Fisiologia do rabanete em diferentes arranjos espaciais

Abstract

The radish (Raphanus sativus L.) is a short cycle crop, which provides a rapid economic return to the producer. For its cultivation, the definition of aspects related to the field implantation, the choice of the ideal crop spacing combined with the density of plants per hole, and the understanding of its effects on the physiology of the crop, help to obtain maximum productive efficiency. Thus, the present study had the objective of evaluate the physiological performance of the radish subjected to different spacings between plants and plant densities per hole. For this, an experiment was carried out in the Didactic Garden of the Federal University of Ceará, under a randomized block design, with four replications, in a 4 x 2 factorial scheme. The first factor was composed of four different plant spacings (0.05; 0.10; 0.15; 0.20 m) and the second by two cultivation densities (one and two plants per hole). The following aspects were evaluated: 1) internal CO2 concentration (Ci); 2) transpiration (E); 3) stomatal conductance (gs); 4) liquid photosynthesis (A); 5) ratio between the internal concentration of CO2 and the environment (Ci/Ca); 6) instantaneous carboxylation efficiency (A/Ci); 7) gross photosynthesis (FB); 8) chlorophyll content 'a' and chlorophyll content 'b'; and, 9) leaf area (FA). The density of two plants per pit combined with the larger spacings were those that provided the highest values of liquid photosynthesis and chlorophyll for the plants. The treatments with seeding densities were only one plant per pit, combined with spacings of 0.05 to 0.15 m between plants were the ones that allowed to obtain higher values for FB.