Ultrastructural observation on esophageal glands and their secretory granules in Bursaphelenchus xylophilus and Bursaphelenchus mucronatus by TEM

The dorsal and subventral esophageal glands and their secretory granules in Bursaphelenchus xylophilus and Bursaphelenchus mucronatus were observed by transmission electron microscopy (TEM) to study their shape and changes in life cycles.Results indicated that the structure of esophageal glands and their changes in larvae and adults appeared degenerate;the subventral glands (SvG) enlarged in larvae and large numbers of secretory granules (SG) appeared.The dorsal gland (DG) enlarged in both male and female, and numbers of SG appeared in it.Two types of secretory granules formed by esophageal glands were different in size and electron-dense, and secretory granules in Bursaphelenchus xylophilus and Bursaphelenchus mucronatus were different in size.