Foliar application of Zn reduces Cd accumulation in grains of late rice by regulating the antioxidant system, enhancing Cd chelation onto cell wall of leaves, and inhibiting Cd translocation in rice

Abstract The gap between the current serious soil heavy metal (HM) contamination situation and the low efficiency of soil remediation has become one of the factors limiting economic development and human health. The aim of this study was to propose a method to improve the efficiency of phytoremediation by exogenous rutin application and to explain the potential mechanism. A series of rutin treatments were designed to evaluate the biomass, cadmium (Cd) accumulation and phytoremediation efficiency responses of Amaranthus hypochondriacus to different levels of rutin (0.5, 1.5, and 5 ppm) under different Cd stress levels (10, 25, 50, and 100 ppm). The determination of cell membrane damage indicators, the subcellular distribution of Cd and the establishment of a predictive model for Cd accumulation were also carried out. The results showed a decline in cell membrane damage with rutin application, and more Cd ions were immobilized in the cell wall than in the vacuole, resulting in an increase in Cd tolerance in plants. The addition of rutin caused significant effects on the synthesis of glutathione (GSH), including the advancement of the conversion of GSH to phytochelatins (PCs). Among them, PC2 and PC3 in the leaves contributed the most to the high accumulation of Cd in Amaranthus hypochondriacus according to the prediction model. Overall, the phytoremediation efficiency and phytoextraction amount of Amaranthus hypochondriacus with foliar rutin application were improved significantly by 260% and 319%, respectively. These findings can contribute to the further development of soil remediation in Cd-contaminated fields.

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Boron application mitigates Cd toxicity in leaves of rice by subcellular distribution, cell wall adsorption and antioxidant system

Ecotoxicology and Environmental Safety ◽

10.1016/j.ecoenv.2021.112540 ◽

2021 ◽

Vol 222 ◽

pp. 112540

Author(s):

Muhammad Riaz ◽

Muhammad Kamran ◽

Muhammad Rizwan ◽

Shafaqat Ali ◽

Yaoyu Zhou ◽

...

Keyword(s):

Cell Wall ◽

Antioxidant System ◽

Subcellular Distribution ◽

Cd Toxicity

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Microstructural and physiological responses to cadmium stress under different nitrogen levels in Populus cathayana females and males

Tree Physiology ◽

10.1093/treephys/tpz115 ◽

2020 ◽

Vol 40 (1) ◽

pp. 30-45 ◽

Cited By ~ 7

Author(s):

Miao Liu ◽

Jingwen Bi ◽

Xiucheng Liu ◽

Jieyu Kang ◽

Helena Korpelainen ◽

...

Keyword(s):

Nitrogen Deficiency ◽

Ion Homeostasis ◽

N Availability ◽

Cd Stress ◽

Cd Accumulation ◽

N Supply ◽

Populus Cathayana ◽

N Deficiency ◽

Cellular Compartments ◽

Cd Translocation

Abstract Although increasing attention has been paid to the relationships between heavy metal and nitrogen (N) availability, the mechanism underlying adaptation to cadmium (Cd) stress in dioecious plants has been largely overlooked. This study examined Cd accumulation, translocation and allocation among tissues and cellular compartments in Populus cathayana Rehder females and males. Both leaf Cd accumulation and root-to-shoot Cd translocation were significantly greater in females than in males under a normal N supply, but they were reduced in females and enhanced in males under N deficiency. The genes related to Cd uptake and translocation, HMA2, YSL2 and ZIP2, were strongly induced by Cd stress in female roots and in males under a normal N supply. Cadmium largely accumulated in the leaf blades of females and in the leaf veins of males under a normal N supply, while the contrary was true under N deficiency. Furthermore, Cd was mainly distributed in the leaf epidermis and spongy tissues of males, and in the leaf palisade tissues of females. Nitrogen deficiency increased Cd allocation to the spongy tissues of female leaves and to the palisade tissues of males. In roots, Cd was preferentially distributed to the epidermis and cortices in both sexes, and also to the vascular tissues of females under a normal N supply but not under N deficiency. These results suggested that males possess better Cd tolerance compared with females, even under N deficiency, which is associated with their reduced root-to-shoot Cd translocation, specific Cd distribution in organic and/or cellular compartments, and enhanced antioxidation and ion homeostasis. Our study also provides new insights into engineering woody plants for phytoremediation.

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Difference in root-to-shoot Cd translocation and characterization of Cd accumulation during fruit development in two Capsicum annuum cultivars

Plant and Soil ◽

10.1007/s11104-015-2535-0 ◽

2015 ◽

Vol 394 (1-2) ◽

pp. 287-300 ◽

Cited By ~ 7

Author(s):

Junliang Xin ◽

Baifei Huang ◽

Hongwen Dai

Keyword(s):

Capsicum Annuum ◽

Fruit Development ◽

Cd Accumulation ◽

Cd Translocation

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Screening of Foliar Reagent Reduces Cadmium Accumulation in Wheat Grains

10.21203/rs.3.rs-639566/v1 ◽

2021 ◽

Author(s):

Shenglan Xia ◽

Jie Wang ◽

Zanming Chen ◽

Hai Lan ◽

Zhenguo Shen ◽

...

