CYCLOIDIEA (CYC) and its homologues have been studied intensively in the model organism Antirrhinum majus and related species regarding their function in controlling floral dorsoventral (adaxial-abaxial) asymmetry, including aborting the adaxial and lateral stamens. This raises the question whether the same mechanism underlies the great morphological diversity of zygomorphy in angiosperms, especially in Lamiales sensu lato, a major clade predominantly with zygomorphic flowers. To address this, we selected a representative in Gesneriaceae, the sister to the remainder of Lamiales s.l., to isolate CYC homologues and further investigate their expression patterns using locus-specific semiquantitative reverse transcriptase polymerase chain reaction. Our results showed that four CYC homologues in Chirita heterotricha differentiated spatially and temporally in expression, in which ChCYC1D was only expressed in the adaxial regions, and transcripts of ChCYC1C were distributed in both the adaxial and lateral regions, while ChCYC2A and ChCYC2B transcripts were only detected in the young inflorescences. ChCYC1C expression in the lateral regions correlated with abortion of the lateral stamens in C. heterotricha hinted at its gain of function, i.e., expanding from the adaxial to the lateral regions in expression. Correlatively, the protein sequences of ChCYC genes exhibited remarkable divergences, in which some lineage-specific amino acids between GCYC1 and GCYC2 in conserved functional domains and two sublineage-specific motifs between GCYC1C and GCYC1D in GCYC1 genes had further been identified. Our results indicated that ChCYC genes had probably undergone an expressional differentiation and specialization in establishing the floral dorsoventral asymmetry in C. heterotricha responding to different selective pressure after gene duplication.

, an ancient ()-like gene, has essential functions in specifying floral organ and meristem identity in rice (). However, how genes control flower development remains largely unknown. In this study, we report that OsMADS6 directly targets (), a rice homolog of the -like gene () from Arabidopsis (). Arabidopsis is involved in RNA-directed DNA methylation and regulates flower development. The expression of overlaps with that of in the palea primordia and the ovule, and OsMADS6 directly promotes expression through binding to regions containing putative CArG motifs within the promoter during rice spikelet development. Consistent with the phenotypes of mutants, the mutants showed floral defects, including altered palea identity with lemma-like shape containing no marginal region of palea, increased numbers of stigmas and fused carpels, and meristem indeterminacy. Moreover, transgenic plants overexpressing displayed floral defects, such as abnormal paleae. Phylogenetic analysis showed that homologs exist only in terrestrial plants. In addition, protein-protein interaction assays showed that OsFDML1 interacts with its close paralog OsFDML2, similar to the activity of OsFDML1 homologs in Arabidopsis. These results provide insight into how the ancient gene regulates floral development.

Rice flower development determines grain yield. Here we reveal the genetic interactions between the rice meristem maintenance gene FON4 and six floral homeotic genes in flower development.

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The cytological characteristics of major green-tide-forming green algae Ulva prolifera collected from Yellow Sea were studied through cutting segments, long time low temperature or dark treatments. After being dried in the shade and preserved at −20˚C for 30 days, the U. prolifera was cultured at 4˚C in sterilized seawater under 40 μmol photons m −2 •s −1 light intensity for 120 days, results indicated that the plastid of U. prolifera continuously shrank with the extension of treatment, and most cells turned white and died, only a small amount of cells still contained a few of visible inclusions at the 120d of treatment. Then those samples were transferred to 20˚C and 40 μmol photons m −2 •s −1 condition for recovery cultivation, after about 10 days, some recovery cells were observed in the thallus, and those cells developed to young thallus gradually and released germ cells almost in the same time. After about 60 days of recovery cultivation, the newly-grown green thallus broke through the original dead thallus, and the germ cells also grew to new individual thallus.Before dark treatment, the U. prolifera cells were filled with plastid, contained visible starch grain and discernible cell outlines, while after 120 days of dark treatment, the plastid shrank and degraded together with the disappearance of cell inclusions, and the cell outlines also blurred, then those samples were transferred to optimal culture conditions at 20˚C in 40 μmol photons m −2 •s −1 light intensity, and 15 days later, newly-grown cells appeared on the almost dead thallus, these cells divided continuously and grew to young thallus, and those newly-grown thallus also generated active germ cells, which developed to new thallus that cytologically identical to the original thallus. Observation of chopped tissue of U. prolifera cultivated at 20˚C, 40 μmol m −2 •s −1 showed that the morphological upper part cells turned to germ cells first, those germ