Comportamento meiótico e estimativa da viabilidade polínica de acessos de Sambucus australis (ADOXACEAE)

Sambucus australis, popularly known as “sabugueiro”, is a plant used in alternative medicine for its diaphoretic, anti-inflammatory and analgesic actions. To encourage the use of this medicinal species native and also enable cytogenetic characterization to assist subsequently preservation programs and genetic improvement, the objective of this study was to characterize the meiotic behavior and to estimate the pollen viability of different accesses of S. australis from Rio Grande do Sul by different stains. To this end, the floral buds of 15 accesses were collected, fixed in ethanol:acetic acid (3:1) and stored in 70% ethanol until use. Slides were prepared using the squashing technique of the anthers. For meiotic analysis, 2% acetic-orcein staining was used, where all phases were analyzed and the meiotic index determined. Three stains were used to estimate pollen viability: Alexander´s reaction, 2% acetic-orcein, and 2% acetic-carmine. Data were analyzed by the Scott-Knott test at 5% significance level. In the 12 accesses analyzed, meiosis was regular, exhibiting chromosome associations preferably in bivalents, finding n = 19 while meiotic index values exceeded 90%. Regarding pollen viability, the majority of the accesses had a high percentage of viable pollens (over 75%), except for the ERE01 access (44%). On the staining comparison, Alexander´s reaction proved the most suitable method for estimating the pollen viability of the specie. Therefore, it can be concluded that the accesses of S. australis studied exhibited regular meiotic behavior, gametic number n = 19 chromosomes, high meiotic index values and a high percentage of viable pollens.