Floral Meristem And Floral Organ Development Pdf
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- Formation of Floral Organs
- Analyzing Floral Meristem Development
- The Molecular Genetics of Floral Transition and Flower Development, Volume 72
Formation of Floral Organs
Metrics details. Flower development directly affects fruit production in tomato. Despite the framework mediated by ABC genes have been established in Arabidopsis, the spatiotemporal precision of floral development in tomato has not been well examined. Here, we analyzed a novel tomato stamenless like flower slf mutant in which the development of stamens and carpels is disturbed, with carpelloid structure formed in the third whorl and ectopic formation of floral and shoot apical meristem in the fourth whorl. Using bulked segregant analysis BSA , we assigned the causal mutation to the gene Solanum lycopersicum GT11 SlGT11 that encodes a transcription factor belonging to Trihelix gene family. SlGT11 is expressed in the early stages of the flower and the expression becomes more specific to the primordium position corresponding to stamens and carpels in later stages of the floral development. The carpelloid stamen in slf mutant indicates that SlGT11 is required for B-function activity in the third whorl.
Developmental Biology of Flowering Plants pp Cite as. The many deep-seated changes that characterize the vegetative growth of plants described in previous chapters are terminated by the production of flowers. This entails the transformation of the shoot apical meristem into a single flower or into a cluster of flowers known as the inflorescence. What prompts, at the physiological and molecular levels, the making of flowers is still a central and unanswered question in plant developmental biology. Despite more than a century of experimentation, we are still in the dark about the intracellular agents and gene products that start the cells of the shoot apical meristem along the developmental pathway of a floral primordium. However, these experiments have greatly advanced our understanding of the links between identifiable types of extracellular factors and early changes in the shoot apical meristem that lead to the formation of flowers. Morphological and anatomical studies aimed at following in the cells of the shoot apical meristem those known features that identify them as related to flower initiation have been an integral part of the early investigations on flowering.
An intriguing phenomenon in plant development is the timing and positioning of lateral organ initiation, which is a fundamental aspect of plant architecture. Although important progress has been made in elucidating the role of auxin transport in the vegetative shoot to explain the phyllotaxis of leaf formation in a spiral fashion, a model study of the role of auxin transport in whorled organ patterning in the expanding floral meristem is not available yet. We present an initial simulation approach to study the mechanisms that are expected to play an important role. Starting point is a confocal imaging study of Arabidopsis floral meristems at consecutive time points during flower development. These images reveal auxin accumulation patterns at the positions of the organs, which strongly suggests that the role of auxin in the floral meristem is similar to the role it plays in the shoot apical meristem.
Analyzing Floral Meristem Development
Developmental Biology of Flowering Plants pp Cite as. The formation of floral organs on the meristem follows on the heels of evocation and overlaps with evocation. The conventional angiosperm flower is made up of four whorls of modified leaves constituting the sterile and fertile parts. The sterile parts consist of an outer whorl of sepals that are usually green and enclose the rest of the flower before it opens, and an inner whorl of brightly colored petals that aid in attracting insects and other pollinators. Aggregates of sepals and petals in a flower are known, respectively, as the calyx and the corolla.
The fon1 mutants exhibit normal vegetative development and produce normal inflorescence meristems and immature flowers before stage 6. The fon1 floral meristem functions longer than does that of the wild type: after the outer three-whorl organ primordia have initiated, the remaining central floral meristem continues to produce additional stamen primordia interior to the third whorl. Prolonged fon1 floral meristem activity also results in an increased number of carpels. The clavata clv mutations are known to affect floral meristem activity. We have analyzed the clv1 fon1, clv2 fon1, and clv3 fon1 double mutants. These double mutants all have similar phenotypes, with more stamens and carpels than either fon1 or clv single mutants. This indicates that FON1 and CLV genes function in different pathways to control the number of third- and fourth-whorl floral organs.
Protocol DOI: Flowers contain the male and female sexual organs that are critical for plant reproduction and survival. Each individual flower is produced from a floral meristem that arises on the flank of the shoot apical meristem and consists of four organ types:. Each individual flower is produced from a floral meristem that arises on the flank of the shoot apical meristem and consists of four organ types: sepals, petals, stamens, and carpels. Because floral meristems contain a transient stem-cell pool that generates a small number of organs composed of a limited number of cell types, they are excellent model systems for studying stem-cell maintenance and termination, cell fate specification, organ morphogenesis, and pattern formation. Arabidopsis thaliana.
The Molecular Genetics of Floral Transition and Flower Development, Volume 72
Floral transition, the onset of plant reproduction, involves changes in shape and identity of the shoot apical meristem SAM. The change in shape, termed doming, occurs early during floral transition when it is induced by environmental cues such as changes in day-length, but how it is regulated at the cellular level is unknown. We defined the morphological and cellular features of the SAM during floral transition of Arabidopsis thaliana. Both cell number and size increased during doming, and these changes were partially controlled by the gene regulatory network GRN that triggers flowering. Furthermore, dynamic modulation of expression of gibberellin GA biosynthesis and catabolism enzymes at the SAM contributed to doming.