【摘要】 <正> 底栖海藻着生在海底的底质上。由于潮汐的作用,覆盖在它们上面的海水的深度也相应地不断变化,使它们经历着周而复始的被海水淹没和干出的过程。海水深度的变化不仅造成照射到海底的阳光的强度的变化,而且由于海水对不同波长的光的选择性衰减作用,还使光谱组成随深度而变化。光谱组成的变化又随海水的光学类型而异。因此,生长在这种环境中的海藻的光合作用对光照条件的适应必然反映在光强适应和光质适应两个方面,呈现错综复杂的关系。更多还原

【Abstract】 Twelve intertidal marine benthic green algae, including Ulva pertusa, U. linza, U. conglobata, Enteromorpha intestinalis, E. spiralis, Monostroma angicava, Bryopsis hypnoides, B. plumosa, Codium fragile, Cladophora sp., C. fasciculata and Ulothrix flacca were employed in the present studies. The effect of light intensity on photo-synthetic rates of these marine benthic green algae were measured by continuously recording oxygen electrode system. The photosynthetic rate of the green alga Ulva pertusa saturated approximately at 14000 Lux, while those of the other species were beyond 20000 Lux. The resulting photosynthetic light curves (Figs. 1-4) indicated that all the species under investigation have relatively high saturation levels.Absorption spectra of the pigments in 80% acetone and the chlorophyll a/b ratio of intertidal benthic green algae were measured. A marine seed plant, Zostera marina and two other species of land seed plants Robinia pseudoacacia and Spinacia oleracea were measured similarly for comparison. The thalli of marine green algae were found to be diffrent from higher plant leaves in the absorption bands of chlorophyll b relative in height to those of chlorophyll a (Fig. 5 and Fig. 6). The a/b ratios found for Ulva pertusa, Enteromorpha spiralis, Codium fragile and Bryopsis hypnoides were respectively 1.75, 1.74, 1.48 and 1.44 which are apprecibly different from the rations obtained for Zostera marina and Robinia pseudoacacia, being 2.40 and 3.02 respectively. Adaptation to higher light intensity and the lower a/b ratio are characteristic of the intertidal benthic green algae and seem to be of significance in the evolution of photosynthetic organisms.更多还原