Comportamento morfoanatômico e crescimento de Garcinia madruno (Kunth) Hammel (Clusiaceae) sob condições de alagamento

Abstract

Garcinia madruno (Kunth) Hammel is a tropical tree that occurs naturally in dry or humid forests and is considered a viable alternative to Amazon for being a major source of population's income, as well as its medicinal importance, which latex is used for curing various diseases. The aim of the study was to describe and compare the responses of morphoanatomic stressed plants and normoxia conditions, and analyzing the growth and biomass plants in flooding. To characterize the morphoanatomic responses and growth of young plants G. madruno were subjected experimentally to two water regimes (control and waterlogged). The flooding was imposed in about 5 cm of water depth above the soil surface using vessels with 12 L. Plant capacity not flooded (control) were irrigated daily, close to field capacity. The plant height, stem diameter, number of leaves, dry weight of shoot (MSPA), root dry mass (MSR), total dry matter (MST), ratio root/shoot (R / PA), lenticels hypertrophic, adventitious roots and anatomical characteristics of root and leaf blade were measured at 0, 21, 42, 63, and 84 days. The flooded plants had 100% survival over the period of stress. The leaves of G. madruno presented the whole limbo, flexible, smooth and elliptical. The margin is the acuneada type, acute apex and peninérvea veining of craspedódroma type. The midrib is more prominent on the abaxial surface, containing secondary veins with angulation of 90 ° to the main. The root is pivotable with poorly developed secondary roots. For the morphological parameters evaluated during the flooding, changes in leaf structure were observed, only leading to a decrease in the amount of roots and browning, indicating a degree of tolerance of the species. However, there were cracks shoot, hypertrophic lenticels and adventitious roots as a way of adapting to waterlogged environment. Also the morphological parameters, anatomical changes arose only in the roots of plants flooded occurring thickening exodermal in the main root and root pericycle the side, moreover, the plants showed flooded aerenchyma and lower amount of starch grains. The histochemical tests detected: starch in the midrib, in the mesophyll, petiole and root flooded plants and petiole of controls; Alkaloids in the midrib, petiole and root flooded plants; Phenolic compounds in the petiole of flooded plants. The flooding caused a significant increase in plant height over stress (p = 0.03), an increase of 5.81%. The stem diameter (DC) showed a slight decrease, with a reduction of 1.8% of the flooded plants, however, this reduction was not significant. Regarding the number of leaves, although the average flooded have been higher than the average of the controls, the parameter also showed no significant differences, indicating that the DC and the number of leaves are not affected by the stress imposed, suggesting some degree of tolerance species. The MSPA was significantly higher in waterlogged period, an increase of 7.9%. The MST was significantly reduced over time stress, a reduction of 4.4%. The MSR also reduced significantly throughout the experiment. Thus, it can be concluded that the bacurizinho is a resistant strain to flooding.