Silicon Fertilization: A Step towards Cadmium-Free Fragrant Rice

Abstract

Soil contamination with toxic cadmium (Cd) is becoming a serious global problem and poses a key hazard to environments and the health of human beings worldwide. The present study investigated the effects of foliar applications of three forms of silicate chemicals (calcium silicate, sodium silicate, and potassium silicate) at four rates (0.25%, 0.5%, 0.75%, and 1.0%) at tillering stage on rice growth and the accumulation of Cd under Cd stress (30 mg kg−1). The results showed that Cd stress reduced the yield-related traits and enlarged Cd contents in different rice organs. The leaf gas exchange attributes and yield traits were enhanced, and the Cd accumulation and bioaccumulation factor in rice organs were reduced, especially in grains, through silicon application. In shoots, roots, and grains, foliar spray of Si reduced Cd contents by 40.3%, 50.7%, and 47.9%, respectively. The effectiveness of silicate compounds in reducing Cd toxicity varied with the kind of chemicals and doses of foliar applications. Foliar application of potassium silicate, at a rate of 0.5%, at tillering stage, showed the best effectiveness in improving grain yield, while mitigating Cd accumulation in rice grains. The outcome of this study provides a promising practicable approach in alleviating Cd toxicity in rice and preventing the entrance of Cd into the food chain.

Silicon fertilization counteracts salinity-induced damages associated with changes in physio-biochemical modulations in spinach

“…The turgidity loss of guard cells causes stomatal cessation resulting in a reduced availability of CO 2 which leads to a decreased photosynthetic efficiency [ 58 , 60 ]. By the use of Si fertilizer, leaves and stem epidermal cells show minimum loss of water by reducing the rate of transpiration [ 62 – 64 ]. Silicon influences water relations in crop plants by inducing the development of a double layer silica cuticle under the epidermis of the leaf which decreases the loss of water through cuticular transpiration.…”

“…Silicon increases the stress tolerance of crop plants by extracting water from the soil as a result of root elongation and up-regulation of aquaporin genes [ 65 ]. There is a multifunctional role of Si that improves the plant physiology under saline conditions and results in reduced Na + influx, up-regulation of the antioxidant resistance system, improves the rate of photosynthesis, and enriches activity of ribulose biphosphate carboxylase [ 25 , 51 , 64 , 66 ].…”

“…The damage in the cell membrane is also observed by the oxidative damage under the salinity atmosphere [ 82 ]. Antioxidant enzymes like SOD, CAT, and POD are regulated by reducing the rate of oxidative damage through the use of Si fertilizer [ 27 , 30 , 64 , 78 ]. Additionally, Si fertilizer reduces the effects of salinity and moderates the flow of antioxidant enzymes [ 83 ].…”

Alleviation of Cadmium Stress by Silicon Supplementation in Peas by the Modulation of Morpho-Physio-Biochemical Variables and Health Risk Assessment

“…Soil is a fundamental supporting medium in terrestrial ecological systems, serves as a main sustainable source of nutrients accessible to plants for growth [ 1 ] and provides conditions under which the diffusion of materials and energy takes place. Soil contains heavy metals (HMs), including cadmium (Cd), arsenic (As), lead (Pb) and mercury (Hg), that may build up in the environment and endanger humans and other living things on the earth [ 2 ].…”

“…Soil contains heavy metals (HMs), including cadmium (Cd), arsenic (As), lead (Pb) and mercury (Hg), that may build up in the environment and endanger humans and other living things on the earth [ 2 ]. The HM contamination of soil is a significant threat aggravated by human activities and operations, including wastewater and sewage sludge usage for irrigation purposes, the mining of minerals, fertilizer, pesticide use and increasing vehicle and industrial emissions [ 1 , 2 , 3 ]. Plant HM contamination leads to changes in morphology, physiology, biochemistry and ultrastructure [ 4 ].…”