不同光质及胁迫处理对鼠尾藻及附生藻类光合生理的影响

利用鼠尾藻(Sargassun thumbergii)、菱形藻(Nitzschia)、石莼(Ulue pertusa)和绢丝藻(Callithamnion corymbosum)作为研究对象，通过白光、蓝光、红光照射，1%硝酸铵、1%柠檬酸、3%硫酸铵处理不同时间，淡水浸泡不同时间3种杂藻清除方法，系统研究光质、药物和淡水处理对鼠尾藻及杂藻光合生理的影响。结果显示，对于相对生长速率(RGR)、表观光合速率(Pn)及表观光合速率与呼吸耗氧速率(R)的比(Pn/R)，鼠尾藻幼孢子体在蓝光下均明显大于在白光和红光下，而菱形藻则在红光下较大，且鼠尾藻幼孢子体与菱形藻在蓝光下的Pn比明显大于其在白光和红光下的Pn比。结果显示，鼠尾藻幼孢子体若与菱形藻进行竞争，在蓝光下相对于在白光和红光下更有优势。硝酸铵、硫酸铵、柠檬酸药物处理对鼠尾藻幼孢子体的生理状态有一定的影响，且这种伤害具有不可逆性；对鼠尾藻嫩芽的伤害较小，且可恢复正常；对石莼的清除效果不明显，对绢丝藻有伤害。淡水处理对鼠尾藻幼孢子体有伤害，对鼠尾藻嫩芽伤害较小，对石莼影响不大，对绢丝藻有伤害。研究表明，在鼠尾藻幼苗早期培育过程中，可增大蓝光的照射或减少红光的照射，在一定程度上能促进鼠尾藻的生长且抑制菱形藻的生长；在鼠尾藻早期幼苗的杂藻清除中，应避免使用1%硝酸铵、1%柠檬酸和3%硫酸铵处理，会对鼠尾藻幼孢子体产生伤害；鼠尾藻育苗早期不宜使用淡水浸泡除去杂藻，鼠尾藻嫩芽每次淡水浸泡30 min，可清除杂藻，且对藻体无伤害。

Effects of different light quality and stress treatments on photosynthetic efficiencies and physiological characteristics of Sargassum thunbergii and epiphyllous algae

In this paper, Sargassum thunbergii, Nitzschia, Ulva lactuca, and Callithamnion corymbosum were used as the experimental species to determine the influence of different light qualities (white, blue, and red light), medical treatments (1% ammonium nitrate, 3% ammonium sulfate, and 1% citric acid), and freshwater immersion on their photosynthetic efficiencies. The effectiveness of various harmful algae removal methods which are harmless to young sporophytes of S. thunbergii, were also discussed. The results showed that: for RGR (relative growth rate), Pn (apparent photosynthetic rate), and Pn/R (the ratio of apparent photosynthetic rate and respiratory oxygen consumption rate), S. thunbergii under blue light were significantly larger than those under white and red light. In comparison, Pn of Nitzschia reached its peak under the red light. The Pn of S. thunbergii and Nitzschia under blue light was significantly higher than that under white and red light, indicating that S. thunbergii outcompetes Nitzschia under blue light. Irreversible injury appeared when young sporophytes of S. thumbergii were exposed to ammonium nitrate, ammonium sulfate, and citric acid. These chemical treatments also inhibited the growth of C. corymbosum, but the effects were not significant on newborn branches of S. thunbergii and U. lactuca. Freshwater treatment caused harm to S. thumbergii young sporophytes and C. corymbosum, but there was little negative effect on U. lactuca, and newborn branches of S. thunbergii. These results suggest that in the early stages of S. thunbergii cultivation, increasing the irradiation of blue light or reducing the irradiation of red light to a certain extent, can promote the growth of S. thunbergii, and inhibit the growth of Nitzschia. The use of ammonium nitrate, ammonium sulfate, and citric acid should be avoided in the removal of unwanted algae from young sporelings of S. thunbergii. While it is not advisable to use fresh water during the early stages, a fresh water soak for half an hour can remove the unwanted algae and causes no harm to the newborn branches of S. thunbergii.