本文初步探讨了一次间距的调整机理,指出在胞晶及不发达枝晶生长时,“淹没”及“分枝”是一次间距的主要调整机理,对于发达枝晶生长,主要靠“分枝”机理调整。同时指出一次枝晶是在“生长—淹没—竞争再生长”的往复过程中生长的,竞争再生长的主要生长方式是“淹没—扰动分枝” In this paper, the mechanism of primary spacing adjustment was discussed. It was pointed out that “submerging” and “branching” are the main adjusting mechanisms of spacing in the growth of the cellular and undeveloped dendrites. For the developed dendrite growth, Mechanism adjustment. At the same time, it is pointed out that primary dendrites grow during the reciprocal process of “growth-inundation-competition and regrowth”, and the main growth mode of competition and regrowth is “submerged-perturbation branching”