02478nas a2200229   4500008004100000245011100041210006900152260001200221300001400233490000700247520169600254653002601950653002201976653001101998653002902009653002202038653001902060100001602079700001802095700001902113856011602132       1982                        eng d00aThe ligule of isoetes lacustris: Ultrastructure, mucilage composition, and a possible pathway of secretion0 aligule of isoetes lacustris Ultrastructure mucilage composition   c1982///  a569 - 5840 v493 aMature ligules of Isoetes lacustris can be divided anatomically into three ultrastructurally different regions. First, the basal region contains large numbers of two types of protein bodies. Second, the cells of the sub-marginal region are characterized by a well developed Golgi apparatus closely associated with the tubular compartments of the endoplasmic reticulum. Third, the peripheral region consists of one to three layers of cells showing an extremely well developed rough asternal and smooth tubular endoplasmic reticulum (ER). The tubular ER compartments are frequently observed in close attachment to the plasmalemma. The outermost peripheral cells are covered with a mucilaginous layer. The dry matter in the mucilage consists of 49 per cent polysaccharides and 22 per cent proteins. The polysaccharide fraction, analysed by ion exchange chromato-graphy, consists mainly of glucose, arabinose, galactose and uronic acids. The protein fraction was analysed by SDS gel dectrophoresis and by high performance liquid-chromatographic separation of the amino acids. The analysis shows a protein pattern very similar to that of the peripheral ligule tissue. It is suggested, therefore, that the material of the external mucilage is secreted by the peripheral ligule cells. The secretional mechanism appears to be a direct release of polysaccharides and proteins by the tubular components of the ER. There is no indication of secretion via the Golgi apparatus. Because of its high activity in protein synthesis and secretion, it is suggested that the ligule is a vestigial structure, which, in extinct genera, might have functioned as a digestive organ. © 1982 Annals of Botany Company.10aEndoplasmic reticulum10aIsoetes lacustris10aLigule10aPolysaccharide secretion10aProtein secretion10aUltrastructure1 aKristen, U.1 aLiebezeit, G.1 aBiedermann, M.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-0008468496&partnerID=40&md5=1f528bd1dc2bfcc71d9f4a8b7f66d66002200nas a2200205   4500008004100000245010400041210006900145260001200214300001400226490000700240520149600247653002601743653002501769653001101794653001901805653001901824100001601843700001901859856011601878       1981                        eng d00aUltrastructure, origin, and composition of the protein bodies in the ligule of Isoetes lacustris L.0 aUltrastructure origin and composition of the protein bodies in t  c1981///  a655 - 6630 v483 aThe basal cells in the ligule of Isoetes lacustris contain numerous protein bodies, the contents of which can be digested enzymically by pronase and are stained red by treatment with ninhydrin Schiff's reagent. Two types of protein bodies can be distinguished ultrastructurally: spherically-shaped bodies with granular contents and spindle-like bodies with fibrillar contents. Both are ensheathed by single membranes and do not show any solid inclusions within their matrix.The protein bodies probably arise from dilatation of the endoplasmic reticulum (ER) cisternae. This conclusion is based upon three observations: (a) The protein bodies occasionally show membrane continuity with the ER; (b) ribosomes and polysomes are frequently attached to the protein-body membranes; (c) the contents of the protein bodies and of the dilated ER cisternae show similar ultrastructural features.The dilatation of the ER cisternae is assumed to be a result of protein accumulation in the intracisternal space.Based upon the results of polyacrylamide gel electrophoresis, it is likely that the spherically-shaped protein bodies store predominately two proteins with molecular weights of 51300 and 55800 D, while the spindle-like bodies store two proteins with molecular weights of 92000 and 98000 D.The results presented do not permit a definite conclusion regarding the function of the ligule of Isoetes lacustris but it is suggested that it may have a nutritive role. © 1981 Annals of Botany Company.10aEndoplasmic reticulum10aIsoetes lacustris L.10aLigule10aProtein bodies10aUltrastructure1 aKristen, U.1 aBiedermann, M.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-0008618938&partnerID=40&md5=225bcc66f2d5de1b9179c020a2fac78201345nas a2200205   4500008004100000245004900041210004900090260001200139300001400151490000700165520072400172653002700896653001900923653001300942653001900955100001900974700001600993700001301009856011701022       1979                        eng d00aRoot cap structure in Isoetes macrospora Dur0 aRoot cap structure in Isoetes macrospora Dur  c1979///  a739 - 7440 v443 aRoot meristem cells of Isoetes macrosporausually have one plastid which is associated with the prominent nucleus, numerous ribosomes and mitochondria, and small vacuoles. During mitosis each plastid appears to replicate so that each daughter cell contains one plastid. The cell walls of the meristem cells are traversed by numerous plasmodesmata. Central cells of the root cap lack distally displaced plastids but have one or more amyloplasts associated with the nucleus. These cells also contain large protein deposits. Peripheral root cap cells are characterized by being vacuolated, and by possessing a few dictyosomes and protein deposits. They appear to be sloughed infrequently. © 1979, Annals of Botany Company.10aIsoetes macrospora Dur10aProtein bodies10aRoot cap10aUltrastructure1 aPeterson, R.L.1 aScott, M.G.1 aKott, L.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-49249140974&partnerID=40&md5=d822938e26f53beb365672ef21f6dec9