Stomatal abundance and distribution in Prosopis strombulifera plants growing under different Iso-Osmotic salt

Changes in several environmental parameters are thought to affect stomatal development. Under salt stress, plants can regulate their transpiration flux through a better control of the stomatal opening (as a short-term response) and through modifications of leaf anatomy (as a long-term response). We investigate how leaf micromorphology (stomatal abundance and distribution) of the halophyte Prosopis strombulifera (a spiny shrub particularly abundant in high-salinity areas of central Argentina) responds to different water status when plants are subjected to different salt treatments (NaCl, Na2SO4 and their iso-osmotic mixture). Different salt treatments on P. strombulifera plants influenced leaf micromorphological traits differently. In this study, Na2SO4-treated plants showed an increase in stomatal density (SD) and epidermal cell density (ECD) (with smaller stomata) at moderate and high salinity (−1.9 and −2.6 MPa), whereas in NaCl and NaCl + Na2SO4 treated plants, a decrease in these variables was observed. In Na2SO4-treated plants, transpiration was the highest at moderate and high salinity, with the highest content of ABA registered. A possible explanation is that, despite of these high ABA levels, there is no inhibition in stomatal opening, resulting in increased water loss, growth inhibition, and acceleration of senescence processes. We demonstrate that P. strombulifera responds to progressive salt stress by different salts changing the leaf development, particularly in Na2SO4-treated plants, leading to structural modifications in leaf size and micro-morphology of leaf cells.Fil: Reginato, Mariana Andrea. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular. Laboratorio de Fisiología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Reinoso, Herminda Elmira. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; ArgentinaFil: Llanes, Analia Susana. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular. Laboratorio de Fisiología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Luna, Maria Virginia. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular. Laboratorio de Fisiología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Physiological responses of a halophytic shrub to salt stress by Na2SO4 and NaCl: oxidative damage and the role of polyphenols in antioxidant protection

Salt stress conditions lead to increased production of reactive oxygen species (ROS) in plant cells. Halophytes have the ability to reduce these toxic ROS by means of a powerful antioxidant system that includes enzymatic and non-enzymatic components. In this research, we used the halophytic shrub Prosopis strombulifera to investigate whether the ability of this species to grow under increasing salt concentrations and mixtures was related to the synthesis of polyphenolic compounds and to the maintenance of leaf pigment contents for an adequate photosynthetic activity. Seedlings of P. strombulifera were grown hydroponically in Hoagland's solution, gradually adding Na2SO4 and NaCl separately or in mixtures until reaching final osmotic potentials of −1, −1.9 and −2.6 MPa. Control plants were allowed to develop in Hoagland's solution without salt. Oxidative damage in tissues was determined by H2O2 and malondialdehyde content. Leaf pigment analysis was performed by high-performance liquid chromatography with ultraviolet, and total phenols, total flavonoids, total flavan-3-ols, condensed tannins, tartaric acid esters and flavonols were spectrophotometrically assayed. Treatment with Na2SO4 increased H2O2 production and lipid peroxidation in tissues and induced a sharp increase in flavonoid compounds (mainly flavan-3-ols) and consequently in the antioxidant activity. Also, Na2SO4 treatment induced an increased carotenoid/chlorophyll ratio, which may represent a strategy to protect photosystems against photooxidation. NaCl treatment, however, did not affect H2O2 content, lipid peroxidation, pigments or polyphenols synthesis. The significant accumulation of flavonoids in tissues under Na2SO4 treatment and their powerful antioxidant activity indicates a role for these compounds in counteracting the oxidative damage induced by severe salt stress, particularly, ionic stress. We demonstrate that ionic interactions between different salts in salinized soils modify the biochemical and morpho-physiological responses of P. strombulifera plants to salinity.Fil: Reginato, Mariana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquímicas y Naturales. Cátedra de Fisiología Vegetal; ArgentinaFil: Castagna, Antonella. Università degli Studi di Pisa; ItaliaFil: Furlan, Ana Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; ArgentinaFil: Castro, Stella Maris. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; ArgentinaFil: Ranieri, Annamaria. Università degli Studi di Pisa; ItaliaFil: Luna, Maria Virginia. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquímicas y Naturales. Cátedra de Fisiología Vegetal; Argentin

