Estabelecimentos de plantas de sorgo granífero sob diferentes regimes hídricos

Abstract

The present study aimed to identify the effect of water availability on the initial growth of sorghum plants, as well as to identify the drought and excess water tolerance strategy. The work was conducted under a bench in a greenhouse covered with transparent plastic and sides with shade that intercept 50% of solar radiation at the State University of Goiás, Campus Sul, UnUIpameri. The seeds of Sorghum bicolor were sown in vases with a capacity of five liters containing a mixture of soil, sand and manure in the proportion of 3:1:1 respectively. A completely randomized design with six treatments and six replications was used. After emergence and initial development for 20 days, the plants were irrigated with volumes of water corresponding to 0%, 25%, 50%, 100%, 200% and 400% of daily evapotranspiration. The evaluations occurred at 40 days after emergence. Water restriction limits the growth of sorghum plants, however, to tolerate stress the plants increase the length of the root system and reduce transpiration through efficient stomatal control and remain hydrated for growth continuity. Excess water between 100% and 400% of the ET did not limit the growth of Sorghum bicolor plants, since the high transpiration rate eliminated the excess water in the soil from the atmosphere, however, from 230% of the ET the plants showed skimpy signs of decrease in leaf initiation and relative water content.