Author: VIVIANA PAOLA SOSA FLORES

La irradiación de semillas de melón (cucumis melo l.) con uv-b causa modificaciones morfológicas e histológicas en las plantas

VIVIANA PAOLA SOSA FLORES (2014)

"Se sabe que la exposición de plántulas o plantas a la radiación UV-B induce cambios en la expresión génica que resultan en modificaciones bioquímicas y morfológicas. Sin embargo, existe poca información sobre los efectos y la utilidad potencial de la irradiación de semillas con UV-B. El objetivo de este estudio fue verificar el impacto sobre el crecimiento y la morfología de la planta al irradiar la semilla de melón (Cucumis melo) utilizando distintas dosis de UV-B 0, 99, 198 y 297 mJ/cm-2. Se utilizó semilla de melón cantaloupe variedad `Topmark´, la cual se expuso a irradiación UV con una longitud de onda centrada en 302 nm. Las semillas se sembraron en sustrato peat moss y perlita en invernadero. Se realizaron tres muestreos en los cuales se evaluaron los siguientes parámetros morfológicos: la altura de planta, el diámetro del tallo, el número de hojas, y el área foliar, además peso fresco y seco. Se revisaron algunas variables de la morfología epidérmica incluyendo la frecuencia estomática, el índice estomático, el largo y ancho de estomas. Las variables evaluadas en el estudio histológico de tallo fueron, área del haz vascular, área de vasos de xilema, ancho y largo de haces vasculares área del lumen de vasos de xilema y numero de vasos de xilema. El análisis de varianza encontró diferencias significativas (P≤ 0.005) entre tratamientos, determinando que la dosis de 99 mJ/cm-2 de exposición a radiación UV-B produjo 24.87 y 32.42% mayor biomasa fresca y seca respectivamente. En la superficie adaxial de la hoja el índice estomático sufrió variaciones observándose un incremento del 52.26, 7.14 y 13. 55 % respecto al testigo en los tratamientos de 99, 198 y 297 mJ/cm-2 y la longitud de estomas fue un 6.99 % mayor en el 198 mJ/cm-2. Por su parte la frecuencia estomática no fue modificada por la exposición a la radiación. La irradiación de las semillas causó disminución en el contenido de P, Ca y Na en las hojas de las plantas"

Is well known that exposure of plant seedlings or plants to UV-B radiation induces changes in gene expression resulting in biochemical and morphological modifications. However, there is little information on the effects and potential utility of irradiation of seeds with UV-B. The aim of this study was to apply UV-B radiation in melon seeds using various irradiation times and then assess the effect on growth and morphology of the plant. Seeds of cultivar 'Topmark' were exposed to UV irradiation with wavelength centered at 302 nm, for periods of 0, 15, 30 and 45 minutes (UV dosages of 0, 99, 198 and 297 mJ cm-2, respectively). The irradiated seeds were seeded in a mixture of peat moss and viii perlite for greenhouse germination. Morphological parameters such as plant height, stem diameter, number of leaves, leaf area, fresh and dry weights were evaluated. Stomatal frequency, stomatal index, and length and width of stomata were studied. Histological analyses were conducted to determine the areas of the stem vascular bundle and xylem vessels, width and length of vascular bundles, and the area of the lumen of xylem vessels. The analysis of variance indicated significant differences between treatments, with the treatment of 15 minutes (99 mJ cm-2) of seed exposure to UV-B radiation generating 24.87 and 32.42 % more fresh and dry weight of the plants, respectively. Stomatal index was augmented on the adaxial surface by 52.26, 7.14 and 13.55 %, in the treatments of 99, 198 and 297 mJ cm-2, respectively, in contrast with the control treatment, while the length of stomata was increased by 6.99% in the treatment with 30 minutes exposure time (198 mJ cm-2). Stomatal frequency was unchanged by exposure to radiation. The irradiation of the seeds caused decrease in P, Ca and Na in the leaves of plants.

Master thesis

Irradiancia Fotoreceptores Cucumis melo CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Crecimiento y desarrollo de anturío (Anthurium andreanum Lind.) en función del balance iónico en la solución nutritiva

VIVIANA PAOLA SOSA FLORES (2017)

"El anturio (Anthurium andreanum Lind.) es una planta epífita sudamericana, valorada por su brillante colorido y por su espata y espádice de larga duración. Pertenece a la familia Araceae y es nativa de las zonas tropicales de Centro y Sur América. El nombre anturio se deriva de la palabra griega 'anthos' y 'oura' que significa cola en referencia a su inflorescencia (Mari, 2016). El comercio de anturios en EE.UU se valora alrededor de 50 millones de dólares y entre las flores cortadas tropicales ocupa el segundo lugar en importancia sólo después de las orquídeas. Los Países Bajos y Hawaii son los principales productores y Alemania, Italia, Japón, Francia y Estados Unidos son los principales consumidores (Murguia et al., 2002). En México, los anturios son cultivados desde hace cincuenta años, principalmente en el estado de Veracruz (Castillo, 2012), principalmente para la producción de flores de corte pero puede adecuarse a cultivos en maceta, es una planta habitualmente grande, de disposición relativamente abierta."

