Anatomical and physiological traits of maize under contrasting water level and cattail occurrence

Abstract

Maize is one of the most important and cultivated crops in the world, with cultivar BRS-4154, known as 'Saracura' maize, a tolerant to flooding genotype. The Southern cattail, Typha domingensis, is an aquatic plant with known activity of radial oxygen losses, being widely diffused around the world and highly invasive. The objective of the study was to analyze the interaction of 'saracura' maize with cattail in two distinct environments, under waterlogging and in an in soil at field capacity. The experiment was conducted in a greenhouse at the Federal University of Lavras in the Biology department, where maize seeds were germinated in red latosol at the field capacity with nutrient solution, after 10 days of germination, when the maize plants reached an average height of 12.5 cm and 2 fully expanded leaves per plant, the sources of variation were introduced, the sources being the presence or absence of Southern cattail and waterlogging or field capacity, the experiment was conducted in a 2 x 2 factorial with a completely randomized design and the conditions maintained throughout the experiment by refilling of the water lost by evapotranspiration bidaily. Plant growth data, such as height, number of fully expanded leaves, number of dead leaves were collected fortnightly until the sixty day of the experiment conduction and dry weight was measured at the eightieth day. The analysis of gas exchange and chlorophyll content were made at 30 and 60 days after introduction of sources of variation using an infrared gas exchange analyzer and a SPAD unit meter. At that time, 1 leaf per plant was collected for each date and submitted to usual microtechnique procedures. In the final 5 days of the experiment, the dissolved oxygen content in the substrate of the waterlogged plots was measured consecutively with a dissolved oxygen meter and at the end of the experiment, one root per plant was collected and submitted to usual microtechnique procedures. The waterlogging was detrimental in the growth parameters, gas exchange, foliar and root anatomy of the maize, while southern cattail increased the dissolved oxygen content of the substrate and contributed to maize enhancement in growth, leaf and root anatomy, and gas exchange without presenting effects of competition.