97 results on '"Xunzhong Zhang"'
Search Results
2. Methyl jasmonate enhances salt stress tolerance associated with antioxidant and cytokinin alteration in perennial ryegrass
- Author
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Xunzhong Zhang, Mike Goatley, Kehua Wang, Jamie Conner, Isabel Brown, and Kelly Kosiarski
- Published
- 2023
3. Correlations of Arsenic and Nutrient Elements in Different Tissues of Perennial Ryegrass Under Arsenic Stress
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Guilong Song, Zhehan Yang, Xunzhong Zhang, and Jinbo Li
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0106 biological sciences ,Absorption (pharmacology) ,Nutrient solution ,Perennial plant ,Chemistry ,fungi ,food and beverages ,Soil Science ,Biomass ,chemistry.chemical_element ,04 agricultural and veterinary sciences ,Plant Science ,Positive correlation ,01 natural sciences ,Horticulture ,Nutrient ,Nutrient absorption ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Agronomy and Crop Science ,Arsenic ,010606 plant biology & botany - Abstract
The objectives of this study were to investigate the growth and nutrient absorption in different tissues of perennial ryegrass under several levels of As stress, and to determine the relationships between absorption As and nutrient elements. As treatments at 0, 5, 10, 25, and 50 μM were applied to perennial ryegrass in hydroponic systems, and As and nutrient absorption in the mature leaves, expanded leaves, emerging leaves, and roots were determined. The effects of P, Ca, and Mg on the growth and As absorption of perennial ryegrass under As stress were also investigated. The biomass of the different tissues of perennial ryegrass decreased when the As concentration was greater than 5 μM. The As content was higher in roots relative to leaves regardless of As concentrations in nutrient solution, and leaf As content was greatest in the mature leaves and least in the emerging leaves. The As treatment reduced N, P, Ca, and Mg absorption in different tissues. A positive correlation of As content was found with the Mn content in the roots and all three kinds of leaves. The N, P, and K contents in the leaves were greatest in the emerging leaves and least in the mature leaves. The P, Ca, and Mg application decreased the As absorption of As-challenged perennial ryegrass. Our results indicated that As stress treatment reduced N, P, Ca, and Mg absorption and the As absorption was associated with leaf age and also levels of nutrients. Proper application of mineral nutrients may reduce As absorption of perennial ryegrass.
- Published
- 2021
4. Humic acids‐based biostimulants impact on root viability and hormone metabolism in creeping bentgrass putting greens
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Xunzhong Zhang, Michael Goatley, Frank Reith, Kelly Kosiarski, and David S. McCall
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chemistry.chemical_classification ,Chemistry ,Botany ,Humic acid ,Hormone metabolism ,Hormone - Published
- 2021
5. An integrated plant nutrition system (IPNS) for corn in the Mid-Atlantic USA
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Michael S. Strickland, Jose Franco Da Cunha Leme Filho, Wade Everett Thomason, Andre A. Diatta, Xunzhong Zhang, Bee Khim Chim, Gregory K. Evanylo, and School of Plant and Environmental Sciences
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0106 biological sciences ,chemistry.chemical_classification ,compost tea ,Physiology ,Agroforestry ,business.industry ,Biofertilizer ,humic acid ,04 agricultural and veterinary sciences ,01 natural sciences ,corn ,chemistry ,Agriculture ,manure tea ,humates ,040103 agronomy & agriculture ,biofertilizer ,0401 agriculture, forestry, and fisheries ,Environmental science ,Humic acid ,business ,biostimulant ,Agronomy and Crop Science ,Plant nutrition ,010606 plant biology & botany - Abstract
Current trends in agriculture have moved toward more sustainable cultivation systems with higher efficiency of input use. A variety of materials, derived from different resources, can serve as a crop nutrient sources. An Integrated Plant Nutrition System (IPNS) uses the combined and harmonious use of inorganic, organic and biological nutrient resources to maximize efficiency of inputs. We evaluated the effects of commercial nitrogen (N) fertilizer, humic acid compounds (HA), compost/manure teas and bioinoculants as inorganic, organic and biological resources, respectively and their synergy over three years on corn (Zea mays L.) in the Mid-Atlantic USA. The individual and combined application of HA and biofertilizer following the IPNS influenced corn height and leaf greenness to varying degrees, most likely due to biostimulant effects. In 2017, corn height, NDVI, greenness and vigor responded positively to biostimulant application to varying magnitudes and growth stages, however grain yield and nutrient content were not affected. In combined studies from 2018 and 2019 corn height was not impacted by biostimulant application but NDVI, photosynthetic efficiency, greenness and vigor were increased at different doses and corn growth stages. The combined use of HA + biofertilizer (Microlife Humic + Microgeo) was the only treatment leading to increased grain yield. This study demonstrates that the individual and combined application of HA and biofertilizer can influence corn growth and vigor at various points during the growing season. However, the current study cannot conclusively confirm that the integrated use of HA and biofertilizers (IPNS) is a better practice than the application of each compound individually. Virginia Tech -College of Agriculture and Life Sciences This work was supported by Virginia Tech -College of Agriculture and Life Sciences. Public domain – authored by a U.S. government employee
- Published
- 2020
6. Influence of synthetic phthalocyanine pigments on light reflectance of creeping bentgrass
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Alexander Wong, Dana G. Sullivan, Xunzhong Zhang, David S. McCall, S. Bruce Martin, and Erik H. Ervin
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chemistry.chemical_compound ,Pigment ,chemistry ,visual_art ,Phthalocyanine ,visual_art.visual_art_medium ,Light reflectance ,Biology ,Photochemistry ,Agronomy and Crop Science - Published
- 2020
7. The Synergistic Effects of Humic Substances and Biofertilizers on Plant Development and Microbial Activity: A Review
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Andre A. Diatta, Jose Franco Da Cunha Leme Filho, Michael S. Strickland, Bee Khim Chim, Xunzhong Zhang, Gregory K. Evanylo, and Wade Everett Thomason
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chemistry.chemical_classification ,Plant development ,Plant growth ,chemistry ,Biofertilizer ,Environmental chemistry ,fungi ,food and beverages ,Humic acid ,General Medicine - Abstract
Agroecosystem and ecological cycling loops are open when considering the reutilization of inputs applied in farming areas. Non-renewable resources have been transformed or relocated from the air, water and land into the system and are flowing out as wastes rather than reusable, recyclable resources. This current environmental situation is promoting the development of methods able to optimize nutrient cycling, minimize use of external inputs, and maximize input use efficiency. Some humic products are derived from lignin found in wheat straw and biofertilizers as compost and manure teas can be made using residues. Also, these biostimulants might decrease the necessity of synthetic inputs. This review strives to enhance our understanding of the conjunctive use of humic substances (HS) and biofertilizers. The biostimulant effects of each of these compounds are shown in the literature. Thus, our review question is whether the combined application of HS and biofertilizers can promote synergy between both compounds and potentially more efficacy. The effects promoted by using HS plus biofertilizers on plants and microorganisms are very interconnected, so sometimes these effects can be confounded. For instance, the root elongation promoted by HS might increase hyphal fungi colonization. Therefore, this review as divided in three sections: Responses of plants, fungi and bacteria. The findings indicate that the source and application rate of HS will have a strong impact on whether plant growth and microbial activity significantly improved. The microbial species and plant type also influence the response to HS. The prospects of the conjunctive use of and biofertilizers to stimulate plant development and microbial activity in agricultural systems are theoretically substantial when considering the total number of studies included in this review.
- Published
- 2020
8. Differential responses of antioxidants and dehydrin in two Switchgrass (Panicum virgatum L.) cultivars contrasting in drought tolerance
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Guoqiang Wu, Guofu Hu, Linling Yan, Bingyu Zhao, Xunzhong Zhang, and Yiming Liu
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fungi ,Drought tolerance ,food and beverages ,Biology ,Malondialdehyde ,APX ,biology.organism_classification ,Superoxide dismutase ,chemistry.chemical_compound ,Horticulture ,chemistry ,Catalase ,parasitic diseases ,biology.protein ,Panicum virgatum ,Cultivar ,Panicum - Abstract
Drought stress is a major limiting factor for plant growth and development in many regions of the world. This study was designed to investigate antioxidant metabolism and dehydrin expression responses to drought stress in two switchgrass cultivars (drought tolerant Alamo, and drought sensitive Dacotah) contrasting in drought tolerance. The plants were subjected to well-watered [100% evapotranspiration (ET)] or drought stress (30%-50% ET) conditions for up to 24 d in growth chambers. Drought stress decreased leaf relative water content (RWC), increased leaf electrolyte leakage (EL), leaf malondialdehyde (MDA) content in two cultivars, but Alamo exhibited higher leaf RWC level, lower leaf EL and MDA when compared to Dacotah at 24 d of drought treatment. Drought stress also increased superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activities in two cultivars, Alamo had relatively higher SOD, CAT and APX activities and greater abundance of SOD and APX isozymes than Dacotah at 24 d of drought treatment. Alamo had higher abundance of 55 KDa and 18 KDa dehydrin accumulation than Dacotah under drought treatment. Relative genes expression level of PvCAT1, PvAPX2, PvERD and PvPIP1;5 in Alamo were significantly higher than Dacotah at 24 d of drought treatment. These results suggest that increase in antioxidant enzymes and accumulation of dehydrin were highly related with switchgrass drought tolerance. Antioxidant enzyme activity, isozyme expression and dehydrin abundance could provide a useful screening tool to identify relative drought tolerance in switchgrass cultivars.
