INFLUENCIA DE LA ALTA TEMPERATURA EN LOS TEJIDOS RADICULARES DE TOMATE (Lycopersicon esculentum Mill.)

Qualitative changes of root tissues, as a result of high temperature (38 o C for 1.5 h) were studied in two tomato (Lycopersicon esculentum Mill.) seedlings with different heat tolerance degrees. Seven days after rice seeds started to germinate, the heat treatment was applied to rootlets of each variety, which were isolated in pots containing water and later put on the stove for 1.5 h at 38 o C, whereas the control treatment consisted of leaving the other group of rootlets under laboratory conditions while applying high temperature. Afterwards, rootlet samples were taken and processed through light microcopy, including epon resin and 2 µm-wide sections were cut and stained with toluidine blue, observed and photographed under a microscope with a digital camera. Longitudinal sections of rootlets showed that high temperature increased vacuole size and expanded cell walls, among other disorders; such changes became more evident at the heat stress tolerant variety. RESUMEN. Los cambios cualitativos en los tejidos radiculares, como consecuencia de la alta temperatura empleada en este trabajo (38 o C durante 1.5 horas), fueron estudiados en plantulas de dos variedades de tomate (Lycopersicon esculentum Mill.), con diferentes grados de tolerancia a altas temperaturas. A los siete dias de puestas a germinar las semillas de arroz, se aplico el tratamiento de alta temperatura a las radiculas de cada varie- dad, que fueron puestas en recipientes con agua, por separa- do, y colocadas en la estufa durante 1.5 h a 38 0 C y el tratamien-