Search

Your search keyword '"Restrepo-Díaz, Hermann"' showing total 112 results
Start Over Author "Restrepo-Díaz, Hermann"
112 results on '"Restrepo-Díaz, Hermann"'

9. Evaluation of brassinosteroids and plant growth-promoting bacteria on the growth and yield of Lactuca sativa L. under soilless cultivation conditions.

Author

Benavides, Hansel Smith, Uribe-Velez, Daniel, and Restrepo-Díaz, Hermann

Subjects
BRASSINOSTEROIDS, HYDROPONICS, AZOSPIRILLUM brasilense, BACILLUS (Bacteria), BACTERIA, LETTUCE, LEAF area
Abstract

Soilless crops have become an important alternative for large-scale vegetable production because of the quality of their products and optimization of resources. Brassinosteroids (Brs) and Plant Growth-Promoting Bacteria (PGPB), has been reported to promote growth and physiological parameters in soil crops, but there are few reports on the application of these compounds in soilless crops. The effects of Brs ((25R)-3β 5α-dihydroxy-spirostan-6-one) and three strains of PGPB (Bacillus velezensis, Pseudomona sp., and Azospirillum brasilense) on the growth and yield of lettuce under hydroponic conditions were evaluated. Two separate experiments were carried out: one using a substrate in pots under greenhouse conditions and the other using a deep-flow hydroponic system in a growth room with artificial LED lighting. Plant physiological parameters (yield, dry weight, root surface area, and leaf area) and PGPB attributes under in vitro tests (phosphate solubilization and indole-3-acetic acid (IAA) synthesis) were determined using in vitro tests. A completely randomized design was used in all experiments. The results showed that in in vitro tests Azospirillum brasilense and Pseudomonas sp. were the strains that synthesized the highest amounts of IAA (36 mg mL−1 and 34 mg mL−1, respectively). Phosphorus solubilization was significantly higher in the Pseudomonas sp. strain (110.35 µg mL−1). Regarding physiological and quality parameters, the application of Brs (0.5 ppm), Bacillus velezensis, and Azospirillum brasilense (1 × 106 CFU mL−1) caused an increase between 20% and 40% on variables such as plant yield, leaf area, root surface area, and colorimetry of lettuce for substrate or hydroponic conditions, respectively. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

12. Ecophysiology of horticultural crops: an overview

Author

Restrepo-Díaz Hermann, Melgar Juan Carlos, and Lombardini Leonardo

Subjects
vegetable crops, fruit trees, water stress, temperature., Plant ecology, QK900-989
Abstract

Horticultural crops include a wide range of commodities, such as fruits and vegetables that are highly valuable for humanity. They are extensively grown worldwide, and their production can be described as an open and highly complex system affected by many factors, among which we can count weather, soil and cropping system, as well as the interaction between these factors. The aim of environmental physiology is to characterize the interaction between environmental stress and crop response, in order to maximize both yield quantity and quality. This review presents the most recent findings about the effects of the main abiotic environmental factors (light, temperature, and water) on whole plant physiology of horticultural crops. Environmental stresses can cause morpho-anatomical, physiological and biochemical changes in crops, resulting in a strong profit reduction. A clear understanding of environmental factors and their interaction with physiological processes is extremely important for improving horticultural practices (irrigation, light management, mineral nutrition, greenhouse design, etc.), optimizing photosynthetic carbon assimilation and increasing fruit productivity and crop quality. In addition, the information obtained by ecophysiological studies can be incorporated into breeding programs or agricultural zoning strategies.

