Effects of silicon on antioxidant enzymes, CO2, proline and biological activity of in vitro-grown cape gooseberry under salinity stress

Abstract

Cape gooseberry (Physalis peruviana L.) cannot tolerate high levels of salinity. Salt stress is one of the most damaging abiotic stresses that affects plant development. However, there are some evidences that silicon (Si) can act as a mitigating agent of environmental stresses. Towards understanding the stress using tissue culture, we investigated the effect of in vitro NaCl-induced salt stress in cape gooseberry and the potential mitigating effect provided by Si. Nodal segments were inoculated in MS medium with different combinations of NaCl concentrations (0.5 and 1.0% NaCl) and silicic acid (0.0, 0.5, and 1.0 g L -1 ). The experimental design was completely randomized, in a factorial design with a control treatment [(2x3) + 1], totalizing 7 treatments. The control treatment consisted of an additional treatment without the addition of any of the factors. Isoenzyme activity, proline content, CO 2 level and biological activity were assessed after 30 d. We found an increase in all antioxidant enzymes (SOD, CAT and POD) activities when salt stress was imposed, indicating that the plant has an efficient system to protect itself against stress. Among these enzymes, Si played a mitigating role only in POD activity. In relation to other evaluated enzymes, NaCl enhanced the EST and MDH activities, followed by a subsequent decrease in MDH. Si showed different performances according to the concentration of NaCl. Electrophoretic analysis represented by bands illustrated these behaviors. Proline content increased as salinity increased, and Si effect was observed by increasing the levels of this amino acid. High CO 2 level was found at the concentration of 1.0% NaCl, and Si contributed to decrease this variable to normal levels. The reduction in the respiratory rates may contribute to the allocation of carbon to other chemical reactions such as the synthesis of new tissues. Salt stress also increased the biological activity of leaves and there was no effect of Si for this variable. We conclude that salt stress causes a great damage to in vitro-grown cape gooseberry plants and the addition of 1.0 g L -1 Si can ameliorate that damage for some characteristics. However, more studies are necessary since the physiological changes played by Si have been poorly understood for dicots.

Silicon and agar on in vitro development of cockscomb (Amaranthaceae)

“…Therefore, the results achieved cannot be attributed exclusively to silicon, but also to other associated elements, as reported by other authors (Soares et al, 2011;Colombo et al, 2016). In contrast, in the present study, a pure source of silicon was used, silicic acid (H 4 SiO 4 ), which may have been insufficient to ensure a significant result regarding the phytotechnical characteristics, although it has contributed to reduce damage caused by saline stress under in vitro conditions (Rezende et al, 2017 However, some studies show that silicate sources did not affect the in vitro development of various plant species, mainly of ornamentals, such as the C. loddigesii (Soares et al, 2013) and C. forbesii Lindl. (Colombo et al, 2016) orchids.…”

Salt stress and exogenous silicon influence physiological and anatomical features of in vitro-grown cape gooseberry

“…In view of all this information, P. peruviana was chosen to compose this study due to its increasing importance as an economic alternative for small producers in several Brazilian regions and for its appeal as a plant of medicinal interest for industry. Its cultivation in vitro revealed that cape gooseberry is a non-tolerant plant to salt stress (REZENDE et al, 2017).Thus, it is necessary to increase the knowledge concerning the physiological and anatomical changes to better understand the plant responses and to propose alternatives that mitigates damages, such as the use of Si.…”

Effect of cadmium, chromium, and lead on micropropagation and physio-biochemical parameters of Bacopa monnieri (L.) Wettst. cultured in vitro

“…This technique can be carried out in small areas, short periods and under controlled conditions, and thus stress-tolerant variants can be determined (Rai et al 2011). The responses of plants propagated by tissue culture under stress conditions such as salt (Summart et al 2010;Rezende et al 2017), drought (Safarnejad 2004;Matheka et al 2008) and heavy metal (Leung 2017; have been studied previously.…”