- Published
- 2020
9. Copper Chlorophyllin Impacts on Growth and Drought Stress Tolerance of Tomato Plants
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Michael Goatley, Megan Wilkins, Jun Liu, Teshler Inna, Michael Fefer, Xunzhong Zhang, Wenzi Ckurshumova, and Jamie Conner
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Drought stress ,Horticulture ,Copper chlorophyllin ,Chemistry ,fungi ,food and beverages - Abstract
Plant-based pigments have been used as substances to improve crop yield and quality, but the mechanisms of their action on plant growth and stress tolerance are not well understood. The objective of this study was to investigate effects of two formulations of plant-based copper chlorophyllin (Cu-Chl) with and without synthetic paraffinic oil. These formulations, referred to as B18-0074 and B18-0075, were applied as a soil drench plus foliar or a foliar-only application. We investigated their impact on physiological responses of tomato plants under prolonged drought stress conditions. In addition, we examined photosynthetic impacts associated with the application of Cu-Chl formulations. B18-0074 increased leaf photosynthetic rate (Pn) by 8.8% with soil plus foliar application and 18.6% with foliar application relative to the control under drought stress at day 21. Similarly, B18-0075 increased Pn by 16.9% with soil plus foliar application and 24.6% with foliar application relative to the control under drought stress at day 21. The application of the two Cu-Chl–containing products increased leaf antioxidant enzyme catalase (CAT) and ascorbate peroxidase (APX) activity, as well as glutathione (GSH) content. The two products also increased leaf soluble sugars and proline content, indicating improvement of osmotic adjustment. Soil plus foliar and foliar application only of B18-0075 increased root biomass but did not consistently affect plant shoot growth. The results of this study suggest that application of Cu-Chl in combination with synthetic paraffinic oil may improve photosynthetic function, osmotic adjustment, antioxidant defense capacity, and root growth of tomato plant grown under drought stress conditions.
- Published
- 2019
10. Stimulation of Growth and Alteration of Hormones by Elevated Carbon Dioxide for Creeping Bentgrass Exposed to Drought
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Bingru Huang, Xunzhong Zhang, Cathryn Chapman, and Patrick Burgess
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0106 biological sciences ,Agrostis stolonifera ,biology ,Stolon ,Jasmonic acid ,fungi ,Drought tolerance ,food and beverages ,Tiller (botany) ,04 agricultural and veterinary sciences ,biology.organism_classification ,01 natural sciences ,Horticulture ,chemistry.chemical_compound ,chemistry ,Shoot ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Agronomy and Crop Science ,Water content ,Abscisic acid ,010606 plant biology & botany - Abstract
Drought stress inhibits shoot growth of cool-season turfgrass species, and elevated CO₂ concentration may mitigate the adverse effects of drought through alteration of hormone production. The objective of this study was to determine whether elevated CO₂–enhanced drought tolerance in creeping bentgrass (Agrostis stolonifera L.) was associated with the stimulation of tiller and stolon growth and the alteration of stress-regulating and growth-regulating hormone accumulation. Creeping bentgrass (cv. Penncross) plants were established for 24 d at ambient (400 μL L⁻¹) or elevated (800 μL L⁻¹) CO₂ concentration and subsequently exposed to drought stress for 23 d by withholding irrigation. Drought stress caused significant reduction in leaf relative water content and tiller density, whereas both parameters, as well as stolon length, were maintained at significantly higher values in CO-treated plants compared with those at ambient CO₂ under drought stress. The positive effects of elevated CO₂ on the maintenance of leaf hydration and the promotion of tiller density and stolon growth in creeping bentgrass exposed to drought stress could be associated with the suppression of drought-induced accumulation of abscisic acid and the increase in the endogenous content of isopentenyladenosine, jasmonic acid, and the jasmonic acid precursor 12-oxo-phytodienoic acid. These results suggest that the elevated CO₂–enhanced growth of tillers and stolons in creeping bentgrass under drought stress could be regulated in part by the adjustment of endogenous hormone levels.
- Published
- 2019
11. Mitigating Effect of Glycinebetaine Pretreatment on Drought Stress Responses of Creeping Bentgrass
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Lu Gan, Xunzhong Zhang, Shuxia Yin, and Silu Liu
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0106 biological sciences ,0301 basic medicine ,Fight-or-flight response ,03 medical and health sciences ,Drought stress ,030104 developmental biology ,Agronomy ,Water stress ,Crop quality ,Horticulture ,Biology ,01 natural sciences ,010606 plant biology & botany - Abstract
Turfgrass performance under drought stress is impeded by plant water deficit and oxidative damage, which might be improved by the external application of osmoprotectants. Creeping bentgrass (Agrostis stolonifera L.) is a valuable species for low-cut golf surfaces as a result of its high density and fine texture. However, weak tolerance to drought stress is a primary shortcoming. In this study, the effect of exogenous glycinebetaine (GB) pretreatment on mitigating the damage from drought stress in creeping bentgrass cultivar ‘T-1’ was evaluated. Pieces of creeping bentgrass sod were subjected to four treatments: 1) well-watered control, 2) well watered and sprayed with 100 mm GB, 3) drought stress, and 4) drought stress and sprayed with 100 mm GB. Drought stress resulted in a remarkable decrease in turf quality (TQ), relative water content (RWC), and chlorophyll content, with significant increases in superoxide anion content (O2–), malondialdehyde (MDA) content, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activity. In contrast, pretreatment with 100 mm GB decreased the O2– and MDA content in water-stressed plants, and increased turf quality, chlorophyll content, SOD, CAT, and POD activity. Meanwhile, the expression level of the psbA, SAMS4, CMO, and ACS1 genes in leaf samples collected during the drought-stress stage was elevated in GB pretreatment. Notably, SAMS4 gene expression in GB pretreatment was significantly greater than in the untreated GB groups subjected to water stress. These results suggested that GB could mitigate the adverse effect of water stress on creeping bentgrass. The amelioration related strongly to the maintenance of the antioxidant enzyme system, accumulated endogenous compatible metabolites, and the elevation of gene expression levels. These findings lead us to conclude that GB pretreatment could be used as an ameliorative agent for creeping bentgrass against the deleterious effects of water stress.
- Published
- 2018
12. Additional file 1 of De novo transcriptome in roots of switchgrass (Panicum virgatum L.) reveals gene expression dynamic and act network under alkaline salt stress
- Author
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Zhang, Pan, Tianqi Duo, Fengdan Wang, Xunzhong Zhang, Zouzhuan Yang, and Hu, Guofu
- Abstract
Additional file 1: Table S1. Statistics of sample sequencing evaluation data.
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- 2021
- Full Text
- View/download PDF
13. Additional file 19 of De novo transcriptome in roots of switchgrass (Panicum virgatum L.) reveals gene expression dynamic and act network under alkaline salt stress
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Zhang, Pan, Tianqi Duo, Fengdan Wang, Xunzhong Zhang, Zouzhuan Yang, and Hu, Guofu
- Abstract
Additional file 19: Table S16. List of primers used in qRT-PCR.
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- 2021
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- View/download PDF
14. Additional file 2 of De novo transcriptome in roots of switchgrass (Panicum virgatum L.) reveals gene expression dynamic and act network under alkaline salt stress
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Zhang, Pan, Tianqi Duo, Fengdan Wang, Xunzhong Zhang, Zouzhuan Yang, and Hu, Guofu
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Additional file 2: Table S2. Statistics of reassembly results.
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- 2021
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- View/download PDF
15. List of contributors
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A. Joseph Thatheyus, Mohd Aamir, Leandro Afonso, Mushtaq Ahmed, Oluwatosin Joseph Aladekoyi, Sajeewa Amaradasa, N. Amaresan, Galdino Andrade, Ashly Lisset Arévalo, Charles W. Bacon, Ashok Bankar, André Riedi Barazetti, Daniel A. Bastías, Rahul Bhadouria, Khalida Bloch, Ana Cristina Bolaños, Bárbara Gionco Cano, John R. Caradus, Stuart D. Card, Shivani Chandra, Pranav Chettri, Andreas Lazaros Chryssafidis, Li Chunjie, Pompi Das, Matheus Felipe de Lima Andreata, Mickely Liuti Dealis, M. Elakkya, Janaína Emiliano, Çeknas Erdinç, Natasha T. Forester, P. Ghosh, Sougata Ghosh, Patrick Gillevet, Surendra K. Gond, Iti Gontia-Mishra, Raj Kumar Gothwal, Lingua Guido, Linda J. Johnson, David Johnston-Monje, Ünal Kal, Rahul Kaldate, Saveetha Kandasamy, Sarvesh Pratap Kashyap, Turnau Katarzyna, Ashraf Y.Z. Khalifa, Baban Preet Kour, Ajay Kumar, Kanchan Kumar, Ertan Sait Kurtar, Rusi Lata, George Lazarovits, Scott Lowman, Wade J. Mace, Poonam Meena, Chuansheng Mei, Taryn A. Miller, Manisha Mishra, Arpan Modi, Christina D. Moon, N. Jennifer Michellin Kiruba, Sampat Nehra, Erika Tyemi Goya Niekawa, Kin Israel Notarte, Jerzy Nowak, Olubusola Ayoola Odeniyi, Gaurav Pal, Smita Patil, Greg Patterson, Prasanta Kumar Prusty, E.K. Radhakrishnan, Ashutosh Rai, Balasubramanian Ramakrishnan, Anjul Rana, Swarnmala Samal, A. Sankaranarayanan, Swapnil Sapre, Musa Seymen, Abhishek Sharma, Awadhesh Kumar Shukla, Masoumeh Sikaroodi, Sumana Sikdar, Gianinazzi Silvio, Ane Stéfano Simionato, Amit Kishore Singh, Archana Singh, Pardeep Singh, Pooja Singh, Rishikesh Singh, Sandeep Kumar Singh, Sushil Kumar Singh, Vipin Kumar Singh, Pooran Singh Solanki, Dharmendra Kumar Soni, Navnita Srivastava, Ramya Sugavanam, Chen Taixiang, Mary Theresa, Sharad Tiwari, P.C. Trivedi, Önder Türkmen, John Onolame Unuofin, Ram S. Upadhyay, Alok Kumar Varshney, Akanksha Verma, Anand Verma, Satish K. Verma, Christine R. Voisey, Thomas J. Webster, Nimalka Weerasuriya, James F. White, Mohammad Tarique Zeyad, Wei Zhang, Xunzhong Zhang, Chen Zhenjiang, and Suat Şensoy
- Published
- 2021
16. Potential application of plant growth promoting bacteria in bioenergy crop production
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Patrick M. Gillevet, Jerzy Nowak, Scott Lowman, Chuansheng Mei, Sajeewa Amaradasa, Xunzhong Zhang, and Masoumeh Sikaroodi
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Abiotic component ,Rhizosphere ,Resource (biology) ,business.industry ,Agroforestry ,fungi ,Fossil fuel ,food and beverages ,Biomass ,Nutrient ,Bioenergy ,Alternative energy ,Environmental science ,business - Abstract
Food and energy demands are expected to increase dramatically due to the rapidly growing world population. With the limited supply of finite fossil fuel resources, accompanied by negative environmental impacts caused by their combustion, it is necessary to develop alternative energy resources. Bioenergy generated from plant biomass is one such promising resource. However, biomass production for energy use should not compete for fertile lands with food or feed production. Instead, bioenergy crops should grow on marginal lands and poor soils, which are not suitable for growing food crops. Dedicated bioenergy crops should be developed for high biomass yield and tolerance to biotic and abiotic stresses, with low inputs for sustainable production. Plant growth-promoting bacteria (PGPB), including rhizosphere and endophytic, are proven to improve plant growth, enhance nutrient uptake, increase tolerance to abiotic stresses, and inhibit pathogen growth. In this chapter, we outlines PGPB mechanisms of plant growth promotion and disease control and discusses future prospects.
