中层

Male-sterility mainly results from the abnormality of mesospore,tapetum tissue and vascular bundle.

中组织、绒毡组织及药隔维管束异常均败育的因素。

There are two other forms of arteriosclerosis (hardening of the arteries) in addition to atherosclerosis: arteriolosclerosis and medial calcific sclerosis.

除动脉粥样硬之外,还有其它两种式的动脉硬（动脉变硬）∶细动脉硬症和动脉中。