The plastochron index: Still useful after nearly six decades

Meicenheimer, Roger D.

doi:10.3732/ajb.1400305

Cited by 27 publications

(23 citation statements)

References 120 publications

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“…This difference in node number itself was significantly different than na2‐1 mock‐treated controls for only the PAC treatment, but the delay in flower emergence without additional node production suggests the plastochron depends on BR and GA in maize. The plastochron is the time it takes to initiate each lateral organ from the meristem (Erickson & Michelini, ; Meicenheimer, ). We quantified total number of nodes and time to tassel emergence, so we may overestimate the effect of these treatments on flowering time as decreased elongation should delay emergence of the tassel.…”

Section: Discussionmentioning

confidence: 99%

Phytohormone inhibitor treatments phenocopy brassinosteroid–gibberellin dwarf mutant interactions in maize

2017

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SummaryPhytohormone biosynthesis produces metabolites with profound effects on plant growth and development. Modulation of hormone levels during developmental events, in response to the environment, by genetic polymorphism, or by chemical application, can reveal the plant processes most responsive to a phytohormone.Applications of chemical inhibitors and subsequent measurements of specific phytohormones can determine whether, and which, phytohormone is affected by a molecule. In many cases, the sensitivity of biochemical testing has determined multiple pathways affected by a single inhibitor. Genetic studies are not subject to this problem, and a wealth of data about the morphological impacts of hormone biosynthetic inhibition have accumulated through the study of enzyme mutants. In this work, we sought to assess the specificity of three triazole inhibitors of cytochrome P450s by determining their abilities to recapitulate the phenotypes of single and double mutants affected in the production of brassinosteroid (BR) and gibberellin (GA) biosynthesis. The GA biosynthetic inhibitors uniconazole (UCZ) and paclobutrazol (PAC) were applied to the BR biosynthetic mutant nana plant2 (na2), and all doublemutant phenotypes were recovered in the UCZ treatment. PAC was unable to suppress the retention of pistils in the tassels of na2 mutant plants. The BR biosynthetic inhibitor propiconazole (PCZ) suppressed tiller outgrowth in the GA biosynthetic mutant dwarf5 (d5). All treatments were additive with genetic mutants for effects on plant height. Due to additional measurements performed here but not in previous studies of the double mutants, we detected new interactions between GA and BR biosynthesis affecting the days to tassel emergence and tassel branching. These experiments, a refinement of our previous model, and a discussion of the extension of this type of work are presented.

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Section: Discussionmentioning

confidence: 99%

Phytohormone inhibitor treatments phenocopy brassinosteroid–gibberellin dwarf mutant interactions in maize

2017

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“…Based on the assumption that plant organs (1) have an exponential phase of growth, (2) grow at equal rates at successive nodes, and (3) initiate equally spaced in time (i.e., constant plastochron) [33], the PI provides a morphological time scale which is reliable for staging development and providing chronological ages of plant organs. Since its establishment, PI has been applied in various species in developmental studies to determine the ages of various plant, mainly floral, organs [36]. This method is further expanded to estimate the PI by an alternative approach when the rate of organ initiation does not remain constant [3,6].…”

Section: Introductionmentioning

confidence: 99%

Temporal Distinction between Male and Female Floral Organ Development in Nicotiana tabacum cv. Xanthi (Solanaceae)

Chang

Sun

2020

Plants

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Early floral developmental investigations provide crucial evidence for phylogenetic and molecular studies of plants. The developmental and evolutionary mechanisms underlying the variations in floral organs are critical for a thorough understanding of the diversification of flowers. Ontogenetic comparisons between anthers and pistil within single flowers were characterized over time in Nicotiana tabacum cv. Xanthi. The ages of 42 tobacco flower or flower primordia were estimated using corolla growth analysis. Results showed that the protodermal layer in carpel primordia contributes to carpel development by both anticlinal and periclinal divisions. Periclinal divisions in the hypodermal layer of the placenta were observed around 4.8 ± 1.3 days after the formation of early carpel primordia (ECP) and ovule initiation occurred 10.0 ± 0.5 days after ECP. Meiosis in anthers and ovules began about 8.9 ± 1.1 days and 14.4 ± 1.3 days after ECP, respectively. Results showed an evident temporal distinction between megasporogenesis and microsporogenesis. Flower ages spanned a 17-day interval, starting with flower primordia containing the ECP and anther primordia to the tetrad stage of meiosis in megasporocytes and the bicellular stage in pollen grains. These results establish a solid foundation for future studies in order to identify the developmental and molecular mechanisms responsible for the mating system in tobacco.

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“…Previous studies linking leaf morphological development (e.g. leaf length) to leaf aging (Erickson & Miche lini, ; Chen et al ., ; Meicenheimer, ) involved laborious measurements over long time periods or relied on uncertain assumptions. Near‐surface remote sensing (e.g.…”

Section: Introductionmentioning

confidence: 99%

Convergence in relationships between leaf traits, spectra and age across diverse canopy environments and two contrasting tropical forests

Chavana‐Bryant

Prohaska

et al. 2016

New Phytologist

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SummaryLeaf age structures the phenology and development of plants, as well as the evolution of leaf traits over life histories. However, a general method for efficiently estimating leaf age across forests and canopy environments is lacking.Here, we explored the potential for a statistical model, previously developed for Peruvian sunlit leaves, to consistently predict leaf ages from leaf reflectance spectra across two contrasting forests in Peru and Brazil and across diverse canopy environments.The model performed well for independent Brazilian sunlit and shade canopy leaves (R 2 = 0.75-0.78), suggesting that canopy leaves (and their associated spectra) follow constrained developmental trajectories even in contrasting forests. The model did not perform as well for mid-canopy and understory leaves (R 2 = 0.27-0.29), because leaves in different environments have distinct traits and trait developmental trajectories. When we accounted for distinct environment-trait linkages -either by explicitly including traits and environments in the model, or, even better, by re-parameterizing the spectra-only model to implicitly capture distinct trait-trajectories in different environments -we achieved a more general model that well-predicted leaf age across forests and environments (R 2 = 0.79). Fundamental rules, linked to leaf environments, constrain the development of leaf traits and allow for general prediction of leaf age from spectra across species, sites and canopy environments.

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The plastochron index: Still useful after nearly six decades

Cited by 27 publications

References 120 publications

Phytohormone inhibitor treatments phenocopy brassinosteroid–gibberellin dwarf mutant interactions in maize

Phytohormone inhibitor treatments phenocopy brassinosteroid–gibberellin dwarf mutant interactions in maize

Temporal Distinction between Male and Female Floral Organ Development in Nicotiana tabacum cv. Xanthi (Solanaceae)

Convergence in relationships between leaf traits, spectra and age across diverse canopy environments and two contrasting tropical forests

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