Keyword(s):

Field Experiment ◽

Foliar Application ◽

Grain Filling ◽

Cadmium Content ◽

Cd Accumulation ◽

Wheat Grains ◽

Flag Leaves ◽

Filling Stage ◽

Grain Filling Stage ◽

The Relationship

Abstract Cadmium (Cd) in agricultural soils can be taken up by wheat and transferred into the grains, risking human health. In this study, we tested the effects of nineteen foliar treatments alone, and also combined treatments on the Cd concentration of grains in pot/field experiments, and the field experiment, respectively. In addition, we tested the better growth period for foliar application to inhibit Cd accumulation in wheat grains. Foliar application of Ethylenediaminetetraacetic acid (EDTA), Sodium selenite (Se) and Sodium nitroprusside (SNP) can significantly reduce Cd concentration of wheat grains, with 49.2%, 29.6%, and 28.8% decreased respectively in the field. Foliar application of EDTA, Se, Zinc sulphate (Zn), Ascorbic acid (ASA), Sodium silicate (Si) and Ammonium molybdate (Mo) can significantly reduce Cd concentration of wheat grains in different treatments, with 32.3%, 32.0%, 27.7%, 27.7%, 26.3% and 25.9% decreased respectively in the pot. Thus, foliar application of 2 mM EDTA and 2 mM Se exerted excellent effects in controlling the Cd accumulation of wheat grains for both in pot and field experiment. We were concerned about the transfer of different aboveground tissues to the grain, foliar application with 0.1 mM Se or 2 mM EDTA significantly reduced Cd concentrations in grains both in grain filling stage and heading + grain-filling stage. Spraying at the filling stage of wheat has a better effect than at the heading stage for reducing the cadmium content in grains. In addition, the relationship between Cd concentration of grains and husks were significantly positive, while the relationship between Cd concentration of grains and flag leaves was significantly negative. Cd content in wheat grains decreased may be due to the Cd accumulation of flag leaves and the decrease of Cd transport from flag leaves and husks to the grains, which in turn reduces the transport of Cd to the grains.

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Silicon Fertilization: A Step towards Cadmium-Free Fragrant Rice

Plants ◽

10.3390/plants10112440 ◽

2021 ◽

Vol 10 (11) ◽

pp. 2440

Author(s):

Qamar uz Zaman ◽

Muhammad Rashid ◽

Rab Nawaz ◽

Afzal Hussain ◽

Kamran Ashraf ◽

...

Keyword(s):

Foliar Application ◽

Leaf Gas Exchange ◽

Foliar Spray ◽

Potassium Silicate ◽

Human Beings ◽

Cd Stress ◽

Cd Accumulation ◽

Cd Toxicity ◽

Rice Grains ◽

Silicon Fertilization

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.

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Cadmium uptake, translocation, and redistribution affect Cd accumulation in grain of common wheat (Triticum aestivum L.) cultivars

10.21203/rs.3.rs-22672/v1 ◽

2020 ◽

Author(s):

Yiran Cheng ◽

Xu Zhang ◽

Sha Wang ◽

Xue Xiao ◽

Jian Zeng ◽

...

Keyword(s):

Common Wheat ◽

Translocation Factor ◽

Triticum Aestivum L ◽

Wheat Cultivars ◽

Cd Stress ◽

Cd Uptake ◽

Cd Accumulation ◽

Flag Leaves ◽

Physiological Processes ◽

Cd Translocation

Abstract Background To study the cadmium (Cd) accumulation in wheat grain, we evaluated the grain Cd concentrations of 46 common wheat cultivars grown at two sites in Sichuan, China and selected five different grain Cd accumulators (a high-Cd accumulator ZM18, four low-Cd accumulators YM51, YM53, SM969 and CM104) to explore the physiological processes of Cd accumulation in the grain of wheat grown under varying degrees of Cd stress. Results Our results showed that the Cd concentration in grain differed among genotypes. Under low-Cd stress, the grain Cd concentration was correlated with the Cd translocation factor (TF) of roots to grain and all the Cd redistribution factors (RFs). Compared with the ZM18, the cultivars YM53 and SM969 accumulated less Cd in the grain due to low Cd redistribution from lower stems and older leaves to grain. The low-Cd accumulators YM51 and CM104 were due to low Cd transport from roots to grain, and low Cd redistribution from glumes, flag leaves, lower stems, and older leaves to grain. Under high-Cd stress, the ZM18, YM53, and SM969 accumulated significantly more Cd in the grain, root and other tissues than did YM51 and CM104. Correlation analyses showed that the grain Cd concentration of wheat under high Cd stress was positively correlated with the Cd concentration in each tissue and the TFs of roots to grains, rachis, internode 1 and flag leaves. Conclusions Cd translocation directly from roots to grain and Cd redistribution from shoots to grain determines the Cd accumulation in grain of wheat cultivars under low-Cd stress. Cd uptake by root and then synchronously transported to new shoots determined the differences of Cd accumulation in the grain of wheat cultivars under high Cd stress.

