Pressure or suction 证实接合过程需要细胞间的直接接触的“U”型管实验: Met Thr Lev Thi Met Thr Lew Thi Figure 14.13 The U-Tube Experiment. The U-tube experiment used to show that genetic recombination by conjugation requires direct physical contact between bacteria. See text for details. Fritted glass filter 接合的机制?10 接合的机制？ 证实接合过程需要细胞间的直接接触的“U”型管实验：