Liquid Culture Systems for in vitro Plant Propagation

244 C. Damiano et al.
Over the last 15 years several systems for the TIS technique have been
tested, and recently Teisson and Alvard (1995) described a system for plant
propagation called RITA ® , that could be easily automated. The RITA ®
system has been successfully applied to the micropropagation of several
tropical plants such as banana (Alvard et al., 1993), pineapple (Escalona et
al., 1999), sugarcane (Lorenzo et al., 1998) and to mass production of
somatic embryos in Musa spp. (Escalant et al., 1994), Hevea brasiliensis
(Etienne et al., 1997), Citrus (Cabasson et al., 1997), allowing a significant
increase in the multiplication rate and improvement in the quality of
micropropagated plants. More recently, the feasibility of the successful
application of the TIS to temperate fruit trees has started to be investigated
(Damiano et al., 2000).
The advantages of this technique can be related to reduced
hyperhydricity of the tissues (due to the frequent renewal of the atmosphere
in the culture bottle), the economics (minimal operator handling is required)
and the reduction of contamination levels. In this work, the TIS technique
was applied to in vitro propagation of apple, peach, cherry and plum,
compared to stationary liquid and solid media, in order to assess its influence
on multiplication response, shoot quality and physiological state of the
treated plants.
2. Materials and methods
2.1 Plant material and cultural conditions
Apple (Jork 9), peach (cv. Yumyeong), cherry (cv. Bigarreau Burlat),
plum (cv. Adara) shoots, in vitro grown for two years on solid media, were
used. Plants were cultured for 60 days in: 1) solid medium (0.6% agar,
B&V-Italy); 2) TIS with one immersion period of 30 min or 60 min per day;
3) stationary liquid medium, using the media reported in table 1. For all
treatments the medium was renewed every 20 days. The culture conditions
were: temperature 24°C ±1, photoperiod of 16 hours with light intensity of
25 �mol m -2 s -1 , provided by Osram fluora L58 W/77 lamps.