Impacts of silicon and silicon nanoparticles on leaf cell ultrastructure of pea plant under salinity stress

Document Type : Original Article

Authors

1 Botany Department, Faculty of Science, Mansoura University, Mansoura, 35516, Egypt.

2 Faculty of Agriculture, Mansoura University, Mansoura, 35516, Egypt.

Abstract

Salinity is one of the most important environmental stresses that reduce plant growth and makes field crops less productive. Therefore, finding an effective, environmentally acceptable remedy for salinity stress is currently of paramount importance. There are many indications that silicon can ameliorate the injuries caused by high salinity. The current study was carried out to: (1) investigate the effect of NaCl-induced salt stress on the leaf cell ultrastructure of pea (Pisum sativum L.) plant, and (2) assess the possible ameliorative effects of silicon (Si) or nanosilicon (NSi) on the ultrastructural properties of pea plants grown in saline conditions. Various concentrations of NaCl (0, 100, 150, 200, and 250 mM) were used alone or in combination with Si (3 mM sodium silicate) or NSi (3 mM silicon dioxide nanoparticles) in this study. Transmission electron microscopy analysis revealed that chloroplasts underwent the most dramatic changes in leaf cell ultrastructure in response to salt stress. TEM micrographs of plants treated with different concentrations of salinity exhibited morphological deformations of chloroplasts such as swelling of thylakoids, disruption of the envelope, accumulation of plastoglobuli, and a reduction in the number of starch grains. The ultrastructural deformities of cellular organelles, especially chloroplasts, caused by salt were similarly seen to be largely repaired after treatments with Si or NSi. Ultrastructural alterations in these plants shed new light on the cellular-level effects of salt. In conclusion, we affirmed that salt stress is harmful to pea plants, and the addition of silicon showed effectiveness in mitigating the saline harmful effects.

Keywords