Photosynthetic Parameters and Growth of Rice, Lettuce, Sunflower and Tomato in an Entisol as Affected by Soil Acidity and Bioaccumulation of Ba, Cd, Cu, Ni, and Zn.

Flávio Henrique Silveira Rabêlo,Flávio Araújo Pinto,Luís Reynaldo Ferracciú Alleoni,José Lavres

doi:10.1007/s00244-021-00850-2

Flávio Henrique Silveira Rabêlo, Flávio Araújo Pinto + Show 2 more

Open Access

https://doi.org/10.1007/s00244-021-00850-2

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Abstract

The bioaccumulation of trace elements (TEs) in crops consumed by humans can reduce food production as a consequence of photosynthetic damage in plants and cause several diseases in humans. Liming is a soil management strategy designed to alleviate soil acidity and mitigating these problems by reducing the TE bioavailability. In this study, we evaluated the effect of liming on photosynthesis, growth, and bioaccumulation of barium (Ba), cadmium (Cd), copper (Cu), nickel (Ni), or zinc (Zn) in lettuce (Lactuca sativa L.), rice (Oryza sativa L.), sunflower (Helianthus annuus L.), and tomato (Solanum lycopersicum L.) grown in a sandy Entisol. The crops were grown in either uncontaminated or contaminated Entisol, at two base saturation (BS%) ratios: 30% for all crops or 50% for rice and 70% for lettuce, sunflower, and tomato. The photosynthesis-related parameters varied depending on the metal and the crop, but in general, increasing BS% did not attenuate photosynthetic damage induced by Ba, Cd, Cu, Ni, and Zn in the crops. There was no strong correlation between the photosynthetic parameters and biomass production, which indicates that the suppression of biomass induced by Ba, Cd, Cu, Ni, or Zn is related to other metabolic disorders in addition to the impairment of CO2 assimilation or chlorophyll synthesis in the crops assayed, with the exception of Ni and Zn in lettuce. In conclusion, increasing BS% was not consistent in reducing Ba, Cd, Cu, Ni, and Zn accumulation in the edible parts of lettuce, rice, sunflower, and tomato grown in the sandy soil, which is probably related to the low capacity of this soil to control TE bioavailability.

Highlights

Trace elements (TEs) are minor components of the solid soil phase, but they play an important role in soil fertility, soil contamination and food production (Gupta et al 2019)
There was no strong correlation between the photosynthetic parameters measured and biomass production, which suggest us that the suppression on biomass induced by Ba, Cd, Cu, Ni or Zn is related to other metabolic disorders besides the impairment on CO2 assimilation or chlorophyll synthesis in the crops assayed, with exception of Ni and Zn in lettuce
The pseudo-total Ba concentration in the Entisol cultivated with lettuce was 20% lower at base saturation of 70% compared to 30% (Fig. 1A)

Summary

Introduction

Trace elements (TEs) are minor components of the solid soil phase, but they play an important role in soil fertility, soil contamination and food production (Gupta et al 2019). The increasing soil contamination with these elements through anthropogenic activities, like mining, have become a global issue and environmental threat because these TEs can be accumulated in plant tissues and enter into food chain (Jolly et al 2013) Crops such as lettuce (Lactuca sativa L.), rice (Oryza sativa L.), sunflower (Helianthus annuus L.) and tomato (Solanum lycopersicum L.) are between the most consumed food in the world, and these crops can accumulate TEs in their edible parts in concentrations enough to cause clinical problems to humans (Piotto et al 2018; Gupta et al 2019; Lavres et al 2011, 2019). The employment of strategies that mitigate TEs uptake by crops is quite important to decrease their intake

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