@article {161,
	title = {The ligule of isoetes lacustris: Ultrastructure, mucilage composition, and a possible pathway of secretion},
	journal = {Annals of Botany},
	volume = {49},
	year = {1982},
	note = {Cited By (since 1996):7Export Date: 11 November 2013Source: Scopus},
	month = {1982///},
	pages = {569 - 584},
	abstract = {Mature 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. {\textcopyright} 1982 Annals of Botany Company.},
	keywords = {Endoplasmic reticulum, Isoetes lacustris, Ligule, Polysaccharide secretion, Protein secretion, Ultrastructure},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0008468496\&partnerID=40\&md5=1f528bd1dc2bfcc71d9f4a8b7f66d660},
	author = {Kristen, U. and Liebezeit, G. and Biedermann, M.}
}
@article {162,
	title = {Ultrastructure, origin, and composition of the protein bodies in the ligule of Isoetes lacustris L.},
	journal = {Annals of Botany},
	volume = {48},
	year = {1981},
	note = {Cited By (since 1996):4Export Date: 11 November 2013Source: Scopus},
	month = {1981///},
	pages = {655 - 663},
	abstract = {The 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{\textquoteright}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. {\textcopyright} 1981 Annals of Botany Company.},
	keywords = {Endoplasmic reticulum, Isoetes lacustris L., Ligule, Protein bodies, Ultrastructure},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0008618938\&partnerID=40\&md5=225bcc66f2d5de1b9179c020a2fac782},
	author = {Kristen, U. and Biedermann, M.}
}
@article {164,
	title = {Root cap structure in Isoetes macrospora Dur},
	journal = {Annals of Botany},
	volume = {44},
	year = {1979},
	note = {Cited By (since 1996):1Export Date: 11 November 2013Source: Scopus},
	month = {1979///},
	pages = {739 - 744},
	abstract = {Root 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. {\textcopyright} 1979, Annals of Botany Company.},
	keywords = {Isoetes macrospora Dur, Protein bodies, Root cap, Ultrastructure},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-49249140974\&partnerID=40\&md5=d822938e26f53beb365672ef21f6dec9},
	author = {Peterson, R.L. and Scott, M.G. and Kott, L.}
}
@article {36,
	title = {Morphology and ultrastructure of megaspores and microspores of isoetes sehnemii fuchs (lycophyta)},
	journal = {Anais da Academia Brasileira de Ciencias},
	volume = {82},
	year = {2010},
	note = {Cited By (since 1996):1Export Date: 11 November 2013Source: Scopus},
	month = {2010///},
	pages = {341 - 352},
	abstract = {The morphology and wall ultrastructure of megaspores and microspores of Isoetes sehnemii that grows in Brazil were analyzed as part of the study of the Isoetaceae present in Southern South America. The observations were performed with light, scanning and transmission electron microscopes. The megaspores are trilete, 350-450μm in equatorial diameter. The surface is reticulate. In section, the sporoderm is 100μm thick including the ornamentation. The wall is composed of a siliceous perispore, which consists of short fused flatten, elements forming a three-dimensional mesh. The exospore has two zones of different structure. The endospore is fibrillar. The microspores are monolete, 21-27μm in equatorial diameter. The sporoderm is composed of a sporopollinic rugulate perispore. A space between the para-exospore and the exospore is evident. The exospore is compact. The endospore is fibrillar. The ultrastructural analysis akes hoologies evident concerning structure and organization of the layers belo the perispore in both spore types. A possible similarity and stability in the ultrustructure of the present spores and fossils could be also inferred. In addition, there would be a correlation among the plant habitat, the spore ornamentation and the geographic distribution.},
	keywords = {Brazil, Isoetes, Lycophyta, Palynology, Sculpture, Spores, Ultrastructure},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-77954194457\&partnerID=40\&md5=1434918a400d7fc28cb2b2ec5338958d},
	author = {Macluf, C. and Morbelli, M. and Giudice, G.}
}
