Comportamento fisiológico de sapindus saponaria l. submetidas à restrição hídrica

Abstract

The man action on the environment carries injurious consequences to the ecosystem. Thus, different species, such as Sapindus saponaria L., are being established in pioneer plantations in degraded areas. The plants, on these scenarios, experience fluctuations and environmental stresses, such as water stress, characterized as a major cause of mortality and growth retardation of native species in degraded areas, acting in several physiological processes of plants. Based on this, the aim of the work was to study the physiological responses in S. saponaria plants grown in early development stage under drought conditions. For this, seeds were seeded in trays containing commercial substrate and grown in the greenhouse. After 60 days from seeding, the plants were transferred to perforated plastic pots (8L capacity), keeping one plant per pot. Three months after transplantation, the pots were weighed and the heights and the stem diameters of plants were measured. This time were established three irrigation levels: irrigated, partially irrigated and non-irrigated, under which the plants were grown for 75 days; reviews and collections were made every 15 days. Growth parameters, relative water content in leaves, chlorophyll index, proline contents, hydrogen peroxide and lipid peroxidation, as well as activity of antioxidant enzymes were evaluated. For each evaluation period were collected four plants per treatment, and the experimental unit consisting of a plant in a completely randomized design. The results were submitted to analysis of variance, and means were compared by Tukey test at 5% probability. Based on the results, S. saponaria plants partially irrigated shown reduced growth rate, chlorophyll index and APX activity only after 60 days of stress, although a it was a significant increase in lipid peroxidation at 30 and 45 days. On the other hand, when non-irrigated, there was no response pattern, but in general terms, the results may indicate a tolerance level within 45 days the stress. After this period, the majority of parameters showed negative responses.