01867nas a2200181   4500008004100000245014500041210006900186260001200255300001400267490000700281520121700288100001101505700001301516700001101529700001101540700001701551856011701568       2004                        eng d00aChromosome behavior during meiosis and development of spore mother cells in the Chinese quillwort Isoetes sinensis T. C. Palmer (Isoetaceae)0 aChromosome behavior during meiosis and development of spore moth  c2004///  a183 - 1950 v943 aChromosome behavior during meiosis of the tetraploid Isoetes sinensis was observed to be similar to that of basic diploid Isoetes species. This observation was consistent with the previous report that polyploid species of Isoetes are allopolyploids. Meiosis was generally similar in both megaspore and microspore mother cells, but differences were observed. Due to the smaller size of the microspore mother cells, during prophase I, chromosomes are not as dispersed as those in megaspore mother cells. Cytomixis was observed in all stages of meiosis in microspore mother cells, but it was not seen at any stage of meiosis in megaspore mother cells. Cytomixis, lagging chromosomes, chromosome bridges, chromosome fragments, and micronuclei, observed during meiosis in I. sinensis, can affect sexual reproduction, but it does not appear to be a major cause of population decline in this species. The major cause of decline is habitat degradation from human disturbance. The few remaining populations of the Chinese quillwort are fragmented and the numbers of individuals contained in these populations dwindle as a result of habitat degradation. Conservation efforts are needed to save I. sinensis from extinction.1 aHe, Z.1 aWang, H.1 aLi, J.1 aYe, Q.1 aTaylor, W.C.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-11444270683&partnerID=40&md5=e3b19a6dd117ccd20573e526dceb63bf03003nas a2200229   4500008004100000245011300041210006900154260001200223300001600235490000700251520223800258653000902496653002802505653002202533653002102555653002502576653001702601100001302618700001102631700001402642856011702656       2005                        eng d00aGenetic consequence of restricted habitat and population decline in endangered Isoetes sinensis (Isoetaceae)0 aGenetic consequence of restricted habitat and population decline  c2005///  a1265 - 12740 v963 a• Background and Aims: Isoetes sinensis (Isoeteaceae) is a critically endangered aquatic quillwort in eastern China. Rapid decline of extant population size and local population extinction have occurred in recent years and have raised great concerns among conservationists. • Methods: Amplified fragment length polymorphisms (AFLPs) were used to investigate the genetic variation and population structure of seven extant populations of the species. • Key Results: Eight primer combinations produced a total of 343 unambiguous bands of which 210 (61·2 %) were polymorphic. Isoetes sinensis exhibited a high level of intra-population genetic diversity (H E) = 0·118; hs = 0·147; I = 0·192; P = 35·2 %). The genetic variation within each of the populations was not positively correlated with their size, suggesting recent population decline, which is well in accordance with field data of demographic surveys. Moreover, a high degree of genetic differentiation (FST = 0·535; G ST = 0·608; θB = 0·607) was detected among populations and no correlation was found between geographical and genetic distance, suggesting that populations were in disequilibrium of migration-drift. Genetic drift played a more important role than gene flow in the current population genetic structure of I. sinensis because migration of I. sinensis is predominantly water-mediated and habitat range was highly influenced by environment changes. • Conclusions: Genetic information obtained in the present study provides useful baseline data for formulating conservation strategies. Conservation management, including both reinforcement for in situ populations and ex situ conservation programmes should be carefully designed to avoid the potential risk of outbreeding depression by admixture of individuals from different regions. However, translocation within the same regional population should be considered as a measure of genetic enhancement to rehabilitate local populations. An ex situ conservation strategy for conserving all extant populations to maximize genomic representation of the species is also recommended. © The Author 2005. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.10aAFLP10aGenetic differentiation10aGenetic diversity10aIsoetes sinensis10aPopulation structure10aPteridophyte1 aKang, M.1 aYe, Q.1 aHuang, H.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-27944462292&partnerID=40&md5=26404edf2320e666820f93f6dd369ebf