Responses of seminal wheat seedling roots to soil water deficits.

The aims of this paper are to develop our understanding of the ways by which soil water deficits influence early wheat root growth responses, particularly how seminal roots respond to soil drying and the extent to which information on differences in soil water content are conveyed to the shoot and their impact on shoot behaviour. To achieve this, wheat seedlings have been grown, individually for around 25 days after germination in segmented soil columns within vertical plastic compartments. Roots were exposed to different soil volumetric moisture contents (SVMC) within the two compartments.

Expression of Fragaria vesca PIP aquaporins in response to drought stress: PIP down-regulation correlates with the decline in substrate moisture content.

PIP aquaporin responses to drought stress can vary considerably depending on the isoform, tissue, species or level of stress; however, a general down-regulation of these genes is thought to help reduce water loss and prevent backflow of water to the drying soil. It has been suggested therefore, that it may be necessary for the plant to limit aquaporin production during drought stress, but it is unknown whether aquaporin down-regulation is gradual or triggered by a particular intensity of the stress. In this study, ten Fragaria PIP genes were identified from the woodland strawberry (Fragaria vesca L.

Contributions of roots and rootstocks to sustainable, intensified crop production.

Sustainable intensification is seen as the main route for meeting the world's increasing demands for food and fibre. As demands mount for greater efficiency in the use of resources to achieve this goal, so the focus on roots and rootstocks and their role in acquiring water and nutrients, and overcoming pests and pathogens, is increasing. The purpose of this review is to explore some of the ways in which understanding root systems and their interactions with soils could contribute to the development of more sustainable systems of intensive production.

Hydraulic conductivity and PAT determine hierarchical resource partitioning and ramet development along Fragaria stolons.

Co-ordination of metabolic and physiological activity between plant parts is key to the control of growth and development. Here the movement of resources and their allocation between mother plants and daughter ramets along Fragaria stolons was quantified with respect to hierarchy. Gradients of internodal ramet leaf water potential (ψ) and stolon and ramet hydraulic conductivities (L) were measured together with apparent stolon IAA movement via the polar auxin transport pathway (PAT).

Root signals and stomatal closure in relation to photosynthesis, chlorophyll a fluorescence and adventitious rooting of flooded tomato plants.

Background And Aims: An investigation was carried out to determine whether stomatal closure in flooded tomato plants (Solanum lycopersicum) results from decreased leaf water potentials (psi(L)), decreased photosynthetic capacity and attendant increases in internal CO(2) (C(i)) or from losses of root function such as cytokinin and gibberellin export.

Methods: Pot-grown plants were flooded when 1 month old. Leaf conductance was measured by diffusion porometry, the efficiency of photosystem II (PSII) was estimated by fluorimetry, and infrared gas analysis was used to determine C(i) and related parameters.

Anti-transpirant activity in xylem sap from flooded tomato (Lycopersicon esculentum Mill.) plants is not due to pH-mediated redistributions of root- or shoot-sourced ABA.

In flooded soils, the rapid effects of decreasing oxygen availability on root metabolic activity are likely to generate many potential chemical signals that may impact on stomatal apertures. Detached leaf transpiration tests showed that filtered xylem sap, collected at realistic flow rates from plants flooded for 2 h and 4 h, contained one or more factors that reduced stomatal apertures. The closure could not be attributed to increased root output of the glucose ester of abscisic acid (ABA-GE), since concentrations and deliveries of ABA conjugates were unaffected by soil flooding.

The role of polar auxin transport through pedicels of Prunus avium L. in relation to fruit development and retention.

It was investigated whether premature fruit abscission in Prunus avium L. was triggered by a reduction in polar auxin transport (PAT). The capacity of pedicels to transport tritiated IAA ([3H]-IAA) via the PAT pathway was measured at intervals throughout flower and fruit development.