Water Stress and Temperature Effects on Germination and Early Seedling Growth of Digitaria eriantha

Abstract

We assessed seed germination and seedling survival of the grass Digitaria eriantha cv. Irene to determine its potential for re-vegetation in the arid parts of Argentina. We evaluated the effects of (1) water stress and temperature on the germination, and (2) water stress on the early seedling growth under controlled conditions. During the first 24 hrs the germination at constant temperature exceeded by 50 % (one-way ANOVA: F3,20=67.40, p<0.001) the germination at the 30—10ºC alternating temperatures, although the total germination was about 80% in all temperature treatments. Germination percentages and coefficients of velocity were lower (two-way ANOVA main effect of water potential: Germination: 15 h, 18 h, 2006: F6,35=4.69, p<0.0013, 2007: F6,35=38.99, p<0.0001; 24 h, 2006: F6,35=10.66, p<0.0001, 2007: F=44.99, p<0.0001; 36 h, 2006: F6,35=6.05, p<0.0002, 2007: F6,35=23.54, p<0.0001; 60 h, F6,70= 2.46, p<0.0325; Coefficient of velocity: F6,70=30.33, p<0.0001) as water potentials decreased. Early seedling growth was lower (three-way-ANOVA main effect of water potential: F5,120=19.14, p<0.001) at lower water potentials. The high sensitivity of the two studied processes in D. eriantha suggests that it is quite susceptible to be considered for revegetation purposes in the rangelands of arid Argentina.