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- 2021
17. Additional file 3 of De novo transcriptome in roots of switchgrass (Panicum virgatum L.) reveals gene expression dynamic and act network under alkaline salt stress
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Zhang, Pan, Tianqi Duo, Fengdan Wang, Xunzhong Zhang, Zouzhuan Yang, and Hu, Guofu
- Subjects
Data_FILES - Abstract
Additional file 3: Table S3. Statistics of unigene annotations.
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- 2021
- Full Text
- View/download PDF
18. The genome of the warm-season turfgrass African bermudagrass (Cynodon transvaalensis)
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Kehua Wang, Xunzhong Zhang, Manli Li, Fengchao Cui, Xiaoxia Dai, Nan Hang, Geli Taier, and Xiangfeng Wang
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0106 biological sciences ,0301 basic medicine ,Plant evolution ,Comparative genomics ,biology ,Sequence assembly ,Plant Science ,Horticulture ,biology.organism_classification ,01 natural sciences ,Biochemistry ,Genome ,Article ,03 medical and health sciences ,Cynodon ,030104 developmental biology ,Botany ,Genetics ,Chloridoideae ,Ploidy ,Adaptation ,010606 plant biology & botany ,Biotechnology - Abstract
Cynodon species can be used for multiple purposes and have high economic and ecological significance. However, the genetic basis of the favorable agronomic traits of Cynodon species is poorly understood, partially due to the limited availability of genomic resources. In this study, we report a chromosome-scale genome assembly of a diploid Cynodon species, C. transvaalensis, obtained by combining Illumina and Nanopore sequencing, BioNano, and Hi-C. The assembly contains 282 scaffolds (~423.42 Mb, N50 = 5.37 Mb), which cover ~93.2% of the estimated genome of C. transvaalensis (~454.4 Mb). Furthermore, 90.48% of the scaffolds (~383.08 Mb) were anchored to nine pseudomolecules, of which the largest was 60.78 Mb in length. Evolutionary analysis along with transcriptome comparison provided a preliminary genomic basis for the adaptation of this species to tropical and/or subtropical climates, typically with dry summers. The genomic resources generated in this study will not only facilitate evolutionary studies of the Chloridoideae subfamily, in particular, the Cynodonteae tribe, but also facilitate functional genomic research and genetic breeding in Cynodon species for new leading turfgrass cultivars in the future.
- Published
- 2020
19. Comprehensive analysis of transcriptional regulation and functional genes induced by alkaline salt stress in roots of two switchgrass (Panicum virgatum L.) genotypes
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Pan Zhang, Tianqi Duo, Fengdan Wang, Xunzhong Zhang, Zouzhuan Yang, and Guofu Hu
- Abstract
Background: Soil salinization is a major limiting factor for crop cultivation. Switchgrass is a perennial rhizomatous bunchgrass that is considered an ideal plant for marginal lands, including sites with saline soil. Here, we investigated the physiological responses and transcriptome changes in the roots of two switchgrass genotypes under alkaline salt stress.Results: Alkaline salt stress significantly affected the membrane, osmotic adjustment and antioxidant systems in switchgrass roots, and the ASTTI values between Alamo and AM-314/MS-155 were divergent at different time points. A total of 108,319 unigenes were obtained after reassembly, including 73,636 unigenes in AM-314/MS-155 and 65,492 unigenes in Alamo. A total of 10,219 DEGs were identified, and the number of upregulated genes in Alamo was much greater than that in AM-314/MS-155 in both the early and late stages of alkaline salt stress. The DEGs in AM-314/MS-155 were mainly concentrated in the early stage, while Alamo showed greater advantages in the late stage. These DEGs were mainly enriched in plant-pathogen interactions, ubiquitin-mediated proteolysis and glycolysis/gluconeogenesis pathways. We characterized 1,480 TF genes into 64 TF families, and the most abundant TF family was the C2H2 family, followed by the bZIP and bHLH families. A total of 1,718 PKs were predicted, including CaMK, CDPK, MAPK and RLK. WGCNA revealed that the DEGs in the blue, brown, dark magenta and light steel blue 1 modules were associated with the physiological changes in roots of switchgrass under alkaline salt stress. The consistency between the qRT-PCR and RNA-Seq results confirmed the reliability of the RNA-seq sequencing data. A molecular regulatory network of the switchgrass response to alkaline salt stress was preliminarily constructed on the basis of transcriptional regulation and functional genes.Conclusions: The alkaline salt tolerance of switchgrass may be achieved by the regulation of ion homeostasis, transport proteins, detoxification, heat shock proteins, dehydration and sugar metabolism. These findings provide a comprehensive analysis of gene transcription and regulation induced by alkaline salt stress in two switchgrass genotypes and contribute to the understanding of the alkaline salt tolerance mechanism of switchgrass and the improvement of switchgrass germplasm.
- Published
- 2020
20. Ethephon Seed Treatment Impacts on Drought Tolerance of Kentucky Bluegrass Seedlings
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Xunzhong Zhang, Lixin Xu, Lu Han, and Na Zhang
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0301 basic medicine ,fungi ,Drought tolerance ,food and beverages ,Horticulture ,Biology ,Enzyme assay ,Lipid peroxidation ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,chemistry ,Catalase ,Seed treatment ,biology.protein ,Proline ,Peroxidase ,Ethephon - Abstract
Ethephon [ETH (2-chloroethylphosphonic acid, an ethylene-releasing compound)] has been used as a plant growth regulator in turfgrass management. The aim of the study was to assess the effects of ETH seed treatment on drought tolerance of kentucky bluegrass (Poa pratensis) seedlings. Seeds of two kentucky bluegrass cultivars, Midnight and Nuglade, were exposed to ETH treatment or untreated as controls. Seedlings were then exposed to two water regimes: well-watered conditions and polyethylene glycol (PEG)–induced drought conditions. ETH-treated plants exhibited better turf performance relative to the untreated control under PEG-stressed conditions illustrated by higher relative water content (RWC) and lower lipid peroxidation and lower electrolyte leakage (EL). In both cultivars, ETH treatment increased enzyme activity of ascorbate peroxidase (APX), peroxidase (POD), and catalase (CAT); proline content; and soluble protein content under PEG-induced drought conditions. The results suggest that ETH seed treatment can improve drought tolerance in kentucky bluegrass seedlings.
- Published
- 2018
21. Remediation of heavily saline-sodic soil with flue gas desulfurization gypsum in Arid-Inland China
- Author
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Zhiping Yang, Long Liang, Wang Yongliang, Guo Caixia, Zhang Qiang, Xunzhong Zhang, and Guo Junling
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Topsoil ,Soil salinity ,Environmental remediation ,Environmental engineering ,Soil Science ,Sodic soil ,04 agricultural and veterinary sciences ,Plant Science ,010501 environmental sciences ,01 natural sciences ,Bulk density ,Hydraulic conductivity ,Lysimeter ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Environmental science ,Leaching (agriculture) ,0105 earth and related environmental sciences - Abstract
Soil salinity is a major limiting factor for crop production in arid and semi-arid regions of northwest China. Flue gas desulfurization gypsum (FGDG) is valuable waste resource which can be used to improve saline soil. Monolith lysimeter leaching experiment was conducted with FGDG in heavily saline-sodic soil of northwest China. The four FGDG treatments with nine replicates for each treatment were applied when the FGDG rate was 0, 15, 30, and 60 t ha−1, respectively. Undisturbed sodic-saline soil was carefully collected in the 40-cm deep soil column. The results indicated that improvement effect on the depth of 0–10 cm soil layer was the best when the rate of FGDG was 60 t ha−1. It can reduce pH by 1.85, exchangeable sodium percentage (ESP) by 44%, and exchangeable Na+ by 7.37 cmol/kg in top soil layer. The values of the above soil parameters fell in the normal range due to FGDG treatment. At the same time, FGDG application reduced soil bulk density and increased saturated hydraulic conductivity. ...
- Published
- 2018
22. Salt Stress-induced Injury is Associated with Hormonal Alteration in Kentucky Bluegrass
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Kim Harich, Wenli Wu, Xunzhong Zhang, Erik H. Ervin, and Chao Shang
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0106 biological sciences ,chemistry.chemical_classification ,021110 strategic, defence & security studies ,Stress induced ,0211 other engineering and technologies ,food and beverages ,Salt (chemistry) ,02 engineering and technology ,Horticulture ,Photosynthesis ,01 natural sciences ,Salinity ,chemistry.chemical_compound ,chemistry ,Chlorophyll ,Gibberellin ,Abscisic acid ,010606 plant biology & botany ,Hormone - Abstract
Plant hormones play an important role in plant adaptation to abiotic stress, but hormonal responses of cool-season turfgrass species to salt stress are not well documented. This study was carried out to investigate the responses of hormones to salt stress and examine if salt stress-induced injury was associated with hormonal alteration in kentucky bluegrass (KBG, Poa pratensis L.). The grass was grown in a growth chamber for 6 weeks and then subjected to salt stress (170 mm NaCl) for 28 days. Salt stress caused cell membrane damage, resulting in photosynthetic rate (Pn), chlorophyll (Chl), and turf quality decline in KBG. Salt stress increased leaf abscisic acid (ABA) and ABA/cytokinin (CK) ratio; reduced trans-zeatin riboside (ZR), isopentenyl adenosine (iPA), and indole-3-acetic acid (IAA), but did not affect gibberellin A4 (GA4). On average, salt stress reduced ZR by 67.4% and IAA by 58.6%, whereas it increased ABA by 398.5%. At the end of the experiment (day 28), turf quality, Pn, and stomatal conductance (gs) were negatively correlated with ABA and ABA/CK ratio, but positively correlated with ZR, iPA, and IAA. Electrolyte leakage (EL) was positively correlated with ABA and ABA/CK and negatively correlated with ZR, iPA, IAA, and GA4. GA4 was also positively correlated with turf quality and gs. The results of this study suggest that salt stress-induced injury of the cell membrane and photosynthetic function may be associated with hormonal alteration and imbalance in KBG.
