Search Results (4)

The morphological characteristics of metamorphosis in stamens of Anemone barbulata Turcz. were investigated using morphological and histological analyses. The results showed that stamens were transformed into either white sepaloid organs or more frequently green leaflike structures with successive variations. The extreme metamorphic stamen was represented as a three-lobed leaflike structure with a long stalk, highly consistent with the morphological characters of the normal leaves of the plant. It was hypothesized that the connective and two pollen sacs of the anther were transformed into the three lobes of the metamorphosed stamen, respectively. The depression and circinate stages were identified as the important and necessary processes in the transformation of stamens from axial to foliar organs, suggesting probably the alternative evolutionary process of the formation of anthers derived from foliar organs. The morphological traces of leaf, sepal, and carpel observed in the metamorphosed stamens suggested the homeotic transformations among these organs. The foliar stage in the ancestral stamens of angiosperms was reflected ontogenically in the metamorphosed stamens of A. barbulata. Our findings of a series of metamorphic stamens probably represent the morphological evidence to support the hypothesis that the flowers of angiosperms were derived from metamorphic leaves with the progressive development mode in the evolution of floral organs. Full article

Morphological concepts are used in plant evo-devo (evolutionary developmental biology) and other disciplines of plant biology, and therefore plant morphology is relevant to all of these disciplines. Many plant biologists still rely on classical morphology, according to which there are only three mutually exclusive organ categories in vascular plants such as flowering plants: root, stem (caulome), and leaf (phyllome). Continuum morphology recognizes a continuum between these organ categories. Instead of Aristotelian identity and either/or logic, it is based on fuzzy logic, according to which membership in a category is a matter of degree. Hence, an organ in flowering plants may be a root, stem, or leaf to some degree. Homology then also becomes a matter of degree. Process morphology supersedes structure/process dualism. Hence, structures do not have processes, they are processes, which means they are process combinations. These process combinations may change during ontogeny and phylogeny. Although classical morphology on the one hand and continuum and process morphology on the other use different kinds of logic, they can be considered complementary and thus together they present a more inclusive picture of the diversity of plant form than any one of the three alone. However, continuum and process morphology are more comprehensive than classical morphology. Insights gained from continuum and process morphology can inspire research in plant morphology and plant evo-devo, especially MorphoEvoDevo. Full article

Crab-eating frogs (Fejervarya cancrivora) can live in brackish water with a salinity of up to 18‰, although most amphibians are not able to tolerate such high saline environments. To investigate its potential osmoregulation, we conducted experiments in F. cancrivora and F. multistriata. The results showed that F. cancrivora made use of ions (such as Na⁺ and Cl⁻) to increase intracellular concentrations via the Na⁺/K⁺-ATPase (NKA) enzyme. The mRNA expression of aldose reductase (AR) was significantly higher in F. cancrivora (p < 0.05), indicating that more organic osmolytes were produced and transported to maintain cellular homeosis. The mRNA expressions of Aquaporin 1 (AQP1) and AQP3 in kidney were significantly higher in F. cancrivora, while AQP expression in skin was higher in F. multistriata (p < 0.05). The mRNA level in activating the transcription of the nuclear factor of activated T cells-5 (NFAT5) which is one of the target genes of regulating the cellular response to hypertonicity, was higher in F. cancrivora. The protein expression of CDK5, the upstream protein of the NFAT5 pathway, was 2 times higher in F. cancrivora. Therefore, we can conclude that CDK5/NFAT5-regulated transporters might be involved in osmoregulation in F. cancrivora. Full article

Floral organ formation has been the subject of intensive study for over 20 years, particularly in the model dicot species Arabidopsis thaliana. These studies have led to the establishment of a general model for the development of floral organs in higher plants, the so-called ABCDE model, in which floral whorl-specific combinations of class A, B, C, D, or E genes specify floral organ identity. In Arabidopsis, class A, B, C, D, E genes encode MADS-box transcription factors except for the class A gene APETALA2. Mutation of these genes induces floral organ homeosis. In this review, I focus on the roles of these homeotic genes in bread wheat (Triticum aestivum), particularly with respect to the ABCDE model. Pistillody, the homeotic transformation of stamens into pistil-like structures, occurs in cytoplasmic substitution (alloplasmic) wheat lines that have the cytoplasm of the related wild species Aegilops crassa. This phenomenon is a valuable tool for analysis of the wheat ABCDE model. Using an alloplasmic line, the wheat ortholog of DROOPING LEAF (TaDL), a member of the YABBY gene family, has been shown to regulate pistil specification. Here, I describe the current understanding of the ABCDE model for floral organ formation in wheat. Full article