Regulated deficit irrigation in different phenological stages of potted geranium plants: Water consumption, water relations and ornamental quality

The irrigation water requirements and sensitivity to water deficits of ornamental plants is of great interest to horticultural producers for planning irrigation strategies. The effect of different deficit irrigation strategies on physiological and morphological parameters in geranium plants was studied in different growth phases to evaluate how such strategies can be safely used and to ascertain whether the flowering phase is sensitive to deficit irrigation. Pelargonium × hortorum L. H. Bailey plants, grown in a controlled growth chamber, were subjected to four irrigation treatments: control (100 % water field capacity throughout the experiment), sustainable deficit irrigation (75 % water field capacity throughout the experiment), and two regulated deficit irrigation treatments that included water stress during the vegetative growth phase or during the flowering development phase. Although the total amount of irrigation water was similar in the three deficit irrigation treatments (around 80 % of the control value), the lowest values for both height and flowering were found when deficit irrigation was applied during flowering. This indicates that plant quality does not only depend on the amount of water applied but also on the time when the reduction is applied, and that flowering is the most sensitive phase to water stress. Evapotranspiration was related to the formation of inflorescences and to increased plant height. When the irrigation strategy was changed, plants increased or decreased their water consumption and stomatal conductance to adjust to the new conditions by regulating stomatal opening, although, in general, the values of both parameters remained below those observed in the control plants. © 2012 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.This work was supported by the Spanish Ministry of Science and Innovation (AGL 2008-05258-C02-1-2, AGL 2011-30022-C02-01) and Fundación Séneca (15356/PI/10).Peer Reviewe

Assessment of soil salinity indexes using electrical conductivity sensors

The salinity tolerance of plants can be improved by efficient irrigation management and salt flushing, which require a continuous and precise knowledge of the salinity in the soil or substrate. Soil sensors that measure electrical conductivity play an essential role in monitoring soil salinity. However, the correct interpretation of salinity measurements using soil sensors depends on developing appropriate salinity indexes. This work studied the potential of several salinity indexes based on the bulk EC (ECb) directly measured by soil sensors, and on pore water EC (ECw) estimated by the Hilhorst model (ECwHI). The methodology used in the experiments is based on the simultaneous use of scales and sensors, which allowed the automatic monitoring of the real salinity levels of the substrate, and the conductivity measurements made with the soil sensor. Regression studies were carried out to know how well the proposed salinity indexes explain real salinity. In general, all the indexes were suitable for estimating the relative changes in substrate salinity, as long as they met certain requirements. For example, ECwHI was seen to be a reliable salinity index when substrate moisture was high and constant. However, there was no such requirement when the ECwHI was corrected according to the current substrate water content, or when the salinity index was calculated as the average of the ECwHI values between two successive irrigation events. ECb was an efficient salinity indicator as long as the moisture content was constant, although its accuracy increased at a high moisture level. The findings led us to propose a new salinity index calculated with the slopes of the linear section of the quadratic moisture adjustment, which avoids the need for the substrate moisture content to be constantThis research was funded by the Ministry of Science, Innovation, and Universities of Spain, and the European Regional Development Fund, grant number RTI2018-093997-B-I00, and by the Spanish AEI (grant number PCI 2019-103608) under the PRIMA programme in the frame of the PRECIMED project. PRIMA is an Art.185 initiative supported and co-funded under Horizon 2020, the European Union’s Programme for Research and Innovatio

Regulated deficit irrigation in potted Dianthus plants: Effects of severe and moderate water stress on growth and physiological responses

The purpose of this study was to analyze the physiological and morphological response of carnation plants to different levels of irrigation and to evaluate regulated deficit irrigation as a possible technique for saving water through the application of controlled drought stress. Carnations, Dianthus caryophyllus L. cultivar, were pot-grown in an unheated greenhouse and submitted to two experiments. In the first experiment, the plants were exposed to three irrigation treatments: (control); 70% of the control (moderate deficit irrigation, MDI) and 35% of the control (severe deficit irrigation, SDI). In the second experiment, the plants were submitted to a control treatment, deficit irrigation (DI, 50% of the control) and regulated deficit irrigation (RDI). After 15 weeks, MDI plants showed a slightly reduced total dry weight, plant height and leaf area, while SDI had clearly reduced all the plant size parameters. RDI plants had similar leaf area and total dry weight to the control treatment during the blooming phase. MDI did not affect the number of flowers and no great differences in the colour parameters were observed. RDI plants had higher flower dry weight, while plant quality was affected by the SDI (lower number of shoots and flowers, lower relative chlorophyll content). Leaf osmotic potential decreased with deficit irrigation, but more markedly in SDI, which induced higher values of leaf pressure. Stomatal conductance (gs) decreased in drought conditions more than the photosynthetic rate (Pn). Osmotic adjustment of 0.3 MPa accompanied by decreases in elasticity in response to drought resulted in turgor less at lower leaf water potentials and prevented turgor loss during drought periods. © 2009 Elsevier B.V. All rights reserved.This work was supported by CICYT projects AGL 2005-05588-C02-1 and AGL 2005-05588-C02-2 and by the Consejería de Agricultura y Agua de la Región de Murcia, programme (UPCT-CEBAS-IMIDA.2005).Peer Reviewe

