Effect of alginate matrix composition on regrowth of in vitro-derived encapsulated apical microcuttings of hybrid aspen

Abstract

Effect of alginate matrix composition on regrowth performance of encapsulated microcuttings of hybrid aspen (Populus tremula L. × P. tremuloides Mincx.) was studied. Both high regrowth frequency and viability of explants were registered in all encapsulation mixtures tested. Some ingredients of the matrix (nutrient medium salts, sugars, growth regulators) significantly affected the initial development of the microcuttings. Sucrose appeared to play an important role in the starting stage of the regrowth event.Additional key words: encapsulation, propagules, Populus sp. ⎯⎯⎯⎯Despite of being basic alternative for production of 'synthetic seeds' (Redenbaugh et al. 1986, Attree and Fowke 1993, Uozumi and Kobayashi 1995, the encapsulation technique offers attractive opportunities for supplementary applications. The encapsulation of nonembryogenic in vitro-derived explants in Na-Ca alginate beads could be useful tool both for transfer of aseptic material between laboratories and for storage of valuable germplasm (Standardi and Piccioni 1998). In realizing the idea of providing an 'artificial endosperm', the nutritive ingredients of the alginate beads are of key importance for both the storage and conversion efficiencies of the propagules encapsulated. Effects of various compositions of sodium alginate matrix on regrowth performance of encapsulated apical cuttings of hybrid aspen were examined in a pilot study.Shoot apical microcuttings 0.5 -0.7 cm in length isolated from in vitro proliferating clone of Populus tremula L. × P. tremuloides Mincx. were used in the experiment. Microcuttings were encapsulated in accordance with the following procedure. For coating with sodium alginate, explants were immersed in sterilized encapsulation mixtures with different composition: a) distilled water + 4 % sodium alginate (W); b) distilled water + 3 % sucrose + 4 % sodium alginate (W+S); c) Murashige and Skoog (1962, MS) nutrient medium + 4 % sodium alginate (M); d) MS medium + 1.3 μM 6-benzylaminopurine (BAP) + 4 % sodium alginate (M+B); e) MS medium + 3 % sucrose + 4 % sodium alginate (M+S); f) MS medium + 1.3 μM BAP + 3 % sucrose + 4 % sodium alginate (M+B+S). The alginate-covered microcuttings were dropped into stirred 1.4 % CaCl 2 solution and kept 5 min for complexation and formation of capsules. The capsules were rinsed thrice 1 min each time with liquid MS medium supplemented with 1.3 μM BAP and 3 % sucrose.Encapsulated microcuttings were transferred for regeneration on MS medium supplemented with 1.3 μM BAP, 3 % sucrose and solidified with 0.8 % agar. Glass jars (300 cm 3 ) with 50 cm 3 nutrient medium were used for all experimental treatments. Each variant consisted of five jars, with five capsules being placed into each of them. Non-encapsulated microcuttings were directly placed on the same medium as a control. The jars were kept in a cultivation room at 24 ± 1 ºC, 16-h photoperiod and irradiance of 40 μmol m -2 s -1 provided by cool-white fluorescent lamps (GroLux ™ , Sylvania, Raunheim, Germany).After period of four weeks...

Organogenesis and encapsulation of in vitro-derived propagules of Carrizo citrange [Citrus sinensis (L.) Osb. × Poncirius trifoliata (L.) Raf]

“…The positive effect of encapsulation on the regrowth of microcuttings that we observed is in agreement with results obtained in different woody species (Gardi et al 1999;Micheli and Standardi 2005;Micheli et al 2007). Moreover, the effectiveness of the cold temperature on the short-term storage of the synthetic seeds confirms previous results obtained in olive ), guava (Rai et al 2008), aspen (Tsvetkov et al 2006), and other woody species (Kinoshita and Saito 1990;Tsvetkov and Hausman 2005). Based on findings reported in other species (Sarkar and Naik 1998;Alvarez et al 2002;Lucaccioni et al 2005;Micheli et al 2007), we conclude that the rooting inductive treatment tested in our study was able to achieve synthetic seed conversion, confirming the suitability of the adopted procedure, although further investigations are required to significantly improve the conversion rates of the Carrizo citrange synthetic seeds.…”

Plant regeneration from alginate-encapsulated shoot tips of Spilanthes acmella (L.) Murr., a medicinally important and herbal pesticidal plant species

“…Gelling matrix supplemented with nutrient ingredients served as 'artificial endosperm' which provides nutrients to the encapsulated propagules for plant regrowth (Singh et al 2006a). In realizing the idea of providing an 'artificial endosperm,' the nutritive ingredients (nutrient medium salts, sugars, growth regulators) of the alginate beads are of key importance for both the storage and conversion efficiencies of the propagules encapsulated (Tsvetkov et al 2006). Tsvetkov et al (2006) also found that the addition of adjuvant components in the gelling matrix improved the plant growth of hybrid aspen.…”

Storage and conversion of Eclipta alba synseeds and RAPD analysis of the converted plantlets

“…It suggested that sucrose concentration less than 1 % might not be suitable. Similarly, Tsvetkov et al (2006) revealed the effect of alginate matrix composition on regrowth of encapsulated apical microcuttings of aspen. They showed that sucrose has pronounced effect on regrowth and synseeds without sucrose displayed significantly worse regrowth.…”