Influence of in vitro growth conditions on in vitro and ex vitro photosynthetic rates of easy- and difficult-to-acclimatize sea oats (Uniola paniculata L.) genotypes

Abstract

Net photosynthetic rates (P n ) of easy and difficult-to-acclimatize (EK 11-1) sea oats genotypes were examined under the following culture conditions: (1) photoautotrophic [sugar-free medium, high photosynthetic photon flux (PPF), high vessel ventilation rates and CO 2 enrichment, (PA)]; (2) modified photomixotrophic [sugarcontaining medium diluted with sugar-free medium over time, high PPF, and high vessel ventilation rates (PM)]; (3) modified photomixotrophic enriched [same as PM with CO 2 enrichment, (PME)]; or (4) conventional photomixotrophic [sugar-containing medium, low PPF, and low vessel ventilation rates (control)]. Regardless of genotype, plantlets cultured under PA conditions died within 2 wk, whereas under PM and PME conditions, plantlets increased their P n . After 6 wk, P n per gram dry weight was 1.7 times greater in EK 16-3 than EK 11-1 plantlets cultured under PME conditions. In vitro-produced leaves of EK 16-3 plantlets were elongated with expanded blades, whereas EK 11-1 produced short leaves without expanded blades, especially under control conditions. After in vitro culture, EK 16-3 PME plantlets exhibited the highest dry weights among treatments. EK 16-3 PME and EK 16-3 PM had similarly high survivability, shoot and root dry weights and leaf lengths ex vitro compared to EK 16-3 control and EK 11-1 PM and PME plantlets. Ex vitro growth, survivability and P n per leaf area of either genotype were not affected by CO 2 enrichment under modified photomixotrophic conditions. These results suggest that growth and survivability of sea oats genotypes with different acclimatization capacities can be enhanced by optimizing culture conditions.

Development and application of photoautotrophic micropropagation plant system

“…Two genotypes of C 4 grass sea oat (Uniola paniculata L.) responded differently to photoautotrophic micropropagation (Valero-Aracama et al 2007). Sea oats required an initial source of carbon from the medium until they are capable of using CO 2 from the vessel headspace as their main carbon source, which is consistent with the findings of Arigita et al (2002) with kiwi explants (Actinidia deliciosa Chev.…”

“…Liang and Ferguson 'Hayward'). Similar to many C 3 species, sea oats benefited from photoautotrophic micropropagation in that plantlet growth and development of photoautotrophy were enhanced during in vitro culture (Valero-Aracama et al 2007).…”

Substitution of benzyladenine with meta-topolin during shoot multiplication increases acclimatization of difficult- and easy-to-acclimatize sea oats (Uniola paniculata L.) genotypes

“…Each donor plant was genotyped using random amplified polymorphic DNA (RAPD) genetic analyses (Ranamukhaarachchi 2000) prior to in vitro establishment. Two genotypes, previously characterized as easy-and difficult-to-acclimatize (EK 16-3 and EK 11-1, respectively), were used (Valero-Aracama et al 2007). To minimize carryover effects, shoot clusters of both genotypes were cultured on basal MS medium without plant growth regulators (Stage II medium without BA) for 6 weeks prior to experimentation.…”

Wood formation during ex vitro acclimatisation in micropropagated true service tree (Sorbus domestica L.)

“…In forestry, however, the use of micropropagated noble hardwoods is still limited by its relatively high production costs and low survival rates of regenerants during ex vitro transplanting. Several investigations have linked low ex vitro survival directly or indirectly to the use of heterotrophic or photomixotrophic in vitro culture conditions (Seon et al 2000;Mosaleeyanon et al 2004;Valero-Aracama et al 2007). Due to these stressful conditions, in vitro plantlets often show reduced amounts of epicutilar waxes, poor cuticle development and improperly functioning stomata.…”