Crescimento de mudas de paricá submetidas à desfolha e ao déficit hídrico

Abstract

Paricá, Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby, is a native tree species, widely used in reforestation in the Amazon because of its high timber value. However, the increasing cultivated areas was not accompanied by phytosanitary actions of systematic monitoring of insects and due to damage caused by insects, interfering with their growth, it is necessary to measure the intensity of defoliation and damage and, therefore, artificial defoliation can be a valuable tool. Furthermore, plantations that use this kind are located in areas subject to water stress, which may lead to lowering of plant defenses, reducing growth and photosynthesis. Thus, the work presented aimed at evaluating the recoverability of Schizolobium kind parahyba var. amazonicum, by simulating defoliation and identifying strategies of tolerance to water deficit plants paricá to promote breeding programs. The experiments were conducted at the State University of Goiás, University Unit Ipameri -. Goiás In chapter 1, the experimental design of randomized blocks, divided into two experiments, separated into two distinct periods of plant development, 30 and 60 days was used after emergency, and an experiment with removing the leaves in the percentages of 0, 50 and 100% and the other with the removal of the leaflets, the percentages of 0, 25, 50, 75, and 100%, with four replications. When he was 30 and 60 days after germination, the defoliation treatments were carried out as quoted, and 30 after defoliation, recovery characteristics of plants were evaluated by analyzing the variables plant height, stem diameter and number of leaves. Data were subjected to analysis of variance and, subsequently, for the regression of percentage defoliation. Paricá decreased in the simulation development of defoliation, however, was tolerant of all percentages tested, showing good ability to recover the damages. Thus, in a satisfactory manner, the development paricá presented under the two stresses tested, making it tolerant during the changes and adaptation to drier and attack defoliating pests regions. Chapter 2 was conducted in a greenhouse in pots with eight liters of substrate consisting of 0-20 cm soil layer. The experiment was carried out in a randomized block design with five treatments (plants irrigated with water volume relating to 20, 40, 60, 80 and 100% evapotranspiration) and six replications. The plants were irrigated daily with a volume corresponding to 100% of evapotranspiration and water, at 90 days after germination, the plants were subjected to ten days of water deficit, then the plants were irrigated for over ten days with different percentages plant height, stem diameter, number of leaves, carotenoids, chlorophyll, daily transpiration total: cited in evapotranspiration and 110 days after germination, after 10 days of water deficit, the analysis was performed on variables that were measured as , relative water content, also measurement of the ratio of root mass, stem mass ratio, leaf mass ratio and total biomass. Data were subjected to analysis of variance and, where the F test was significant, we performed a regression analysis for the percentages of evapotranspiration, a 5% probability. Statistical analyzes were conducted using SISVAR. The results indicated that the paricá is tolerant to water stress, as it has defense mechanisms, but in the seedling stage in the development was reduced.