Spinach (Spinacia oleracea L.) develops leaf rosettes under short-day conditions, and starts reproductive growth including bolting and flowering under long-day conditions. Japanese people prefer Oriental spinach that ...Spinach (Spinacia oleracea L.) develops leaf rosettes under short-day conditions, and starts reproductive growth including bolting and flowering under long-day conditions. Japanese people prefer Oriental spinach that bolts easily with a shorter photoperiod than European spinach. This is one of the main reasons that Oriental spinach is difficult to grow year-round. In order to understand spinach flowering mechanisms and obtain knowledge for spinach breeding, we isolated one CONSTANS-like (COL) and two FLOWERING LOCUS T (FT) homologs, which are key components of photoperiodic regulation of flowering time, from a Japanese cultivar. The expression of SoCOL1 showed diurnal rhythm with the highest expression at the end of the dark cycle. This diurnal rhythm is similar to the expression of BvCOL1 from sugar beet (Beta vulgaris), whose flower-promoting effect was observed when overexpressed in Arabidopsis. Phylogenetic analysis showed that SoCOL1 is the closest homolog of BvCOL1, suggesting that SoCOL1 is an ortholog of BvCOL1. SoFT1 and SoFT2 are closely related to BvFT1 and BvFT2, respectively. The expression of SoFT1 and SoFT2 were induced in advance of flower bud formation after changing the photoperiod, but the expression level of SoFT1 was much lower than SoFT2. Currently, we are speculating that SoFT2 is a flower-promoting factor of spinach, and that SoFT1 has a role in light signaling because the expression of SoFT1 showed a diurnal rhythm.展开更多
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 ...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-dichloro-phenyl)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.展开更多
文摘Spinach (Spinacia oleracea L.) develops leaf rosettes under short-day conditions, and starts reproductive growth including bolting and flowering under long-day conditions. Japanese people prefer Oriental spinach that bolts easily with a shorter photoperiod than European spinach. This is one of the main reasons that Oriental spinach is difficult to grow year-round. In order to understand spinach flowering mechanisms and obtain knowledge for spinach breeding, we isolated one CONSTANS-like (COL) and two FLOWERING LOCUS T (FT) homologs, which are key components of photoperiodic regulation of flowering time, from a Japanese cultivar. The expression of SoCOL1 showed diurnal rhythm with the highest expression at the end of the dark cycle. This diurnal rhythm is similar to the expression of BvCOL1 from sugar beet (Beta vulgaris), whose flower-promoting effect was observed when overexpressed in Arabidopsis. Phylogenetic analysis showed that SoCOL1 is the closest homolog of BvCOL1, suggesting that SoCOL1 is an ortholog of BvCOL1. SoFT1 and SoFT2 are closely related to BvFT1 and BvFT2, respectively. The expression of SoFT1 and SoFT2 were induced in advance of flower bud formation after changing the photoperiod, but the expression level of SoFT1 was much lower than SoFT2. Currently, we are speculating that SoFT2 is a flower-promoting factor of spinach, and that SoFT1 has a role in light signaling because the expression of SoFT1 showed a diurnal rhythm.
文摘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-dichloro-phenyl)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.
