The effect of ventilation rate on proliferation and hyperhydricity of Dianthus caryophyllus L

Abstract

Comparative studies of carnation micropropagation under four different ventilation rates showed that using gas-permeable filters, with gelled or liquid media and modifying the volume of culture medium, it was possible to establish a suitable hydric state to obtain good proliferation rates with gelled and liquid medium, as well as optimal acclimatization of microcuttings. The following parameters were measured: ventilation rate, gas exchange coefficients, relative water loss, increase of agar concentration, micropropagation rates, percentage of hyperhydricity, and acclimatization rates. Our results confirm that it is possible to avoid hyperhydric plants cultured in liquid medium with the use of ventilated culture vessels through the control of the water relations during the multiplication phase and, at the same time, keeping the micropropagation rate.

Physical environment in non-ventilated culture vessels affects in vitro growth and morphogenesis of several cultivars of Dianthus Caryophyllus L.

“…3). Hyperhydricity induced by lack of ventilation is described for several in vitro-cultured plants (McCown and Sellmer, 1987;Smith and McClelland, 1991;Debergh et al, 1992) and, particularly, in other D. caryophyllus cultivars in our previous reports (Majada et al, 1997(Majada et al, , 2000Fal et al, 1999). However, total hyperhydricity was induced only in 'Pink Calypso' explants cultured in jam jars with metal caps (the lowest E and desiccation), but not in the other cultivars (Table 3).…”

“…Our previous results (Majada et al, 1997(Majada et al, , 2000Fal et al, 1999) showed differences between some Dianthus caryophyllus L. cultivars in their behavior when cultured in vessels ventilated through porous membrane closures. This ventilation system was adequate for improving micropropagation when hyperhidricity was a problem.…”

“…value (measured on the culture shelf) was considered the transmittance (T ) of each type of vessel. The temperature and the relative humidity were measured inside the vessels as described previously (Majada et al, 1997), with a probe connected to a transmitter able to operate at high humidity (358 RHSolomat, Paris, France). The desiccation of the medium in each type of vessel, filled with medium (Table 2) but without explants, was calculated as the grams of water lost after 30 d in the growth chamber.…”

“…This has led to the design of new vessels that allow ventilation of the internal atmosphere, specially for culturing species prone to hyperhydricity (Majada et al, 1997(Majada et al, , 2000Fal et al, 1999). However, excess ventilation in the culture vessels can have the unwanted effect of producing fast desiccation of the culture medium and reduction of tissue growth (Walker et al, 1989;Sallanon and Maziere, 1992).…”

Hiperidricidade: uma desordem metabólica

“…O tipo de fechamento dos recipientes é outro fator de controle da UR. O uso de tampas com filtros de 0.2μm (MAJADA et al, 1997), ou de membranas permeáveis ao ar associadas, ou não, a sistema de ventilação forçada (ZOBAYED et al, 2001), são exemplos de alternativas para controlar a UR e evitar a hiperidricidade. O emprego de meio líquido associado a sistemas de aeração permite evitar a hiperidricidade e aumentar a taxa de micropropagação (DANTAS et al, 2001).…”