中文摘要：

采用DIVING-PAM叶绿素荧光测定仪比较了坛紫菜（porphyra haitanensis）藻体在不同光合有效辐射强度（photosynthetically active radiation，PAR）、暗处理时间和不同测量时间间隔下光合效率值的变化。结果表明，为了在最短的测量时间内获得准确的坛紫菜藻体叶绿素荧光指标测量结果，叶绿素荧光测定仪的最佳参数应设定为：PAR100 μmol·m-2·s-1，最佳测量时间间隔30s，最适暗处理时间15min。同时发现坛紫菜藻体光合效率的日变化在每天的10：30～18：30时间段内最为稳定，可以作为测量叶绿索荧光指标的最适时间段。

英文摘要：

The modulated chlorophyll fluorometer （DIVING -PAM） was used to measure the photosyn- thesis efficiency of Porphyra haitanensis thallus under different dark-adaption time, different photosynthetically active radiation （PAR） and different time interval of photosynthetic induction curve. The results showed that the measurement of photosynthetic efficiency was most accurate when the parameters were set as： 15 rain of dark-adaptation time, 100 μmol · m-2 · s-1 of PAR and 30 s of time interval. The results also showed that the photosynthesis efficiency is the most stable between 10：30 and 18：30 in daytime, thus this period is ap- propriate for measuring photosynthesis efficiency of P. haitanensis thallus.