Qualidade de sementes e crescimento de plântulas de alface (Lactuca sativa L.) submetidas a estresse nutricional

Abstract

In order to obtain high quality seeds, it is indispensable adequate mineral fertilizing, being important for plant development and reprodution, as well as it has influence in the strength and the physiological quality from the seeds and consequently, the growth of seedling. This way, the research was done with objective to evaluate the effect of alternating retreat of the macronutrients nitrogen (N), phosphorus (P) and potassium (K) in the physiological quality of seeds and in the first growth of letucce seedlings. It was also evaluated the effect of presence and absence of the complete nutritive solution in the physiological quality of the seeds and in the first growth of letucce seedlings. The experiment was carried in the seeds laboratory and the greenhouse of the Departament Botany, Universidade Federal de Pelotas. The experimental design was completely randomized with three replications. The means were compared by Tukey test (p<5%). The assay was conducted three times, in each one was Haglands solution ½ strength, Hoaglands solution ½ strength minus one element (N, P and K) and water. The following tests were leaded: germination (TG), first counting of germination (PCG), germination speed index (IVG), eletric conductivity (CE), seedlings emergence (E), emergence speed index (IVE), shoot (PA) and roots (SR) lengths of seedlings, fresh (MF) and dry (MS) matters of shoot and root seedlings, leaf area, leaf number, and pigments (chlorophylls) content. The physiological quality of seeds was affected by treatments. The complete Hoagland solution ½ strength produced increments on the majors growth characteristics of seedlings under greenhouse conditions, meanly on dry matter accumulation and leaf area. In general, the chlorophylls content was not affected by different treatments.