The chronic effects of three different stressors, irradiance, temperature, and desiccation, on Photosystem II (PSII) photochemical efficiency were investigated in two heteromorphic life-history stages of a cultivated red alga, Pyropia yezoensis f. narawaensis (Bangiales) from Japan. The maximum quantum yields of PSII (F_v/F_m) over the range of temperature between 4 and 36 °C for 96-h exposure showed different responses in the two life-history stages. In the macroscopic gametophyte, the highest value (0.47) occurred at 12.0 °C; however, F_v/F_m quickly decreased at higher temperatures. In contrast, F_v/F_m in the microscopic sporophyte were less sensitive to temperature, suggesting adaptation to the broad range of temperature with a high value (0.40) that occurred at 21.1 °C. Continuous 6-h exposures to the 50, 100, and 1000 μmol photons m⁻² s⁻¹ revealed greater decline in their effective quantum yields of PSII (ΔF/F_m′) in the sporophyte. As known in the photoprotective response and its PSII repair system in the photosynthesis, the recovery of quantum yield in two life-history stages after subsequent acclimation (darkness and dim-light treatments) was more accelerated in dim-light than those of darkness. The response to continuous desiccation (240-min aerial exposure) in two life-history stages was also different, and the ΔF/F_m′ in the gametophyte returned to initial values after re-immersion in seawater. In contrast, those in the sporophyte dropped to zero after a 5-min aerial exposure and did not return to initial values, suggesting that farming protocols for the conchospore seeding in Nori-net cultivation need to pay careful attention to desiccation to ensure successful production.

在栽培红藻（Pyropia yezoensis f）的两个异形生命历史阶段中，研究了三种不同压力源（辐照度，温度和干燥）对光系统II（PSII）光化学效率的慢性影响。narawaensis（Bangiales）来自日本。暴露96 h时，在4至36°C的温度范围内，PSII的最大量子产率（F _v / F _m）显示出不同的响应。在宏观配子体中，最高值（0.47）出现在12.0°C处。但是，F _v / F _m在较高温度下迅速下降。相反，F _v / F _m微观孢子体中的温度对温度的敏感性较弱，表明它适应了在21.1°C时出现的高值（0.40）的宽温度范围。在50、100和1000μmol光子m ^-2  s ^-1处连续6h暴露表明，在孢子体中，它们的PSII有效量子产率（ΔF/ F _m '）有更大的下降。如光合作用中的光保护反应及其PSII修复系统所知，在暗适应条件下（暗和暗光处理）在随后的适应（暗和暗光处理）的两个生命历史阶段中，量子产率的恢复比暗光更加加快。在两个生命历史阶段对持续干燥（240分钟的空中暴露）的响应也不同，并且重新浸入海水后，配子体中的ΔF/ F _m '恢复到初始值。相反，那些在孢子体下降到零5分钟的空中暴露后并没有返回到初始值，这表明了壳孢子在播种耕种协议海苔-net培养需要认真注意干燥，以确保成功生产。