翡翠贻贝幼体附着和变态的离子控制

IONIC CONTROL OF ATTACHMENT AND METAMORPHOSIS IN THE GREEN MUSSEL PERNA VIRIDIS (LINNAEUS) LARVAE

于1993年5－12月在厦门大学海滨实验场，以人工培养的翡翠贻贝幼体作为实验材料，在人工海水中添加3－15mmol／LK＋或通过离子替代减少40－48．smmol／LMg2＋而设计成一系列检测介质，在作用72－120h后分别观察幼体在检测介质中附着和变态反应结果们时采用药理学检测法就翡翠贻贝幼体附着和变态的离子控制机制进行探讨。结果表明：在人工海水中增加6－12mmol／LK＋或减少16．0－33．5mmol／LMg2＋可有效诱导幼体的附着和变态，添加12mmol／LK＋可诱导幼体48．0％附着率和50．0％变态率，而减少23mmol／LMg2＋可诱导41．6％附着率和52．1％变态率。细胞膜K＋通道阻滞剂TEA，可以阻抑增加K＋或减少Mg2＋对幼体附着和变态的诱导作用，而阴离子交换阻滞剂SITS，却无阻抑作用：说明幼体一些可兴奋细胞在附着和变态过程中起重要作用。此外，在自然海水中添加gmmol／LK＋和12nunol／LK＋可分别诱导幼体较高的附着率（43．1％）和变态率（57.0％）；这一实验结果可应用于翡翠贻贝人工育菌技术的改进。

From mp to December 1993, an artificially cultivated green mussel, Perna viridis(Linnasus) larvae, were used as experimental material to study the effects of changes in ionicconcentrations of environmental media on larval attachment and metamorphosis, and to discuss themechaoisms of ionic control on these two events using methods of phannasology. This study wasundrtakn in a seashore experimental field of Xiamen University.The settling and metamorphic responses of the larvae were observed after 72- 120h ofcultivation in a series of detecting media, namely, artificial seawarer designed by adding 3- 15mmol / L K+ or decreasing 4.0 -48.5mmol / L Mg2+ through ionic substitution. The results were asfollow. Attachment and metamorphosis of the larvae were effechvely indoced by increasing 6- 12mmol / L K+ or decreasing 16.0-33.5mmol / L Mg2+ in the artificial seawater. The addition of 6-12mmol / L K + indued 48% attachment and 50% metamorphosis; these were reduced by 41.6%and 52.1% in response to a decrease of 23mmol / L in Mg2+. At 24h, 48h, 72h and 120h intervals,the attachment and metamorphic rates of the lareae were examined for a joint action of cellmembran K+ - channel blocker TEA (tetraethhylammonium ) (5×10-5 mol / L) and theaddition of 9mmol / L K+, or for a combination of edon exchange blocker SITS (4-acetamido-4-isothiocyanostilbene-2.2-disulfonate)(1×10-5mol/L),TEA(5×10-5mol/L) and a 23 mmol/LMg2+ decrease in the artificial seawater. The results show that the action of increasing k+ ordecreasing Mg2+in inducing those two events is inhibited by the K+- channel blocker TEA,whilst the anion exchange blocker SITS has no inhibition, indicating that some K+-channels in the cell membrane play an important role on excitable cells sensitive to TEA in the process ofattachment and metamorphosis. In addition,a higher attachment the (43.1 percent) was ashieved as aresult of a suppement of 9mmol / L K+ or 12mmol / L K+, suggesting tha the experimentalmethods can be appied to improving the technology of the artificial seed breeding of thes species.The induhve effect of the addition of K+ on Perna virde larvae,which resulted in 48%attaChmnt and 50% metamorphosis in thes experimenL was much greater than on Saccastreacomrcialis larvee, and K+ had no induction on attachment and metamorphosis of M edulis lareas.However, such an effect was significantly lower for Perna viridis larvae than in marine gastrogh larvaestudied previously elsewhere. Based on these results, cotnped to drine gastropod larvae, settling andmetamorphic responses of marine bivalve larvas have a low sensitivity to the addition of K+.