In arid lands many trees develop broad crowns that affect many ecological interactions, but how that form is acquired is unresolved. We measured crown shape and carbon isotope ratios. We found that upper branches suffered more water stress than laterally spreading branches, and that lower branches were affected by self-shading. When lower and upper branches are stressed, lateral spreading at middle crown become the best alternative for growth. These results advance our understanding of crown development in trees.

Pseudomonas syringae pv. actinidiae (Psa) the causal agent of bacterial canker of kiwifruit, has become a worldwide threat for the kiwifruit industry. In this work, we show that Psa can be detected at early stages of infection both at leaf and canopy scale using infrared thermography. At leaf scale, this method will be able to assist fundamental research of infection mechanisms; at canopy scale, the method could be used to identify regions of Psa-infection to be pruned out to prevent further devastating spread of the disease.

For enhancing precision and efficiency in chickpea breeding especially for drought tolerance, large-scale genomic resources have been developed. These resources together with genetics and physiological approaches facilitated dissecting complex phenomenon of drought tolerance. Marker-assisted backcrossing has generated several lines with enhanced yield under rained conditions. Such advances have made it possible to deploy genomics-assisted breeding for drought tolerance in chickpea.

Trade-offs between crop yield and water productivity (WP; yield divided by water use) are important in water-limited situations. Genetic improvement for WP generally has yield trade-offs, whereas management measures devised to improve WP tend to enhance yield as well. In contrast to the behaviour of the major herbaceous crops, WP increases in woody crops in response to water stress, facilitating the application of deficit irrigation strategies.

Salinity is one of the major stresses that limits crop production worldwide and affects most physiological activities in plants. An experiment was undertaken to determine genetic variability in Medicago truncatula, and to identify quantitative trait loci (QTLs). Nineteen QTLs were identified under 100 mm salt stress conditions. The results should be helpful information for further functional analysis of salt tolerance in M. truncatula.

Improving the ratio of biomass produced to water transpired is one way to improve water productivity, which is necessary to increase production to feed 9.6 billion by 2050. The study aimed to understand the genetic basis of the transpiration ratio (A : E), and the genetic and physiological determinants of water use in sorghum. Favourable alleles for A : E traits related to preflowering drought tolerance along with stay-green may help develop more drought-tolerant sorghum cultivars.

Droughts are often accompanied by rising temperatures, severely affecting seed filling. The effects of these stresses, individually or combined, on biochemical processes related to seed filling was investigated in chickpea genotypes having contrasting sensitivity to heat and drought stress. Leaf photosynthetic function and sucrose metabolism in seeds were severely disrupted, especially by combined stress, resulting in reductions in seed weight and yield. A drought-tolerant genotype appeared to have partial cross-tolerance to heat stress.

Epidermal pavement cells appear with a fascinating irregular wavy shape in the Arabidopsis thaliana leaf. This review addresses the possible biomechanical benefits of this cell shape over other organisations as well as the biomechanical accomplishment of shape and refers to the cell wall and cytoskeletal involvement herein. A current model for pavement cell development integrating genetic and biochemical regulatory pathways is discussed, but remaining questions and pitfalls are put forward.

We examined the effects of a genetic factor (an introgression segment) and an environmental factor (heat) on grain filling in wheat. Both factors accelerated senescence and affected grain protein, but only the heat treatment reduced grain size.

Sucrose production, transport and utilisation are central processes determining crop yield. Their relative quantitative contributions (limitations) to yield are a core plank to direct strategies for crop improvement. Using published responses of a selection of crop species to elevated carbon dioxide concentrations, our analysis demonstrates that numbers in particular and, to a lesser extent potential sizes, of harvested organs are sucrose production/transport (i.e. supply) limited whereas filling these organs is sucrose utilisation limited. These conditions apply across a range of harvested organ types including storage stems and roots, fleshy fruits, grains and tubers.

As roots take up water and the soil dries, water depletion is expected to occur near the root surface, ultimately limiting root water uptake. By exuding mucilage, a gel that can hold much water, roots keep the soil in their vicinity wet and can better extract water from dry soils. Mucilage exudation seems to be an optimal plant trait that favours the capture of water during drought.

