scholarly journals Exogenous Glycinebetaine Promotes Soil Cadmium Uptake by Edible Amaranth Grown during Subtropical Hot Season

Author(s):  
Wei-Qing Yao ◽  
Yong-Kang Lei ◽  
Ping Yang ◽  
Qu-Sheng Li ◽  
Li-Li Wang ◽  
...  

Exogenous glycinebetaine treatment is an effective measure for preventing crops from being exposed to drought and high temperature; however, the effects of this approach on the soil Cd uptake and accumulation by crops remain unclear. Pot experiments were conducted in this study to analyze the effect of glycinebetaine on the soil Cd uptake and accumulation by edible amaranth cultivated in Cd-contaminated soil. Results revealed that after exogenous glycinebetaine treatment on amaranth leaves during the vigorous growth period, the plant biomass, the Cd concentrations in the roots and shoots, and the Cd translocation factor (TF) were significantly higher than those of the control group. The highest Cd concentrations in the roots and shoots and the TF were higher by 91%, 96% and 23.8%, respectively, than the corresponding values in the control group. In addition, exogenous glycinebetaine treatment significantly increased leaf chlorophyll content and promoted the photosynthesis of edible amaranth. Consequently, the contents of soluble sugar, dissolved organic carbon, and low-molecular-weight organic acids significantly increased in the rhizosphere, resulting in Cd mobilization. Significant positive correlations were observed among the contents of leaf chlorophyll, Mg, Fe, pectin and Ca. Given that Cd shares absorption and translocation channels with these elements, we speculated that the increased leaf chlorophyll and pectin contents promoted the absorption and accumulation of Mg, Fe and Ca, which further promoted the absorption and translocation of Cd. These results indicated that exogenous glycinebetaine treatment during hot season would aggravate the health risks of crops grown in Cd-contaminated soils.

2020 ◽  
Author(s):  
Yiran Cheng ◽  
Xu Zhang ◽  
Sha Wang ◽  
Xue Xiao ◽  
Jian Zeng ◽  
...  

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.


Author(s):  
Zhangxiong Han ◽  
Xuan Wei ◽  
Dejun Wan ◽  
Wenxiang He ◽  
Xijie Wang ◽  
...  

This study investigated the beneficial effect of molybdenum (Mo) application on rape plants (Brassica napus L.) grown in a soil polluted by cadmium (Cd). A pot experiment was conducted to determine how different concentrations of exogenous Mo (0, 50, 100, and 200 mg/kg) affect plant physiology, biomass, photosynthesis, cation uptake, and Cd translocation and enrichment in rape plants under Cd stress (0.5 and 6.0 mg/kg). Under single Cd treatment, plant physiological and biochemical parameters, biomass parameters, leaf chlorophyll fluorescence parameters, and macroelement uptake of rape plants decreased, while their malonaldehyde content, proline content, non-photochemical quenching coefficient, and Cd uptake significantly increased, compared to those of the control group (p-values < 0.05). High-Cd treatment resulted in much larger changes in these parameters than low-Cd treatment. Following Mo application, the accumulation of malondialdehyde and proline decreased in the leaves of Cd-stressed plants; reversely, the contents of soluble protein, soluble sugar, and chlorophyll, and the activities of superoxide dismutase and glutathione peroxidase, all increased compared to those of single Cd treatment (p-values < 0.05). Exogenous Mo application promoted shoot and root growth of Cd-stressed plants in terms of their length, fresh weight, and dry weight. The negative effect of Cd stress on leaf chlorophyll fluorescence was substantially mitigated by applying Mo. Exogenous Mo also improved the uptake of inorganic cations, especially potassium (K+), in Cd-stressed plants. After Mo application, Cd uptake and accumulation were inhibited and Cd tolerance was enhanced, but Cd translocation was less affected in Cd-stressed plants. The mitigation effect of Mo on Cd stress in rape was achieved through the immobilization of soil Cd to reduce plant uptake, and improvement of plant physiological properties to enhance Cd tolerance. In conclusion, exogenous Mo can effectively reduce Cd toxicity to rape and the optimal Mo concentration was 100 mg/kg under the experimental conditions.


