Left–right leaf asymmetry in decussate and distichous phyllotactic systems

Abstract

One contribution of 17 to a theme issue 'Provocative questions in left -right asymmetry'. Leaves in plants with spiral phyllotaxy exhibit directional asymmetries, such that all the leaves originating from a meristem of a particular chirality are similarly asymmetric relative to each other. Models of auxin flux capable of recapitulating spiral phyllotaxis predict handed auxin asymmetries in initiating leaf primordia with empirically verifiable effects on superficially bilaterally symmetric leaves. Here, we extend a similar analysis of leaf asymmetry to decussate and distichous phyllotaxy. We found that our simulation models of these two patterns predicted mirrored asymmetries in auxin distribution in leaf primordia pairs. To empirically verify the morphological consequences of asymmetric auxin distribution, we analysed the morphology of a tomato sister-of-pin-formed1a (sopin1a) mutant, entire-2, in which spiral phyllotaxy consistently transitions to a decussate state. Shifts in the displacement of leaflets on the left and right sides of entire-2 leaf pairs mirror each other, corroborating predicted model results. We then analyse the shape of more than 800 common ivy (Hedera helix) and more than 3000 grapevine (Vitis and Ampelopsis spp.) leaf pairs and find statistical enrichment of predicted mirrored asymmetries. Our results demonstrate that left-right auxin asymmetries in models of decussate and distichous phyllotaxy successfully predict mirrored asymmetric leaf morphologies in superficially symmetric leaves.This article is part of the themed issue 'Provocative questions in leftright asymmetry'.

Phenotypic diversity and plasticity index of Eurycoma apiculata populations in Eastern Sumatra, Indonesia based on leaves morphology

“…Furthermore, Dhkar and Pareek (2014) affirmed that besides genetic control, environmental factors (mainly temperature and light) have significant contributions in the final adjustment of the shape of the leaf. Martinez et al (2016) reported that plastic properties of leaf shape are caused by variation in lamina growth At the population level, PPI value ranged from 0.41 to 0.51, and the mean value was 0.47. The lowest PPI value is observed in the Rumbio population (0.41), followed by the Sentajo population (0.43), while the highest PPI value is observed in the Lingga-1 population (0.51).…”

Diversification of ranunculaceous petals in shape supports a generalized model for plant lateral organ morphogenesis and evolution

“…S12D). When ADD was set to promote the growth of only one side of the primordium, organs with oblique, bilaterally asymmetrical bases, like the ventral (rather than dorsal or lateral) sepals of Delphinium and leaves of Begonia (Begoniaceae) ( 33 ), were generated (fig. S12, E and F).…”

<b>Leaf architecture and symmetry of understory tree species of an Araucaria forest

“…In spiral systems, the peak of auxin concentration is displaced towards the descending side of the center of mass of leaf primordia and is influenced by architecture of the shoot apical meristem, as observed in tomato (Déb, Marti, Frenz, Kuhlemeier, & Reinhardt, 2015). Studies on Vitis spp and Hedera helix showed that the asymmetric flux of auxin in the shoot apical meristem accentuates differences along the left-right axis and is influenced by phyllotaxis (Martinez, Chitwood, Smith, & Sinha, 2016).…”