Biochemical and Histochemical Studies on Protease Activity and Reserve Protein Metabolism in the Cotyledons of Germinating Cowpeas (Vigna unguiculata),

Changes in protein and protease distribution in cotyledons ofgerminating cowpea have been followed by histochemical, biochemical,and ultrastructural techniques. A close relationship, in locationand timing, between an enhanced protease activity and proteinmobilization has been demonstrated. The major enzyme(s) involvedin protein breakdown is of the endopeptidase type. Initiationof protein mobilization appears to be associated with the fusionof cytoplasmic vesicles with the protein bodies.     

The early evolution of the mega‐diverse genus Begonia (Begoniaceae) inferred from organelle DNA phylogenies

Begonia L. is one of the largest flowering plant genera, a ubiquitous component of many tropical forests and an economically important ornamental plant. In the present study, we address the early evolution of Begonia by generating molecular phylogenies from approximately 7000 bases of chloroplast DNA and approximately 6000 bases of mitochondrial DNA for each of 30 exemplar Begonia species. Broadscale biogeographic patterns found in the phylogenies, together with previously estimated divergence dates, indicated that extant Begonia lineages first diversified in Africa and then subsequently in America and Asia. The phylogenies also revealed that the closest African relatives of the American and Asian Begonia are seasonally‐adapted species. Moderate to strong incongruence between the phylogenies suggested that they differ genealogically. These differences could have been the result of either interspecific hybridization and/or incomplete lineage sorting. The results obtained in the present study provide a much needed genus‐wide framework for future evolutionary studies of this exceptionally diverse tropical genus. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 243–250.