A precocious flowering system of regenerants in asparagus (Asparagus officinalis) was achieved by treatment with a chemical inducer. Somatic embryos withered completely by being processed for 8 -12 days with 200 μM n-propyl N-(3,4-dichlorophenyl)carbamate that had been dissolved in distilled water. In contrast, precocious flowering occurred at an extremely low rate (3.4%) when somatic embryos were processed in carbamate dissolved in Murashige and Skoog's liquid medium. To encapsulate the female and male embryos, we surveyed the optimum conditions of viscosity and concentration of sodium alginate for encapsulating the seeds, and we screened the values of 80 -120 cps and 2% -3%, respectively. The synthetic seeds produced also withered when they were processed with the carbamate dissolved in distilled water. However, when Murashige and Skoog's liquid medium was used for the solvent, the flowering frequency of the synthetic seeds was enhanced (13.3%). Based on our morphological and histological observations, female and male regenerants that were processed with the carbamate solution produced individual flower organs. The conversion of sex expression did not occur. A precocious flowering system would allow a significant reduction in the time required for perennial seedlings to flower and can, therefore, save time required for further experiments that employ floral homeotic mutants.

An aseptic bioassay system to estimate allelopathy in asparagus calluses was established. Allelopathic activities of calluses were measured according to the callus packed cell volume (PCV) by means of the sandwich method, and remarkable inhibition of acceptor plants was observed by the addition of over 0.1 mL PCV. When female and male calluses were separately used for the sandwich method, there was no sexual difference in allelopathic activity. To detect the allelopathic activities of the callus cells in detail, we improved the plant box method that substituted the calluses for the seedlings, and serious inhibition of acceptor plants was observed with the addition of over 0.35 mL PCV as donor material. Allelopathic activities were accelerated by irradiating the calluses with light-emitting diodes (LEDs) prior to performing the aseptic bioassay. It also seemed that the light quality would affect their activities. The allelopathic activity appeared intensely with irradiation of the calluses with a blue LED. The aseptic bioassay system that employed LED-irradiated calluses established here could accelerate effectively the isolation and identification of allelochemical(s).

An aseptic bioassay utilizing female and male donor materials was performed in order to assess the allelopathic activities of cladophylls and root systems in dioecious asparagus. The aseptic sandwich method revealed that the growth of acceptor plants was significantly inhibited by the addition of over 30 mg fresh weight of cladophylls. When female and male cladophylls were separately adopted for the sandwich method, there was no sexual difference in the allelopathic activity of both youthful and senescent cladophylls. To detect the allelopathic effects of root systems, the plant box method employing female and male regenerants was used aseptically, and the growth of acceptor plants was seriously inhibited irrespective of sex expression in donor plants. Early in vitro flowering seedlings expressing individual sex were effectively used for the bioassay, and the results indicated that the degree of allelopathic activities was the same as that in regenerants. These results show that allelopathic activity in female and male plants was equivalent, and that the application of materials that can distinguish between the sexes would be useful for assaying the mutual effects of sexuality on allelopathy. The aseptic bioassay system that employed female and male materials presented here could promote the isolation and identification of allelochemicals.