- Published
- 2018
23. Antioxidant metabolism variation associated with salt tolerance of six maize (Zea mays L.) cultivars
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Guo Caixia, Xunzhong Zhang, Guo Junling, Wang Yongliang, Danli Jia, and Zhiping Yang
- Subjects
0106 biological sciences ,0301 basic medicine ,Antioxidant ,biology ,medicine.medical_treatment ,food and beverages ,General Medicine ,Malondialdehyde ,01 natural sciences ,Enzyme assay ,Salinity ,Superoxide dismutase ,03 medical and health sciences ,Horticulture ,chemistry.chemical_compound ,030104 developmental biology ,chemistry ,Agronomy ,Catalase ,biology.protein ,medicine ,Cultivar ,Proline ,010606 plant biology & botany - Abstract
Salt stress is a major limiting factor for crop production in many regions. This study examined antioxidant metabolism variation associated with salt stress tolerance of six maize cultivars (Luyu39, Huanong138, Xianyu335, Aoyu3007, Yayu8, Jinping618) under growth chamber environments. The seedlings of six cultivars were subjected to seven NaCl concentrations ranging from 0 to 295 mM for 20 days. The salt stress tolerance of the six cultivars varied largely, with their salt tolerance threshold values ranging from 184.5 to 303.4 mM. Luyu39 had the highest threshold value and was considered as salt tolerant cultivar, and Jinping618 had the lowest threshold (184.5 mM) and was considered as salt sensitive cultivar. Luyu39 had lower MDA content, higher antioxidant enzyme (SOD, CAT, and POD) activity, and lower proline content when compared to Jinping618 at 245 mM and 295 mM NaCl levels. The results suggest that MDA, antioxidant enzyme activity, and proline content can be used as metabolic markers to evaluate relative salt tolerance of different maize cultivars under severe salt stress (245 mM or higher concentration NaCl) conditions.
- Published
- 2017
24. Melatonin suppression of heat-induced leaf senescence involves changes in abscisic acid and cytokinin biosynthesis and signaling pathways in perennial ryegrass ( Lolium perenne L.)
- Author
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Yi Shi, Hongmei Du, Jing Zhang, Bingru Huang, Bin Xu, and Xunzhong Zhang
- Subjects
0106 biological sciences ,0301 basic medicine ,Senescence ,Perennial plant ,Plant Science ,01 natural sciences ,Lolium perenne ,Melatonin ,03 medical and health sciences ,chemistry.chemical_compound ,Botany ,medicine ,Abscisic acid ,Ecology, Evolution, Behavior and Systematics ,biology ,fungi ,food and beverages ,biology.organism_classification ,Cell biology ,030104 developmental biology ,chemistry ,Chlorophyll ,Cytokinin ,Growth inhibition ,Agronomy and Crop Science ,hormones, hormone substitutes, and hormone antagonists ,010606 plant biology & botany ,medicine.drug - Abstract
Leaf senescence is a typical symptom of heat damage in cool-season plant species. The objective of this study was to determine whether melatonin could suppress heat-induced leaf senescence in perennial ryegrass (Lolium perenne L.) and whether melatonin interacted with abscisic acid (ABA) and cytokinin (CK) to exert its biological function. Perennial ryegrass (cv. ‘Pinnacle’) plants were foliar sprayed with melatonin or water and exposed to heat stress at 38/33 °C (day/night) and non-stress condition at 22/17 °C for 28 d in growth chambers. Exogenous application of melatonin alleviated growth inhibition and leaf senescence induced by heat stress, as manifested by significant higher tiller number, above-ground dry weight, plant height, turf quality, leaf chlorophyll (Chl) content, photochemical efficiency (Fv/Fm), net photosynthesis rate, and cell membrane stability in melatonin-treated plants compared to non-melatonin treatment under heat stress. The suppression of heat-induced leaf senescence by melatonin was also reflected by the reduction of transcript levels of senescence-associated genes (LpSAG12.1 and Lph36) in plants exposed to heat stress. Melatonin treatment increased the endogenous content of melatonin and CK content, whereas it decreased ABA content under heat stress. The expression of CK biosynthesis genes and its signaling response transcription factors (type B ARRs) were up-regulated, while the biosynthesis and signaling genes involved in ABA were down-regulated by melatonin treatment under heat stress. These results indicate that the suppression of heat-induced leaf senescence by exogenous melatonin could be associated with activating CK synthesis and signaling while inhibiting ABA synthesis and signaling in perennial ryegrass.
- Published
- 2017
25. An Integrated Nutritional and Chemical Approach to Poa Annua Suppression in Creeping Bentgrass Greens
- Author
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Erik H. Ervin, Xunzhong Zhang, Shawn D. Askew, Nathaniel Reams, and Adam P. Boyd
- Subjects
0106 biological sciences ,biology ,Botany ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Poa annua ,04 agricultural and veterinary sciences ,biology.organism_classification ,01 natural sciences ,Agronomy and Crop Science ,010606 plant biology & botany - Published
- 2017
26. Cysteine protease RD21A regulated by E3 ligase SINAT4 is required for drought-induced resistance to Pseudomonas syringae in Arabidopsis
- Author
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Yi Liu, Qiang Cheng, Zhibo Wang, Qi Xie, Bingyu Zhao, Jinfang Chu, Jiamin Miao, Qian Wang, Hong-Qing Ling, Qi Li, Kunru Wang, Danyu Kong, Jijun Yan, and Xunzhong Zhang
- Subjects
0106 biological sciences ,0301 basic medicine ,Physiology ,Ubiquitin-Protein Ligases ,Arabidopsis ,Plant Immunity ,Pseudomonas syringae ,Plant Science ,01 natural sciences ,03 medical and health sciences ,Ubiquitin ,Immunity ,Cysteine Proteases ,Gene Expression Regulation, Plant ,Plant Diseases ,biology ,Effector ,Arabidopsis Proteins ,fungi ,food and beverages ,biology.organism_classification ,Cysteine protease ,Cell biology ,Ubiquitin ligase ,Droughts ,030104 developmental biology ,biology.protein ,010606 plant biology & botany - Abstract
Plants can be simultaneously exposed to multiple stresses. The interplay of abiotic and biotic stresses may result in synergistic or antagonistic effects on plant development and health. Temporary drought stress can stimulate plant immunity; however, the molecular mechanism of drought-induced immunity is largely unknown. In this study, we demonstrate that cysteine protease RD21A is required for drought-induced immunity. Temporarily drought-treated wild-type Arabidopsis plants became more sensitive to the bacterial pathogen-associated molecular pattern flg22, triggering stomatal closure, which resulted in increased resistance to Pseudomonas syringae pv. tomato DC3000 (Pst-DC3000). Knocking out rd21a inhibited flg22-triggered stomatal closure and compromised the drought-induced immunity. Ubiquitin E3 ligase SINAT4 interacted with RD21A and promoted its degradation in vivo. The overexpression of SINAT4 also consistently compromised the drought-induced immunity to Pst-DC3000. A bacterial type III effector, AvrRxo1, interacted with both SINAT4 and RD21A, enhancing SINAT4 activity and promoting the degradation of RD21A in vivo. Therefore, RD21A could be a positive regulator of drought-induced immunity, which could be targeted by pathogen virulence effectors during pathogenesis.
- Published
- 2019
27. Arsenic and nutrient absorption characteristics and antioxidant response in different leaves of two ryegrass (Lolium perenne) species under arsenic stress
- Author
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Hongyan Wu, Guilong Song, Qian Zhao, Jinbo Li, Bohan Xue, and Xunzhong Zhang
- Subjects
0106 biological sciences ,Leaves ,Perennial plant ,Species Delimitation ,Speciation ,Plant Science ,010501 environmental sciences ,Heavy Metals ,Toxicology ,Pathology and Laboratory Medicine ,01 natural sciences ,Biochemistry ,Antioxidants ,Plant Resistance to Abiotic Stress ,Medicine and Health Sciences ,Toxins ,Magnesium ,Multidisciplinary ,biology ,Ecology ,Plant Anatomy ,food and beverages ,Eukaryota ,Phosphorus ,Oxides ,Plants ,Peroxides ,Horticulture ,Chemistry ,Catalase ,Plant Physiology ,Physical Sciences ,Medicine ,Research Article ,Chemical Elements ,Frond ,Evolutionary Processes ,Nitrogen ,Science ,Toxic Agents ,chemistry.chemical_element ,Lolium perenne ,Phosphorus metabolism ,Arsenic ,Plant-Environment Interactions ,Lolium ,Plant Defenses ,Grasses ,0105 earth and related environmental sciences ,Manganese ,Evolutionary Biology ,Plant Ecology ,fungi ,Ecology and Environmental Sciences ,Organisms ,Chemical Compounds ,Biology and Life Sciences ,Lolium multiflorum ,Hydrogen Peroxide ,Plant Pathology ,APX ,biology.organism_classification ,Plant Leaves ,chemistry ,biology.protein ,Potassium ,Calcium ,Ryegrass ,010606 plant biology & botany - Abstract
Arsenic (As), a heavy metal element, causes soil environmental concerns in many parts of the world, and ryegrass has been considered as an effective plant species for bioremediation of heavy metal pollution including As. This study was designed to investigate As content, nutrient absorption and antioxidant enzyme activity associated with As tolerance in the mature leaves, expanded leaves and emerging leaves of perennial ryegrass (Lolium perenne) and annual ryegrass (Lolium multiflorum) under 100 mg·kg-1 As treatment. The contents of As, calcium (Ca), magnesium (Mg), manganese (Mn) in the leaves of both ryegrass species were greatest in the mature leaves and least in the emerging leaves. The nitrogen (N), phosphorus (P), potassium (K) contents of both ryegrass species were greatest in the emerging leaves and least in the mature leaves. The As treatment reduced biomass more in the mature leaves and expanded leaves relative to the emerging leaves for annual ryegrass and reduced more in emerging leaves relative to the mature and expanded leaves for perennial ryegrass. Perennial ryegrass had higher As content than annual ryegrass in all three kinds of leaves. The As treatment increased hydrogen peroxide (H2O2) in expanded leaves of two ryegrass species, relative to the control. The As treatment increased the ascorbate peroxidase (APX) activity in the expanded leaves of perennial ryegrass and the mature leaves of annual ryegrass, the catalase (CAT) activity in the mature and expanded leaves of perennial ryegrass and the emerging leaves of annual ryegrass, relative to the control. The As treatment reduced peroxidase (POD) activity in all three kinds of leaves of annual ryegrass and superoxide dismutase (SOD) activity in expanded leaves of perennial ryegrass, relative to the control. The results of this study suggest that As tolerance may vary among different ages of leaf and reactive oxygen species (ROS) and antioxidant enzyme activity may be associated with As tolerance in the ryegrass.
