This is particularly important when the conducting tissues between the SA node and the ventricles fail only from time to time. 尤其在竇房結和心房之間的傳導組織有時(shí)發(fā)生故障時(shí)這點(diǎn)尤為重要。
Roots also differ from roots in the arrangement of xylem and phloem, having a solid central strand of vascular tissue rather than a hollow cylinder of conducting tissue. 根和莖不同，它無(wú)葉綠素，沒(méi)有芽和葉，木質(zhì)部和韌皮部的排列順序也不同，其內部為實(shí)心的維管組織，而莖的內部為中空的圓柱形輸導組織。
