Effects of Artificial Light Treatments on Growth, Mineral Composition, Physiology, and Pigment Concentration in Dieffenbachia maculata “Compacta” Plants

Specific wavebands may allow precise control of plant growth. However, light sources must be carefully evaluated before the large-scale use of supplemental light sources can be implemented. Dieffenbachia maculata “Compacta” plants were grown for 8 weeks in pots in a growth chamber under tightly controlled temperature and humidity in order to assess the effects of supplemental light. Three treatments were applied: (i) using 18-W fluorescent bulbs (T1), (ii) using the same bulbs with supplemental light emitting diodes (LEDs) (Pure Blue and Pure Red Mix-Light-Emitting Diodes (BR-LEDs)) (T2), and (iii) using high-efficiency TL5 fluorescents (T3). Plant biomass, mineral composition, and physiological and photosynthetic parameters were assessed under each light treatment. Total plant dry weight was highest in plants grown under treatments T1 and T3. Other differences were observed between different light treatments, including variation in biomass partitioning as well as N and K concentrations in roots, stems, and leaves. Further, proline and indole 3-acetic acid (IAA) levels were higher in plants grown under the T1 treatment, whereas total soluble sugars and starch were higher in plants grown under treatment T3. Plants grown under treatment T1 had the lowest chlorophyll concentrations. No differences were observed in organ water content and P concentration. T2 was not the best treatment, as expected. The model proposed a linear regression between integrated use of spectral energy (IUSE) and total dry weight (TDW), which showed a good relationship with an R2 value of 0.83. Therefore, we recommend this methodology to discern the effects of the different spectral qualities on plant biomass

Fittonia verschaffeltii Response to Artificial Light Treatments: BIOMASS, Nutrient Concentrations and Physiological Changes

The purpose of the present study was to evaluate the effects of different light treatments on biomass, nutrient concentrations and physiological parameters of Fittonia verschaffeltii (Lem) Van Houtte. The aim was to establish a methodology to evaluate the effect of photosynthetically active radiation (PAR) emitted by lamps on biomass. The light treatments used were tube luminescent Dunn (TL-D), tube luminescent Dunn + light emitting diodes (LEDs) and Tube luminescent 5 (TL-5). At the end of the experimental period, biomass, nutritional, biochemical, and physiological parameters were assessed. A clear reduction in total plant dry weight under TL-D + LEDs at the end of the experiment was recorded. With respect to nutrient concentration in the different organs assessed, there was no clear response under the different light treatments. The growth under TL-D lamps resulted in the highest concentration of total soluble sugars and starch in leaves, whereas the highest value of indole 3-acetic acid concentration was under TL-5 lamps. Plants grown under TL-D + LEDs showed the lowest values of chlorophyll a, b and a + b. The relationship proposed between integrated use of spectral energy (IUSE) and total dry weight (TDW) showed a good correlation with an R2 value of 0.86, therefore we recommend this methodology to discern the effects of the different spectral qualities on plant biomass

Comparative Behavior of Dracaena marginata Plants Integrated into a Cascade Cropping System with the Addition of Hydrogen Peroxide

The reuse of crop drainage into other crops, in the form of a cascade cropping system, is a feasible environmental solution where high inputs of water and fertilizer are used for crop growth and lower efficiency rates, associated with a high discharge of water and fertilizers into the environment, are present. Dracaena marginata plants were cultured in containers with sphagnum peat moss and were subjected to three different fertigation treatments for eight weeks: Dm0 (standard nutrient solution or control treatment), Dm1 (raw leachates), and Dm2 (raw leachates with additional H2O2), where the leachates were collected from a Chrysalidocarpus lutescens-Dracaena deremensis cascade cropping system. At the end of the harvesting, growth parameters, pigment concentration, leaf and root proline, total soluble sugar concentrations, and water and nutrient use efficiencies were assessed for each fertigation treatment. Plant height, root, stem, and total dry weight increased under fertigation with leachates with H2O2. The fertigation with leachates with or without H2O2 increased the red index value. There were no clear trends between the fertigation treatments with regards to pigment concentrations and biochemical parameters (proline and total soluble sugar concentrations). The addition of H2O2 to the leachate increased N concentration in the organs assessed, as well as the water and nutrient use efficiencies. There were no variations in H2PO4−, SO42−, Na+, and Mg2+ concentration in the chemical composition of the substrate between fertigation treatments. The positive results reported in this experiment suggest the potential growth of Dracaena marginata with leachate and hydrogen peroxide in a cascade cropping system

Evaluación de diferentes diseños de Aprendizaje Basado en Proyectos en el entorno de un máster profesional

XXI Congreso Universitario de Innovación Educativa en las Enseñanzas Técnicas (CUIEET 2013) Valencia, 10-12 julio 2013Este trabajo presenta el diseño y puesta en marcha de algunas variantes del Aprendizaje Basado en Proyectos (ABP) llevadas a cabo en un título Máster en Sistemas Electrónicos. Los resultados obtenidos animan a usar ABP en las titulaciones de Grado, pero confirman que su aplicación no es trivial cuando los proyectos son complejos y es alto el nivel de autoaprendizaje requerido al estudiante. Se discute también la importancia que tendría el desarrollo de las competencias transversales para el correcto funcionamiento del ABPUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Water and Nutrient Balance in an Ornamental Cascade Cropping System

