Visualizing polymeric components that define distinct root barriers across plant lineages

ABSTRACT Hydrophobic cell wall depositions in roots play a key role in plant development and interaction with the soil environment, as they generate barriers that regulate bidirectional nutrient flux. Techniques to label the respective polymers are emerging, but are efficient only in thin roots or sections. Moreover, simultaneous imaging of the barrier constituents lignin and suberin remains problematic owing to their similar chemical compositions. Here, we describe a staining method compatible with single- and multiphoton confocal microscopy that allows for concurrent visualization of primary cell walls and distinct secondary depositions in one workflow. This protocol permits efficient separation of suberin- and lignin-specific signals with high resolution, enabling precise dissection of barrier constituents. Our approach is compatible with imaging of fluorescent proteins, and can thus complement genetic markers or aid the dissection of barriers in biotic root interactions. We further demonstrate applicability in deep root tissues of plant models and crops across phylogenetic lineages. Our optimized toolset will significantly advance our understanding of root barrier dynamics and function, and of their role in plant interactions with the rhizospheric environment.

Down-to-earth Approach as A Sociological Solution: Learning from Ineffectiveness of Maternity Waiting Home Implementation in Wonogiri, Indonesia

A maternity waiting home is a health facility that is considered helpful in preventing maternal deaths. The service aims to be a transit place for pregnant women to get primary health services. Due to geographic reasons, there is a waiting house for births—many cases of successful implementation of maternity waiting homes in various developing countries, especially in African countries. As a developing country, certain regions in Indonesia have implemented the service in imitation of the successful implementation of other countries. However, the implementation is not entirely effective. This study explores the root barriers in the implementation of the service from a sociological perspective. This study uses a qualitative research method with a case study approach. The data were collected through literature study, observation, in-depth interviews, and FGD. The results of this study were that various factors were found that caused the implementation of the maternity waiting home to be ineffective. Using a sociological analysis, the top-down policy of the maternity waiting for home is a significant factor in this ineffectiveness. This paper presents a concrete solution that uses an approach to emphasize the aspirations and needs of the community as a foundation in the implementation of this service.

Towards Eradication of Phytophthora cinnamomi Using a Fallow Approach in a Mediterranean Climate

While eradication from haul roads was achieved, more work is required to eradicate P. cinnamomi from stockpiles and bunds. We can now implement different management strategies to the construction of bunds and stockpiles to facilitate eradication. Infestation by Phytophthora cinnamomi results in large financial and management constraints to environmental managers. This pathogen was considered impossible to eradicate until recent success with treatments including host removal, herbicide and fungicide application, soil fumigation and physical root barriers. We investigated the most benign of these treatments; keeping the area devoid of living host material. In a Western Australian mine site within a Mediterranean climate, haul roads, stockpiles and roadside bunds had P. cinnamomi colonised Pinus stem plugs buried at multiple depths. Over time, we examined the effects of soil moisture and temperature in different soil conditions and types to compare the recovery of the pathogen. Results: Within 12 months, the pathogen could not be recovered from the haul roads. In the stockpiles, depth produced significantly different results. In 3 of the 4 sites, the pathogen was not recovered at 10 cm after 20 months. By 12 months, at 50 cm, there was an 80% reduction in recovery, but only one stockpile had no recovery from 50 cm, which occurred by 36 months. Bunds were up to 1.75 m high and had variable results for plugs buried at 30 cm, influenced by height, the types of soils and shading. One of the smallest bunds was the only bund where the pathogen was not recoverable (by 22 months). This study provides strong support for using a fallow period to reduce or eliminate P. cinnamomi inoculum.

