A new Swartzia (Leguminosae: Papilionoideae: Swartzieae) species with trimorphic stamens from Amazonian Brazil

A new species Swartzia trimorphica Mansano & A. L. Souza (Leguminosae, Papilionoideae, Swartzieae) from the Amazonian Brazil, is described and illustrated. The new species is notable and distinct from all the other species of Swartzia by its highly unusual trimorphic stamens, while the other species have either an isomorphic or a dimorphic androecium. The new species is included in the section and subsection Swartzia , ser. Orthostylae based on its bracteolate pedicels, the cauligerous inflorescences, lateral style and the relative size of the ovary compared to the style. The atypically small gynoecium in the material suggests the possibility that flowers may be functionally unisexual. Field observations and more collections are needed to resolve this question.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 147 , 235–238.     

A Process of Reproduction of Trypanosoma conorhini Different from Binary or Multiple Fission

SYNOPSIS. In cultures of Trypanosoma conorhini the authors have detected "cyst-like bodies" (CLBs) that, in the initial phase, have the appearance of 2 or more overgrown crithidiae fused together; after disorganization of the internal structure of the parent flagellates and division of their organelles, new crithidiae are formed within the CLB. The wall of the CLB consists of an irregularly thick layer of cytoplasm surrounded by the periplast of the parent flagellates and a true cystic membrane is not evident. The daughter crithidiae eventually escape from the CLB leaving the periplast and other residues of the parent flagellates. It is suggested that this represents a method of reproduction entirely different from binary or multiple fission, that is probably common to other trypanosomes of the Section STERCORARIA, and that it may provide for genetic exchange even if it is not a true sexual process.     

Development and cytology of pollen in Dahlstedtia Malme (Leguminosae: Papilionoideae)

Microsporogenesis, chromosome number, meiotic behaviour and meiotic index were investigated in Dahlstedtia pinnata and D . pentaphylla , two legume species occurring largely in Brazil, in order to ascertain whether the pollen could limit fertilization events. Archesporial cells originate primary sporogenous and anther wall precursor cells, the tapetum is uniseriate, uninucleate and glandular. Tetrads are tetrahedric or decussate, and cytokinesis is of the simultaneous type. Mature pollen grains are tricolpate and bicellular. No abnormalities in microsporogenesis were found. In both species the chromosome number is n = 11, a number not reported previously. The base number for Dahlstedtia is also 11, because cytological observations include both species of Dahlstedtia . D. pentaphylla has a higher meiotic index and lower individual variation values, and it is considered meiotically stable. Its pollen grains do not limit fertilization. D. pinnata has a lower meiotic index, and the pollen is one of the factors which limit fertilization. Furthermore, D. pinnata has numerous adventitious shoots, which suggest that vegetative propagation is important in its reproductive process. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 461–471.     

Comparison of Coding and Spacer Region Sequences of Chromosomal rRNA-Coding Genes of Two Sequevars of Pneumocystis carinii

Two distinct sequevars, denoted Pc1 and Pc2, of the opportunistic pathogen Pneumocystis carinii have been previously identified based on the sequence of their 26S rRNA genes, the location of group I self-splicing introns and pulsed field electrophoretic patterns of chromosomal DNA. This study shows that the sequences of 16S and 5.8S rRNA genes also vary between these sequevars, and that greater variation was seen in the internal transcribed spacer regions. Polymerase chain reaction and restriction analysis can distinguish between these sequevars.     

Sperm dimorphism in the Triatoma brasiliensis species complex and its applications

Morphological and structural features of the sperm of the Triatoma brasiliensis Neiva, 1911 (Hemiptera: Reduviidae) species complex were examined in this first study investigating the sperm of Heteroptera and the genus Triatoma. Males were dissected and their seminal vesicles removed. For measurement, seminal vesicles were squashed on glass slides, spread, fixed and observed under a photomicroscope. The images were analysed and measures of sperm were made. Data were analysed using one‐way analysis of variance and Tukey's test to detect differentiation among taxa. Furthermore, seminal vesicles were prepared for studies of transmission electron microscopy. All taxa studied showed polymorphic (short and long) sperm. The sperm of Triatoma brasiliensis macromelasoma was significantly longer (in total length) than that of the other four members of the complex, which supports the hypothesis of hybrid speciation of this member of the complex as an increase in the size of typical hybrids under heterosis was previously shown. The sperm cells of the five taxa have similar ultrastructural morphology. The ultrastructural features observed confirm the hypothesis, raised by previous studies, that they are synapomorphic to the suborder Heteroptera.     

Molecular genetic variation in Passiflora alata (Passifloraceae), an invasive species in southern Brazil

A total of 85 wild plants were collected in different areas of southern and south-eastern Brazil, and studied for nrDNA internal transcribed spacers (ITS). Thirty-two of them were also investigated for two other nuclear ( G3pdh and LEAFY ), as well as eight plastid systems. Sixty-one ITS sequence types were identified, in a region of 412 bp, whereas 42 G3pdh haplotypes were found in a region of 1010 bp, and 23 LEAFY haplotypes in a region of 565 bp. GC content was higher in ITS (65%) than in the two other nuclear regions (40–42%), whereas nucleotide diversity was markedly higher in G3pdh than in the other two. No variability was found in the plastid systems. Most of the nuclear molecular diversity (56–86%) occurs at the intrapopulation level, and there is clear evidence of population expansion and little geographical structure. Historical information and field studies indicate that Passiflora alata is actively colonizing previously unoccupied areas in southern Brazil. High indices of intrapopulation variability were found in the region that is being colonized, similar to those found in areas where P. alata is native. Multiple introductions, as well the species' genetic structure and human interference, may explain these findings.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 611–630.