Histological analysis of pollen-pistil interactions in sour passion fruit plants (Passiflora edulis Sims)

The success of sexual plant reproduction is directly influenced by specific interactions between the pollen and pistil.Light,fluorescence and scanning electron microscopy techniques were used to evaluate the steps of pollination in sour passion fruit plants(Passiflora edulis Sims).In the compatible interaction,pollen tubes grow through stigma projections towards the ovary.The pollen grain surface was found to be spheroidal and to consist of heteroreticulate exine with six colpi.Furthermore,analysis in vivo of pollenpistil interactions indicated that stigmas of flowers 24 hours before anthesis are unable to discriminate compatible(genetically unrelated)and incompatible(genetically related)pollen grains.Taken together,these results provide insight into the cellular mechanisms underlying pollination in passion fruit plants.

Leaf Anatomy of Prosthechea moojenii(Pabst)W.E.Higgins and P.silvana Cath.&V.P.Castro(Orchidaceae)as an Approach to Taxonomy of Species Occurring in Biomes Cerrado and Atlantic Forest of the Bahia

Prosthechea is a neotropical genus, belonging to the family Orchidaceae. The Brazil recorded 32 species of the genus of which nine occur in the state of Bahia, including P. silvana and P. moojenii. The first, P. silvana is epiphytic, endemic Atlantic Forest areas of South and Southeast of the Bahia and morphologically similar to P. moojenii, rupicolous species considered endemic to the Chapada Diamantina. There are doubts whether these two species are really distinct, because they differ only as to the way of life and aspects related to the size of the inflorescence and floral structure. Thus the anatomical study of these two species, emerges as a tool that aims to investigate the delimitation of these taxa. For this study, the sheet was cut freehand with a razor blade to obtain cross sections and treated by chemical means to obtain paradermic sections, all the material was stained with safranine/Astra blue (safrablau) and safranin, respectively, and the sections were then mounted between a semipermanent and cover slipped slides. The results allowed to distinguish P. silvana of the P. moojenii through the following characteristics observed in the leaf (thickening of the cell walls of epidermal cells, amount and disposition of sclerenchyma fibers and fiber arrangement of vascular and vascular bundles in the mesophyll) and root (number of arcs of xylem and phloem, thickening of cells median cortex), infers taxonomic characters for the genus. The data indicated anatomical distinction between the two species studied here of the Prosthechea, however, suggest the anatomical analysis of other organs to reproductive and vegetative.

香椿的树木年轮宽度与超年生殖行为的相互关系:对树轮学研究的警示

资源分配到生殖过程涉及到生态和进化因素,可能会减少植物的营养生长。这种相互关系在自然界中不容易观察到,因为有许多参数可以限制生殖结构的产生或生物量的增加。我们将香椿(Cedrela odorata L.,楝科)在里约热内卢州大西洋森林中的树木年轮宽度与超年生殖行为相关联。总体而言,生殖结构的发育发生在湿润的年份,在生长季初期没有出现水分亏缺。然而,在这些年份,树木年轮宽度较小。这些结果可能与树木年轮宽度与当地气候之间缺乏相关性有关。因此,我们强调在径向生长研究中纳入生殖数据的重要性,以扩大对热带森林生长变异性的理解。