See also the Commentary on this article by McGrath, 226: 1225–1227.

Salinity aggravates B toxicity symptoms in several plant species. In the present study the interactive effects of B toxicity and salinity stresses on the subcellular distribution of boron, cations and proteins in basal and apical leaf sections of wheat were investigated. High B supply increased total B concentrations in all leaf parts, but values remained below 25 mg B kg⁻¹ dry weight (DW) in basal sections, whereas they reached more than 600 mg B kg⁻¹ DW in leaf tips. In basal leaf sections intercellular soluble B concentrations closely reflected the external supply, whereas intracellular soluble B concentrations remained lower by a factor of two, indicating some retention of excess B in the apoplast. Combined salinity and B toxicity stresses significantly increased soluble B concentrations in inter‐ and intracellular compartments of basal leaf sections in comparison with either stress alone, probably related to salinity‐induced changes in water status. The combined stresses also induced quantitative and qualitative changes in inter‐, but not intracellular protein composition. Most obvious was the induction of a 25 kDa protein and an increase in amount of a 33 kDa protein. It is suggested that these changes might be due to structural modifications of the cell wall. The concentration of soluble boron in cells is proposed to be an indicator of boron toxicity.

Boron deficiency symptoms point to a role for boron in plant membranes, but the molecular partners interacting with boron have not yet been identified. The objective of the present study was to isolate and identify membrane-associated proteins with an ability to interact with boron. Boron-interacting proteins were isolated from root microsomal preparations of arabidopsis (Arabidopsis thaliana) and maize (Zea mays) using phenylboronate affinity chromatography, subsequently separated by two-dimensional gel electrophoresis and identified using MALDI-TOF (matrix-assisted laser desorption ionization-time of flight) peptide mass fingerprinting. Twenty-six boron-binding membrane-associated proteins were identified in A. thaliana, and nine in Z. mays roots. Additional uniden-tified proteins were also present. Common to both species were the β-subunit of mitochondrial ATP synthase, several β-glucosidases, a luminal-binding protein and fructose bisphosphate aldolase. In A. thaliana, binding of these proteins to boron was significantly reduced after 4 d of boron deprivation. The relatively high number of diverse proteins identified as boron interacting, many of which are usually enriched in membrane microdomains, supports the hypothesis that boron plays a role in plant membranes by cross-linking glycoproteins, and may be involved in their recruitment to membrane microdomains.

The search for approaches to a holistic sustainable agriculture requires the development of new cropping systems that provide additional ecosystem services beyond biomass supply for food, feed, material, and energy use. The reduction of chemical synthetic plant protection products is a key instrument to protect vulnerable natural resources such as groundwater and biodiversity. Together with an optimal use of mineral fertilizer, agroecological practices, and precision agriculture technologies, a complete elimination of chemical synthetic plant protection in mineral-ecological cropping systems (MECSs) may not only improve the environmental performance of agroecosystems, but also ensure their yield performance. Therefore, the development of MECSs aims to improve the overall ecosystem services of agricultural landscapes by (i) improving the provision of regulating ecosystem services compared to conventional cropping systems and (ii) improving the supply of provisioning ecosystem services compared to organic cropping systems. In the present review, all relevant research levels and aspects of this new farming concept are outlined and discussed based on a comprehensive literature review and the ongoing research project “Agriculture 4.0 without Chemical-Synthetic Plant Protection”.

The main objective of this work was to provide the chronology of physiological and metabolic alterations occurring under drought and demonstrate how these relate to a phenotypic approach (infrared thermal imaging, IRT). This should provide tools to tailor phenotyping approaches for drought tolerance and underlying metabolic alterations. In the present study, destructive analysis of growth and cell morphology, water status, osmotic adjustment, metabolic changes and membrane damage were combined with non-destructive determination of leaf temperature using infrared thermography (IRT) in 6-week-old sugar beets subjected to progressive drought stress and subsequent rewatering. Different methods were suitable for the characterisation of the dynamic development of distinct stress phases: although IRT allowed detection of initial impairment of transpiration within 1 day of drought stress, destructive methods allowed us to distinguish a phase of metabolic adjustment including redirection of carbon flow into protective mechanisms and a subsequent phase of membrane destabilisation and cellular damage. Only the combination of invasive and non-invasive methods allowed for the differentiation of the complete sequence of physiological changes induced by drought stress. This could be especially beneficial for the selection of phenotypes that are adapted to early drought. During rewatering, sugar beet shoots rapidly re-established water relations, but membrane damage and partial stomatal closure persisted longer, which could have an impact on subsequent stress events. During the onset of secondary growth, taproots required more time to recover the water status and to readjust primary metabolites than shoots.