2012 ◽  
Vol 518-523 ◽  
pp. 4994-4999
Author(s):  
Ling Zhi Liu ◽  
Zong Qiang Gong ◽  
Yu Long Zhang ◽  
Pei Jun Li

The effects of three arbuscular mycorrhizal fungi (AMF) on the growth, Cd uptake and some physio-biochemical indexes of Solanum lycopersicum seedlings under different levels of Cd stress were investigated in a pot study. Generally, the symbiotic relationship between Solanum lycopersicum and AMF can be well established under Cd stress. This was reflected by the better physio-biochemical index of the plants inoculated with G. constrictum, G. mosseae and G. intraradices whose colonization rates were between 41.4% and 76.1%. Compared with the non-inoculated ones, G. constrictum inoculation enhanced the plant biomass at 50 mg kg-1 Cd addition level. AM colonization increased the Cd distribution to the roots in plants and alleviated shoots from high Cd stress, and thus increased the shoot biomass in the end. At the high Cd addition level, mycorrhizal plants reacted differently in the reduction of the contents of MDA, by influencing the soluble sugar, POD activity, SOD activity and so on. Our results showed that mycorrhizal colonization was beneficial to the Cd translocation in plants and reduced the membrane lipid peroxidation in plants under serious Cd stress. However, the mechanisms of mycorrhizal protection in plants were influenced by many factors and still need to be further studied.


Toxics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 91
Author(s):  
Sifan Wang ◽  
Yong Liu ◽  
Khalil Kariman ◽  
Jialin Li ◽  
Huihua Zhang ◽  
...  

Co-cropping is an eco-friendly strategy to improve the phytoremediation capacity of plants growing in soils contaminated with heavy metals such as cadmium (Cd). This study was conducted to investigate the effects of co-cropping Indian mustard (Brassicajuncea) and silage maize (Zeamays) and applying peat on the phytoremediation of a Cd-contaminated acid paddy soil via characterizing plant growth and Cd uptake in pot experiments. There were six planting patterns (Control: no plants; MI-2 and MI-4: mono-cropping of Indian mustard at low and high densities, respectively; MS: mono-cropping of silage maize; CIS-2 and CIS-4: co-cropping of Indian mustard at low and high densities with silage maize, respectively) and two application rates of peat (NP: 0; WP: 30 g kg−1). When Indian mustard and silage maize were co-cropped, the shoot biomass of Indian mustard plants per pot was significantly (p < 0.05) lower than that obtained in the mono-cropping systems, with a substantial reduction (55–72%) in the same plant density group. The shoot biomass of silage maize plants in the mono-cropping systems did not differ significantly from that in the co-cropping systems regardless of the density of Indian mustard. The growth-promoting effect of the peat application was more pronounced in Indian mustard than silage maize. Under the low density of Indian mustard, the co-cropping systems significantly (p < 0.05) decreased Cd uptake by silage maize. Additionally, soil amendment with peat significantly (p < 0.05) increased shoot Cd removal rate and Cd translocation factor value in the co-cropping systems. Taken together, the results demonstrated that silage maize should be co-cropped with Indian mustard at an appropriate density in Cd-polluted soils to achieve simultaneous remediation of Cd-contaminated soils (via Indian mustard) and production of crops (here, silage maize). Peat application was shown to promote the removal of Cd from soil and translocation of Cd into shoots and could contribute to enhanced phytoremediation of Cd-contaminated acid paddy soil.


