scholarly journals Effect of lead on growth of warm season turf grasses

Author(s):  
SYEDA AMENA KAUSAR

The ability to tolerate metals targeted for remediation in existing soil conditions is one of the important features possessed by plants used in phytoextraction programs. Pot experiments were conducted using Stenotaphrum dimidiatum (L.) Brongn, Zoysia matrella var. pacifica Goudsw and Axonopus compressus (Sw.) P. Beauv plants to identify ability of these turf grasses to withstand and tolerate lead when grown in contaminated soil from across Musi River region of Hyderabad which had lead metal in concentrations higher than permissible limits. Plants were exposed to 131.2, 223.3 and 326.2 mg kg-1of lead in contaminated soil and examined under three metal exposure periods of 120, 240, and 360 days. Control samples were obtained by growing plants in normal soil with 42.2 mg kg-1of lead. The pot cultures were maintained at a nursery under normal day light conditions and shoots were harvested every 60 days during the 360 days of study period from June 2017 to June 2018. Results showed that for all three grasses a decrease in heights was seen with an increase in soil lead concentrations and exposure time. Decrease in lengths was more for roots than shoots.Zoysia matrella was the most lead affected plant with a mean phytotoxicity of 14.7% compared to 10.9 and 8.5% seen in Stenotaphrum dimidiatum and Axonopus compressus. Lead tolerance was highest for Axonopus compressus with Metal tolerance index (MTI) of 91.5%, followed by Stenotaphrum dimidiatum (89.1%) and least by Zoysia matrella (85.3%). At the highest given soil lead concentration of 326.2 mg kg-1with Axonopus compressus was found significantly better having higher tolerance index compared to Zoysia matrella. The study concludes that Axonopus compressus popularly known as Carpetgrass has a greater scope for use in lead phytoextraction programs compared to the other two tested grasses as it had the ability to tolerate and withstand lead in contaminated soil at higher concentration

2020 ◽  
Vol 9 (1) ◽  
pp. 42-49
Author(s):  
L. Herlina ◽  
B. Widianarko ◽  
H. R. Sunoko

Phytoremediation is a practical, environmentally-friendly, low-cost technological solution used to clean various types of pollution, including metals, pesticide residues, and oils from contaminated soil and water. In this study, Cordyline fruticosa was planted in the lead-contaminated soil. Each pot was given 250 mg/kg and 375 mg/kg of lead. The parameters observed included biomass (mg), lead content in the root, stem, and leaf, bioaccumulation factor, translocation factor, metal tolerance index, and amount of metal extraction, which were analyzed after 30, 60, and 90 days. The results revealed that root, stem and leaf biomass (g) were significantly different from control (T0). The lead contents were root<stem <leaf, while the translocation factor value was more than one, except for lead exposure 375 mg/kg (T2) in the second month and 250 mg/kg lead (T1) in the third month. The bioaccumulation factor for all treatments was less than one, and the metal tolerance index ranged from 90.87% - 93.07%. Besides, the amount of root metal extraction was smaller than the shoot. In sum, C. fruticosa is potential phytoremediation. 


Author(s):  
A. Liatukienė ◽  
R. Skuodienė

Abstract The morphological traits of alfalfa under acid soil conditions with different mobile aluminium (Al) concentrations were investigated. The study site was Vėžaičiai Branch of the Lithuanian Research Centre for Agriculture and Forestry, 55°70 N, 21°49 E. The experiment featuring the 30 most Al-tolerant alfalfa accessions (populations and cultivars), determined from laboratory trials was established on a Bathygleyic Dystric Retisol in 2018. In 2019 and 2020, the biological and morphological traits were evaluated: plant regrowth, plant height before flowering, wintering, leafiness, stem thickness, plant vigour, stem density, seed yield and resistance to spring black stem leaf spot. The resistance of alfalfa to mobile Al toxicity was determined using a filter-based screening method of selection cycles C1 and C2. The accessions grown in the soil with mobile Al (20.6–23.4 mg/kg) showed better tolerance to Al toxicity in the cycle C2. The hypocotyl tolerance index of these accessions was better at 8, 16, 32 and 64 mm AlCl3 concentrations in the cycle C2. The correlation analysis showed strong significant positive and negative relationships between the morphological traits. A cluster analysis showed that the accessions, grown in the soil with mobile Al (20.6–23.4 mg/kg) were the most resistant to Al toxicity in the cycle C2. These accessions produced a better seed yield and demonstrated lower values of morphological traits compared to cluster 2. Also, these accessions are considered as tolerant to mobile Al toxicity and might be used as donors in breeding for Al toxicity tolerance.