Published
2010

40. Growth and yield of rice cultivars sowed on different dates under tropical conditions

Author

Garcés-Varon, Gabriel and Restrepo-Díaz, Hermann

Subjects
leaf area index, rice, solar radiation, Unfilled Spikelet percentage, fechas de siembra, radiación solar, porcentaje de espiguillas sin llenar, Arroz, índice de área foliar, planting date, Grain yield, hijuelos, rendimiento de grano, tillers
Abstract

Rice plants are susceptible to low light or high temperature conditions during the reproductive and maturity stages. Two rice cultivars, Fedearroz 50 ('F50') and Fedearroz 733 ('F733'), were planted on three planting dates, January 1st (PD1), February 15th (PD2) and April 1st (PD3), to expose them to different climatic conditions during the different stages of rice development. The experiment was a factorial arrangement. Of the various weather parameters, solar radiation fluctuated the most among the three different planting dates, with PD1 having the highest number of days with values ≥ 450 cal·cm-2·d-1. The yield components were influenced by the planting time. PD3 showed the lowest number of tillers per unit of area and the highest percentage of sterility spikelets. With respect to grain yield, PD1 and PD3 performed the best for both 'F50' and 'F733.' On the other hand, the optimum leaf area index (7) was reached at approximately 85-90 days for both cultivars for all three different planting dates. Similarly, solar radiation had a high correlation with the biomass production (dry matter) and leaf area index. In conclusion, the rice planting date should be adjusted so that the reproductive stage and grain filling do not coincide mainly with periods of low solar radiation (≤ 430 cal·cm-2·d-1) in tropical conditions. Las plantas de arroz han demostrado susceptibilidad a condiciones de bajas o altas temperaturas durante las etapas reproductivas y de madurez. Dos cultivares de arroz: Fedearroz 50 (F50) y Fedearroz 733 (F733) se plantaron en tres fechas de siembra: 1 de enero (PD1), 15 de febrero (PD2) y 1 de abril (PD3), con el fin de tener diferentes condiciones climáticas durante las diferentes etapas de desarrollo del arroz. El experimento se desarrolló bajo un arreglo factorial. En cuanto a los datos del clima, la radiación solar fue el parámetro más fluctuante en las tres fechas de siembra, siendo PD1 el que tuvo un mayor número de días con valores ≥ 450 cal·cm-2·d-1. Los componentes del rendimiento fueron influenciados por la época de siembra; PD3 mostró el menor número de macollas por unidad de superficie y el mayor porcentaje de espiguillas estériles. En cuanto a rendimiento de grano, PD1 y PD3 tuvieron el mejor comportamiento para las dos variedades 'F50' y 'F733'. Por otro lado, se alcanzó el índice de área óptimo de la hoja (7) aproximadamente a 85-90 días, para ambos cultivares en sus tres diferentes fechas de siembra, respectivamente. Del mismo modo, la radiación solar presentó una alta correlación con la producción de biomasa (materia seca) y el índice de área foliar. En conclusión, la fecha de siembra de arroz debe ajustarse de modo que la etapa reproductiva y llenado de grano no coinciden principalmente con periodos de baja radiación solar (≤ 430 cal·cm-2·d-1), en condiciones tropicales.

Published
2015

45. Ecophysiology of horticultural crops: an overview

Author

Restrepo-Díaz, Hermann, Melgar, Juan Carlos, and Lombardini, Leonardo

Subjects
hortalizas, fruit trees, water stress, estrés térmico, árboles frutales, temperature, sequía, vegetable crops
Abstract

