Early process on embryogenesis of cultured carrot suspension cells.

将含2，4-D培养基中的胡萝卜悬浮细胞分离并转移到含10 μ <-7>M玉米素但缺乏2，4-D的培养基中培养，低密度（&lt;12%Ficoll）的细胞合成花青素，而高密度（&gt; 14%Ficoll）的细胞形成体细胞胚。1.当在培养基中测量培养的胡萝卜细胞的膜电位时，它约为-40 mV，并且不因添加盐或添加（或耗尽）2，4-D而改变。2.当在测试介质（含低浓度盐）中进行测量时，这些值分布很广（从-60到-110 mV），并且随外部K^+浓度而变化很大，但不随Mg^&lt;++&gt;或Ca^&lt;++&gt;浓度而变化。3.当通过Ficoll密度梯度离心分离细胞时，较高密度（&gt; 14%Ficoll）的细胞的膜电位在测试培养基中约为-150mV，并且在2，4-D耗尽的胚胎发生期间不发生变化。另一方面，在试验培养基中，较低密度的细胞（6 - 10%Ficoll之间的条带）的膜电位负性较小（-60<wave>-110 mV）。当这些细胞转移到含有玉米素但缺乏2，4-D的培养基中培养时，在花青素苷合成之前，膜电位负移约15 mV。当2，4-D加入到含有玉米素的培养基中的花色素苷合成细胞中时，在花色素苷合成受到抑制之前观察到膜的瞬时超极化和随后的去极化。

Carrot suspension cells in a medium containing 2,4-D are fractionated and transferred and cultured in a medium containing 10^<-7>M zeatin but lacking 2,4-D, cells of lower density (<12% Ficoll) synthesize anthocyanin while those of higher density (>14% Ficoll) form somatic embryos. 1. When the membrane potenitals of cultured carrot cells were measured in culture medium, it was about -40 mV and did not change by addition of salts or addition (or depletion) of 2,4-D. 2. When the measurement was performed in test medium (containing low concentration of salts), the values were widely distributed (from -60 to -110 mV)and changed largely with external concentration of K^+ but no Mg^<++> or Ca^<++>. 3. When the cells were fractionated by Ficoll density gradient centrifugation, the membrane potential of the cells of higher density (>14% Ficoll) was about -150 mV in the test medium and did not change during embryogenesis with depletion of 2,4-D. On the otherhand, the membrane potential of the cells of lower density (banding between 6 - 10% Ficoll) was less negative (-60<wave> -110 mV) in the test medium. When such cells were transferred and cultured in the medium containing zeatin but lacking 2,4-D, the membrane potential was shifted negatively by about 15 mV prior to anthocyanin synthesis. When the 2,4-D was added to anthocyanin-synthesizing cells in the medium containing zeatin, a transient hyperpolarization and subsequent depolarization of the membrane were observed prior to the inhibition of anthocyanin synthesis.