Germination responses of lycium humile, an extreme halophytic Solanaceae: Understanding its distribution in saline mudflats of the southern puna

Although knowledge about halophytic Solanaceae is scarce, it is known that several species within genus Lycium tolerate salinity. Lycium humile grows in highly saline soils in mudflats near saline Andean lakes. This study evaluated the germination responses of L. humile under different scarification methods, photoperiods, temperatures and saline conditions and, simultaneously, tested seedling survival under different iso-osmotic conditions. Dormancy and germination were found to be regulated by interactions with different factors, with the highest germination percentages being obtained by immersion in sulfuric acid, with a temperature of 25 °C and a temperature regime of 5/25 °C, under which seeds were neutrally photoblastic. As osmotic potential of saline solutions decreased, germination also decreased drastically but the seedling survival percentage was higher than 30 % at 600 mM NaCl. No seeds germinated in any of the polyethylene glycol (PEG) solutions and no seedling survival was observed from-1.2 MPa PEG solutions. More than 90 % of seeds incubated in NaCl were able to recover germination after being transferred to distilled water, independently of NaCl treatments. We concluded that the effects of extreme environmental conditions on germination responses and seed tolerance to salinity may determine the occurrence and restricted distribution of L. humile.Fil: Palchetti, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Llanes, Analia Susana. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones Agrobiotecnológicas - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Agrobiotecnológicas; ArgentinaFil: Reginato, Mariana Andrea. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones Agrobiotecnológicas - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Agrobiotecnológicas; ArgentinaFil: Barboza, Gloria Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Luna, María Virginia. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones Agrobiotecnológicas - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Agrobiotecnológicas; ArgentinaFil: Cantero, Juan Jose. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Seeing the forest through many trees: multi-taxon patterns of phylogenetic diversity in the Atlantic Forest hotspot

We combine phylogenetic and point locality data from selected lineages of the Atlantic Forest flora and fauna to compare spatial patterns of biodiversity sustained by the current configuration of forest remnants to a scenario of complete forest preservation. We then ask the question "how much biodiversity is likely lost, already"? Specifically, we assess how habitat loss likely impacted the climatic spaces occupied by the local species, the inferred composition of local communities and the spatial distribution of phylogenetic diversity and endemism

Phytohormones as Growth Regulators During Abiotic Stress Tolerance in Plants

Phytohormones (PHs) play crucial role in regulation of various physiological and biochemical processes that govern plant growth and yield under optimal and stress conditions. The interaction of these PHs is crucial for plant survival under stressful environments as they trigger signaling pathways. Hormonal cross regulation initiate a cascade of reactions which finely tune the physiological processes in plant architecture that help plant to grow under suboptimal growth conditions. Recently, various studies have highlighted the role of PHs such as abscisic acid, salicylic acid, ethylene, and jasmonates in the plant responses toward environmental stresses. The involvement of cytokinins, gibberellins, auxin, and relatively novel PHs such as strigolactones and brassinosteroids in plant growth and development has been documented under normal and stress conditions. The recent identification of the first plant melatonin receptor opened the door to this regulatory molecule being considered a new plant hormone. However, polyamines, which are not considered PHs, have been included in this chapter. Various microbes produce and secrete hormones which helped the plants in nutrient uptake such as N, P, and Fe. Exogenous use of such microbes help plants in correcting nutrient deficiency under abiotic stresses. This chapter focused on the recent developments in the knowledge related to PHs and their involvement in abiotic stresses of anticipation, signaling, cross-talk, and activation of response mechanisms. In view of role of hormones and capability of microbes in producing hormones, we propose the use of hormones and microbes as potential strategy for crop stress management.Fil: EL Sabagh, Ayman. Scientific And Technological Research Council Of Turkey; TurquíaFil: Islam, Mohammad Sohidul. Kafrelsheikh University; EgiptoFil: Hossain, Akbar. Hajee Mohammad Danesh And Technology University; BangladeshFil: Iqbal, Muhammad Aamir. University Of Poonch; PakistánFil: Mubeen, Mohammad. Comsats University Islamabad; PakistánFil: Waleed, Mirza. Comsats University Islamabad; PakistánFil: Reginato, Mariana Andrea. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones Agrobiotecnológicas. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Agrobiotecnológicas; ArgentinaFil: Battaglia, Martin. Cornell University; Estados UnidosFil: Ahmed, Sharif. International Rice Research Institute; FilipinasFil: Rehman, Abdul. The Islamia University Of Bahawalpur; PakistánFil: Arif, Muhammad. The University Of Agriculture; PakistánFil: Athar, Habib-Ur-Rehman. Bahauddin Zakariya University; PakistánFil: Ratnasekera, Disna. University Of Ruhuna; Sri LankaFil: Danish, Subhan. Bahauddin Zakariya University; PakistánFil: Raza, Ali. Sichuan Agricultural University; ChinaFil: Rajendran, Karthika. Vellore Institute Of Technology; IndiaFil: Mushtaq, Muntazir. Icar-national Bureau Of Plant Genetic Resources; IndiaFil: Skalicky, Milan. Czech University Of Life Sciences Prague; República ChecaFil: Brestic, Marian. Czech University Of Life Sciences Prague; República ChecaFil: Soufan, Walid. King Saud University; Arabia SauditaFil: Fahad, Shah. University Of Haripur; PakistánFil: Pandey, Saurabh. Guru Nanak Dev University; IndiaFil: Abdelhamid, Magdi T.. National Research Centre Dokki; Egipt

