@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 {85,
	title = {Non-destructive assessing and monitoring of populations of Isoetes lacustris L},
	journal = {Limnologica},
	volume = {34},
	year = {2004},
	note = {Cited By (since 1996):1Export Date: 11 November 2013Source: Scopus},
	month = {2004///},
	pages = {147 - 153},
	abstract = {Extensive studies of Isoetes lacustris, performed throughout Europe, resulted in regressions between the number of leaves per rosette and (1) the number of spores per megasporangium, (2) length of seasonal growth, (3) Secchi depth and (4) water colour plus a relationship between pH and the number of spores per megasporangium. The evaluation of Isoetes populations requires measurements of the lake data Secchi depth, water colour, pH and conductivity, the establishment of climate data and leaf counts on 20-30 plants with the aid of SCUBA. The method may be applied to lakes in a range of situations, varying between lowland and highland, and between temperate and subarctic climate regions. The regressions are displayed graphically. The actual mean leaf number and corresponding megaspore number are compared with the numbers referred to in the environmental data. Consistent values point to the parameters which influence growth and vitality of the quillwort and to what extent, in a particular lake. Examples of evaluation and monitoring are given.},
	keywords = {Climate, Conductivity, Evaluation, Isoetes lacustris, Leaf number, Light availability, Megaspore number, pH value},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-17944391690\&partnerID=40\&md5=bc81c2908849af47d9ff68a2cff5dbc9},
	author = {V{\"o}ge, M.}
}
@article {58,
	title = {The reproductive phenology of Isoetes lacustris L.: Results of field studies in Scandinavian lakes},
	journal = {Limnologica},
	volume = {36},
	year = {2006},
	note = {Cited By (since 1996):1Export Date: 11 November 2013Source: Scopus},
	month = {2006///},
	pages = {228 - 233},
	abstract = {The phenologic change of the leaf rosette structure of Isoetes lacustris L. was studied in 26 lakes of temperate, boreal, or subarctic Scandinavia between 59{\textdegree} and 70{\textdegree} n.l. The investigations were carried out during six defined seasons: late winter, spring, early summer, late summer, autumn, and early winter. From 640 plants, gained with the aid of SCUBA, six leaf types were distinguished: immature megasporophylls, mature megasporophylls, immature microsporophylls, mature microsporophylls, and sporophylls that had released their spores and leaves with undeveloped sporangia. Mean numbers per rosette of each leaf type were established in each study lake and study season, resulting in a common pattern embracing all lakes studied. Megasporophylls are developed throughout the year, whenever the water temperature is about 10 {\textdegree}C. Their share was always more than 30\%, excepting winter. Microsporophylls are produced preferentially in spring/early summer when the days are longest; they amount to more than 50\% of the rosette leaves during this period, but only to some 10\% in the remaining seasons. The spores mature and are released between late summer and early winter. It is concluded that not all spores mature in the year of their birth, and those that do not mature are released in the early summer of the following year, as well as the old empty leaves become detached. {\textcopyright} 2006 Elsevier GmbH. All rights reserved.},
	keywords = {Climate, Isoetes lacustris, Reproductive phenology, Rosette development, Seasons},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-33750991320\&partnerID=40\&md5=43e430d0fc4386c8148a6682853d96ab},
	author = {V{\"o}ge, M.}
}
