Taxa de aparecimento de folhas de azevém anual com diferentes durações de déficit hídrico

Abstract

This study evaluate the influence of different durations of water deficits in leaf appearance rate (LAR) of ryegrass plants. The study was carried in a greenhouse at the Federal University of Pampa, Campus Itaqui, RS, from July to November 2011. Plants were grown in pots of 20 l , it was used the completely randomized design with four treatments (durations of water stress) and four repetitions, totaling 16 pots. It was applied 0 (T1), 5 (T2), 10 (T3) and 15 (T4) days of water deficit in the 6th leaf of the main stem of plant. Four plants per pot were identified with colored wires (white, green, blue and orange), to quantify the Haun Stage (HS). The LAR was determined from the slope of the linear regression between HS and number of days after emergence. It was found that moderate water stress on ryegrass plants, lasting up to 5 days, presents TAF higher than plants grown with good water availability. There was reduction in TAF when there was a greater duration of water deficit.