Potential Role of Plant Growth Regulators in Administering Crucial Processes Against Abiotic Stresses

Plant growth regulators are naturally biosynthesized chemicals in plants that influence physiological processes. Their synthetic analogous trigger numerous biochemical and physiological processes involved in the growth and development of plants. Nowadays, due to changing climatic scenario, numerous biotic and abiotic stresses hamper seed germination, seedling growth, and plant development leading to a decline in biological and economic yields. However, plant growth regulators (PGRs) can potentially play a fundamental role in regulating plant responses to various abiotic stresses and hence, contribute to plant adaptation under adverse environments. The major effects of abiotic stresses are growth and yield disturbance, and both these effects are directly overseen by the PGRs. Different types of PGRs such as abscisic acid (ABA), salicylic acid (SA), ethylene (ET), and jasmonates (JAs) are connected to boosting the response of plants to multiple stresses. In contrast, PGRs including cytokinins (CKs), gibberellins (GAs), auxin, and relatively novel PGRs such as strigolactones (SLs), and brassinosteroids (BRs) are involved in plant growth and development under normal and stressful environmental conditions. Besides, polyamines and nitric oxide (NO), although not considered as phytohormones, have been included in the current review due to their involvement in the regulation of several plant processes and stress responses. These PGRs are crucial for regulating stress adaptation through the modulates physiological, biochemical, and molecular processes and activation of the defense system, upregulating of transcript levels, transcription factors, metabolism genes, and stress proteins at cellular levels. The current review presents an acumen of the recent progress made on different PGRs to improve plant tolerance to abiotic stress such as heat, drought, salinity, and flood. Moreover, it highlights the research gaps on underlying mechanisms of PGRs biosynthesis under stressed conditions and their potential roles in imparting tolerance against adverse effects of suboptimal growth conditions.Fil: Sabagh, Ayman EL. Kafrelsheikh University; EgiptoFil: Mbarki, Sonia. National Institute Of Research In Rural Engineering; TúnezFil: Hossain, Akbar. Bangladesh Agricultural Research Institute; BangladeshFil: Iqbal, Muhammad Aamir. University Of Poonch Rawalakot; PakistánFil: Islam, Mohammad Sohidul. Hajee Mohammad Danesh And Technology University; BangladeshFil: Raza, Ali. Fujian Agriculture And Forestry University; ChinaFil: Llanes, Analia Susana. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Instituto de Investigaciones Agrobiotecnologicas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Instituto de Investigaciones Agrobiotecnologicas.; ArgentinaFil: Reginato, Mariana Andrea. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Instituto de Investigaciones Agrobiotecnologicas. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Instituto de Investigaciones Agrobiotecnologicas.; ArgentinaFil: Rahman, Md Atikur. Grassland And Forage Division National Institute; Corea del SurFil: Mahboob, Wajid. Nuclear Institute Of Agriculture,; PakistánFil: Singhal, Rajesh Kumar. Indian Council Of Agricultural Research; IndiaFil: Kumari, Arpna. Guru Nanak Dev University; IndiaFil: Rajendran, Arvind. Vellore Institute Of Technology; IndiaFil: Wasaya, Allah. Bahauddin Zakariya University; PakistánFil: Javed, Talha. Fujian Agriculture And Forestry University; JapónFil: Shabbir, Rubab. University Of Poonch Rawalakot; PakistánFil: Rahim, Junaid. University Of Çukurova; PakistánFil: Barutçular, Celaleddin. Institute Of Crop Science And Resource Conservation; AlemaniaFil: Habib Ur Rahman, Muhammad. Sichuan Agricultural University; ChinaFil: Raza, Muhammad Ali. Sichuan Agricultural University; ChinaFil: Ratnasekera, Disna. University Of Ruhuna; Sri LankaFil: Konuskan l, Ömer. Mustafa Kemal University; TurquíaFil: Hossain, Mohammad Anwar. Bangladesh Agricultural Research Institute; BangladeshFil: Meena, Vijay Singh. Indian Council Of Agricultural Research; IndiaFil: Ahmed, Sharif. Bangladesh Agricultural Research Institute; BangladeshFil: Ahmad, Zahoor. Bangladesh Wheat And Maize Research Institute; BangladeshFil: Mubeen, Muhammad. Sichuan Agricultural University; ChinaFil: Singh, Kulvir. Punjab Agricultural University; IndiaFil: Skalicky, Milan. Czech University Of Life Sciences Prague; República ChecaFil: Brestic, Marian. Slovak University Of Agriculture; EslovaquiaFil: Sytar, Oksana. Slovak University Of Agriculture; EsloveniaFil: Karademir, Emine. Siirt University; TurquíaFil: Karademir, Cetin. Siirt University; TurquíaFil: Erman, Murat. Siirt University; TurquíaFil: Farooq, Muhammad. College Of Agricultural And Marine Sciences Sultan; Omá

