摘要
在含１ｍｏｌ／ＬＮａＣｌ的杜氏盐藻（Ｄｕｎａｌｉｅｌａｓａｌｉｎａ（Ｄｕｎａｌ）Ｔｅｏｄ．）培养液中加入５０ｍｍｏｌ／Ｌ以上的ＫＣｌ可观察到Ｋ＋对杜氏盐藻生长有明显的抑制作用，而当ＫＣｌ达１００ｍｍｏｌ／Ｌ时，杜氏盐藻的生长被完全抑制。另一方面，当培养液中缺乏Ｋ＋时，杜氏盐藻的生长也被显著抑制。在正常培养条件下，伴随着杜氏盐藻的生长，培养液的ｐＨ由８左右升高至１０左右，而高浓度Ｋ＋则显著抑制杜氏盐藻培养液ｐＨ的升高；而在培养液ｐＨ为７．０至１０．０的范围内，不同ｐＨ对杜氏盐藻的生长无明显影响。将杜氏盐藻在高浓度Ｋ＋条件下预处理１２ｈ以上，杜氏盐藻的光合放氧速率显著下降，光合速率下降的程度与Ｋ＋浓度的高低和预处理的时间长短呈正相关。高浓度Ｋ＋处理也引起杜氏盐藻叶绿素含量的显著下降。对经高浓度Ｋ＋预处理的杜氏盐藻的光合放氧速率与培养液中ｐＨ变化同时进行测定的结果表明，Ｋ＋抑制杜氏盐藻光合速率的同时也显著抑制了光照条件引起的培养液ｐＨ的上升。实验结果表明，Ｋ＋抑制杜氏盐藻光合作用以及抑制杜氏盐藻生长与Ｋ＋影响跨盐藻质膜的质子运输之间可能存在一定关系。
It was observed in our preliminary experiments that the growth of Dunaliella salina (Dunal) Teod. cultured in medium containing 1 mol/L NaCl was almost completely inhibited by the addition of 100 mmol/L KCl. This study was focused on elucidating the physiological mechanisms by which high K + inhibits D. salina growth. Under the control conditions, the pH of the medium rapidly increased from 8 to 10 along with the growth of D. salina . However, addition of 100 mmol/L KCl significantly inhibited the increase of medium pH. The results suggested that the growth of D. salina may require a low environmental of H + concentration or be related to the H + transport into the D. salina cells. Interestingly, D. salina cultured in various media with different pH buffered with 40 mmol/L Tris HCl (or Tris NaOH) did not show any significant difference in the growth rates. This result brings up the question on the previous hypothesis that Na +/H + antiport plays a major role in Na + extrusion in D. salina . The photosynthetic rate of D. salina was not inhibited immediately following the addition of high K + in the reaction medium, but it was significantly inhibited after the pretreatment of algae with high K + for 12 hours or longer. The results from simultaneous measurements of O 2 evolution of D. salina and the changes in pH of the medium revealed that the inhibitory effect of high K + on D. salina growth was somehow associated with K + effect on pH changes in the medium. The high K + treatment of D. salina also resulted in significant decrease of chlorophyll contents in the algae. It is concluded that the inhibitory effects of high K + on photosynthesis of D. salina may, at least partially, account for the growth inhibition of D. salina growth by high K +; the inhibitory effects of high K + on D. salina photosynthesis may result from the influence of K + on H + transport across the plasma membranes of D. salina cells.
基金
国家自然科学基金
关键词
杜氏盐藻
钾
光合作用
质子运输
Dunaliella salina, Potassium ions, Photosynthesis, Proton transport
