Silício na nutrição mineral e acúmulo de alumínio em plantas de arroz de terras altas

Abstract

RESUMO O silício é capaz de proteger as plantas contra vários estresses bióticos e abióticos, entre eles o estresse por alumínio. No entanto, a interação entre silício e alumínio ainda é pouco conhecida, sendo que há diversas hipóteses para justificar o papel do silício na amenização do estresse causado por alumínio. Objetivou-se avaliar o efeito da aplicação de silício nos teores e acúmulos de macro e micronutrientes, alumínio e silício na parte aérea de plantas de arroz de terras altas cultivadas sob estresse por alumínio, bem como as características químicas do solo após a colheita. O delineamento experimental utilizado foi o de blocos casualizados, disposto em modelo fatorial 2 x 5, com quatro repetições. Os tratamentos consistiram de duas cultivares de arroz de terras altas (BRS Talento - não tolerante ao alumínio; Guarani - tolerante ao alumínio) e cinco doses de silício (0 mg dm-3, 30 mg dm-3, 60 mg dm-3, 90 mg dm-3 e 120 mg dm-3). O silício aplicado aumenta o teor de silício na planta e no solo e diminui o teor de alumínio na parte aérea, porém, não incrementa a absorção de macro e micronutrientes e não altera o teor de alumínio e pH do solo.

Silicate fertilization potentiates the nodule formation and symbiotic nitrogen fixation in soybean1

“…However, some studies have reported that the Si source application has not been sufficient to enhance the N level of plants. Freitas et al (2015) reported that application rates of 50-120 mg kg -1 of Si did not result in a significant effect on the N concentration in rice leaves. Similarly, the soybean leaf N concentration was not significantly affected by application rates of 50-200 mg kg -1 of Si (Ruppenthal et al 2016).…”

“…In this study, the silicate fertilization could be expected to result in thickening the leaves (i.e., lower specific leaf area) in various crops, since this element has been reported to accumulate in the leaf epidermal cell walls (Meena et al 2014). In a study made by Gong et al (2003), it was found that wheat plants grown in pots with Si applied before sowing had lower specific leaf area, if compared to those without Si applied under drought stress conditions. This demonstrates that the leaves of stressed plants growing in pots with applied Si were thicker, when compared to those without Si.…”

“…Xie et al (2014) applied 750 kg ha -1 of silicate and also observed chlorophyll levels 20 % higher in maize plants. In a study made by Hattori et al (2005), a marked Si-induced enhancement in photosynthesis and chlorophyll fluorescence was reported in sorghum plants [Sorghum bicolor (L.) Moench], under water deficit conditions. The beneficial effect of Si on chlorophyll level has been attributed to the accumulation of silica on the tissue stirface (Ma & Yamaji 2006), which changes the architecture of the plants and keeps the leaves more exposed to light.…”

“…Calcium and magnesium silicate can be used as a corrective of soil acidity (Castro & Crusciol 2015, Sarto et al 2015 and as a Si source (Ruppenthal et al 2016). The application of Si shows beneficial effects on the growth and yield of several crops, especially those considered as Si-accumulating plants, such as rice, sugarcane, maize, sorghum and wheat (Hattori et al 2005, Kaya et al 2006, Zanão-Júnior et al 2010, Sarto et al 2015, Camargo et al 2017. However, dicotyledonous species, considered as non-Si accumulating plants, such as tomato, cucumber, cowpea, cotton, potato and soybean, have also responded positively to the soil-applied Si (Nelwamondo & Dakora 1999, Toresano-Sánchez et al 2012, Ferraz et al 2014, Pilon et al 2014, Wang et al 2015, Pascual et al 2016.…”

Pasture recovery with the application of agricultural gypsum associated with nitrogen fertilization

“…To obtain good indicators of soil quality, a combination of physical, chemical and biological attributes will occur, which together, hypothetically, would represent an ideal combination in order to provide optimal conditions for plant development and maximum expression of their biological potential (Colodel et al, 2018). In this sense, alternatives should be sought in management that are simple, economically viable and that contain technologies accessible to producers, where they seek less impact and movement in the soil structure, among them, the application to the surface of agricultural corrective products becomes a strategy to mitigate these damages to the soil (Neves Junior et al, 2013) The substantial increase in the levels of exchangeable aluminum in the soil solution can cause several morphophysiological disorders for most cultivated plants (Freitas et al, 2015), mainly affecting the root system, altering or even impeding water and nutrient absorption patterns (Pezzopane et al, 2015;Fidelis et al, 2018). These disorders also manifest deleterious effects on the aerial part of the plant body, such as reduced size and dry mass and Research, Society and Development, v. 9, n. 9, e913997981, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i9.7981 leaf deformity (Derré et al, 2013).…”