Current knowledge about Na2SO4 effects on plants: What is different in comparison to NaCl?

In some areas of the world, high levels of sodium sulfate (Na2SO4) are found in the soil together with sodium chloride (NaCl). However, most studies on salinity are performed utilizing only NaCl as a salinizing agent. Generally, plant species have different tolerance/susceptibility responses when grown in the presence of these salts. Some studies showed that Na2SO4 seems to be more inhibitory than NaCl for the growth of species such as barley, wheat, sugar cane, beet, tomato, wild potato, and others. However, studies focusing on how Na2SO4 can affect the biochemical and physiological processes of plants are very scarce. This review provides an overview on the effects of Na2SO4 on different crops and plants species with a special emphasis on the tolerance/non-tolerance mechanisms of the halophyte Prosopis strombulifera under elevated NaCl and Na2SO4. A better understanding of the tolerance mechanisms in this particular species will help to identify cultivars of crop species that are more tolerant to Na2SO4. This knowledge could be used to extent cultivation of certain crop plants on Na2SO4 containing soils.Fil: Reginato, Mariana Andrea. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Ciencias Naturales; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones Agrobiotecnológicas. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Agrobiotecnológicas; ArgentinaFil: Luna, Maria Virginia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones Agrobiotecnológicas. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Agrobiotecnológicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Ciencias Naturales; ArgentinaFil: Papenbrock, Jutta. Leibniz Universitat Hannover; Alemani

Soil chemical composition modifies the morphophysiological responses of Prosopis strombulifera, a halophyte native to South America

In some salty areas of South America, and especially in central Argentina, high levels of sodium sulfate (Na2SO4) are found together with sodium chloride (NaCl). Plant species show differences in their susceptibility to growth in the presence of these salts. Some studies showed that Na2SO4 may inhibit the growth of species such as wheat, sugar cane, beet, tomato, wild potato, barley, more than NaCl. However, studies focusing on how sodium sulfate can affect the biochemical and physiological processes of plants are very scarce. This chapter provides an overview of the tolerance/non-tolerance mechanisms of the halophyte P. strombulifera, with a special emphasis on the effects of Na2SO4 on growth parameters, ion accumulation, production of secondary metabolites, antioxidant system and hormonal regulation, showing that the presence of the SO42- anion in the culture medium was determinant in the toxicity observed in Na2SO4 treated P. strombulifera plants. It is proposed that, as SO42- assimilation may be limited by the high concentration in the culture medium, the sulfur that has not been metabolized to cysteine would be in excess, and could be binding to cytochrome b559 of PSII blocking its activity partially or completely and thus inhibiting photosynthesis. Carbon metabolism and partitioning of are also affected, and energy resources should be diverted to synthesis of secondary metabolites such as condensed tannins and lignin and polyphenol precursors to cope with the high oxidative stress. As a consequence, there is a strong inhibition of Na2SO4 treated plants growth with chlorosis, necrosis and foliar abscission.Fil: Reginato, Mariana Andrea. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones Agrobiotecnológicas - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Agrobiotecnológicas; ArgentinaFil: Llanes, Analia Susana. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones Agrobiotecnológicas - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Agrobiotecnológicas; ArgentinaFil: Luna, María Virginia. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones Agrobiotecnológicas - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Agrobiotecnológicas; Argentin

