New outcomes on how silicon enables the cultivation of Panicum maximum in soil with water restriction

Abstract

Climate change increases the occurrence of droughts, decreasing the production of tropical forages through the induction of physiological stress. Si is expected to broaden the limit from physiological stress of forages grown under water restriction, which may come from an improvement in the stoichiometric homeostasis of Si with N and C, favoring physiological aspects. This study assessed whether Si supply via fertigation improves physiological aspects and the water content in the plant by means of an antioxidant defense system and changes in the C:N:Si stoichiometry during the regrowth of two cultivars of Panicum maximum grown under two soil water regimes (70 and 40% of the soil’s water retention capacity). The forages studied are sensitive to water deficit without silicon supply. The application of Si via fertigation attenuated the water deficit, favoring plant growth by stabilizing the stoichiometric homeostasis C:N and C:Si, which are responsible for increasing the plant capacity of converting accumulated C in dry mass, favoring the water content of the plant tissue and the photosynthetic efficiency. This study highlights the importance of the physiological function of Si, and effects on the stoichiometry of C and N, which are neglected in most research on forages grown under water restriction.

Impact of Si on C, N, and P stoichiometric homeostasis favors nutrition and stem dry mass accumulation in sugarcane cultivated in tropical soils with different water regimes

“…However, studies on this species and most crops focus on plants grown under abiotic (Verma et al, 2020b;Sousa Junior et al, 2021;Teixeira et al, 2021) and biotic stress conditions (Tomaz et al, 2021). There are indications that the beneficial element modifies the C:N:P stoichiometry, guaranteeing productivity gains, which was observed in forage plants cultivated in Quartzarenic Neosol (Rocha et al, , 2022 and young sugarcane plants cultivated for only 30 days (Teixeira et al, 2020) and 80 days (Oliveira Filho et al, 2021). However, it is unknown whether these effects could reflect in a later growth stage of the crop's stems.…”

New approaches to the effects of Si on sugarcane ratoon under irrigation in Quartzipsamments, Eutrophic Red Oxisol, and Dystrophic Red Oxisol

“…Additionally, water deficit reduced the stoichiometric ratio C:N in leaves of sugarcane plants cultivated in Eutrophic Red Oxisols and decreased the stoichiometric ratio C:Si in sugarcane plants cultivated in Eutrophic Red Oxisols and Dystrophic Red Oxisols. In regrowth of Panicum maximum , the stoichiometric ratio C:N decreased, reducing the concentration of C and causing instability in the metabolism of the culture [ 26 ]. However, plants of the first cycle of Panicum maximum had no impact of water deficit on C:N stoichiometry ratio, as observed for the cultivar Masai.…”

“…The induction of a new homeostatic balance of C:N:P caused by Si under water deficit conditions also occurs in 30-day pre-sprouted seedlings [ 13 ], and 90-days [ 32 ], 150-days [ 33 ] and 160-days [ 31 ] sugarcane plants. The induction of a new C:N:P homeostasis is not only restricted in sugarcane plants, but has also been observed in forage [ 26 , 27 ], quinoa [ 35 ], wheat [ 36 ], sorghum and sunflower [ 17 , 37 ]. This helps to consolidate another benefit of Si in the cultivation of sugarcane that also occurs in sugarcane ratoons, but it is not restricted only to this crop.…”

Silicon induces resistance to leaf scald in sugarcane under water deficit

“…Abiotic stresses such as drought (Kemesyte et al, 2017) and high temperature (Ahammed et al, 2019) threaten the persistence and regrowth capacity of tropical grasses (Rocha et al, 2022b). One of the factors that make production environments more restrictive for sugarcane is water de ciency (Landell et al, 2014).…”