Influence of Nano Silicon and Nano Selenium on Root Characters, Growth, Ion Selectivity, Yield, and Yield Components of Rice (Oryza sativa L.) under Salinity Conditions.

Shimaa A Badawy,Sherif M A Bassiouni,Esmat F Ali,Bassiouni A Zayed,Mahmoud F Seleiman,Ayman H A Mahdi,Ali Majrashi

doi:10.3390/plants10081657

Abstract

Rice production under salinity stress is a critical challenge facing many countries, particularly those in arid and semi-arid regions. This challenge could be handled by applying novel approaches to overcome yield limiting factors and improve resource use efficiency. The usage of nanoparticles (NPs) could be a beneficial approach to managing the growing problem of soil salinity. The aim of our study was to investigate the advantageous effects of soaking and foliar application of silicon (Si) and selenium (Se), (NPs-Si at 12.5 mg L−1 and NPs-Se at 6.25 mg L−1) on root characteristics, moropho-physiological traits, and yields of two rice varieties (i.e., Giza 177 as a salt sensitive and Giza 178 as a salt tolerant) grown in saline soil compared to untreated plants (control treatment). Results showed that soaking NPs-Se resulted in the highest value of root thickness for Giza 178 (0.90 mm, 0.95 mm) and root volume (153.30 cm3, 154.30 cm3), while Giza 177 recorded 0.83 mm, 0.81 mm for root thickness and 143.30 cm3, 141.30 cm3 for root volume in the 2018 and 2019 seasons, respectively. Soaking NPs-Se, NPs-Si and foliar application of NPs-Se at BT resulted in the highest relative water content and dry matter, while foliar application of NPs-Si at BT gave the highest leaf area index of rice plants compared to the other treatments. Giza 178 (i.e., salt tolerant variety) significantly surpassed Giza 177 (i.e., salt sensitive variety) in the main yield components such as panicle number and filled grains/ panicle, while Giza 177 significantly exceeded Giza 178 in the panicle weight, 1000-grain weight, and unfilled grains number/ panicle. Soaking NPs-Se and foliar application of NPs-Si at BT resulted in the highest grain yield of 5.41 and 5.34 t ha−1 during 2018 and 5.00 and 4.91 t ha−1 during 2019, respectively. The salt sensitive variety (Giza 177) had the highest Na+ leaf content and Na+/K+ ratio as well as the lowest K+ leaf content during both seasons. Applying nano nutrients such as NPs-Si and NPs-Se improved the yield components of the salt sensitive variety (Giza 177) by enhancing its ion selectivity. Both NPs-Si and NPs-Se had almost the same mode of action to mitigate the harmful salinity and enhance plant growth, and subsequently improved the grain yield. In summary, the application of NPs-Si and NPs-Se is recommended as a result of their positive influence on rice growth and yield as well as minimizing the negative effects of salt stress.

Highlights

Soil salinization is a critical concern worldwide and has expanded significantly, resulting in crop yield losses [1]
The treatments were the control, grain soaking in NPs-Si, grain soaking in nanoparticles of selenium (NPs-Se), NPs-Si foliar application at mid tillering stage (MT), NPs-Se foliar application at MT, NPs-Si foliar application at panicle initiation (PI), NPs-Se foliar application at PI, NPs-Si foliar application at mid booting stage (BT), and NPs-Se foliar application at BT
On the other hand, soaking grains at NPs-Se treatment recorded the highest results for the three root characteristics compared to other application treatments during both seasons, followed by NPs-Si foliar at BT and NPs-Se foliar at BT for root thickness in 2018 and 2019 seasons and for root length in 2018

Summary

Introduction

Soil salinization is a critical concern worldwide and has expanded significantly, resulting in crop yield losses [1]. It is a major limitation reducing agricultural productivity on almost 20% of the world’s cultivated and irrigated land [2]. Rice susceptibility to salinity stress varies with growth stage. It is very sensitive to the salinity during germination, immature seedling, and early growth phases [5,6]. Rice at the young seedling stage is sensitive, which affects the density of the plants in the salt fields [11]. The sensitivity and levels of tolerance for successful crop production in a saline environment of the varieties should be identified during early seeding

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Conclusion