Growth, water relations and ion accumulation in Phlomis purpurea plants under water deficit and salinity

The effect of different levels of water deficit and salinity on physiological and morphological alterations in Phlomis purpurea plants was studied to evaluate their adaptability to such conditions. P. purpurea plants growing under greenhouse conditions were subjected to four irrigation treatments between November and May 2008: control (C, 1 dS m-1), moderate water deficit (MWD, 1dS m-1, 60% of the control), severe water deficit (SWD, 1 dS m-1, 40% of the control) and saline (S, 4 dS m-1). Aerial dry weight decreased with salinity, response that was more marked in the water deficit treatments, especially SWD. Stem diameter and leaf number were similarly reduced in both water deficit treatments, while leaf area also decreased in saline treated plants. Throughout the experiment, plant height was similar in both control and saline treated plants and was inhibited 10 weeks after application of the deficit irrigation onwards. Only at the end of the experiment were there significant differences in plant height between all treatments. Plants irrigated with saline water had higher Na+ concentrations in their leaves than in their roots and shoots, while Cl- concentrations were similar in leaves and roots, suggesting some resistance to the movement of the latter ions from root to shoots. The accumulation of salt in the leaves was associated with osmotic adjustment, which maintained midday leaf turgor in saline treated plants. However, no osmotic adjustment was observed in plants submitted to water stress. The results indicate that the effect of osmotic stress due to water deficit was more severe than the toxic effect of salt.This work was supported by the projects: CICYT (AGL 2008-05258-C02-1-2), CDTI (IDI-20070868) and Convenio de la Consejería de Agricultura y Agua de la Región de Murcia-UPCT-CEBAS, 2008.Peer Reviewe

Physiological mechanisms involved in the recovery of euonymus and laurustinus subjected to saline waters

The scarcity of water has frequently led to saline water being reused for the irrigation of ornamental shrubs. However, before the use of such waters can be expanded, the salt tolerance and other characteristics of the ornamentals involved, need to be considered along with their capacity to recover after salinity exposure. For this reason, Euonymus japonica (euonymus) and Viburnum tinus (laurustinus) plants were submitted for twenty weeks to three irrigation treatments applied at 100% water holding capacity: Control (EC<0.9dSm-1); NaCl solution, NaCl (EC: 4dSm-1); and wastewater, WW (EC: 4dSm-1). This was followed by a recovery period of eight weeks, when all the plants were watered in the control irrigation conditions. The results showed that biomass, leaf number and total leaf area of plants subjected to the saline treatments were lower than in the control at the end of both periods in both species. However, after recovery, only euonymus showed lower growth parameters than those observed in the saline period. The highest Na+ and Cl- concentrations were observed in saline plants at the end of saline period for both species, and were higher in shoots than in roots. The opposite was observed for the K+/Na+ and the Ca2+/Na+ ratios. In Laurustinus, the Ψstem did not diminish in the wastewater-irrigated plants with respect to the control, maintaining osmotic adjustment and a high Ψt, even after recovery, whereas in euonymus this did not occur at the end of recovery period. In both species the Pn and gs were similarly reduced during the saline exposure period. However, the recovery of gas exchange in laurustinus irrigated with wastewater might be closely related to the better water status of these plants. Although the aesthetic value and growth decreased in the plants of both species, the chemical properties of the waters applied had different effects in each case, especially as regards the capacity to recover from salinity. These results underline the importance to studying the physiological mechanisms involved in the recovery of plants. © 2013 Elsevier B.V.This work was supported by the projects: CICYT (AGL 2008-05258-CO2-1-2-AGR and AGL 2011-30022-CO2-01-02) and Fundación Séneca (15356/PI/10).Peer Reviewe

Distribution in plant ,substrate and leachate of paclobutrazol following application to containerized Nerium oleander L.seedlings

