Photosynthesis, fluorescence and microclimate measurements of several species of mosses and lichens from Botany Bay at Granite Harbour

The photosynthetic rate of Antarctic mosses and lichens was studied with investigations into the effects of high levels of light radiation and of possible UV effects. The mosses Pottia heimii, Bryum argenteum, B. pseudotriquetrum, Ceratodon purpureus and Sarconeurium glaciale had their photosynthetic performance monitored for full diel results under natural light conditions. Continuous measurements of photosynthetic rates together with all environmental parameters and light harvesting systems were measured. Concurrently, fluorescence measurements were also made. Further detailed studies were carried out on B. argenteum where photosynthesis and fluorescence was measured from plants kept in two conditions (deep shade and normal light conditions). The experiment was repeated with the UV component of sunlight filtered out. The photosynthesis of Umbilicaria aprina (a large lichen common at Botany Bay) was studied with light-response curves and water content curves constructed, several diel measurements made and the minimum temperature for photosynthesis investigated. A full study was carried out on Buellia frigida where the CO2 exchange and fluorescence yield were compared. The microclimate was recorded in a rich lichen/bryophyte location in Botany Bay. Measurements were made continuously from 12 January to 2 February, 1992. In the 1999-2000 season the photosynthetic response to temperature and light of two moss species Bryum subrotundifolium and Ceratodon purpureus was measured.

本研究以南极苔藓与地衣的光合速率为核心考察对象，同时探究了高强度光辐射的影响效应，以及潜在的紫外线（UV）作用效果。针对波氏壶藓（Pottia heimii）、银叶真藓（Bryum argenteum）、假三列真藓（B. pseudotriquetrum）、紫萼藓（Ceratodon purpureus）以及冰生硬叶藓（Sarconeurium glaciale）这五种苔藓，本研究在自然光照条件下对其全昼夜光合表现进行了连续监测，测定过程中同步记录了光合速率、全部环境参数以及光捕获系统的相关数据，并同步开展了荧光相关测定。此外，本研究针对银叶真藓（B. argenteum）开展了更为细致的专项实验：将培养植株分别置于深荫与正常光照两种环境条件下，测定其光合与荧光指标，并在滤除太阳光紫外线（UV）组分的条件下重复了整套实验流程。针对石脐地衣（Umbilicaria aprina）——一种常见于植物湾（Botany Bay）的大型地衣，本研究构建了其光响应曲线与含水量曲线，开展了多组昼夜尺度的测定工作，并探究了其光合作用的最低温度阈值。本研究还针对冷生布氏衣（Buellia frigida）开展了全面系统的研究，对比分析了其CO₂交换与荧光产额的相关特性。此外，研究团队在植物湾一处物种组成丰富的地衣-苔藓群落中开展了微气候监测，监测时段为1992年1月12日至1992年2月2日，全程采用连续记录模式。在1999-2000年科考季中，本研究测定了近圆真藓（Bryum subrotundifolium）与紫萼藓（Ceratodon purpureus）这两种苔藓的光合响应与温度、光照之间的关联特性。