[en] Tetrazolium salt solutions, 2,3,5-Triphenyltetrazolium chloride has been employed by several workers in many problems involving differences in tissue viability for both animal and plant tissues, e. g. for testing the germinating ability of seeds, especially cereals; for determining freezing injury in plants during the growing period at the field and for estimating damage in artificially cured peanuts, as well as for testing viability in bacteria and yeast. But we know of no reference regarding use of Tetrazolium Salt solutions to test pollen viability. In practical work it is very important to know whether pollen is living or not before using it in genetic work. In the present work have reported 0,5, 1,0 and 2,0% Tetrazolium Salt solutions were employed to test viability of maize pollen grains, a positive reaction being obtained with all three solutions. With such concentrations insoluble red triphenyl formazan occurred at 5, 6 and 8 minutes respectively when temperature was at 20° C and pH 7,0. To make the test, fresh pollen grains were placed on a slide, and Tetrazolium Salt solutions added before putting on a cover slip. With the lowest concentrations solutions many pollen grains burst; this did not occur however when a 2,0% solution was employed. So all tests to determine the speed of reduction of the Tetrazolium Salt have been made using this concentration at temperatures 20, 30, 40, 50, 60, 70 and 80°C. The highest speed occurred at 50° C which appears to be the optimum temperature for Tetrazolium reduction by pollen grains. At 50°C, positive pollen exhibits a uniform red colour over the whole surface. At 60 and 70° C the colour with positive pollen is a pale rose, occupying only a small part of the surface. It is evident that enzyme systems are responsible for this reduction since it does not occur when pollen grain subjected to enzyme inhibitor treatment; e. g. cooling to O°C or heating to 80°C or higher. Red triphenyl formazan occurs only with living pollen grains. Dead pollen grains produce no red colour. It seems that Tetrazolium Salt solutions provide a quick reliable index for pollen viability, especially those of Graminaceae type. It is recommended that the test be made at 50°C, using a 2% solution.

[es] Diversos autores han empleado soluciones de Tetrazolium, cloruro de 2,3,5-Trifeniltetrazolium, para probar la vitalidad de tejidos animales y vegetales; bacterias, levaduras,pero muy particularmente como indicador de la capacidad germinativa de semillas, preferentemente cereales. Hasta el presente no se poseen referencias de que haya sido utilizado este reactivo para probar la vitalidad del polen. Prácticamente tiene mucho interés saber si el polen que se va a emplear para ciertos trabajos genéticos está vivo o muerto. Por esta razón es muy interesante disponer de un medio rápido y eficaz para determinar la vitalidad del polen. En el presente trabajo se empleó el Tetrazolium en soluciones al 0,5, 1,0 y 2,0 por 100, obteniéndose reacción positiva en cinco, seis y ocho minutos respectivamente, a 20°C y pH 7,0. Con las concentraciones más bajas revientan gran número de granos de polen, por lo que se recomienda la solución al 2,0 por 100. Con esta solución se hicieron pruebas de la velocidad de reducción a 20, 30, 40, 50, 60, 70 y 80°C, comprobando que la temperatura óptima es 50°C. La reducción de Tetrazolium en el polen para formar trifenil formazan rojo parece ser de naturaleza enzimática, por cuanto no tiene lugar a 0°C ni a 80°C, ni después de tratar el polen con inhibidores de las reacciones enzimáticas. Puede concluirse que la solución al 2 por 100 de Tetrazolium constituye un buen indicador de la vitalidad para el polen, tipo graminoide principalmente, debiendo hacerse la prueba a 50°C.