[ENG]Paclobutrazol(PBZ)is a retardant often used in potted ornamental plants to control their growth and compactness. The distribution in plant,substrate and leachate of PBZ applied to containerized oleander seedlings were studied after a single liquid drench application to the substrate surface(20mga.i.perplant) in a nursery dedicated to pot production in SE Spain. PBZ significantly reduced all growth parameters, providing more compact plants of good commercial value and confirming its ability to reduce the vertical growth of native oleander in the nursery. The level of PBZ residues in leaves washigh-erat the end of pot cultivation (156 days post PBZ application) than at the first sampling time(30 days after PBZ applica-tion), where as the level in stems decreased for the same period of time. PBZ residues in roots remained constant during the experimental period. The high level of PBZ residues detected in the substrate 30 days after application had decreased significantly(by67%) by the end of the experiment. A greater leaching fraction was detected for PBZ-treated seedlings and so a greater amount of PBZ was leached into the nursery soil with the irrigation water attheend of the experiment. This greater amount of PBZ leached into the soil represents an important way of contamination in the nursery and a substantial risk to the environment. [ESP] Paclobutrazol (PBZ) es un retardante del crecimiento frecuentemente utilizado en el cultivo de plantas ornamentales en maceta para el control de su crecimiento y compacidad. La distribución en el sustrato, planta y drenaje de PBZ aplicado a plántulas de adelfa en contenedor fue estudiada tras la aplicación de una única dosis a la superficie del sustrato de la maceta (20 mgi.a.por planta) en una plantación comercial de un vivero localizado en el Sureste de España. PBZ redujo significativamente todos los parámetros del crecimiento, proporcionando plantas más compactas de buen valor comercial y conformando su capacidad para reducir el fuerte crecimiento vertical de la adelfa nativa en el vivero. El nivel de residuos de PBZ en hojas resultó más elevado al final del ciclo de cultivo en maceta (156 días tras la aplicación) que a los 30 días de la aplicación, mientras que la cantidad de residuos presentes en el tallo disminuyó para el mismo periodo de tiempo. Los residuos de PBZ en las raíces permanecieron constantes durante todo el período experimental. El elevado contenido de residuos de PBZ detectadosen el sustrato 30 días después de la aplicación se redujo significativamente (enun 67%) al final del experimento. Una mayor fracción de drenaje fue detectada en las plántulas tratadas con PBZ, a la vez que una mayor cantidad de PBZ fue drenado en el suelo del vivero conjuntamente con el agua de riego al final del experimento. Esta mayor cantidad de PBZ drenado en el suelo representa una vía importante de contaminación en el vivero así como un riesgo importante de contaminación medioambiental.This research was supported by CICYT projects(AGL2005-05588-C02-1 and AGL2005-05588-C02-2)and by the Consejería de Agricultura y Agua de la Región de Murcia,program (UPCT-CEBAS-IMIDA 2005)

Ruiz Hidalgo Park in Murcia (1908-1955)

[SPA] Se estudia el primer parque público de la Región de Murcia a través de la Guía del Parque escrita por Codorniú, el primer documento de ésta índole publicado en España. La ciudad de Murcia disfrutó de un Parque en la ribera del río Segura entre 1908 y 1955. Fue construido junto a las edificaciones mas representativas de la ciudad y llegó a suponer un 6% de superficie de zona verde en la misma. Promovido por Ricardo Codorniú fue concebido desde la idea de un arboreto donde mostrar diferentes especies a la población y obtener conocimientos sobre las condiciones de aclimatación para posibles usos forestales. El Parque albergó gran número de actividades sociales desarrolladas en la ciudad hasta recibir el abandono de las autoridades antesala de su destrucción. [ENG] The Garden is studied through the Guide to the Park written by Codorniú. This Guide was the first document of this nature published in Spain. The city of Murcia had a park on the riverside of Rio Segura from 1908 to 1955. This huge garden was built next to the landmarks of the city and it represented 6% of green space over the total city area. It was promoted by Ricardo Codorniú and its main purpose was to show people the different plant species and to get the necessary information to adapt these plants to possibly forest uses. The Park was the centre of countless city social activities and it was abandoned by the city authorities who led to its completely destruction

Influencia del ciclo de cultivo y la conservación frigorífica en el color de la coliflor

La coliflor es un cultivo en aumento en la Región de Murcia, provocado principalmente por el incremento de su producción destinada a la exportación. Para mantener dicha cuota de exportación es necesaria la producción de una coliflor de gran calidad, requisito que cada vez más, aprecian los mercados nacionales. Esta calidad se basa fundamentalmente en su aspecto externo, donde el color de la pella es uno de los parámetros más importantes a tener en cuenta.Este trabajo ha sido financiando por el proyecto Séneca AGR/9/FS/9

Nursery pre-conditioning of plants for revegetation, gardening and landscaping in semi-arid environments

In landscaping and xerogardening projects, under semi-arid conditions, appropriate techniques used in the nursery during seedling production are crucial for the establishment, survival and subsequent growth of plants after transplanting (Figure 1). Morphological and anatomical adaptations in seedlings include reductions in shoot height and/or leaf area, rises in root-collar diameter and root growth potential and, often, a reduction in the shoot:root ratio; in addition, there are physiological characteristics of seedlings related to osmotic adjustment and water-use efficiency, such as low stomatal conductance, leaf water potential, leaf turgor potential and relative water content. These occur as a result of hardening and acclimation processes (pre-conditioning) during the nursery period, and are correlated with the ability to withstand the shock of transplantation and to increase survival and plant growth following transplantation in xerogardens and semi-arid landscapes (Franco et al., 2006). Deficit irrigation is the most commonly used pre-conditioning technique to produce high-quality seedlings (Arreola et al., 2006; Franco et al., 2008). In addition, using large-sized containers and appropriate substrates, withholding N nutrition, inoculating arbuscular mycorrhizal fungi, applying plant growth retardants and mechanical conditioning methods are common. Varying microclimatic conditions are also used to control growth to produce high-quality seedlings (Franco et al., 2006)