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Aspects of cultivar variation in physiological traits related to Cd distribution in rice plants with a short-term stress

10.21203/rs.3.rs-34413/v2 ◽

2020 ◽

Author(s):

Wan-Ting Chiao ◽

Bo-Ching Chen ◽

Chien-Hui Syu ◽

Kai-Wei Juang

Keyword(s):

Shoot Growth ◽

Rice Grain ◽

Rice Cultivars ◽

Cd Accumulation ◽

Physiological Regulation ◽

Rice Plants ◽

Cd Contamination ◽

Cultivar Variation ◽

Cd Distribution ◽

Cd Translocation

Abstract Background Genotypic variations are seen in cadmium (Cd) tolerance and accumulation in rice plants. Cultivars that show low Cd translocation from the root into shoot can be selected to reduce Cd contamination in rice grains. This study aims to clarify the physiological regulation related to Cd absorption by rice plants for screening out the cultivars, which have relatively low Cd accumulation in grains. Eight Taiwan mega cultivars of paddy rice: japonica (TY3, TK9, TNG71, and KH145 cultivars), indica (TCS10 and TCS17 cultivars), and glutinous (TKW1 and TKW3 cultivars), which are qualified with the criteria for rice grain quality by the Council of Agriculture, Taiwan, were used for illustration. An experiment in hydroponics was conducted for the rice seedlings with a treatment of 50 μM CdCl 2 for 7 days. Results and discussion After the Cd treatment, the reductions in shoot growth were more significant than those in root growth; however, Cd absorbed in the rice plant was sequestered much more in the root. The malondialdehyde (MDA) was preferentially accumulated in rice root but the hydrogen peroxide (H 2 O 2 ) was increased more significantly in the shoot; the antioxidative enzymes, superoxide dismutase (SOD) and ascorbate peroxidase (APX), were pronounced more in rice shoot. Conclusions The rice cultivars preferentially accumulated Cd in the root rather than the shoot with the Cd treatment, which resulted in significant enhancements of MDA and growth reductions in the root. However, H 2 O 2 accumulation was toward the shoot to retard shoot growth suddenly and then the root could keep a gradual growth. Also, the rice cultivars, which preferentially accumulate Cd in the root, would have the regulation tendency of SOD toward the shoot. Due to that SOD is responsible for H 2 O 2 production, H 2 O 2 accumulation would be thus toward the shoot. Moreover, the cultivars, which have a less regulation tendency of APX toward the shoot, would present higher translocation of Cd into the shoot.

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Overexpression of OsLCT2, a Low-Affinity Cation Transporter Gene, Reduces Cadmium Accumulation in Shoots and Grains of Rice

Rice ◽

10.1186/s12284-021-00530-8 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Li Tang ◽

Jiayu Dong ◽

Longtao Tan ◽

Zhongying Ji ◽

Yaokui Li ◽

...

Keyword(s):

Genetic Resource ◽

Xylem Sap ◽

Cadmium Accumulation ◽

Cd Accumulation ◽

Rice Grains ◽

Hydroponic Experiment ◽

Zn Uptake ◽

Transporter Family ◽

Molecular Regulatory Mechanisms ◽

Cd Translocation

AbstractCadmium (Cd)-contaminated rice is a serious issue affecting food safety. Understanding the molecular regulatory mechanisms of Cd accumulation in rice grains is crucial to minimizing Cd concentrations in grains. We identified a member of the low-affinity cation transporter family, OsLCT2 in rice. It was a membrane protein. OsLCT2 was expressed in all tissues of the elongation and maturation zones in roots, with the strongest expression in pericycle and stele cells adjacent to the xylem. When grown in Cd-contaminated paddy soils, rice plants overexpressing OsLCT2 significantly reduced Cd concentrations in the straw and grains. Hydroponic experiment demonstrated its overexpression decreased the rate of Cd translocation from roots to shoots, and reduced Cd concentrations in xylem sap and in shoots of rice. Moreover, its overexpression increased Zn concentrations in roots by up-regulating the expression of OsZIP9, a gene responsible for Zn uptake. Overexpression of OsLCT2 reduces Cd accumulation in rice shoots and grains by limiting the amounts of Cd loaded into the xylem and restricting Cd translocation from roots to shoots of rice. Thus, OsLCT2 is a promising genetic resource to be engineered to reduce Cd accumulation in rice grains.

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