- Published
- 2019
28. Enhancing cytokinin synthesis by overexpressingiptalleviated drought inhibition of root growth through activating ROS-scavenging systems inAgrostis stolonifera
- Author
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Xunzhong Zhang, Patrick Burgess, Yi Xu, and Bingru Huang
- Subjects
0106 biological sciences ,0301 basic medicine ,Alternative respiration ,Cytokinins ,Agrostis stolonifera ,Physiology ,Ascorbic Acid ,Plant Science ,Plant Roots ,01 natural sciences ,Antioxidants ,Electrolytes ,chemistry.chemical_compound ,Agrostis ,Gene Expression Regulation, Plant ,Superoxides ,Malondialdehyde ,Biomass ,2. Zero hunger ,chemistry.chemical_classification ,biology ,drought stress ,food and beverages ,Free Radical Scavengers ,Catalase ,Plants, Genetically Modified ,Glutathione ,6. Clean water ,Droughts ,Cytokinin ,Antioxidant ,Research Paper ,Nitroprusside ,Cell Respiration ,Real-Time Polymerase Chain Reaction ,Superoxide dismutase ,03 medical and health sciences ,Stress, Physiological ,parasitic diseases ,Botany ,RNA, Messenger ,ROS scavenging system ,Reactive oxygen species ,Alkyl and Aryl Transferases ,Superoxide Dismutase ,root respiration ,fungi ,qRT-PCR ,15. Life on land ,Ascorbic acid ,biology.organism_classification ,030104 developmental biology ,chemistry ,turfgrass ,biology.protein ,Reactive Oxygen Species ,010606 plant biology & botany - Abstract
Highlight The relationship between an adenine isopentenyltransferase transgene, reactive oxygen species (ROS) content and the ROS-scavenging system, mechanistically contributing to improved root growth under drought stress in creeping bentgrass, is discussed., Drought stress limits root growth and inhibits cytokinin (CK) production. Increases in CK production through overexpression of isopentenyltransferase (ipt) alleviate drought damages to promote root growth. The objective of this study was to investigate whether CK-regulated root growth was involved in the alteration of reactive oxygen species (ROS) production and ROS scavenging capacity under drought stress. Wild-type (WT) creeping bentgrass (Agrostis stolonifera L. ‘Penncross’) and a transgenic line (S41) overexpressing ipt ligated to a senescence-activated promoter (SAG12) were exposed to drought stress for 21 d in growth chambers. SAG12-ipt transgenic S41 developed a more extensive root system under drought stress compared to the WT. Root physiological analysis (electrolyte leakage and lipid peroxidation) showed that S41 roots exhibited less cellular damage compared to the WT under drought stress. Roots of SAG12-ipt transgenic S41 had significantly higher endogenous CK content than the WT roots under drought stress. ROS (hydrogen peroxide and superoxide) content was significantly lower and content of total and free ascorbate was significantly higher in S41 roots compared to the WT roots under drought stress. Enzymatic assays and transcript abundance analysis showed that superoxide dismutase, catalase, peroxidase, and dehydroascorbate reductase were significantly higher in S41 roots compared to the WT roots under drought stress. S41 roots also maintained significantly higher alternative respiration rates compared to the WT under drought stress. The improved root growth of transgenic creeping bentgrass may be facilitated by CK-enhanced ROS scavenging through antioxidant accumulation and activation of antioxidant enzymes, as well as higher alternative respiration rates when soil water is limited.
- Published
- 2016
29. Protective effect of exogenous spermidine on ion and polyamine metabolism in Kentucky bluegrass under salinity stress
- Author
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Xunzhong Zhang, Liebao Han, Lixin Xu, Mengying An, and Xuehua Puyang
- Subjects
0106 biological sciences ,0301 basic medicine ,Spermine ,Plant Science ,Horticulture ,Biology ,01 natural sciences ,Ornithine decarboxylase ,Spermidine ,Salinity ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,chemistry ,Biochemistry ,mental disorders ,Putrescine ,Proline ,Arginine decarboxylase ,Polyamine oxidase ,010606 plant biology & botany ,Biotechnology - Abstract
Spermidine (Spd) acts as a plant protectant under salinity stress. The objective of this study was to determine whether exogenous Spd pre-treatment could improve the salinity tolerance of Kentucky bluegrass (Poa pratensis L.). Exogenous Spd was applied before the grass was exposed to 200 mM sodium chloride (NaCl) for 28 d in the growth chamber. Salinity stress decreased chlorophyll (Chl) content, K+/Na+ ratio and K+, Ca2+, and Mg2+ contents, and increased electrolyte leakage (EL), proline, Na+, putrescine (Put), Spd and Spermine (Spm) levels and the activities of arginine decarboxylase (ADC), ornithine decarboxylase (ODC), S-adenosylmethionine decarboxylase (SAMDC) and polyamine oxidase (PAO). Pre-treatment with 1 mM Spd effectively alleviated the decline of Chl content, K+/Na+ ratio and K+, Ca2+, and Mg2+ contents under salinity stress conditions. Spd pre-treatment also reduced EL, Na+ content, Put levels and the activities of ADC and PAO, but increased proline content, endogenous Spd and Spm levels and the activities of ODC and SAMDC upon salinity stress. These results indicate that exogenous Spd pre-treatment could enhance salinity tolerance by increasing proline levels and regulating ion and polyamine metabolism.
- Published
- 2016
30. Differential Responses of Antioxidants, Abscisic Acid, and Auxin to Deficit Irrigation in Two Perennial Ryegrass Cultivars Contrasting in Drought Tolerance
- Author
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Jasper B. Alpuerto, Takeshi Fukao, Erik H. Ervin, Chao Shang, Guofu Hu, Yiming Liu, and Xunzhong Zhang
- Subjects
chemistry.chemical_classification ,Perennial plant ,fungi ,Deficit irrigation ,Drought tolerance ,food and beverages ,Horticulture ,Biology ,chemistry.chemical_compound ,chemistry ,Agronomy ,Auxin ,Genetics ,Cultivar ,Abscisic acid - Abstract
Water deficit is a major limiting factor for grass culture in many regions with physiological mechanisms of tolerance not yet well understood. Antioxidant isozymes and hormones may play important roles in plant tolerance to water deficit. This study was designed to investigate antioxidant enzymes, isozymes, abscisic acid (ABA), and indole-3-acetic acid (IAA) responses to deficit irrigation in two perennial ryegrass (Lolium perenne L.) cultivars contrasting in drought tolerance. The plants were subjected to well-watered {100% container capacity, 34.4% ± 0.21% volumetric moisture content (VWC), or deficit irrigation [30% evapotranspiration (ET) replacement; 28.6% ± 0.15% to 7.5% ± 0.12% VWC]} conditions for up to 8 days and rewatering for 4 days for recovery in growth chambers. Deficit irrigation increased leaf malondialdehyde (MDA) content in both cultivars, but drought-tolerant Manhattan-5 exhibited lower levels relative to drought-sensitive Silver Dollar. Superoxide dismutase (SOD) activity declined and then increased during water-deficit treatment. ‘Manhattan-5’ had higher SOD activity and greater abundance of SOD1 isozyme than ‘Silver Dollar’ under water deficit. Deficit irrigation increased catalase (CAT) and ascorbate peroxidase (APX) activity in ‘Manhattan-5’, but not in ‘Silver Dollar’. ‘Manhattan-5’ had higher CAT, APX, and peroxidase (POD) activity than ‘Silver Dollar’ during water limitation. Deficit irrigation increased mRNA accumulation of cytosolic cupper/zinc SOD (Cyt Cu/Zn SOD), whereas gene expression of manganese SOD (Mn SOD) and peroxisome APX (pAPX) were not significantly altered in response to deficit irrigation. No differences in Cyt Cu/Zn SOD, Mn SOD, and pAPX gene expression were found between the two cultivars under deficit irrigation. Water limitation increased leaf ABA and IAA contents in both cultivars, with Silver Dollar having a higher ABA content than Manhattan-5. Change in ABA level may regulate stomatal opening and oxidative stress, which may trigger antioxidant defense responses. These results indicate that accumulation of antioxidant enzymes and ABA are associated with perennial ryegrass drought tolerance. Activity and isozyme assays of key antioxidant enzymes under soil moisture limitation can be a practical screening approach to improve perennial ryegrass drought tolerance and quality.