Horticultural crops include a wide range of commodities, such as fruits and vegetables, that are highly valuable for humanity. They are extensively grown worldwide, and their production can be described as an open and highly complex system affected by many factors, among which we can count weather, soil and cropping system, as well as the interaction between these factors. The aim of environmental physiology is to characterize the interaction between environmental stress and crop response, in order to maximize both yield quantity and quality. This review presents the most recent findings about the effects of the main abiotic environmental factors (light, temperature, and water) on whole plant physiology of horticultural crops. Environmental stresses can cause morpho-anatomical, physiological and biochemical changes in crops, resulting in a strong profit reduction. A clear understanding of environmental factors and their interaction with physiological processes is extremely important for improving horticultural practices (irrigation, light management, mineral nutrition, greenhouse design, etc.), optimizing photosynthetic carbon assimilation and increasing fruit productivity and crop quality. In addition, the information obtained by ecophysiological studies can be incorporated into breeding programs or agricultural zoning strategies. Los productos hortícolas como frutas y vegetales son ampliamente cultivados, dado que incluyen un extenso abanico de alimentos de gran valor para la humanidad. Los sistemas hortícolas son abiertos y altamente complejos, y se ven afectados por factores como el clima, el suelo y el sistema de producción, así como por la interacción entre estos factores. Por lo anterior, la importancia de la fisiología ambiental o ecofisiología radica en que permite caracterizar la interacción entre los factores de estrés ambiental y la respuesta de los cultivos, con el propósito de obtener una producción exitosa. El objetivo de esta revisión consiste en reunir los resultados de las investigaciones más recientes acerca del efecto de los factores ambientales abióticos (luz, agua y temperatura) sobre la respuesta fisiológica de los cultivos hortícolas. Los factores de estrés ambiental pueden causar distintos cambios morfológicos, fisiológicos y bioquímicos en los cultivos, determinando una considerable reducción en su rendimiento. La comprensión de la interacción entre estos factores ambientales y procesos fisiológicos es importante en el mejoramiento de las prácticas hortícolas (riego, manejo de la luz, nutrición mineral, diseño de infraestructuras, etc.), con el objetivo de optimizar la fotosíntesis e incrementar la productividad de los cultivos. Adicionalmente, la información que se obtiene mediante la ecofisiología es una herramienta útil en los programas de mejoramiento genético, o en estrategias de ordenación del territorio agrícola.

Published
2010

50. Physiological response of 'Castillo el Tambo' coffee plants to biochar and chemical fertilization applications.

Author

Sánchez-Reinoso, Alefsi David, Colmenares-Jaramillo, Alejandra, Lombardini, Leonardo, and Restrepo-Díaz, Hermann

Subjects
*WATER efficiency, *PLANT nutrition, *PHYTOCHEMICALS, *HYDRAULIC conductivity, *NUTRITIONAL requirements, *CHEMICAL plants, *COFFEE, *GAS exchange in plants
Abstract

The fertilizers costs are currently elevated, and it is necessary to evaluate complementary agronomic strategies. Biochar (BC) offers several potential benefits at a relatively low cost. The research aimed was to study the effect of the application of four different doses of biochar (BC) (0, 4, 8, and 16 tha-1) and four fertilization levels (FL) (0%, 33%, 66% and 100% of the nutritional requirements). We obtained the BC from coffee (Coffea arabica L.) pulp. The selected response variables were: Stomatal conductance (gs), water use efficiency (WUE), root hydraulic conductivity (K), leaf photosynthetic pigments (Chl), and total dry weight (TDW) of coffee 'Castillo el Tambo'. The experiment was conducted under greenhouse conditions. The results showed that plants with 0 t ha-1 and 0% FL registered low values in the physiological parameters evaluated (gs = 60.5 mmol m-2 s-1; WUE = 3.03 g DM L-1 H2O; Chl = 59.4 atLEAF readings; Kr = 9.7×10-6 kg s-1 MPa-1; TDW = 9.7 g). On the other hand, we recorded a positive effect when 'Castillo el Tambo' coffee plants received 8 t ha-1 BC (Kr = 11.8×10-6 kg s-1 MPa-1), especially at fertilization levels of 66% and 100% (gs = 146.7 and 167.5 mmol m-2 s-1; Chl = 72.8 and 66.6 Chl content; WUE = 4.3 and 5.0 g DM L-1 H2O; TDW = 13.6 and 16.0 g, respectively). In conclusion, the use of BC manufactured with coffee pulp, mainly at a dose of 8 t ha-1, can be an alternative to complement the chemical nutrition of coffee plants. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results