Responses of antioxidant enzymes, photosynthetic pigments and carbohydrates in micropropagated Pitcairnia encholirioides L.B. Sm. (Bromeliaceae) under ex vitro water deficit and after rehydration

Abstract

In this study, the activities of antioxidant enzymes, photosynthetic pigments, proline and carbohydrate contents in Pitcairnia encholirioides under ex vitro conditions of water deficit were evaluated. Results show that plants under progressive water stress, previously in vitro cultured in media supplemented with 30 g L-1 sucrose and GA3, accumulated more proline and increased peroxidase (POD) activity and the contents of photosynthetic pigments and carbohydrates. For plants previously in vitro cultured with 15 g L-1 sucrose and NAA, no differences were found for proline content and there were reductions in activities of peroxidase (POD), catalase (CAT) and poliphenoloxidase (PPO), and in contents of carbohydrates, with progress of ex vitro water deficit. After rehydration, plants showed physiological recovery, with enzymatic activities and contents of metabolites similar to those found in the controls not submitted to dehydration, regardless of the previous in vitro culture conditions. These results show that micropropagated P. encholirioides has high tolerance to dehydration once in ex vitro conditions, which can ensure the survival of plants from tissue culture when transferred to its natural environment, emphasizing the importance of such biotechnology for the propagation of endangered species.

WATER-RETAINING POLYMER MITIGATES THE WATER DEFICIT IN Schinus terebinthifolia: PHOTOSYNTHETIC METABOLISM AND INITIAL GROWTH

“…Tropical regions, particularly the Cerrado ecoregion, are characterized by different vegetation types and climatic seasonality that are caused by water fluctuations, leading to water deficit in certain periods of the year as a consequence of precipitation fluctuations (Fonseca et al, 2017). The low water availability in the soils of the Cerrado region can cause functional and metabolic damage to plants, such as stomatal closure, reduced Rubisco carboxylation efficiency, and increased intercellular CO2 concentration and production of reactive oxygen species (ROS), thereby compromising plant photosynthetic capacity and growth (França et al, 2017;Resende et al, 2019).…”

Physiology and production of sugar-apple under water stress and application of proline

“…The decrease in internal CO 2 concentration reflects the decrease in the total water potential in the soil, which induces stomatal closure and hence reduces the entry of CO 2 into the substomatal chamber. Physiology and production of sugar-apple Decrease in intercellular CO 2 concentration may also lead to a decline in photosynthesis and reductions in carboxylation efficiency and in the activity of RuBisCO and other enzymes, compromising the photosynthetic capacity and development of plants (Resende et al, 2019). Foliar application of proline at concentration of 10 mM decreased the internal CO 2 concentration compared to plants subjected to 0 mM L -1 (Figure 2B).…”

Shading minimizes the effects of water deficit in Campomanesia xanthocarpa (Mart.) O. Berg seedlings

“…The stress generated by adverse environmental factors stimulates the antioxidant metabolism, which plays an important role in ameliorating the damage caused by drought, extreme temperatures, pollutants, ultraviolet radiation, and high/low light levels. Resende et al (2019) highlighted that little information on the biochemical responses of plants to water stress addresses endangered species, most of which refer to species of economic interest. Thus, to better use available water resources and optimize seedling production for recomposition projects, it is necessary to evaluate the efficiency of the photosynthetic apparatus and antioxidant activity of the seedlings.…”