Andromonoicia funcional em espécies do gênero Solanum L. (Solanaceae)

Abstract

The functional andromonoecy present in the genus Solanum, gives it a peculiar character, where hermaphrodite flowers with short stylet behave as masculine and hermaphrodite flowers with long stylet as fruit formers. With the objective of analyzing the reproductive biology of Solanum paniculatum L., Solanum stramoniifolium Jacq. and Solanum torvum Sw., it was investigated morphofunctional aspects of its flowers and the reproductive system. The work was carried out in anthropic areas near the campus of the Federal Rural University of Pernambuco - UFRPE (8 ° 01'05 "S and 34 ° 56'48" W) and at the edge of the forest at Dois Irmãos State Park - PEDI ( 8 ° 07'30 "S and 34 ° 52'30" W). Pollen viability, pollen / ovule ratio, morphometry, floral biology and morphs distribution were evaluated in inflorescences / individual / species. In addition to intra and inter morphic crosses, in the manual treatments of self-pollination and cross-pollination, slides were made for analysis and pollen tube growth observation. Solanum paniculatum has a pale violet corolla; S. stramoniifolium and S. torvum exhibit white flowers. The species have flowers that have the stylet passing the cone of the anthers and flowers in which the stylet is below the level of the anthers. In addition, they have significant morphological differences only at the stylet level, with polymorphism at the stylet level. For S. paniculatum, the mean value recorded was 1.2 cm (± 0.06) for long-styled flowers and 0.4 cm (± 0.06) for short-styled flowers. For S. stramoniifolium, it was 0.9 cm (± 0.06) for flowers that have a stylet exceeding the anthers cone and 0.31 cm (± 0.07) for short-styled flowers. The species S. torvum was 0.9 cm (± 0.17) for long-styled flowers and 0.3 cm (± 0.07) for short-styled flowers. There is a defined pattern for the proportion of long-styled and / or short-styled flowers in an inflorescence or even in individuals, where more than 80% of flowers have stilettoes that extend beyond the anther cone. Generally, long-styled flowers of S. stramonifolium are found in basal positions of inflorescences and short-styled flowers in distal positions. This pattern was not observed in S. paniculatum and S. torvum. The analyzed morphs offer pollen viability above 97% and high pollen/ovum ratio. Solanum paniculatum and S. stramoniifolium are self-incompatible, presenting mechanisms of gametophytic self-incompatibility. Already S. torvum is self-compatible. All three are considered as crossbreeds. Only the long styled flowers formed pollen tube that reached the eggs after 24h. Short-styled flowers, however, did not form a pollen tube in any treatment. In view of the above, the species can be classified as functional andromonoic, where short stylet flowers act as male and long styloff flowers as hermaphrodite, having reproductive capacity.