandong Province, China.|College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong Province, China.
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Li
authors.affiliation: State Key Lab of Crop Biology, Tai'an, Shandong Province, China.|College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong Province, China.
authors.forename: Hui-Yuan
authors.initials: HY
authors.lastname: Gao
authors.affiliation: Wheat Research Institute, Henan Academy of Agricultural Sciences, Zhengzhou, Henan 450002, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Yang
authors.affiliation: State Key Lab of Crop Biology, Tai'an, Shandong Province, China.|College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong Province, China.
authors.forename: Qing-Wei
authors.initials: QW
authors.lastname: Meng
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000378:metabolism* / Q000528:radiation effects; D031586:Melia azedarach / Q000378:metabolism* / Q000528:radiation effects; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism* / Q000528:radiation effects; D054046:Plant Stomata; D018526:Plant Transpiration; D013472:Sunlight
chemical_list: D002245:Carbon Dioxide