Author(s):  
Innocent A. Ugbong ◽  
Ivan V. Budagov

This paper seeks to show that due to changing climates, there are salient marginal Sahelian conditions (conditions of aridity) emerging on the Northern fringes of Cross River State, a state that is geographical positioned in the southern rainforest belt of Nigeria. The paper adopts a simple descriptive approach and shows the distinct characteristics of this zone, in terms of floristic composition and edaphic and geomorphic structures under changing conditions. Some relationships are established between environmental variables like health, water supply and crop-yield on one hand, and climatic variation, floral life-forms and soil conditions on the other. The changing land use patterns relative to environmental changes are also examined. The paper concludes with a look at current and future adaption strategies to these climate-induced conditions.


Author(s):  
Muhammad Naveed ◽  
Syeda Sosan Bukhari ◽  
Adnan Mustafa ◽  
Allah Ditta ◽  
Saud Alamri ◽  
...  

Nickel (Ni) bioavailable fraction in the soil is of utmost importance because of its involvement in plant growth and environmental feedbacks. High concentrations of Ni in the soil environment, especially in the root zone, may retard plant growth that ultimately results in reduced plant biomass and yield. However, endophytic microorganisms have great potential to reduce the toxicity of Ni, especially when applied together with zeolite. The present research work was conducted to evaluate the potential effects of an endophytic bacterium Caulobacter sp. MN13 in combination with zeolite on the physiology, growth, quality, and yield of sesame plant under normal and Ni stressed soil conditions through possible reduction of Ni uptake. Surface sterilized sesame seeds were sown in pots filled with artificially Ni contaminated soil amended with zeolite. Results revealed that plant agronomic attributes such as shoot root dry weight, total number of pods, and 1000-grains weight were increased by 41, 45, 54, and 65%, respectively, over control treatment, with combined application of bacteria and zeolite in Ni contaminated soil. In comparison to control, the gaseous exchange parameters (CO2 assimilation rate, transpiration rate, stomatal- sub-stomatal conductance, chlorophyll content, and vapor pressure) were significantly enhanced by co-application of bacteria and zeolite ranging from 20 to 49% under Ni stress. Moreover, the combined utilization of bacteria and zeolite considerably improved water relations of sesame plant, in terms of relative water content (RWC) and relative membrane permeability (RMP) along with improvement in biochemical components (protein, ash, crude fiber, fat), and micronutrients in normal as well as in Ni contaminated soil. Moreover, the same treatment modulated the Ni-stress in plants through improvement in antioxidant enzymes (AEs) activities along with improved Ni concentration in the soil and different plant tissues. Correlation and principal component analysis (PCA) further revealed that combined application of metal-tolerant bacterium Caulobacter sp. MN13 and zeolite is the most influential strategy in alleviating Ni-induced stress and subsequent improvement in growth, yield, and physio-biochemical attributes of sesame plant.


2015 ◽  
Vol 1130 ◽  
pp. 263-267 ◽  
Author(s):  
Hee Chan Jang ◽  
Marjorie Valix

In this study, the adaptation of A. thiooxidans to heavy metals leached from saprolitic Ni laterite ores was performed by gradual acclimatisation. The bacteria was cultivated in heavy metals (Ni, Co, Fe, Mg, Cr and Mn) with total concentrations of 2400 to 24000 ppm equivalent to total dissolution of 1 to 10% (w/v) pulp densities of the saprolitic Ni laterite ore. Adaptation evolution mapped from its tolerance index was found to be dependent on metal concentration, acid generation, and period of adaptation. Bio-stimulation of cell growth and acid production was promoted by heavy metal stress on the bacteria. Pre-established heavy metal tolerance of the bacteria improved the leaching rate in its early phase; 20% and 7% increase in Ni and Co metal recoveries were observed in using adapted bacteria. However heavy metal tolerance was also achieved by the bacteria during the leaching process, albeit delayed by a lag phase. These results confirm the robust nature and suitability of A. thiooxidans in direct biomining of Ni ores.


2020 ◽  
Vol 45 ◽  
pp. 101764 ◽  
Author(s):  
Bishal Khatiwada ◽  
Mafruha T. Hasan ◽  
Angela Sun ◽  
Karthik Shantharam Kamath ◽  
Mehdi Mirzaei ◽  
...  

2008 ◽  
Vol 21 (4) ◽  
pp. 802-816 ◽  
Author(s):  
Siegfried D. Schubert ◽  
Max J. Suarez ◽  
Philip J. Pegion ◽  
Randal D. Koster ◽  
Julio T. Bacmeister

Abstract This study examines the predictability of seasonal mean Great Plains precipitation using an ensemble of century-long atmospheric general circulation model (AGCM) simulations forced with observed sea surface temperatures (SSTs). The results show that the predictability (intraensemble spread) of the precipitation response to SST forcing varies on interannual and longer time scales. In particular, this study finds that pluvial conditions are more predictable (have less intraensemble spread) than drought conditions. This rather unexpected result is examined in the context of the physical mechanisms that impact precipitation in the Great Plains. These mechanisms include El Niño–Southern Oscillation’s impact on the planetary waves and hence the Pacific storm track (primarily during the cold season), the role of Atlantic SSTs in forcing changes in the Bermuda high and low-level moisture flux into the continent (primarily during the warm season), and soil moisture feedbacks (primarily during the warm season). It is found that the changes in predictability are primarily driven by changes in the strength of the land–atmosphere coupling, such that under dry conditions a given change in soil moisture produces a larger change in evaporation and hence precipitation than the same change in soil moisture would produce under wet soil conditions. The above changes in predictability are associated with a negatively skewed distribution in the seasonal mean precipitation during the warm season—a result that is not inconsistent with the observations.


