Elevated atmospheric CO₂ concentrations ([CO₂]) will affect the metabolism of tropical forests worldwide; however, critical aspects of the response largely remain unknown. Here, we review the current state of knowledge, aiming to provide a framework that can guide future experimental research. Tropical forest CO₂ enrichment experiments are urgently needed to test predictions of tropical forest functioning as atmospheric [CO₂] rises.

Salinity and drought are increasing problems that humanity will face during the 21st century because of climate change. Halophytes can live in soils with a high concentration of salt, and deploy a range of responses to salinity that confers on them more tolerance to salt than seen in glycophytes. Induction of an antioxidant defence system is one of these responses. The antioxidant defence system protects plants against reactive oxygen species and regulates their level for stress signalling. An understanding of these mechanisms in halophytes may provide information for increasing stress tolerance of crop plants.

Soil salinity is one of the most important environmental factors that reduce crop yields in agriculture and limit plant distribution in nature. In this review, we discuss evidence supporting a functional role of soluble carbohydrates in salt tolerance mechanisms, although their ecological relevance remains largely unknown. We propose that more effort should be invested in field studies of salt-tolerant plants, as a complement to more common experimental approaches based on the analysis of salt-sensitive models under artificial laboratory conditions.

The relationship between water loss in leaves and in floral buds in Brassica species has rarely been studied. The different responses of the leaf and bud in B. rapa has demonstrated a ‘self-adjustment’ mechanism in which the floral bud maintains stomatal function longer into a drying cycle than the leaf. The study suggests that bud temperature may be a useful indicator of drought tolerance in B. rapa.

This study assessed changes in the senescence of wheat plants treated with different fungicidal compounds using innovative sensor methods. Senescence-associated changes (degradation of photosynthetic pigments, photosynthetic activity, leaf reflectance and transpiration of plant tissue) were detected using ground-based optical sensors earlier than with destructive and visual methods. Noninvasive sensors and imaging techniques are an excellent alternative to traditional screening methods for assessing the side-effects of fungicides on plant physiology.

Divergent responses of coexisting species to short- and long-term climatic conditions may be significant in diverse floras, particularly those occurring in highly pulse-driven environments. Our aim was to test the efficacy of miniature external sapflow gauges for capturing physiological response of diverse coexisting functional types, including small monocotyledonous species. Our data show that the gauges approximate measures of transpiration well and that they will allow important fundamental ecophysiological questions to be investigated in future studies.

The carbohydrate availability of a developing grapevine shoot has a direct influence on shoot architecture and leaf development. The initial rate of shoot growth will determine its ability to develop adequate leaf area, which is required for growth. An estimation of the carbohydrates present in a cane or shoot can be determined by using the shoot’s or cane’s cross-sectional area, or by using the total leaf area of the shoot.

Climate change is currently driving important wheat yield decreases worldwide as a result of dryer and warmer conditions. In this study we investigated the impacts of different day and night warming scenarios on key yield-determining traits directly related to the plant’s water use in order to identify potentially tolerant cultivars and the underlying tolerance strategies among a panel of 11 breeding and commercial bread and durum wheat lines. Large variability among cultivars was found, indicating common responses and also different coping strategies that could help in breeding next-generation cultivars adapted to warmer climates.

In arid regions, high NaCl levels in the aquifers, and wastewater contaminated with boron have adverse effects on crops. We determined the water transport and membrane integrity of two broccoli cultivars in response to NaCl–B interaction with aquaporin involvement. An antagonistic effect of the NaCl–B interaction was observed in cv. Naxos through changes in the root hydraulic conductivity and biomass restoration, making Naxos appropriate for saline–boron irrigation.

Surprisingly little is known about the effects of salt stress upon seeds given their pivotal role in plant reproduction and dispersal. This review provides information on redox control in seeds, detoxification mechanisms and tolerance in relation to seed metabolism and performance. Implications of redox control in seeds on the physiological, biochemical and molecular level are discussed; the review concludes with a perspective on future research in relation to salt stress and seed biology.

