| Sixteen cultivars of ornamental kales (Brassica oleracea var. acephala) introduced from Japan were used in this study. Firstly, self-incompatible plants were selected by compatibility index (CI) and their self-incompatibility was further confirmed by fluorescent microscope observation. Secondly, lines with good ornamental traits were selected after genetic analyses of leaf color and shape of purified lines. For the purpose of analyzing molecular mechanism of self-incompatibility of the selected self-incompatible and self-compatible lines, the expression difference in SLG and SRK genes specifically expressed on stigma and SCR and SP11 genes (male determinant) specifically expressed in pollen exine, and spectrum difference of protein were studied using Northern hybridization and protein 2-D electrophoresis.For selection of self-incompatible plants, 3 to 5 plants from each of 16 cultivars were self-pollinated and determined on the CI. Only 5 plants in the first year and 3 plants in the second year matched the criterion of self-incompatibility that CI was less than 1 at anthesis and more than 5 at the bud stage. In order to obtain the number of plants enough for breeding of self-incompatible lines, the criterion was loosened to a tentative self-incompatible criterion that CI was less than 1 at anthesis and more than 1 at the bud stage. As a result, 32 plants in the first year and 13 plants in die second year were obtained. After selection for 2 years, 6 self-incompatible lines and 1 self-compatible line were selected.The germination response of pollens on stigma was observed with a fluorescence-microscope. The germination rate of pollen in self-incompatible 'Osaka Maruba Aka-usagi' plants was low and the growth of pollen tubes was retarded in flowers pollinated after anthesis, but normal in those pollinated at the bud stage. On the other hand, the pollen germination of self-compatible 'White Wave' plants was normal in both flowers pollinated at the bud stage and after anthesis.HPLC analysis indicated that the pigment obtained from red color cultivars was cyanidin. Concentration of anthocyanin in leaves of self-pollinated and cross-pollinated progenies was well correlated with the color of plants in the field. The composition of anthocyanin in progeny leaves was not changed. However, anthocyanin concentration in a leaf was different between leaf positions in a head, where the red color was more intense in developing leaves near the center of a head and became paler toward the outermost leaf. The segregation rate of 'Red Sparrow' (red leaf) x 'White Sparrow' (white leaf) was 3:1, indicating that, in this group, the leaf color was controlled by a pair of genes with red color being dominant. The segregation rate of 'Red Lady' (red leaf) x 'White Wave'(white leaf) was 15:1, indicating that, in this group, the leaf color was controlled by two pairs of produced by crossing among 3 cultivars with different leaf shapes indicated a mixture of the parent characteristics but with a slight likeness to that of maternal plants.Total RNA was extracted from stigma and pollen of self-compatible 'White Wave' plants and the self-incompatible 'Osaka Maruba Aka-usagi' plants at different intervals during a period of 48 hours after self-pollination. The expression of SLG, SRK, SCR and SPll genes was examined by Northern blotting. SLG and SRK genes were expressed abundantly on mature stigma and the expression quantity was not affected by pollination. The expression degree of SLG gene was related to time after pollination and the expression decreased obviously on the stigma 48 hours after pollination, which was consistent with strong reaction of self-incompatibility, which wasobserved commonly on the day of anthesis. On stigma of "White Wave" plants, SRK gene was also expressed remarkably, but the expression quantity decreased 48 hours after pollination, when plants showed self-compatibility. SCR gene was expressed only in young buds and buds of 2 to 3 days before anthesis in 'White wave' plants. The expression quantity wa... |
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