- Published
- 2015
31. Effects of fertilization and straw return methods on the soil carbon pool and CO2 emission in a reclaimed mine spoil in Shanxi Province, China
- Author
-
Chunhua Gao, Qiang Zhang, Xunzhong Zhang, Hua Li, Jianhua Li, and Hongbo Shao
- Subjects
food and beverages ,Soil Science ,Growing season ,04 agricultural and veterinary sciences ,Soil carbon ,engineering.material ,Straw ,Manure ,Human fertilization ,Agronomy ,040103 agronomy & agriculture ,engineering ,0401 agriculture, forestry, and fisheries ,Environmental science ,Fertilizer ,Mine reclamation ,Agronomy and Crop Science ,Mulch ,Earth-Surface Processes - Abstract
Reclaimed soil is similar to an “empty cup” with a large carbon (C) sequestration potential. Agricultural management practices strongly influence C storage and soil carbon dioxide (CO2) emission. The objective of this study was to identify the effects of fertilization and straw return methods on the soil C pool and CO2 emission in a reclaimed mine spoil. Thus, we studied the effects of four fertilization treatments [chemical fertilizer (NP), manure (M), 50% M plus 50% NP (NPM), and unfertilized control (CK)] and three straw return methods [no straw return (no straw), return of straw mixed with soil (straw mixing), and return of straw to the surface of the soil (straw mulching)] in a mine reclamation region by examining changes in the soil C pool and CO2 emission. The soil C pool was evaluated by acid hydrolysis, considering three pools: (a) labile pool I (LP I), obtained by hydrolysis with 5 N H2SO4 at 105 °C for 30 min; (b) labile pool II (LP II), obtained by hydrolysis with 26 N H2SO4 at room temperature overnight, followed by 2 N H2SO4 at 105 °C for 3 h; and (c) the recalcitrant pool, measured as the unhydrolyzed residue. The CO2 emission/C sequestration and CO2 emission/grain yield ratios were used as indicators of C emission. Compared with the CK, the NPM treatment was the most efficient among the fertilization treatments in increasing grain yield (136%) and C sequestration (311%) and reducing the CO2 emission/C sequestration (62%) and CO2 emission/grain yield (32%) ratios. The straw mixing treatment had more soil organic carbon (SOC), a larger LP I and LP II, and more C sequestration than the other straw return treatments. The addition of manure resulted in a higher distribution rate of new organic C to the labile C pool (73–78%) than the addition of inorganic fertilizer (45%). Soil C emissions were mainly concentrated in the maize growing season, accounting for more than 80% of the total annual C emissions. LP I, LP II and CO2 emission were significantly positive correlated with SOC and yield. Therefore, soil C pools and CO2 emissions are significantly influenced by fertilization regimes and straw return methods, which should be used to important indicators to estimate the C balance in agro-ecosystems during the process of mine spoil reclamation.
- Published
- 2019
32. Elucidation and Analyses of the Regulatory Networks of Upland and Lowland Ecotypes of Switchgrass in Response to Drought and Salt Stresses v1
- Author
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Chunman Zuo, Yuhong Tang, Hao Fu, Yiming Liu, Xunzhong Zhang, Bingyu Zhao, and Ying Xu
- Published
- 2018
33. Creeping Bentgrass Responses to a Tryptophan-Containing Organic Byproduct
- Author
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Xunzhong Zhang, Isaac Mertz, Nick Christians, Erik H. Ervin, Benjamin Pease, and Adam Thoms
- Subjects
chemistry.chemical_classification ,Agrostis stolonifera ,biology ,Tryptophan ,food and beverages ,chemistry.chemical_element ,biology.organism_classification ,Nitrogen ,Amino acid ,chemistry.chemical_compound ,chemistry ,Auxin ,Urea ,Plant defense against herbivory ,Fermentation ,Food science - Abstract
Tryptophan is one of the 22 essential amino acids and serves as a building block for protein synthesis. Tryptophan also is a known precursor for auxin in plants. Previous research has shown that applying fertilizers amended with auxin coming from tryptophan may enhance plant defense chemical responses during limited soil moisture conditions. This occurs through increases in root production, as well as changes in endogenous hormone levels, resulting in plant growth regulating activity. Tryptophan is produced industrially through fermentation, and following that process, a byproduct remains. Tryptophan byproduct (TRP-B) is currently considered a waste product. However, the trace amounts of tryptophan and nitrogen containing compounds remaining in the byproduct following fermentation make it an intriguing subject for use as a growth promoter for turfgrasses. The objective of this research was to determine whether applications of TRP-B improve Penn A-4 creeping bentgrass (Agrostis stolonifera L.) performance more than applications of pure tryptophan and/or urea.
- Published
- 2018
34. Cold Acclimation Treatment–induced Changes in Abscisic Acid, Cytokinin, and Antioxidant Metabolism in Zoysiagrass (Zoysia japonica)
- Author
-
Xunzhong Zhang, Mili Zhang, Lixin Xu, and Liebao Han
- Subjects
Antioxidant ,Zoysia japonica ,medicine.medical_treatment ,food and beverages ,Metabolism ,Horticulture ,Biology ,chemistry.chemical_compound ,chemistry ,Botany ,Cytokinin ,Cold acclimation ,medicine ,Abscisic acid - Abstract
Zoysiagrass (Zoysia spp.), a warm-season turfgrass species, experiences freezing damage in many regions. The mechanisms of its cold acclimation and freezing tolerance have not been well understood. This study was designed to investigate effects of cold acclimation treatment on leaf abscisic acid (ABA), cytokinin (transzeatin riboside (t-ZR), and antioxidant metabolism associated with freezing tolerance in zoysiagrass (Zoysia japonica). ‘Chinese Common’ zoysiagrass was subjected to either cold acclimation treatment with temperature at 8/2 °C (day/night) and a photosynthetically active radiation (PAR) of 250 µmol·m−2·s−1 over a 10-hour photoperiod or normal environments (temperature at 28/24 °C (day/night), PAR at 400 µmol·m−2·s−1 and 14-hour photoperiod) for 21 days in growth chambers. Cold treatment caused cell membrane injury as indicated by increased leaf cell membrane electrolyte leakage (EL) and malondialdehyde (MDA) content after 7 days of cold treatment. Cold treatment increased leaf ABA and hydrogen peroxide content and reduced t-ZR content. Leaf superoxide dismutase (SOD), ascorbate peroxidase (APX) activity, and proline content increased, whereas catalase (CAT) and peroxidase (POD) activity declined in response to cold treatment. Cold treatment increased freezing tolerance as LT50 declined from −4.8 to −12.5 °C. The results of this study indicated that cold acclimation treatment might result in increases in ABA and H2O2, which induce antioxidant metabolism responses and improved freezing tolerance in zoysiagrass.
- Published
- 2015
35. Water Deficit Irrigation Impacts on Antioxidant Metabolism Associated with Freezing Tolerance in Creeping Bentgrass
- Author
-
Xunzhong Zhang, Lixin Xu, Li-Juan Zhang, Liebao Han, and Tianxiu Zhong
- Subjects
Irrigation ,Antioxidant ,Agronomy ,medicine.medical_treatment ,Genetics ,medicine ,food and beverages ,Metabolism ,Horticulture ,Biology ,Freezing tolerance ,Water deficit - Abstract
Soil water deficit impacts cold acclimation and freezing tolerance in creeping bentgrass (Agrostis stolonifera L.), but the mechanisms underlying have not been well understood. The objectives of this study were to investigate the effects of deficit irrigation before and during cold acclimation on osmoprotectants, antioxidant metabolism, and freezing tolerance in creeping bentgrass. The grass was subjected to three-soil moisture levels: well-watered [100% container capacity (CC)], deficit irrigation induced-mild drought stress (60% CC), and severe drought stress (30% CC) for 35 days including 14 days at 24/20 °C (day/night) and then 21 days under cold acclimation treatment (2 °C) in growth chambers. Leaf proline and total soluble sugar (TSS) levels were higher in the grass under mild drought stress relative to that under severe drought stress. Superoxide (O2−·), hydrogen peroxide (H2O2), and malondialdehyde (MDA) content were higher in the grass under severe drought relative to that under well-watered and mild drought stress at day 35. Mild drought stress increased catalase (CAT) and guaiacol peroxidase (POD) activity, induced new isoforms and increased band intensities of superoxide dismutase (SOD), CAT, and POD during cold acclimation (days 14 to 35). No differences in osmoprotectants, antioxidant metabolism, and freezing tolerance were found between mild drought and well-watered treatments. The results of this study suggest deficit irrigation-induced mild drought stress in late fall and winter could induce accumulation of osmoprotectants and improve antioxidant metabolism, and freezing tolerance, but severe drought stress could reduce freezing tolerance of creeping bentgrass in the region with limited precipitation.
- Published
- 2015
36. Genotypic Variation of Morphological Traits in Tall Fescue (Festuca arundinacea Schreb.) Accessions
- Author
-
Yanhong Lou, Qingguo Xu, Xunzhong Zhang, and Liang Chen
- Subjects
Variation (linguistics) ,Agronomy ,biology ,Genotype ,Botany ,food and beverages ,Horticulture ,biology.organism_classification ,Festuca arundinacea - Abstract
Tall fescue is an important cool-season grass widely used for forage and turf, and its genotypic variation for morphological traits has not been well documented. One hundred and fifteen tall fescue accessions, including 25 commercial cultivars, were divided into five groups based on their origination. The morphological traits, including plant height, spike length, pulvinus distance, spikelet count, branch count per spike, spike count per plant, and spike weight in different accessions were determined under field conditions in 2013 and 2014. There was significant genotypic variation in morphological traits among the 115 tall fescue accessions. Wild accessions exhibited a greater variation in the morphological traits than commercial cultivars. Close correlations were found among plant height, spike length, pulvinus distance, and spikelet count. The results of this suggest plant height, spike length, pulvinus distance, and spikelet count could be used as key morphological traits for evaluating all fescue germplasm effectively.