"The climatic conditions of the humid tropical areas of México allow the year-round production of cut flowers and potted plants of anthurium. However, there is scarce basic and applied research on tropical ornamental species, limiting the development of technology to increase their productivity and quality. The present study was designed to determine the effect of varying proportions of cations (K+, Ca+2, Mg+2) and anions (NO3 , H2PO4- and SO4-2) on the growth and nutrient status of potted anthurium plants. In this paper we are reporting the information as to the effect of the proportions of K+, Ca+2, Mg+2 in the nutrient solution on plant growth responses Using mixture analysis and response surface methodology. Response surface analysis detected that spathe and leaf areas decreased when fed with solutions of high proportions of Mg+2. Total shoot and root fresh weight, as well as total dry weight and root volume, also demonstrated the deleterious effects of high Mg+2 ratios. In general, considering all the parameters measured, the best growth of anthurium plants was obtained in two areas of the explored space; one area was high in Ca+2, with optimum ranges from 0.24 – 0.44 for K+, 0.54 – 0.68 for Ca+2, and 0.01 – 0.08 for Mg+2, and another area that was high in K+, on which the optimum ranges were 0.54 – 0.65 for K+, 0.25 – 0.29 for Ca+2, and 0.10 – 0.21 for Mg+2. Shoot and root K+, Ca+2 and Mg+2 concentration was significantly affected by the cation ratios, however, there was not a clear tendency as to the effect of each cation in the mixture; nonetheless, the internal K+ : Ca+2 : Mg+2 ratios were affected by the external ratios, as in the shoot they were located in a very specific area, indicating that anthurium plants accumulated more Mg+2 compared to what it is in the external solution, whereas Ca+2 ratio was lower than that of the external solution. As for K+, plants accumulated it at high rates regardless of the external balance. In conclusion, the optimum nutrient solutions for anthurium may contain very wide ratios of K+ as long Ca+2 and Mg+2 are maintained at low proportions."

Doctoral thesis

Planta Familia araceae Desarrollo Cultivo CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Anion proportion in the nutrient solution impacts the growth and nutrient status of anthurium (Anthurium andraeanum Linden ex. André.)

VIVIANA PAOLA SOSA FLORES LUIS ALONSO VALDEZ AGUILAR (2017)

"Anthurium is native to habitats characterized by low nutrient supply, however, when 33 cultivated, it demands a complete fertilization program. The objective of the present study was to 34 determine the effect of varying proportions of anions (nitrate (NO3 ), phosphate (H2PO4 ) and 35 sulphate (SO42) in the nutrient solution on the growth and nutrient status of container grown anthurium. The effect of the anion proportion was modeled using mixture analysis. Plant growth increased when fertigated with solutions containing an anion proportion of 0.78: 0.12: 0.10, 0.20 : 0.12 : 0.68 and 0.80 : 0.02 : 0.18. The contour plots showed that optimum response may be achieved in two areas, an area with high NO3 proportion (0.50-0.80) and an area with high SO4 , provided H2PO4 was high (0.09 – 0.12 for H2PO4 and 0.55-0.70 for SO42 ). The counter 41 plots indicate that high SO42 proportions combined with low NO3 and H2PO4 were detrimental 42 and that optimum growth depends not only on N concentration, as it may be attained at either high or low NO3 . Nitrogen and S concentration was higher in plants fertigated with high NO3 44 (0.55 – 0.80) and SO42- (0.40 -0.70) solutions. Shoot P was higher when plants were fertigated 45 with solutions of low (as long as NO3 was at proportions of 0.50 and SO42- at 0.35) or high 46 H2PO4 proportions (as long as SO42 proportion was at 0.35). At low concentration of S in the shoot, increasing S resulted in increasing shoot N. however, further S increments in the shoot were associated with a decrease in N. Plants fertigated with the highest proportion of H2PO4 resulted in the lowest S concentrations despite some solutions contained high S04, suggesting that H2PO4 counteracted the uptake of SO4. Nitrogen and S were predominantly diverted to the roots in control plants, however, when plants were fed with both high SO4 and high H2PO4 solutions even more S was allocated to the roots, which explains the increased growth due to the lower S concentrations. In conclusion, the increased growth of anthurium was attained at either high or low NO3 proportion and it is able to cope with high SO42- by avoiding the transport of S to the shoot, decreasing SO4 intake, maintaining a favorable internal N/S and S/P proportion, 56 and increasing P tissue concentration."

Article

Soil management Fertilization Irrigation CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA