Suchergebnisse

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.

The objective of the present study was to identify the effect of water availability on corn plant growth. The study was carried out in greenhouse covered with transparent plastic with Sombrite material sides that intercepted this 50% solar radiation located at the State University of Goiás, Brazil, South-East Campus Ipameri. Four corn seeds were planted in each polyethylene pot containing 8 kg substrate consisting of soil, sand and manure at the proportion of 3:1:1, respectively. A completely randomized design was used with six treatments and six replications. After emergence and initial development, the plants were irrigated with volumes of water corresponding to 0%, 25%, 50%, 100%, 200% and 400% of the daily evapotranspiration at 23 days after emergence. At 31 days after emergence the following variables were analyzed: number of leaves, plant height, stem diameter, total biomass, root mass ratio, stem mass ratio, Leaf mass ratio, photosynthetic pigments, relative water content, transpiration rate and chlorophyll a fluorescence. Water shortage and flooding inhibited growth in the corn plants and thus damaged the crop establishment, but at different intensities, because water shortage was much more restrictive to plant development than flooding. Furthermore, it is emphasized that the corn plants are isoydric because they anticipate water shortage through efficient stomata sensitivity that controls water loss by transpiration.