- Published
- 2015
37. Enhanced Soil Moisture Assessment using Narrowband Reflectance Vegetation Indices in Creeping Bentgrass
- Author
-
David S. McCall, Erik H. Ervin, Shawn D. Askew, Dana G. Sullivan, and Xunzhong Zhang
- Subjects
0106 biological sciences ,Soil science ,04 agricultural and veterinary sciences ,Biology ,01 natural sciences ,Reflectivity ,Narrowband ,040103 agronomy & agriculture ,medicine ,0401 agriculture, forestry, and fisheries ,medicine.symptom ,Vegetation (pathology) ,Agronomy and Crop Science ,Water content ,010606 plant biology & botany - Published
- 2017
38. Auxin and Trinexapac‐Ethyl Impact on Root Viability and Hormone Metabolism in Creeping Bentgrass under Water Deficit
- Author
-
Xunzhong Zhang, Erik H. Ervin, Naina Sharma, Alyssa Hamill, and Wenli Wu
- Subjects
0106 biological sciences ,0301 basic medicine ,chemistry.chemical_classification ,Biology ,01 natural sciences ,Trinexapac-ethyl ,03 medical and health sciences ,030104 developmental biology ,chemistry ,Auxin ,Botany ,Hormone metabolism ,Agronomy and Crop Science ,010606 plant biology & botany - Published
- 2017
39. Antioxidant and Hormone Responses to Heat Stress in Two Kentucky Bluegrass Cultivars Contrasting in Heat Tolerance
- Author
-
Xunzhong Zhang, Feifei Li, Liebao Han, Da Zhan, and Lixin Xu
- Subjects
Heat tolerance ,Antioxidant ,Agronomy ,medicine.medical_treatment ,fungi ,Genetics ,medicine ,food and beverages ,Cultivar ,Horticulture ,Biology ,Heat stress ,Hormone - Abstract
Heat stress is a major limiting factor for growth of cool-season perennial grass species, and mechanisms of heat tolerance have not been well understood. This study was designed to investigate antioxidant enzyme and hormone metabolism responses to heat stress in two kentucky bluegrass (Poa pratensis L.) cultivars contrasting in heat tolerance. The plants were subjected to 20/20 °C [day/night (control)] or 38/30 °C [day/night (heat stress)] for 28 days in growth chambers. Heat stress increased leaf electrolyte leakage (EL) and malondialdehyde (MDA) with heat-tolerant cultivar EverGlade exhibiting lower levels of EL and MDA relative to heat-sensitive cultivar Kenblue under heat stress. Superoxide dismutase (SOD) and catalase (CAT) activity increased and then declined during 28 days of heat stress. Peroxidase (POD) and ascorbate peroxidase (APX) activity declined and then increased during heat stress. ‘EverGlade’ had greater activities of SOD, CAT, POD, and APX relative to ‘Kenblue’ under heat stress. In addition, ‘EverGlade’ had two additional SOD isozymes and three additional POD isozymes relative to ‘Kenblue’ under heat stress. Leaf abscisic acid (ABA) increased in response to heat stress. Leaf indole-3-acetic acid (IAA) increased and then declined during heat stress. ‘OverGlade’ had higher ABA and IAA content relative to ‘Kenblue’. At the end of heat stress, leaf IAA and ABA content were 27.8% and 73% higher in ‘EverGlade’ relative to ‘Kenblue’, respectively. The results indicated that antioxidant enzymes and the hormones (ABA and IAA) were associated with kentucky bluegrass heat tolerance. Selection and use of cultivars with higher IAA and ABA content and greater antioxidant enzyme activities may improve kentucky bluegrass growth and quality under heat stress.
- Published
- 2014
40. Effects of Biosolids on Root Growth and Nitrogen Metabolism in Kentucky Bluegrass under Drought Stress
- Author
-
Xunzhong Zhang, Chang Zhihui, Fangfang Yu, and Laiqiang Zhuo
- Subjects
Nutrient ,Agronomy ,Biosolids ,Chemistry ,Soil organic matter ,Drought tolerance ,Hormone metabolism ,Proline ,Horticulture ,Nitrate reductase ,Nitrogen cycle - Abstract
Biosolids are valued as a source of plant nutrients, soil organic matter, and biologically active substances. This greenhouse study was designed to examine if application of biosolids can improve plant drought tolerance by affecting nitrogen (N) and hormone metabolism as well as root growth in kentucky bluegrass (Poa pratensis L.; KBG). The three treatments, which provided N rates equivalent to 75 mg plant-available N/kg soil, included: 1) biosolids at 1× agronomic (Ag) N rate (75 mg N/kg soil completely provided with biosolids); 2) biosolids at 0.5× Ag N rate (37.5 mg N/kg soil provided with biosolids and 37.5 mg N/kg soil provided with NH4NO3); and 3) control (75 mg N/kg soil completely provided with NH4NO3). The treated KBG was grown under either well-watered (90% container capacity) or drought stress (≈25% container capacity) conditions. Biosolids application improved turf quality and delayed leaf wilting under drought stress. The grass treated with biosolids at 1× N rate had higher leaf proline and amino acid content and greater nitrate reductase activity than the control under drought stress. Biosolids treatments also increased leaf and soil indole-3-acetic acid (IAA) content. Moreover, biosolids at 1× N rate increased root length density by 23% compared with the control under drought stress. The results of this study suggest that biosolids may enhance plant drought tolerance by improving N and hormone metabolism and root growth in KBG.
- Published
- 2014
41. Evaluation of Salinity Tolerance and Genetic Diversity of Thirty-Three Switchgrass (Panicum virgatum) Populations
- Author
-
Yiming Liu, Taylor P. Frazier, Linkai Huang, Bingyu Zhao, Jiamin Miao, and Xunzhong Zhang
- Subjects
education.field_of_study ,Stomatal conductance ,Genetic diversity ,Renewable Energy, Sustainability and the Environment ,Population ,Biology ,biology.organism_classification ,Salinity ,chemistry.chemical_compound ,Agronomy ,chemistry ,Genetic marker ,Chlorophyll ,Panicum virgatum ,education ,Agronomy and Crop Science ,Energy (miscellaneous) ,Transpiration - Abstract
Switchgrass (Panicum virgatum) is a warm-season C4 grass that is a target lignocellulosic biofuel species. Salt stress is one of the major limiting factors for switchgrass growth in many regions. The objective of this study was to examine relative salt tolerance and genetic diversity among 33 switchgrass populations. Seeds of each population were planted in cone-tainers and grown in a greenhouse. Two months after establishment, the switchgrass were grown in half strength Hoagland’s nutrient solution with either 0 mM NaCl (control) or half strength Hoagland’s nutrient solution with 250 mM NaCl (salt stress treatment) for 24 days. Salt stress tolerance was determined based on a variety of parameters including leaf electrolyte leakage (EL), chlorophyll content (Chl content), leaf photochemical efficiency (F v/F m), photosynthetic rate (P n), stomatal conductance (g s), and transpiration rate (T r). Significant differences in salt stress tolerance were found among the 33 populations. Based on the P n and salt tolerance trait index (STTI), lowland populations AM-314/MS-155, Kanlow, TEM-LoDorm, Alamo, and BN-13645-64, as well as upland populations T-2086, T-2101, BN-11357-63, and BN-12323-69 were classified as salt tolerant. In contrast, upland populations BN-18757-67, 70SG0021, Summer, 70SG0016, T16971, Dacotah, Turkey, 70SG003, and Pathfinder were classified as salt sensitive populations. Sequence-related amplified polymorphism (SRAP) marker analysis was employed to determine the genetic diversity among the 33 switchgrass populations. UPGMA cluster analysis showed that salt tolerant switchgrass populations TEM-LoDorm, Alamo, Kanlow, BN-12323-69, AM-314/MS-155, T2101, BN-11357-63, T-2086, and BN-13645-64 clustered into one group, indicating that these salt tolerant populations may have a similar genetic background.
- Published
- 2014
42. Expression profiles ofPr5CS1andPr5CS2genes and proline accumulation under salinity stress in perennial ryegrass (Lolium perenneL.)
- Author
-
Jinmin Fu, Huiying Li, Huijuan Guo, and Xunzhong Zhang
- Subjects
chemistry.chemical_classification ,Perennial plant ,fungi ,food and beverages ,Plant Science ,Biology ,biology.organism_classification ,Lolium perenne ,Enzyme ,chemistry ,Gene expression ,Botany ,Genetics ,Osmoprotectant ,Proline ,Cultivar ,Agronomy and Crop Science ,Gene - Abstract
Proline is an important osmoprotectant in plant in response to osmotic stresses. Delta 1-pyrroline-5-carboxylate synthetase (P5CS) is a key enzyme in proline biosynthesis. In this study, two P5CS genes (PrP5CS1 and PrP5CS2) were isolated for the first time from perennial ryegrass. Expression analysis revealed that the transcript of PrP5CS1 in leaves was significantly up-regulated in two ryegrass cultivars exposed to 255 mm NaCl. The up-regulated level of PrP5CS1 was higher in salt-tolerant ‘Overdrive’ than in sensitive ‘Pizzazz’. PrP5CS2 was significantly induced in ‘Overdrive’ but suppressed in ‘Pizzazz’ by NaCl treatment. In stems, however, there was no significant transcript change for both genes under salt treatment. The proline accumulation was significantly induced in both cultivars after salt treatment, and it was higher in ‘Overdrive’ than in ‘Pizzazz’ after 2 days of salt treatment. The results suggested that both genes are salt inducible and may be associated with salt-stress tolerance in perennial ryegrass.
- Published
- 2014
43. Identifying Differences in Abiotic Stress Gene Networks between Lowland and Upland Ecotypes of Switchgrass (DE-SC0008338)
- Author
-
Robin Buell, Bingyu Zhao, Kevin L. Childs, and Xunzhong Zhang
- Subjects
Ecotype ,Ecology ,Abiotic stress ,Botany ,Gene regulatory network ,Biology - Published
- 2016
44. Corn and Soybean Hormone and Antioxidant Metabolism Responses to Biosolids under Two Cropping Systems
- Author
-
Jinling Li, Erik H. Ervin, Kim Harich, Xunzhong Zhang, and Greg K. Evanylo
- Subjects
Antioxidant ,Agronomy ,Biosolids ,business.industry ,medicine.medical_treatment ,medicine ,Metabolism ,Biology ,business ,Agronomy and Crop Science ,Cropping ,Biotechnology ,Hormone - Published
- 2013
45. EFFECTS OF NITRATE AND CYTOKININ ON CREEPING BENTGRASS UNDER SUPRAOPTIMAL TEMPERATURES
- Author
-
Xunzhong Zhang, Erik H. Ervin, and Kehua Wang
- Subjects
Chlorophyll concentration ,Horticulture ,chemistry.chemical_compound ,chemistry ,Agronomy ,Nitrate ,Physiology ,Cytokinin ,chemistry.chemical_element ,Agronomy and Crop Science ,Nitrogen ,Heat stress ,Zeatin riboside - Abstract
Heat stress reduces creeping bentgrass performance in temperate to sub-tropical climates. The research objective was to characterize effects of nitrogen (N) and cytokinin (CK) on creeping bentgrass under heat stress. In a 38°C/28°C chamber, grasses were treated with two nitrogen (2.5 and 7.5 kg N ha−1) and three CK rates (0, 10 and 100 μM) biweekly. Grass grown at high N had better turf quality, higher photochemical efficiency (Fv/Fm), normalized difference vegetation index (NDVI), and chlorophyll concentration at d15 and 28 than low N. CK increased NDVI at d15, with Fv/Fm of the CK100 treatment being 18% higher than that of CK0 at d28. Under high N with 100 μM CK, root trans-zeatin riboside (tZR) and isopentenyl adenosine (iPA) were 160% and 97% higher than under low N without CK, respectively. These results demonstrate positive impacts of N and CK on creeping bentgrass under heat, with N playing a dominant role.
