An improved technique for culture of rice panicles

An improved technique for long-term culture of rice caryopses is necessary for physiological and genetic studies. Panicles of three rice (Oryza sativa) cultivars 'Lemont', 'Gummo-byeu' and 'Hwasung-byeu' were cultured in liquid media with combinations of light versus dark, panicle position, nitrogen level (5-40 mM), and sucrose level (29-351 mM). Grain growth was increased when panicles were positioned horizontally, partially submerged in the media, owing to greater media contact and apoplastic uptake as observed by fluorescent dyes. The optimal media assimilate supply included 175 mM sucrose and 5 mM nitrogen. Grain fill occurred for up to four weeks; grain dry weight reached 80% of that on intact plants, with 50% germination. This technique should allow for future physiological studies with rice or other panicle-bearing species.