Autor(es): Machado, Joana ; Fernandes, Ana Patricia G. ; Bokor, Boris ; Vaculík, Marek ; Heuvelink, Ep ; Carvalho, Susana M. P. ; Vasconcelos, Marta W.
Data: 2024
Identificador Persistente: http://hdl.handle.net/10400.14/41967
Origem: Veritati - Repositório Institucional da Universidade Católica Portuguesa
Assunto(s): Abiotic stress; Antioxidant system; cv Micro-Tom; Phenolics; Plant growth; Silicon
Exploring sustainable strategies for improving crop water and nitrogen use efficiency is essential. Silicon (Si) has been reported as a beneficial metalloid for plants since it alleviates several abiotic stresses (including drought) by triggering the plants´ antioxidant system. However, its role in mitigating the negative impact of nitrogen (N) deficit alone or when combined with water (W) deficit is not well studied. This study applied 0 or 2 mM of Na₂SiO to 3-week-old tomato cv. Micro-Tom seedlings that were grown under the following conditions: control (CTR; 100%N+100% Field Capacity), N deficit (N; 50% N + 100% Field Capacity), water deficit (W; 100% N + 50% Field Capacity) or combined stress (N+W; 50% N + 50% Field Capacity. The Si effect on tomato plant growth depended on the type of stress. Si could only alleviate stress caused by N+W deficit resulting in a higher root dry weight (by 28%), total dry weight (by 23%) and root length (by 37%). Alongside this, there was an increase in the antioxidant (AOX) system activity with the root activity of the studied AOX enzymes APX and CAT being enhanced by 48% and by 263%, respectively. Si application also enhanced AOX enzyme activity when tomato plants were subjected to individual deficits but to a lesser extent. In conclusion, Si-treated tomato plants could efficiently modulate their AOX networks in a situation of combined N and water limitation, thus mitigating some of the adverse effects of this combined stress.
