Eliane Kaltchuk dos Santos

Association between floral bud size and developmental stage in soybean microspores

This study was carried out to establish the association between floral bud size and the corresponding microspore developmental stages for Brazilian soybean cultivars. Microspore developmental stage distributions were examined in young buds from cv Decada, IAS5 and RS7. The data indicated that for a given bud-size group, the microspores of different cultivars were at different developmental stages, with cv RS7 and Decada distributed at the youngest and cv IAS5 at the most advanced stages. Microspore stages distribution were also compared among the ten anthers of the same bud of the above cultivars. The ten anthers from a given bud were clearly distributed at different developmental stages. Caution should be exercised when adopting the standard anther culture practice of using the microspore stage of one anther to represent the entire bud.

Cytotoxicity of essential oils from two species of Heterothalamus (Asteraceae)

Essential oils arewidely foundinplant species.Theycanbeinvolvedinavariety of ecologicalinteractions and may act as inhibitors of germination, suppressing root apical-meristem growth in some species. The present study aimed to determine the potential cytotoxicity of essential oils from leaves of Heterothalamus psiadioides Less. and H. alienus (Sprengel) O.Kuntze on root tips of lettuce (Lactuca sativa L.) and onion (Allium cepa L.). Lettuce seeds germinated with essentialoilsfromH.psiadioidesandH.alienushadareducedmitoticindex(MI)foralltreatments.Onionseedlingstreated withH.psiadioidesoilshowedadecreaseinMI,andseedlingstreatedwithH.alienusoilshowedadecreaseinMIof89%in themostconcentratedtreatment.Analysisoftheresultsshowedchromosomalabnormalities,includingstickiness,c-mitosis, micronuclei and anaphase bridges in lettuce and onion root tips exposed to essential oils of Heterothalamus.

Studies on diversity and evolution of Iridaceae species in southern Brazil

Plants of the family Iridaceae are well represented in the grassland vegetation of southern Brazil, occurring in the Pampa and Atlantic Forest biomes. Nevertheless, little is known about the taxonomy and evolution of Iridaceae species in southern Brazil. The main goal of this review is to compile published information about South American Iridaceae, and to discuss the evolution and genetic diversity of the family presenting our own research data in the light of the published literature. The main focus is on the genera Calydorea, Cypella, Herbertia, and Sisyrinchium. Aspects of reproductive system and of pollinator attraction are also discussed.

Androgênese: uma rota alternativa no desenvolvimento do pólen

Androgenesis is a phenomenon in which pollen grain changes its developmental pathway giving rise to haploid sporophyte. This alternative ontogenetic process is still not completely understood despite of its potencial to basic and applied studies, including crop improvement. The present article has the purpose of reviewing the factors related to the deviation of normal gametophytic route and the fundamental mechanisms of pollen embryogenesis induction.

THE STUDY OF BIODIVERSITY AND PLANT EVOLUTION THROUGH MOLECULAR MARKERS AND CYTOGENETICS: EXAMPLES IN IRIDACEAE AND POACEAE.

We present here a review of the use of molecular markers and cytogenetic data, applied to the detection of plant biodiversity. We mentioned a few examples o...