Seedlings of Chrysalidocarpus lutescens, Dracaena deremensis and Dracaena marginata were grown in plastic containers filled with sphagnum peat-moss to assess the effects of three different water systems on plant growth, water saving and nutrient removal during the experimental period. The experiment lasted for 8 weeks and consisted of three water systems. These consisted of an open draining system fertigated with a standard nutrient solution (system T0) and two closed systems: sequential reuse of the leachate (system T1) and sequential reuse of the leachate with the addition of H2O2 (system T2). Over the course of the experiment, samples of water and supplies generated in each water treatment were collected weekly, and from these data water volume and nutrient loads were calculated. The addition of H2O2 to the leachate resulted in an enhancement in plant dry weight in Dracaena deremensis and Dracaena marginata. Regarding anion loads (Cl−, NO3−, H2PO4−, SO42−) in these water systems, there was a removal rate of 42%, 28%, 27% and 28%, respectively, in the closed systems compared to the open system. For the cation loads (Na+, K+, Ca2+ and Mg2+) in these water systems, there was a removal rate from 28% to 29%, respectively, in the closed systems compared to the open syste

Effects of Exogenous Application of Osmotic Adjustment Substances on Growth, Pigment Concentration, and Physiological Parameters of Dracaena sanderiana Sander under Different Levels of Salinity

We evaluated two osmotic adjustment substances (glycine betaine (GB) and glycine (G) and a combination of both glycine + glycine betaine (G + GB) using two modes of application; irrigation and foliar sprays with Dracaena sanderiana plants. The plants were grown in containers and subjected to two levels of NaCl concentrations (2.0 and 7.5 dS m−1) over 8 weeks. Growth, pigment concentrations, and physiological parameters were assessed at the end of the trial. The foliar application of GB resulted in most optimal plant growth and biomass production in the presence of NaCl. The chlorophyll and carotenoid concentrations showed different trends depending on the osmotic adjustment substance applied and the mode of application. Stomatal density and dimensions varied considerably with respect to the osmotic adjustment substance supplied. The concentration of soluble sugars in leaves did not show a clear trend under the different treatments assessed. The exogenous application of G resulted in the highest concentration of free proline and proteins in leaves. The antioxidant capacity in leaves increased with both osmotic adjustment substances, and both means of application, under low and high saline conditions. We concluded that the foliar application of GB can be recommended in order to achieve cost-effective growth of D. sanderiana under saline conditions

Physiological Responses of Tomato and Cucumber Seedlings under Different Light–Dark Cycles

Tomato and cucumber seedlings were grown in a growth chamber to evaluate the effects of different cycles of light–dark exposure conditions (T0 (control treatment) (1 cycle of 24 h distributed in 18 h of light exposure and six hours of dark), T1 (two cycles of 12 h distributed in nine hours of light exposure and three hours of dark) and T2 (three cycles of eight hours distributed in six hours of light exposure and two hours of dark) on growth, nutrient status, pigment concentration and physiological changes. Total dry weight showed different behaviors in both species, since in tomato the total dry weight remained unchanged under varying light–dark cycles, whereas in cucumber seedlings there was a clear decrease compared to the control treatment. In both species, plants grown under T2 showed the best water content. Nitrogen, P and K content—as well as partitioning in the different organs of the plants—displayed different patterns under varying cycles of light–dark conditions in both species. Chlorophyll (b and a + b) concentration decreased significantly in both species in T1 and T2 compared to the control treatment (T0). At physiological level, the concentration of total soluble sugars and proline in leaf showed the highest value in the control treatment with 18 h of light and six hours of dar

Monitoring Optical Tool to Determine the Chlorophyll Concentration in Ornamental Plants

The accurate estimation of leaf photosynthetic pigments concentration is crucial to check the plant´s health. Traditional methods of measuring photosynthetic pigments involve complex procedures of solvent extraction followed by spectrophotometric determinations. Portable plant instruments such as Soil Plant Analysis Development (SPAD) meters can facilitate this task for the speed and simplicity of the measures. The relationship between chlorophyll index obtained by SPAD-502 and pigment concentration in several ornamental species can help in the management of ornamental plant production. Two trials have been carried out in two different growing seasons (spring and summer) and facilities (greenhouse and open air), involving 30 ornamental species. There was a high linear relationship between concentrations of Chla and Chlb, as well as between Chlt and Ct in different species studied under greenhouse and open field conditions. The ratio between Chla and Chlb was higher at open field conditions and similar between Chlt and Ct. There was also a good relationship between Chlorophyll index and Chlt under both growing conditions, as well as between Chlorophyll index and Ct under greenhouse conditions. However, linear relationships with different slopes were observed for groups of species at open field conditions