2013 ◽  
Vol 726-731 ◽  
pp. 273-276
Author(s):  
Yong Chao Yin ◽  
Lang Chen ◽  
Jian Rong Kai ◽  
Yu Fang Song

33 species Chinese cabbage sold in local market were seeded and growth on Cd polluted (Cd 0.65-9.0 mg/kg) soil in the old irrigation area, Shenyang, P.R.China. The harvested Chinese cabbages were collected for analysis of Cd content, soluble protein and soluble sugar, respectively. Results showed that the Cd content in edible parts of varieties Chinese cabbage does not exceed, partly exceed and all out of the allowed standard of 0.2 mg/kg fresh weight Cd, as the soil Cd contents were in the range of 0.65-1.8 mg/kg, 1.81-4.17 mg/kg and 4.18 to 5.3 mg/kg. Soil Cd content has a positive correlation with Cd content in the edible part of all varieties of Chinese cabbage. And soluble sugar and soluble protein showed increased trend as soil cd increase. According to above results, we concluded that the products of Chinese cabbage is relatively safety in quality if growth in soil with Cd content from 0.65 to 1.81 mg/kg , and appropriate screening of low Cd uptake species for Chinese cabbage is necessary as soil Cd content was from 1.81-4.17 mg/kg, to insure the safety of agricultural products , and suitable remediation technology should be used as soil Cd content was from 4.18-5.3 an till 9.0 mg/kg, in order to reduce the food-chains transportation risk brought by Cd accumulated in Chinese cabbage.


Forests ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 19
Author(s):  
Xiaodeng Shi ◽  
Siyu Chen ◽  
Zhongkui Jia

The effects of varieties, concentrations, and number of applications of plant growth retardants (PGRs) on the morphological, physiological, and endogenous hormones of Magnolia wufengensis L.Y. Ma et L. R. Wang were assessed to obtain the most suitable dwarfing protocol for M. wufengensis and to provide theoretical support and technical guidance for the cultivation and promotion of this species. One-year-old M. wufengensis ‘Jiaohong No. 2’ grafted seedlings served as the experimental materials. In the first part of the experiment, three PGRs (uniconazole, paclobutrazol, prohexadione calcium), three concentrations (500, 1000, 1500 ppm), and three applications (one, three, and five applications) were applied in dwarfing experiments to perform L9 (34) orthogonal tests. In the second part of the study, dwarfing experiments were supplemented with different high uniconazole concentrations (0, 1500, 2000, 2500 ppm). Spraying 1500 ppm uniconazole five times achieved the best M. wufengensis dwarfing effect, related indicators of M. wufengensis under this treatment were better than other treatment combinations. Here, M. wufengensis plant height, internode length, scion diameter, and node number were significantly reduced by 56.9%, 62.6%, 72.8%, and 74.4%, respectively, compared with the control group. This treatment increased superoxide dismutase (SOD) activity by 66.0%, peroxidase (POD) activity by 85.0%, soluble protein contents by 43.3%, and soluble sugar contents by 27.6%, and reduced malondialdehyde (MDA) contents by 32.1% in leaves of M. wufengensis compared with the control. The stress resistance of M. wufengensis was enhanced. The treatment also reduced gibberellin (GA3) levels by 73.0%, auxin (IAA) by 58.0%, and zeatin (ZT) by 70.6%, and increased (abscisic acid) ABA by 98.1% in the leaves of M. wufengensis. The uniconazole supplementation experiment also showed that 1500 ppm was the optimal uniconazole concentration. The leaves exhibited abnormalities such as crinkling or adhesion when 2000 or 2500 ppm was applied. Given the importance of morphological indicators and dwarfing for the ornamental value of M. wufengensis, the optimal dwarfing treatment for M. wufengensis was spraying 1500 ppm uniconazole five times.


Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 912
Author(s):  
Shuming Liu ◽  
Hongmei Liu ◽  
Rui Chen ◽  
Yong Ma ◽  
Bo Yang ◽  
...  