Tissue-autonomous phenylpropanoid production is essential for establishment of root barriers

ABSTRACTPlants deposit polymeric barriers in their root cell walls to protect against external stress and facilitate selective nutrient uptake. The compounds that make up these barriers originate from the fatty acid- and phenylpropanoid biosynthetic pathways. Although the machinery responsible for production of the barrier constituents is well-char-acterized, our pathway models lack spatiotemporal resolution – especially in roots - and the source tissue is often not clear due to the apoplastic nature of barriers. Insights into how the individual root tissues or cells contribute to forming apoplastic barriers is important for elucidation of their ultrastructure, function and development. Manipulation of the associated biosynthesis is delicate, as mutants often display pleiotropic phenotypes due to the broad role of the underlying metabolites. Here, we address these issues by creating a genetic tool that allows in vivo repression of the phenylpropanoid pathway with both spatial and temporal control. We provide strong evidence that tissue-auton-omous production of phenylpropanoids is essential for establishment of the endodermal Casparian strip. Moreover, we find that in order to maintain deposition and attachment of a coherent suberin matrix to the cell wall, cells require continuous production of aromatic constituents. This process is especially crucial in the suberized endodermis where we find that repression of phenylpropanoid production leads to active removal of suberin.

The intersection of nitrogen nutrition and water use in plants: new paths toward improved crop productivity

Water and nitrogen availability limit crop productivity globally more than most other environmental factors. Plant availability of macronutrients such as nitrate is, to a large extent, regulated by the amount of water available in the soil, and, during drought episodes, crops can become simultaneously water and nitrogen limited. In this review, we explore the intricate relationship between water and nitrogen transport in plants, from transpiration-driven mass flow in the soil to uptake by roots via membrane transporters and channels and transport to aerial organs. We discuss the roles of root architecture and of suberized hydrophobic root barriers governing apoplastic water and nitrogen movement into the vascular system. We also highlight the need to identify the signalling cascades regulating water and nitrogen transport, as well as the need for targeted physiological analyses of plant traits influencing water and nitrogen uptake. We further advocate for incorporation of new phenotyping technologies, breeding strategies, and agronomic practices to improve crop yield in water- and nitrogen-limited production systems.

When Green Infrastructure Turns Grey: Implications of Overdesign for Plant Water Stress

Overdesign is a common strategy used by green infrastructure (GI) designers to account for unexpected performance loss, but such a strategy can create undesirable plant responses if it decreases water availability. The seasonal and event-based stomatal conductance data of two woody plant species in a green infrastructure (GI) was analyzed. The GI is a tree trench composed of five tree pits (each one was planted with a tree) in an infiltration bed. Runoff collected from the street was supplied to the bottom of the infiltration bed, although the system never filled completely indicating there was capacity for more runoff than what was observed over 3 years and the infiltration bed was overdesigned. Between the two tree species, evidence suggested that the root system of London plane spread beyond the boundary of the GI system and reached a subsurface water source, while that of hybrid maple did not. London plane showed a slower response to water added in the tree pit soil, which can indicate the reduced dependence on GI soil water after plants have reached an alternative water source. Such reduction is not favored because it defeats the purpose of having plants in GI systems. Designs using root barriers, appropriate plant species selection, etc. are recommended to avoid unwanted root spread. This study also found that GI design relying on upward water movements should be avoided because such design creates a narrow capillary zone on top of a saturated zone, which does not encourage transpiration.

Pursuing Supply Chain Integration

Although supply chain (SC) integration is well discussed in literature, there is a missing link in its multi-faceted nature, in terms of implementation, at the empirical level. Existing empirical research focus has largely been on examining the impact of SC integration (SCI) on business performance while other issues such as barriers and enablers of SCI have mostly been conceptual. This study was thus set to examine the manner in which firms pursue integration; and how resources, competences, experience, and industry-type influence this course. Using questionnaires, data were collected from 117 service and manufacturing firms operating in the Ashanti Region of Ghana. The contribution of this study lies in its ability to critically examine how SCI is pursued and providing validations to the root barriers/enablers of SCI from a contextual standpoint. The findings of the study do not only fill the void in literature but also offer invaluable directions to practitioners and researchers.