In contaminated estuaries, halophytes can be subjected to high levels of metal contamination that inevitably affect their metabolism, namely, their anti-oxidant systems. Considering the more abundant halophyte species in Tagus estuary salt marshes, Spartina maritima proved to be potentially efficient biomonitor species. Also its enzymatic anti-oxidant system revealed a substantial increase of activity under contaminated conditions. Considering this, Spartina maritima and its anti-oxidant enzymatic defences arise as potential biomonitor species and biomarker for heavy metal contamination studies.

Proteome studies can provide important insights into plant responses to salinity stress since proteins are directly involved in mechanisms of stress response and tolerance acquisition. In this review, recent knowledge of proteome response to salinity is summarised with a focus on comparative studies revealing similarities and differences between related plant species with contrasting salinity tolerance – glycophytes and halophytes. The contribution of proteomic studies to a complex picture of plant salinity response is discussed.

Plant-inhabiting micro-organisms have a crucial impact on plant growth and health. Specialised bacterial and fungal communities live inside and on the surface of halophytes and may significantly contribute to the salt tolerance of their host. This review analyses the opportunity that the native microbial world offers crop plants to enlarge their growing space into salt affected areas.

Crops, especially sorghum, are vulnerable to dry periods during the growing season that can result in yield loss. Alteration of the hydraulic conductance in the plant offers the possibility for regulated water loss from the crop to minimize the impact of drought. The results of this study with two sorghum varieties showed differences in hydraulic characteristics and that this trait does indeed offer the possibility for improving crop water use and increased yields.

Examination of the variation of Arabidopsis thaliana from diverse locations has led to breakthroughs in understanding genes that control many important traits. Until now, the variation in A. thaliana wood properties was unknown; our assessment of 12 accessions shows that significant variation exists in wood-like growth characteristics, proportions of cell wall components and biomechanics. This hints that large-scale studies will yield genes that are important to wood formation and properties.

The role of ethylene in controlling the development of nonclimacteric fruit is unclear. Application experiments using an ethylene-releasing compound and an ethylene biosynthesis inhibitor, as well as changes in expression of ethylene biosynthesis and perception genes, provide evidence for the complex involvement of ethylene in grape berry ripening. The ripening-altering properties of ethylene could benefit the wine industries in the face of environmental changes due to climate change.

Soil salinity is a major factor limiting plant productivity. A small group of plants – termed halophytes – are able to grow in saline soils. Here, the knowledge of the adaptation mechanisms of the halophytes is reviewed.

In boron-toxic soils, boron accumulates in the leaves of wheat and barley, causing leaf necrosis. Although progress has been made towards identifying the mechanisms and genes responsible for limiting boron’s entry into plants, it is unclear why some tolerant plants develop fewer toxicity symptoms. We show that the symptoms of germanium toxicity mimic those of boron toxicity. Germanium may be used to dissect the genetic control of symptom development.

Some stem-succulent halophytes inhabit areas of very high salinity, such as inland salt lakes. Tolerance and physiological responses to extreme salinity (2000 mM NaCl) were evaluated for two Tecticornia species; both were highly tolerant. Growth patterns of halophytic species on the margins of salt lakes are likely influenced both by soil salinity and water availability (periodic floods and water deficits).

Owing to global climate change, salt-tolerant plants are more and more important due to their natural stress tolerance. Their potential as sources of valuable and so far unknown compounds is largely unexploited and needs to be investigated in detail. Our overview identifies open research questions and gives suggestions for future applications of secondary compounds of halophytes.

In an attempt to develop Aster tripolium L. as a halophyte vegetable for saline irrigation on dune sand, it was observed that sequential harvesting resulted in leaf chlorosis, yield reduction, reduced nitrate reductase activity (NRA) and enhanced nitrate concentration. Application of suitable Fe-chelates restored leaf colour, NRA and nitrate content indicating that NRA can be an indicator for iron deficiency in A. tripolium.

In this work the metal concentration in three plants species (Scirpus maritimus, Spartina maritima and Zostera noltii) of the Mondego Estuary was analysed. Analysing the concentration of metals in the aboveground and belowground organs and in the sediment was possible conclude that the Mondego Estuary as a low contaminated system could act as a source of metals for nearly systems.