Miscanthus spp. are energy plants and excellent candidates for phytoremediation approaches of metal(loid)s-contaminated soils, especially when combined with plant growth-promoting bacteria. Forty-one bacterial strains were isolated from the rhizosphere soils and roots tissue of five dominant plants (Artemisia argyi Levl., Gladiolus gandavensis Vaniot Houtt, Boehmeria nivea L., Veronica didyma Tenore, and Miscanthus floridulus Lab.) colonizing a cadmium (Cd)-contaminated mining area (Huayuan, Hunan, China). We subsequently tested their plant growth-promoting (PGP) traits (e.g., production of indole-3-acetic acid, siderophore, and 1-aminocyclopropane-1-carboxylate deaminase) and Cd tolerance. Among bacteria, two strains, Klebsiella michiganensis TS8 and Lelliottia jeotgali MR2, presented higher Cd tolerance and showed the best results regarding in vitro growth-promoting traits. In the subsequent pot experiments using soil spiked with 10 mg Cd·kg−1, we investigated the effects of TS8 and MR2 strains on soil Cd phytoremediation when combined with M. floridulus (Lab.). After sixty days of planting M. floridulus (Lab.), we found that TS8 increased plant height by 39.9%, dry weight of leaves by 99.1%, and the total Cd in the rhizosphere soil was reduced by 49.2%. Although MR2 had no significant effects on the efficiency of phytoremediation, it significantly enhanced the Cd translocation from the root to the aboveground tissues (translocation factor > 1). The combination of K. michiganensis TS8 and M. floridulus (Lab.) may be an effective method to remediate Cd-contaminated soils, while the inoculation of L. jeotgali MR2 may be used to enhance the phytoextraction potential of M. floridulus.


1991 ◽  
Vol 116 (6) ◽  
pp. 995-999 ◽  
Author(s):  
Beny Aloni ◽  
Tamara Pashkar ◽  
Lea Karni ◽  
Jaleh Daie

We investigated the effects of N nutrition on growth and carbohydrate partitioning of pepper (Capsicum annuum L., cv. Maor) seedlings in the greenhouse and on their subsequent recovery and development after transplanting. Seedlings received 0, 30, 100, or 200 mg N/liter for 14 days, after which they were transplanted and received 100 mg N/liter. Nitrogen levels below 100 mg·liter−1 inhibited shoot growth and leaf chlorophyll content; both were severely inhibited in the absence of supplemental N. Root growth had a negative relation with N supply; an enhanced root: shoot ratio was observed under low-N regimes. On a unit-leaf-area basis, CO2 fixation was not affected when N was present; however, it was greatly inhibited in the absence of N. Changes in the leaf starch and soluble sugar concentrations occurred as a function of N supply and leaf age. In the roots, low N led to lower sucrose and higher levels of hexose and starch. More sucrose was transported and accumulated into leaf veins of low-N tissue. Exogenously supplied 14C-labeled sucrose was rapidly converted into starch in the low-N tissue. Seedlings that received 100 mg N/liter had the highest post-transplant growth rate and flowered earlier. Carbohydrate status of young pepper seedlings influenced their post-transplant recovery. Optimal N supply is essential for full recovery and development of transplants.


2021 ◽  
Vol 15 ◽  
pp. 117863022110601
Author(s):  
Mekonnen Birhanie Aregu ◽  
Negasa Eshete Soboksa ◽  
Girum Gebremeskel Kanno

It is generally accepted that industrial wastewater like tannery effluent is high strength wastewater. The aim of this study was to examine the capacity of Vetiver grass for the treatment of high strength wastewater in a constructed wetland. Two constructed wetland beds were designed and one of them was not planted used as a control group. The grass was planted with 20 cm by 20 cm distance from each seedling. The biometric characteristics of Vetiver grass was evaluated by taking randomly selected clusters of the grass. The concentration of chromium in the extract of parts of the grass was determined by atomic absorption spectrophotometer. The Chromium bioaccumulation and Translocation factor was estimated. Composite samples before and after treatment of 4 different hydraulic retention time was collected. The physiochemical analysis of the wastewater has been carried out. The constructed wetland bed with Vetiver grass performed that, BOD, COD, NH4-N, NO3-N, TN, PO4-P, and TP were reduced at the retention time of 9 days by 91.9%, 96.3%, 62%, 86%, 88.7%, 96.3%, and 92.2% respectively. Chromium was also reduced by 97% at retention time of both 7 and 9 days over the planted bed. The bed with plant performs significantly better than without plant at P-value <.01. Therefore, Vetiver grass has a capacity to reclaim high strength industrial wastewater in tropical areas.


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