Coffee productivity and survival are posed at risk by ongoing climate changes. Leaf hydraulic capacity and drought vulnerability are key functional traits influencing plant performance under drought stress conditions. Coffee genotypes with small leaves and high vein length per unit leaf area displayed higher leaf hydraulic efficiency, gas exchange rates and resistance to drought-induced hydraulic dysfunction, with respect to large-leaf cultivars.

The amount of water lost by crops during the night through transpiration can represent a substantial fraction of the daytime water loss, but no efforts have been made to identify possible drought tolerance strategies resulting from such responses. Here we report substantial cultivar-dependent night-time transpirational water losses in wheat, which are dependent on nocturnal evaporative conditions and are strongly related to daytime water loss. These findings open new possibilities for breeding drought-tolerant cultivars based on night-time water use.

Saving and sustaining productivity of rice under water limited is essential to feed the growing population. Better water acquisition coupled with higher cellular level tolerance maintained significantly higher spikelet fertility and thus emphasised the relevance of combining these for improving field level tolerance of rice to water limitation. Such lines can be exploited in breeding to develop superior trait pyramided cultivars. Aerobic cultivation of rice saves water but reduced spikelet fertility causes significant yield loss. We demonstrated that superior roots traits when combined with higher cellular level tolerance maintained higher spikelet fertility and yield. The identified trait donor genotypes can be exploited to develop trait pyramided aerobic cultivation worthy cultivars.

In plants, specialised systems for O₂ delivery as in animals are lacking. Plant cells are thus frequently challenged with limited oxygen supply. Under illumination, bark and woody tissue photosynthesis rapidly increased plant internal oxygen concentrations and thereby counteracted localised oxygen deficiency (hypoxia). Beneath its role in plant carbon economy, bark and woody tissue photosynthesis may also be important for preventing low-oxygen limitations of respiration in these dense and metabolically active tissues.

Lowland rice grows in flooded soils which often have low redox potential and high soluble iron (Fe²⁺), so the effects of Fe²⁺ concentrations on growth, root porosity and barrier to radial oxygen loss induction were assessed in aerobic and in stagnant conditions. High Fe²⁺ (0.72 mM) resulted in increased porosity and barrier induction in roots of rice in aerated conditions, whereas in stagnant conditions these root aeration traits were already induced even without addition of high Fe²⁺. Barrier induction and root aeration would contribute to Fe²⁺ tolerance in rice.

Sorghum plants store sugar in their stems, besides yielding grain, making it an attractive crop for food and biofuel production. The role of stem sugar accumulation in helping plants cope with drought has been investigated. Stems serve as independent sinks for photoassimilates in addition to the panicle in some genotypes; in others, the stored stem sugars appear to be mobilised to the panicle to augment grain yields in drought-stressed plants.

This Perspective paper inquires why, after 20 years of extensive research into the genomics of drought resistance, there are hardly any transgenic genetically modified drought-resistant crop cultivar on the market to date. An important reason is that often, the drought stress simulations and testing methods used in genomics are at fault. Guidelines for relevant drought stress physiological methods in genomics are suggested.

High irrigation volumes applied to the wet part of the root system are critical to successfully implement partial root zone drying irrigation (PRI) to improve vine performance compared to regulated deficit irrigation under semiarid conditions. Physiological responses induced by PRI were due to both the placement of irrigation and the volume of water. Thresholds and optima of soil water content in wet and dry root zones were established.

The ecophysiological behaviour of grapevine cultivars in response to drought is influenced by the soil conditions and by the plant genotype. These two components interact through a complex of hydraulic and hormonal signal exchanges occurring between roots and leaves. Our work highlights the differences in these signals observed in a near-isohydric and a near-anisohydric grapevine cultivars on two soil substrates with different textures, causing different dynamics of water deprivation during an imposed increasing water stress.

Salinity is a growing problem worldwide that causes a significant reduction in crop yields. We have addressed this problem by manipulating the programmed cell death pathways in rice, resulting in enhanced salt stress tolerance. The implication is that farmers could grow rice containing such a trait in environments where salinisation of the soil exists, thereby addressing food security needs.