Can a plant physiologist be considered a naturalist?

Abstract not availabl

Efficiency of water usage in plants

La disponibilidad de agua es el principal factor limitante de la producción agrícola y ganadera en ambientes de clima mediterráneo. Limitación que, ante las previsiones de Cambio Climático Global realizadas por organismo internacionales, serán mucho mayores en los próximos años. En este escenario, la eficiencia en el uso de los recursos hídricos debe ser un aspecto transversal de las políticas públicas que debe, por tanto, ser afrontado desde diversos puntos de vista. En este sentido, uno de los temas claves a considerar es la eficiencia con la que las plantas usan el agua. El objetivo de este trabajo es hacer una revisión de los diferentes aspectos relacionados con este tema, considerando las diferentes escalas a las que se estudia la eficiencia en el uso del agua por las plantas (EUA), desde la hoja hasta el cultivo o el ecosistema. Así, se abordan las dificultades técnicas que existen para medir, de una forma precisa, la EUA de un cultivo o de un ecosistema, la importancia del ambiente y de las prácticas agronómicas como determinantes de la EUA, la diversidad genética inter e intraespecífica, y las implicaciones prácticas de estos factores a la hora de incrementar la EUA.Water availability is the most important limiting factor in plant and animal production under Mediterranean conditions. In a Global Climate Change scenario, this limitation will be even greater in the following years, according to the International Institutions predictions. In this sense, the efficiency of water resources utilization should be a key point of public policies that must be discussed from different points of view. One of these is Plant Water Use Efficiency (WUE). The objective of this paper is to review the different aspects related to WUE, considering the approach levels, from leaf to crop or ecosystem. The technical difficulties to measure accurately WUE at crop or ecosystem level, the environment and agronomical practices importance in WUE determination, the inter and intraspecific plant genetic diversity, as well as the practical implications of each factor to increase WUE are discussed.Los trabajos realizados por el Grup de Biologia de les plantes en condicions mediterrànies sobre eficiencia en el uso del agua forman parte de los proyectos: PRIB-2004-10144, financiado por el Govern de les Illes Balears, e INCO-PERMED (PL 509140), financiado por la Unión Europea

Decreased levels of Thioredoxin o1 influences stomatal development and aperture but not Photosynthesis under non-stress and saline conditions

Salinity has a negative impact on plant growth, with photosynthesis being downregulated partially due to osmotic effect and enhanced cellular oxidation. Redox signaling contributes to the plant response playing thioredoxins (TRXs) a central role. In this work we explore the potential contribution of Arabidopsis TRXo1 to the photosynthetic response under salinity analyzing Arabidopsis wild-type (WT) and two Attrxo1 mutant lines in their growth under short photoperiod and higher light intensity than previous reported works. Stomatal development and apertures and the antioxidant, hormonal and metabolic acclimation are also analyzed. In control conditions mutant plants displayed less and larger developed stomata and higher pore size which could underlie their higher stomatal conductance, without being affected in other photosynthetic parameters. Under salinity, all genotypes displayed a general decrease in photosynthesis and the oxidative status in the Attrxo1 mutant lines was altered, with higher levels of H2O2 and NO but also higher ascorbate/glutathione (ASC/GSH) redox states than WT plants. Finally, sugar changes and increases in abscisic acid (ABA) and NO may be involved in the observed higher stomatal response of the TRXo1-altered plants. Therefore, the lack of AtTRXo1 affected stomata development and opening and the mutants modulate their antioxidant, metabolic and hormonal responses to optimize their adaptation to salinity.info:eu-repo/semantics/publishedVersio

The Use of a Tomato Landrace as Rootstock Improves the Response of Commercial Tomato under Water Deficit Conditions

Grafting onto drought tolerant rootstocks has been proposed as a useful strategy to overcome future water scarcity periods. The ‘de Ramellet’ tomato is a drought tolerant landrace selected under semiarid Mediterranean summer conditions under rain-fed or low irrigation. In this manuscript, the responses of a commercial hybrid ‘de Ramellet’ genotype grafted onto a traditional ‘de Ramellet’ (RL) and a commercial Maxifort (Mx) tomato rootstocks under commercial greenhouse conditions are studied. Non-grafted (NON) and self-grafted (SELF) plants were used as controls. Two water regimes were established: well-watered (WW, covering plant water demands) and water deficit (WD, reducing 50% irrigation as compared to WW). The results confirm an improvement in agronomic performance of Mx as compared to NON, but also show a similar improving effect of RL. Grafting enhanced plant growth regardless of the rootstock under WW conditions. Similarly, water-use efficiency (assessed as leaf carbon isotope composition) increased in grafted plants under WD treatment as compared to NON. Despite the lack of significant differences, RL tended to promote higher fruit production and fruit number than Mx, irrespective of the water treatment, whereas RL was the single graft combination with higher fruit production than NON under WD. In conclusion, the results uncover the potential of drought-adapted landraces to be used as rootstocks in order to increase plant growth and fruit production under both well-watered and water deficit cultivation conditions

Stomatal conductance is the main limitation to photosynthesis in sugar beet plants treated with Zn excess

4 Pag., 2 Tabl., 1 Fig.The effects of high Zn concentrations in growth and photosynthetic parameters of sugar beet (Beta vulgaris L.) plants grown in hydroponics were investigated. Zinc toxicity (100 and 300 μM) resulted in large reductions in biomass accumulation (>50%) and photosynthetic rates (40-50%). It was known that high Zn concentrations usually lead to decreases in net photosynthesis, but the effects of excess Zn on each of the possible factors limiting photosynthesis, including photochemistry, stomatal conductance and mesophyll conductance, had not been studied in detail until now. Leaf photochemistry was not affected by Zn, and reduced photosynthesis was due mostly to marked decreases in stomatal conductance, whereas mesophyll conductance decreased to a lower extent. Stomata were study using scanning electron microscopy (SEM) and large structural differences were observed in stomatal frequency, size and shape between 300 μM Zn and control plants. In high Zn plants stomatal density was lower than in the controls, and stomata were smaller and had a more rounded shape than those present in control plants. The presence of these morphological changes could be associated to the reductions in photosynthetic rates under excess Zn.Work supported by the Spanish Ministry of Science and Innovation (projects AGL2007-61948 and BFU2008-01072/BFI). R.S. was supported by an I3P-CSIC predoctoral fellowship.Peer reviewe