Heavy metal pollution is a major environmental problem that is rapidly gaining importance due to its impact on human health through the food chain. Phytoremediation is considered an effective, low cost, preferred cleanup option for moderately contaminated areas. In this context, the available literature on heavy metal bioaccumulation by Spartina sp. was compiled and compared.

Grape flavour management requires knowledge of the derivation of individual aroma characteristics, the main constituents of which are terpenoids. Information about the expression patterns of the genes that are responsible for terpenoid biosynthesis is important. The genes identified in this study on terpene synthase gene transcript profiling in different tissues of two aromatic grapevine varieties will be of interest to viticulturists to improve decision making along the chain of production.

Nowadays understanding of plants drought tolerance mechanisms is a major challenge for plant biologists. To overcome deficiency of classical methods for further progress, we used a proteomics technique to uncover molecular mechanisms of drought tolerance in sunflower and found that modulating energy usage, water transport and activation of defence system could improve sunflower productivity under drought condition. Development of transgenic plants with increased abundance of the involved proteins could help to increase of vegetative oil production in future.

The usefulness of non-carbon stable isotope abundances in dry matter as phenotypic tools for selecting plants better adapted to stress remains inconclusive. This study shows for wheat under Mediterranean conditions that carbon followed by nitrogen isotope abundances exhibited useful characteristics, whereas oxygen isotope abundance performed poorly by comparison. The advantages and limitations of the combined use of these isotopes are discussed.

Early vigour and drought tolerance are crucial to increase and stabilise rice yield. We explored the genetic diversity of japonica rice under drought for traits related to early vigour, hydraulic processes and water use. Our results suggested a negative linkage between early vigour and its maintenance under drought. The limits and opportunities for improving drought tolerance in rice without affecting early vigour are discussed.

Vegetable grafting is currently adopted for improving plant responses to environmental stresses, such as salinity. Melon scions are generally grafted on interspecific rootstocks. In this study, the different components of salinity stress (osmotic stress, ion toxicity and nutritional imbalance) are addressed in nongrafted, self-grafted and interspecific graftings. Grafting per se improved plant water status, whereas the interspecific rootstock is responsible for reduced ion toxicity and nutritional imbalance.

When a gymnosperm grows on an incline, special tissue referred to as ‘compression wood’ forms on the lower side of the stem to restore the stem’s vertical orientation. We observed the posture recovery and stem anatomy of saplings grown on an incline and examined the expression of laccase, which plays a significant role in the formation of compression wood. Based on the results, mechanisms of posture control in gymnosperm trees are suggested.

Plants have adapted to life in saline environments in a myriad of ways, some more broadly successful than others. These adaptations involve the integration of all activities at levels ranging from genes to physiology to life cycles. With the availability of new ‘-omic’ resources, the tools of systems biology and perhaps forgotten tools of physiology and biophysics, we may now be poised to decipher the complexities of the integration of organismal activities as never before.

The mechanism of salinity tolerance in halophytes is a key in developing salt tolerant crops. To establish the role of Na⁺ in salinity tolerance of Aeluropus lagopoides we report here that salinity reduce growth, enhance Na⁺ secretion and gene expression of V-NHX and PM-NHX through regulating Na⁺. Our data provide evidence for the support of the role of Na⁺ in managing growth under saline conditions.

Microsatellites (also called simple repeat sequences) are not ‘junk’ DNA with no function but a ‘jewel’ in plant genomes. We investigated the regularity of generation, evolution and decay of microsatellites, and the relationships among physical structure, variation and functionality of microsatellites. The phenotypic effects of plant microsatellites will increase our understanding of the functionality of repetitive sequences.

Salinity and waterlogging (oxygen deficiency around the roots) are plant stresses that often occur together on saltland. This combination of stresses impacts on plant growth by decreasing the concentration of potassium and increasing the concentrations of sodium and chloride in shoots. The synchronicity between these changes in ion concentrations has important implications for our understanding of the mechanisms of ion regulation in plants.