A Study on the Leaf Structure of Four Reed Ecotypes Development of Vascular Bundles in Aloe arborescens Leaves Immunological Regulation of Rhizoma Imperatae on IL-2 and T Lymphocyte Subpopulation Cytological Studies on the Early Phase of Somatic Embryogenesis in Petiole Explants of Wild Celery Distributed Regularity and Anatomic Feature of Laticiferous Canals of Toxicodendron vernicifluum (Stokes) F. A. Barkley