Initial growth of sunflower plants under differents water regimes

Abstract

The present study aimed to identify through a range of morphophysiological aspects the effect of water availability in the establishment and growth of Helianthus annuus plants. The experiment was carried out in a greenhouse in the State University of Goiás, Ipameri. It was set up in completely randomized design with six treatments (0%, 25%, 50%, 100%, 200% and 400% of evapotranspiration) and six replications of BRS 323 cultivar in 15 liters pots with 12 kg of substrate containing soil, sand and manure in 3:1:1 proportion respectively. The treatments were established 18 days after the seedling emergence and the analysis were performed on 25nd day. Thus, the H. annuus plants tolerate drought due to the high stomatal sensitivity wich limits the loss of water to the atmosphere and by the increase of root system depth. Also, it stands out that H. annuus plants did not show stress symptoms in the excesso of water, because the high transpiration rate removed to atmosphere the amount of excess of water from irrigation.