Condicionamento fisiológico de sementes de salsa com bioestimulante vegetal a base de Ascophyllum nodosum

Abstract

The availability of seed treatment techniques with alternative products is fundamental for the organic vegetable cropping, however, few studies have been done so far on this subject. Seed priming is a technique that can benefit speed and uniformity of seedlings emergence. Therefore, the objective of this work was to evaluate the effect of physiological conditioning of parsley seeds (Petroselinum sativum) with Ascophyllum nodosum extract, on germination, seedling/plant growth and seedlings production. The experiment was carried out in the Seeds Laboratory and in the Experimental Area of the Universidade Federal da Fronteira Sul, Chapecó campus, in two stages. In the initial stage, the time and the ideal temperature for the physiological conditioning were determined, using: 20ºC, 25ºC and 30ºC, with a completely randomized design, with 4 replicates. Parsley seeds of Lisa and Crespa cultivars were used. In the second stage, doses of Ascophyllum nodosum were tested in a completely randomized experimental design, in a 2 x 5 factorial scheme (cultivars x doses), with four replications. The conditioning was carried out at the temperature of 20 °C, at the rates of 0; 1; 2; 4 and 8 mL L-1. After conditioning, germination percentage, primary root protrusion velocity, seedling length and dry mass at temperatures of 20 and 30 °C, were evaluated in the laboratory; and at green house were evaluated: plant emergence, seedling height and number of leaves at 7, 14, 21, 28 and 35 days after sowing (DAS), plant emergence velocity and root length (at 35 DAS). The greenhouse experiment was carried out in a completely randomized experimental design in a 2 x 5 factorial scheme (cultivars x doses), with five replications. The data were submitted to analysis of variance and regression (when the F test was significant), in the Sisvar® software. Differences were observed between the cultivars in relation to the water absorption pattern and the speed of the imbibition process, as well as in relation to the different temperatures used in seed conditioning. The ideal temperature for the physiological conditioning of parsley seeds with Ascophyllum nodosum is 20 °C and the time required is 100 hours. At ideal temperature conditions, at 20 °C, physiological conditioning with Ascophyllum Nodosum at the dose used in this research does not lead to an improvement in the germination and growth capacity of parsley seedlings /plants. Under stress conditions at 30 °C, parsley seeds are thermally inhibited, and conditioning with Ascophyllum nodosum at the doses used in this study does not promote overcoming inhibition. The physiological conditioning of seeds with Ascophyllum nodosum at the doses tested in this research does not promote gains in the production of seedlings. Thus, the physiological conditioning of parsley9 seeds with Ascophyllum nodosum is not feasible with the doses used in this research.