Search

Immature seeds can acquire the traits of desiccation tolerance and germination after precocious maturation. This process is associated with the accumulation of non-reducing sugars and late embryogenesis abundant (LEA) proteins. LEA proteins were first identified from late developmental seeds and were proposed to be associated with desiccation tolerance. In the present study, we examined whether purified LEA fusion proteins from soybean seeds can maintain the integrity of artificial liposomes under desiccation. We also studied the relationship between the protective effects of LEA protein-sucrose glasses and desiccated membrane. GmPM6 (LEA II) but not GmPM16 (LEA IV) provided significant protection to dehydrated liposomes. However, neither GmPM6- nor GmPM16-sucrose glasses could protect these liposomes. We discuss the functions of cellular glass in mature orthodox seeds. [ABSTRACT FROM AUTHOR]

The genus Chamaecyparis (Cupressaceae) is comprised of six taxa native to East Asia and North America. Two independent lineages from eastern North America to East Asia and from western North America to East Asia have been identified from phylogenetic analyses based on variation in plastid DNA (ptDNA). However, the trees inferred from a nuclear ribosomal internal transcribed spacer (nrITS), the NEEDLY intron 2, and combined data from genetic and morphological characters of other studies are incongruent with the tree inferred from ptDNA. In this study, we sequenced the plastid matK gene as well as other sequences acquired from GenBank including the matK, rbcL, and nrITS sequences to reconstruct the phylogenetic trees of Chamaecyparis. The phylogenetic topology inferred from matK was congruent with the previous inference obtained using other ptDNA markers while the rbcL and ITS trees were congruent with previously inferred trees using the combined data and ITS sequences, respectively. Relatively less- (rbcL) and more-informative sites (ITS) may lead to different lineage sorting and incongruent phylogenetic topologies, which were evidenced by rejection of evolutionary homogeneity between ptDNA and ITS sequences in the partition homogeneity test. The phylogenetic tree reconstructed using matK and other ptDNA strongly supports the geographically disjunct distribution of Chamaecyparis in North America and East Asia. A dispersal-vicariance analysis, and geologic and fossil evidence indicated that at least two independent dispersal events occurred from North America to East Asia, which support the previous biogeographic inference by ptDNA. The use of biparental inherited markers for biogeographic inferences should be done with caution. [ABSTRACT FROM AUTHOR]