Impacto da limitação hídrica durante a fase vegetativa em plantas de cubiu (Solanum sessiliflorum Dunal)

Abstract

Coccona ( Solanum sessiliflorum states Dunal) is a native species from Amazon region which it only a few studies concerning stress physiology. Bearing this on mind, wild species and/or landraces are usefful form crop breeding as tomato and eggplant. This work aimed identify physiological response of plant submitted to water shortage followed by re covery. The work design was carried out in greenhouse located in Instituto de Educação, Agricultura e Ambiente. For biometric data, it was used S. sessiliflorum plants kept to the following treatments: control (irrigated every day), moderate (7 days withou t irrigation), severe (10 days without irrigation), with 5 replications. Stem height and diameter were measured every 2 days, dry mass was determined at the end, with the organs (roots, stem and leaves) taken to a forced circulation oven and kept at 70 °C for 72 h, determining whether the allocation of dry matter to the various constituents of the plant in addition to the root/shoot ratio. In general, the allocation of matter in plants did not change in relation to the shoot/root ratio. Evaluating the compo nents separately, leaf dry matter was drastically reduced in the stress treatments compared to the control. Root size, stem diameter and plant height did not differ by origin. To obtain the photochemical parameters, plants grown in a greenhouse maintained for 7 days of water deficit were used, in two treatments: Control (wellirrigated plants) and Stress (nonirrigated plants), with eight experiments each. The Fo collection tweezers were placed on the fifth leaf, preadapted to the dark for 30 min, away fro m the main veins. Chlorophyll a fluorescence parameters (Fv/Fm, Fm, Fo and NPQ and qP) were obtained on day 1, day 3, day 5 and day 7, using the PAM2500 equipment (WALZ, Germany). The values of Fv/Fm remained stable in the first five days of stress, in th e seventh day of stress it was statistically different, values of qP decreased and had statistical difference in the third and seventh day and the values of NPQ as a function of qP with the tendency to increase, had a significant difference on the third da y of stress, which proved that the stress due to water deficit was affecting the integrity of the cubiu plants. The results show that deficit stress causes major disturbances in the biochemical and physiological systems of plants.