This Week in Annals of Botany

Automatic identification and characterization of radial files in light microscopy images of wood
Analysis of anatomical sections of wood provides important information for understanding the secondary growth and development of plants. This study reports on a new method for the automatic detection and characterization of cell files in wood images obtained by light microscopy.

Using virtual 3-D plant architecture to assess fungal pathogen splash dispersal in heterogeneous canopies: a case study with cultivar mixtures and a non-specialized disease causal agent
Recent developments in plant disease management have led to a growing interest in alternative strategies, such as increasing host diversity and decreasing the use of pesticides. Use of cultivar mixtures is one option, allowing the spread of plant epidemics to be slowed down. As dispersal of fungal foliar pathogens over short distances by rain-splash droplets is a major contibutor to the spread of disease, this study focused on modelling the physical mechanisms involved in dispersal of a non-specialized pathogen within heterogeneous canopies of cultivar mixtures, with the aim of optimizing host diversification at the intra-field level.

AGO1 controls arabidopsis inflorescence architecture possibly by regulating TFL1 expression
The TERMINAL FLOWER 1 (TFL1) gene is pivotal in the control of inflorescence architecture in arabidopsis. Thus, tfl1 mutants flower early and have a very short inflorescence phase, while TFL1-overexpressing plants have extended vegetative and inflorescence phases, producing many coflorescences. TFL1 is expressed in the shoot meristems, never in the flowers. In the inflorescence apex, TFL1 keeps the floral genes LEAFY (LFY) and APETALA1 (AP1) restricted to the flower, while LFY and AP1 restrict TFL1 to the inflorescence meristem. In spite of the central role of TFL1 in inflorescence architecture, regulation of its expression is poorly understood. This study aims to expand the understanding of inflorescence development by identifying and studying novel TFL1 regulators.

Explaining ontogenetic shifts in root-shoot scaling with transient dynamics
Simple models of herbaceous plant growth based on optimal partitioning theory predict, at steady state, an isometric relationship between shoot and root biomass during plant ontogeny, i.e. a constant root–shoot ratio. This prediction has received mixed empirical support, suggesting either that optimal partitioning is too coarse an assumption to model plant biomass allocation, or that additional processes need to be modelled to account for empirical findings within the optimal partitioning framework. In this study, simulations are used to compare quantitatively two potential explanations for observed non-isometric relationships, namely nutrient limitation during the experiments and initial developmental constraints.

Callose biosynthesis in arabidopsis with a focus on pathogen response: what we have learned within the last decade
(1,3)-β-Glucan callose is a cell wall polymer that is involved in several fundamental biological processes, ranging from plant development to the response to abiotic and biotic stresses. Despite its importance in maintaining plant integrity and plant defence, knowledge about the regulation of callose biosynthesis at its diverse sites of action within the plant is still limited. Arabidopsis (Arabidopsis thaliana) is one of the best-studied models not only for general plant defence responses but also for the regulation of pathogen-induced callose biosynthesis. This article summarizes what is known about the regulation of callose synthase activity as well as what has been discussed with regard to this topic within the last decade based on results derived from new techniques and available mutant lines, focusing on the progress that has been made in understanding the regulation of callose biosynthesis in response to pathogen attack.

Linking ecophysiological modelling with quantitative genetics to support marker-assisted crop design for improved yields of rice under drought stress
Genetic markers can be used in combination with ecophysiological crop models to predict the performance of genotypes. Crop models can estimate the contribution of individual markers to crop performance in given environments. This study explores the use of crop models to design markers and virtual ideotypes for improving yields of rice (Oryza sativa) under drought stress.