Somatic mutation, a main biological phenomenon of citrus and other fruits, is often used for breeding as a major variation source. Spontaneous mutations often occur in citrus.
体细胞突变是柑橘等果树比较常见的生物学现象，也是品种选育，即芽变选种的主要变异来源。
2
Coal fire is a dynamic process caused by spontaneous combustion of the coal layer in various directions, accompanied by the sensible thermal field variation both in time and in space.
煤层自燃是一个动态变化的过程，随着自燃向不同方向扩大或缩小，其热场随着燃烧过程而发生空间变化。
3
Objective To study the variation of peripheral blood NK Sub-class ratio in recurrent spontaneous abortion.