Leaves are flat determinate organs derived from indeterminate shoot apical meristems. The presence of a specific leaf meristem is debated, as anatomical features typical of meristems are not present in leaves. Here we demonstrate that multiple NGATHA (NGA) and CINCINNATA-class-TCP (CIN-TCP) transcription factors act redundantly, shortly after leaf initiation, to gradually restrict the activity ...

Since the transition from vegetative to floral development in plants is likely to be influenced by gene expression in several plant organs, we have used an in vitro system, the tobacco "thin cell layer" system as a model for investigating gene expression associated with the initiation of flowering in higher plants. cDNA cloning has been used to identify mRNAs abundant during thin cell layer flo...

A major aspect of postembryonic plant development is the formation of secondary axes of growth: vegetative branches, inflorescence branches, or flowers. The first step in side-shoot development is the establishment of lateral meristems in the axils of leaves. GRAS-, MYB-, and bHLH-type transcription factors act as key regulators of early steps in this process. The REVOLUTA subfamily of HD-ZIP t...

Meristems within the plant body differ in their structure and the patterns and identities of organs they produce. Despite these differences, it is becoming apparent that shoot and root apical and vascular meristems share significant gene expression patterns. Class III HD-Zip genes are required for the formation of a functional shoot apical meristem. In addition, Class III HD-Zip and KANADI gene...

To cope with environmental changes, animals respond by altering their behavior, but sessile plants respond by altering their growth and development pattern. One of the major differences between plant and animal development is that plants have the capacity to develop new organs postembryonically. This potential to develop new organs is attributed to sets of cells, called meristems, which are fou...

Above-ground plant architecture is dictated to a large extent by the fates and growth rates of aerial meristems. Shoot apical meristem gives rise fundamental form generating new leaves. However, axillary meristems located in leaf axils have great influence on affect harvest index, yield potential cultural practices. Improving breeding facilitates denser plantations, better resource use efficien...

Shoot branching requires the establishment of new meristems harboring stem cells; this phenomenon raises questions about the precise regulation of meristematic fate. In seed plants, these new meristems initiate in leaf axils to enable lateral shoot branching. Using live-cell imaging of leaf axil cells, we show that the initiation of axillary meristems requires a meristematic cell population con...

To understand the molecular mechanism regulating meristem development in the monocot rice (Oryza sativa), we describe here the isolation and characterization of three floral organ number4 (fon4) alleles and the cloning of the FON4 gene. The fon4 mutants showed abnormal enlargement of the embryonic and vegetative shoot apical meristems (SAMs) and the inflorescence and floral meristems. Likely du...

Multiple hormones, including abscisic acid (ABA) and auxin, regulate cell division and differentiation of Arabidopsis root meristems. AUXIN RESPONSE FACTOR 2 (ARF2) functions as a negative regulator of ABA responses, as seed germination and primary root growth of arf2 mutants are hypersensitive to ABA. In this study, we found that ABA treatment reduced the expression levels of the PIN-FORMEDs (...