Differential effects of NaCl and Na2SO4 on the halophyte Prosopis strombulifera are explained by different responses of photosynthesis and metabolism

Prosopis strombulifera (Lam.) Benth. is a halophytic shrub found in highly saline soils in Argentina, with high tolerance against NaCl but strong growth inhibition by Na2SO4. In the present study, the differences in the physiological responses caused by these salts and an iso-osmotic combination thereof on photosynthesis, mineral composition and metabolism were analyzed. Na2SO4 treated plants were the most affected by salinity, showing a significant decrease in several photosynthetic parameters. Proline and cysteine accumulated significantly in the plants in response to salt stress. These results show by the first time that the SO42− anion is triggering damage in the photosynthetic apparatus and consequently affecting the photosynthetic process, which may explain the strong growth inhibition in these plants at high salinity. Moreover, the SO42− anion provoke challenges in the incorporation of nutrients, decreasing the levels of K, Ca, P and Mg, and inducing a strong antioxidant activity in P. strombulifera.Fil: Reginato, Mariana Andrea. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones Agrobiotecnológicas. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Agrobiotecnológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Botánica. Laboratorio de Fisiología Vegetal; ArgentinaFil: Turcios, Ariel E.. Leibniz Universitat Hannover; AlemaniaFil: Luna, Maria Virginia. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Botánica. Laboratorio de Fisiología Vegetal; Argentina. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones Agrobiotecnológicas. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Agrobiotecnológicas; ArgentinaFil: Papenbrock, Jutta. Leibniz Universitat Hannover; Alemani

Abscisic acid and its metabolites are involved in drought tolerance in four native species of Patagonian semiarid shrublands (Argentina)

Drought is the main stress that affects growth of native species of Patagonian Monte. Physiological and biochemical traits with functional roles in adaptation to drought are still scarce in native species. The aim of this study was to evaluate changes in dry matter content and abscisic acid (ABA) and its metabolites (phaseic acid-PA, dihydrophaseic acid-DPA, ABA conjugated with glucose-ABA-GE) level in green leaves and fine roots of four nativespecies during contrasting seasons regarding water availability. Results show that grasses had higher leaf dry matter content (LDMC) and root dry matter content (RDMC) than Lycium chilense shrub and LDMC decreased during autumnin Larrea divaricata. In green leaves, there was an interaction between species and seasons for ABA and PA contents. L. divaricata had high ABA content during spring and low ABA content during autumn; while L. chilense showed theopposite pattern. During spring, drought tolerant species had high PA content while drought avoidant species had low PA content, and during autumn these species showed the opposite pattern. ABA-GE content was highest in L. chilensegreen leaves. In fine roots, ABA content was highest in L. divaricata and during spring PA was higher in L. divaricata than P. ligularis and L. chilense. PA was the only metabolite that decreased in L. divaricata during autumn. Resultsshowed that ABA homeostasis maintains the functioning of different life forms with different drought resistance strategies in Patagonia semiarid shrublands. In green leaves of the drought avoidant L. chilense shrub, the ABAconjugation pathway was active in both seasons. During spring, the most drought tolerant L. divaricata showed highest activation of ABA synthesis and ABA oxidation pathways. During autumn L. chilense showed highest activation of ABA synthesis and together with P. ligularis showed active the ABA oxidation pathway.Fil: Cenzano, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Reginato, Mariana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Ciencias Naturales; ArgentinaFil: Varela, María Celeste. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Luna, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Ciencias Naturales; Argentin