- Published
- 2013
46. Biosolids Impact Antioxidant Metabolism Associated with Drought Tolerance in Tall Fescue
- Author
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Erik H. Ervin, Xunzhong Zhang, Damai Zhou, Derik Cataldi, Jinling Li, and Greg K. Evanylo
- Subjects
biology ,Biosolids ,Drought tolerance ,food and beverages ,Wilting ,Moisture stress ,Horticulture ,engineering.material ,APX ,Enzyme assay ,Agronomy ,biology.protein ,engineering ,Fertilizer ,Water content - Abstract
The presence of biologically active substances (BAS) in biosolids may enhance plant stress tolerance and growth, but the underlying mechanisms are not well understood. This greenhouse study investigated the effects of two biosolids: Alexandria (anaerobically digested; Class A product from the Alexandria Sanitation Authority Wastewater Treatment Facility in Alexandria, VA) and Blue Plains (lime-stabilized; Class B product from Washington, DC, Water and Sewer Authority) on tall fescue [Lolium arundinaceum (Schreb.) S.J. Darbyshire] antioxidant enzyme activity associated with drought resistance. Treatments included a fertilizer control, Alexandria (11.9 g·kg−1 soil) and Blue Plains (17.6 g·kg−1 soil) biosolids to match the nitrogen in the control. Tall fescue physiological responses were measured under well-watered or drought-stressed conditions. Drought stress reduced turfgrass quality, photochemical efficiency (PE), and catalase (CAT) activity while increasing superoxide dismutase (SOD), ascorbate peroxidase (APX), and peroxidase (POD) activities. The two biosolids improved turfgrass quality and root mass under both soil moisture regimes and delayed leaf wilting during moisture stress. The biosolids also improved PE, SOD, and APX activities relative to the control under both soil moisture regimes. The data suggest that biosolids application may improve antioxidant enzyme activity and subsequent drought resistance.
- Published
- 2012
47. Analysis of salt-induced physiological and proline changes in 46 switchgrass (Panicum virgatum) lines indicates multiple response modes
- Author
-
Yiming Liu, Xunzhong Zhang, Bingyu Zhao, Kevin L. Childs, and Jeongwoon Kim
- Subjects
0106 biological sciences ,0301 basic medicine ,Soil salinity ,Proline ,Physiology ,Sodium ,Salt (chemistry) ,chemistry.chemical_element ,Plant Science ,Biology ,Sodium Chloride ,Photosynthesis ,Panicum ,01 natural sciences ,03 medical and health sciences ,Quantitative Trait, Heritable ,Stress, Physiological ,Genetics ,Cluster Analysis ,chemistry.chemical_classification ,Principal Component Analysis ,Ecotype ,Salt Tolerance ,biology.organism_classification ,030104 developmental biology ,Phenotype ,Agronomy ,chemistry ,Panicum virgatum ,010606 plant biology & botany - Abstract
Switchgrass (Panicum virgatum) is targeted as a biofuel feedstock species that may be grown on marginal lands including those with saline soils. Our study investigated salt stress responses in 46 switchgrass lines from the lowland and upland ecotypes by assessing physiological phenotypes and proline concentrations. Lowland switchgrass lines demonstrated less severe responses to salt stress than most upland switchgrass lines, but a number of upland lines performed as well as lowland individuals. Photosynthetic rate (Pn), the most important physiological trait measured, was reduced by salt treatment in all lines. Tolerant lines showed ∼50% reduction in Pn under salt stress, and sensitive lines exhibited ∼90% reduction in Pn after salt stress. Proline analysis showed the largest amount of variation under salt stress with some lines exhibiting minor increases in proline, but some salt-sensitive lines demonstrated more than 5000-fold increase in proline concentration in response to salt treatment. Clustering of salt-stress phenotypic responses revealed five groups of switchgrass. Lowland lines were present in two of the phenotypic clusters, but upland lines were found in all five of the phenotypic clusters. These results suggest that there are multiple modes of salt response in switchgrass including two distinct modes of salt tolerance.
- Published
- 2016
48. Small Heat Shock Proteins, a Key Player in Grass Plant Thermotolerance
- Author
-
Erik H. Ervin, Xunzhong Zhang, and Kehua Wang
- Subjects
0106 biological sciences ,0301 basic medicine ,fungi ,food and beverages ,Genomics ,Biology ,Proteomics ,01 natural sciences ,Heat stress ,Structure and function ,03 medical and health sciences ,030104 developmental biology ,Botany ,Poaceae ,Small Heat-Shock Proteins ,Function (biology) ,010606 plant biology & botany - Abstract
Small heat shock proteins (sHSPs) are by far the most complex group of HSPs that function to protect practically all cellular compartments in plants under stress due to their unusual abundance and diversity. Recent advances in proteomics, genomics, and other cellular and molecular techniques have facilitated the identification and characterization of sHSPs in higher plants, especially grass plants from the family of Poaceae that are economically important as crops and grasslands. Here we introduce the structure and function of plant sHSPs, and then summarize recent research progress on the role of sHSPs in grass tolerance to heat stress.
- Published
- 2016
49. Enhanced Drought Tolerance of Tobacco Overexpressing OjERF Gene Is Associated with Alteration in Proline and Antioxidant Metabolism
- Author
-
Cong Li, Lie-Bao Han, and Xunzhong Zhang
- Subjects
biology ,Agrobacterium ,Nicotiana tabacum ,Transgene ,fungi ,Drought tolerance ,food and beverages ,Agrobacterium tumefaciens ,Horticulture ,biology.organism_classification ,Molecular biology ,Superoxide dismutase ,Transformation (genetics) ,Botany ,Genetics ,biology.protein ,Proline - Abstract
Drought stress is one of the major limiting factors for plant growth and development. The mechanism of drought tolerance has not been well understood. This study was designed to investigate proline and antioxidant metabolism associated with drought tolerance in transgenic tobacco (Nicotiana tabacum) plants overexpressing the OjERF gene relative to wild-type (WT) plants. The OjERF gene was isolated from mondo grass (Ophiopogon japonicus). The OjERF gene, driven by the CaMV35S promoter, was introduced into tobacco through agrobacterium (Agrobacterium tumefaciens)-mediated transformation. Five transgenic lines were regenerated, of which transgenic Line 5 (GT5) and Line 6 (GT6) were used to examine drought tolerance in comparison with WT plants in a growth chamber. Drought stress caused an increase in leaf malondialdehyde (MDA) and electrolyte leakage (EL), proline content, superoxide dismutase (SOD), and catalase (CAT) activity in both transgenic lines and WT plants. However, the transgenic lines had lower MDA content and EL and higher proline content, SOD and CAT activity relative to WT under drought stress. The activities of SOD and CAT were also greater in the transgenic lines relative to WT plants under well-watered conditions (Day 0). The OjERF activated the expression of stress-relative genes, including NtERD10B, NtERD10C, NtERF5, NtSOD, and NtCAT1 in tobacco plants. The results of this study suggest that the OjERF gene may confer drought stress tolerance through upregulating proline and antioxidant metabolism.
- Published
- 2012
50. Exogenous Glycine Betaine Ameliorates the Adverse Effect of Salt Stress on Perennial Ryegrass
- Author
-
Tao Hu, Jinmin Fu, Xunzhong Zhang, Huancheng Pang, and Longxing Hu
- Subjects
biology ,Chemistry ,food and beverages ,Horticulture ,APX ,Salinity ,Superoxide dismutase ,Lipid peroxidation ,chemistry.chemical_compound ,Animal science ,Ion homeostasis ,Betaine ,Shoot ,Botany ,Genetics ,biology.protein ,Proline - Abstract
Salinity stress may involve the accumulation of glycine betaine (GB). The objective of this study was to examine whether exogenous GB would ameliorate the detrimental effect of salinity stress on perennial ryegrass (Lolium perenne). The grass was subjected to two salinity levels (0 and 250 mm NaCl) and three GB levels (0, 20, and 50 mm). Salinity resulted in a remarkable decrease in vertical shoot growth rate (VSGR), shoot and root fresh weight, relative water content (RWC), relative transpiration rate (Tr), and chlorophyll (Chl) content, superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities. Plants subjected to salt exhibited an increase in leaf electrolyte leakage (EL), lipid peroxidation (MDA), and proline content. Application of GB reduced EL, MDA, and proline content in salt-stressed plants. Perennial ryegrass subjected to salt stress plus GB had a greater level of VSGR, RWC, relative Tr, Chl content, and activities of SOD, CAT, and APX when compared with salt-stressed without GB. Salt stress increased Na+ and decreased K+ content, which resulted in a higher Na+/K+ ratio in perennial ryegrass. Application of 20 mm GB suppressed Na+ accumulation, whereas the K+ content was significantly increased in shoot, which led to a higher K+/Na+ ratio under saline conditions. These results suggested that GB-enhanced salt tolerance in perennial ryegrass was mainly related to the elevated SOD, CAT, and APX activity and alleviation of cell membrane damage by reducing oxidation of membrane lipid and improving the ion homeostasis under salt stress.
- Published
- 2012
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