Types of hairs observed on the surface of aerial organs epidermis of Drosera rotundifolia L. vitroplantlets

Authors: Violeta TURCU޹, Dorina CACHIŢĂ-COSMA¹, Constantin CRĂCIUN²

Affiliation: ¹“Vasile Goldiş” West University, Arad, Romania; ²Electron Microscopy Center, Babes-Bolyai University, Cluj-Napoca, Romania

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ABSTRACT. The electron microscope observations, made at the level of the aerial organs surface of D. rotundifolia vitroplantlets, allowed us to emphasize the fact that on their epidermis we found all types of hairs characteristic to the specie, three categories of glandular, cells hairs and, respectively, long pedicle hairs – surnamed sensitive, tentacle hairs – and short pedicle hairs, and sessile hairs, and, more rarely, a category of tector, cells hairs. It is interesting to notice that, although the D. rotundifolia vitroplantlets benefit from a complex of nutritive substrate, not so much of protein nature (their catabolism being oriented to use as energy source the sacharose present in the culture media), their glandular hairs did not regress as the stomata of the vitroplantlets suffering of hyper hydration. On the miniature leaflets, the glandular hairs have remained, as presence and structure, similar to those existing at Drosera plant in their natural environment. For the first time in scientific literature, we identified the presence of glandular, sessile hairs on the surface of vitro leaflets stipel epidermis, of the floral stems, of the floral peduncle and of the external side of the sepals and petals.

Keywords: Drosera rotundifolia, bicolor rosette, stipel, hairs