Author(s):  
Emmanuel Sey ◽  
Ebenezer J. D. Belford

Introduction: Heavy metal contamination has necessitated a less expensive and non-destructive clean-up technique such as mycoremediation. This study aimed to isolate, identify, and evaluate the tolerance of fungi species in different concentrations of heavy metals for their potential use in bioremediation. Materials and Methods: Fungi were isolated by serial dilution and spread plate techniques from gold tailings and their tolerance to different concentrations of As, Cd, Cr, Cu, Pb, Zn (as potential bioremediation candidates) was evaluated. Fungal radial growths were recorded daily over a 14 days’ incubation period to establish their tolerance levels using the Tolerance Index. Results: Five isolated fungi species belonged to the genera Aspergillus, Trichophyton, Rhizopus, Trametes, and Trichoderma. Except for Trichophyton rubrum, the other fungi species were tolerant to all Cr concentrations (0 – 100ppm), but no significant difference was observed in mycelia growth compared to their controls. With high tolerance index ranging from 0.91 to 1.02, Trichoderma viride and Rhizopus oryzae were tolerant to all Cu concentrations (0 – 125ppm). High tolerance was exhibited by Trametes versicolor to Cd at 25 and 50 ppm, and by Rhizopus oryzae at 25 ppm, but no significant difference was found in mycelia growth. Rhizopus oryzae tolerated all As and Pb concentrations with high tolerance index ranging from 0.81 to 1.00. It also tolerated   Zn at 200-600ppm concentration with a tolerance index from 0.80 to 0.91. Conclusion: The selective nature of these fungi species for specific heavy metal tolerance indicates their potential for selective use as effective bioremediative clean up agent of heavy metals contaminated sites.


HortScience ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 221-223 ◽  
Author(s):  
Haibo Liu

Aluminum toxicity is a major limiting factor for turfgrass establishment and growth when soil pH is <5.0. Limited information on aluminum resistance is available among warm-season turfgrasses and these turfgrasses often grow in the areas with acid soil conditions. The objectives of this study were 1) to evaluate seeded bermudagrass (Cynodon dactylon L.) cultivars for the ability to tolerate a high level of aluminum and 2) to measure the extent of aluminum damage to the root systems. In total, 16 bermudagrass cultivars were evaluated under greenhouse conditions using a solution culture and an acid Tatum soil (Clayey, mixed, thermic, typic, Hapludult). The soil had pH 4.4% and 69% exchangeable aluminum. A concentration of 640 μm aluminum and a pH 4.0 was used for solution culture. The grasses were grown for 28 days in solution culture; 28 days in the acid Tatum soil; and 78 days in the acid Tatum soil before harvesting. Aluminum resistance was determined by measuring the longest root length, the longest shoot length, dry root weight, dry shoot weight, and shoot to root ratio in comparing the control to obtain the relative Al resistance among the cultivars. The results indicate that seeded bermudagrass cultivars differ in their aluminum resistance.


2009 ◽  
Vol 134 (4) ◽  
pp. 417-422 ◽  
Author(s):  
Hongmei Du ◽  
Zhaolong Wang ◽  
Bingru Huang

Heat stress may limit the growth of turfgrasses through the induction of oxidative stress, causing cellular and physiological damage. The objective of the study was to examine the association of heat and oxidative stresses between warm-season (C4) and cool-season (C3) turfgrasses. Plants of zoysiagrass (Zoysia matrella L. Merr. cv. Manila) (C4) and tall fescue (Festuca arundinacea Shreber cv. Barlexus) (C3) were exposed to optimal temperature conditions (24 °C for tall fescue and 34 °C for zoysiagrass) or heat stress (10 °C above the respective optimal temperature for each species) in growth chambers. Zoysiagrass exhibited less severe decline in turf quality and photochemical efficiency and less severe oxidative damage in cellular membranes as demonstrated by lower membrane electrolyte leakage and lipid peroxidation compared with tall fescue when both were exposed to heat stress. The activities of superoxide dismutase (SOD) and peroxidase (POD) declined with heat stress for both species, but to a lesser extent in zoysiagrass than in tall fescue, whereas catalase activity did not change significantly under heat stress and did not exhibit species variation. Our results demonstrate that the superior heat tolerance in zoysiagrass in comparison with tall fescue was associated with greater oxidative scavenging capacity as a result of the maintenance of higher SOD and POD activities.


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