Journal of Integrative Agriculture

Hybrid rice achievements, development and prospect in China

MA Guo-hui, YUAN Long-ping

2015, 14(2): 197-205. DOI: 10.1016/S2095-3119(14)60922-9

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This article reviews the history and progress of hybrid rice development. Hybrid rice research was initiated back in 1964, and commercialized in 1976. Three-line and two-line system hybrid rice were developed in 1974 and 1995, respectively. Research on super hybrid rice, which was first launched by Ministry of Agriculture, China in 1996, is discussed, and the great progress of super hybrid rice had been achieved with a new yield record by 15.4 t ha–1 in the 6.84 ha demonstration location in Xupu, Hunan Province, China in 2014. And the mechanism of heterosis, the techniques of hybrid seed production and the modern field managements in hybrid rice over the past decades are also discussed. Additionally, this article dealt with the intellectual property protection (IPR) and development of hybrid rice seed industry in China. Major factors that constrain hybrid rice development are analyzed and possible solutions to this problems are proposed. Finally, the authors present methods to further increase production yield, and propose an improvement for breeding super high-yielding hybrid rice based on these methods.

Is it possible to save the environment and satisify consumers with artificial meat?

Jean-Francois Hocquette

2015, 14(2): 206-207. DOI: 10.1016/S2095-3119(14)60961-8

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Alternatives for large-scale production of cultured beef: A review

Matilda S M Moritz, Sanne E L Verbruggen, Mark J Post

2015, 14(2): 208-216. DOI: 10.1016/S2095-3119(14)60889-3

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Cultured beef is a method where stem cells from skeletal muscle of cows are cultured in vitro to gain edible muscle tissue. For large-scale production of cultured beef, the culture technique needs to become more efficient than today’s 2-dimensional (2D) standard technique that was used to make the first cultured hamburger. Options for efficient large-scale production of stem cells are to culture cells on microcarriers, either in suspension or in a packed bed bioreactor, or to culture aggregated cells in suspension. We discuss the pros and cons of these systems as well as the possibilities to use the systems for tissue culture. Either of the production systems needs to be optimized to achieve an efficient production of cultured beef. It is anticipated that the optimization of large-scale cell culture as performed for other stem cells can be translated into successful protocols for bovine satellite cells resulting in resource and cost efficient cultured beef.

Artificial meat? Feasible approach based on the experience from cell culture studies

Arkadiusz Orzechowski

2015, 14(2): 217-221. DOI: 10.1016/S2095-3119(14)60882-0

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This short review is to list pros and cons which are based on the literature and personal experience in cell culture studies related to possible commercial production of artificial meat as functional food. The general view of muscle composition and determinants of meat quality are shortly described. Principles of muscle cell propagation in culture and mutual relationships between different cell types present in this organ are briefly discussed. Additionally, the effects of some cytokines and growth factors for muscle cell growth and muscle tissue development are indicated. Finally, conclusion remarks related to detrimental consequences of meat production to natural environment as well as personal opinion of author on the prospects of artificial meat production are declared.

Cultured meat from muscle stem cells: A review of challenges and prospects

Isam T Kadim, Osman Mahgoub, Senan Baqir, Bernard Faye , Roger Purchas

2015, 14(2): 222-233. DOI: 10.1016/S2095-3119(14)60881-9

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Growing muscle tissue in culture from animal stem cells to produce meat theoretically eliminates the need to sacrifice animals. So-called “cultured” or “synthetic” or “in vitro” meat could in theory be constructed with different characteristics and be produced faster and more efficiently than traditional meat. The technique to generate cultured muscle tissues from stem cells was described long ago, but has not yet been developed for the commercial production of cultured meat products. The technology is at an early stage and prerequisites of implementation include a reasonably high level of consumer acceptance, and the development of commercially-viable means of large scale production. Recent advancements in tissue culture techniques suggest that production may be economically feasible, provided it has physical properties in terms of colour, flavour, aroma, texture and palatability that are comparable to conventional meat. Although considerable progress has been made during recent years, important issues remain to be resolved, including the characterization of social and ethical constraints, the fine-tuning of culture conditions, and the development of culture media that are cost-effective and free of animal products. Consumer acceptance and confidence in in vitro produced cultured meat might be a significant impediment that hinders the marketing process.

The environmental prospects of cultured meat in China

SUN Zhi-chang, YU Qun-li, HAN Lin

2015, 14(2): 234-240. DOI: 10.1016/S2095-3119(14)60891-1

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To deal with concerns in China about environmental degradation and a growth in population accompanied by increased consumption of livestock products, a meat alternative is required. This study compared the environmental impacts of producing different protein sources for nutrition, including crops, livestock products, and cultured meat. The results showed that cultured meat has the lowest land use per unit of protein and unit of human digestible energy. China’s crops have the lowest energy use and greenhouse gas (GHG) emissions per unit of energy and protein. The energy use in cultured meat production is slightly higher than that of current pork production in China, whereas GHG emissions are lower. It is concluded that the overall impact of replacing livestock products with cultured meat would be beneficial for China’s environment and would potentially improve food security because less land is needed to produce the same amount of protein and energy.

In vitro meat production: Challenges and benefits over conventional meat production

Zuhaib Fayaz Bhat, Sunil Kumar, Hina Fayaz

2015, 14(2): 241-248. DOI: 10.1016/S2095-3119(14)60887-X

Abstract ( ) PDF in ScienceDirect

In vitro meat production system is the production of meat outside the food animals by culturing the stem cells derived from farm animals inside the bioreactor by using advanced tissue engineering techniques. Besides winning the favour of animal rights activists for its humane production of meat, in vitro meat production system also circumvents many of the issues associated with conventional meat production systems, like excessively brutal slaughter of food animals, nutrition-related diseases, foodborne illnesses, resource use, antibiotic-resistant pathogen strains, and massive emissions of methane that contribute to global warming. As the conditions in an in vitro meat production system are controlled and manipulatable, it will be feasible to produce designer, chemically safe and disease-free meat on sustainable basis. However, many challenges are to be faced before cultured meat becomes commercially feasible. Although, the production cost and the public acceptance are of paramount importance, huge funds are desperately required for further research in the field.

A case for systemic environmental analysis of cultured meat

Carolyn S Mattick, Amy E Landis, Braden R Allenby

2015, 14(2): 249-254. DOI: 10.1016/S2095-3119(14)60885-6

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The environmental implications of cultured meat are profound. An anticipatory life cycle assessment of cultured meat published in 2011 suggested it could have a smaller impact than agricultural meat in all categories except energy consumption. As with most technologies, cultured meat will almost certainly be accompanied by unintended consequences as well as unforeseen costs and benefits that accrue disproportionately to different stakeholders. Uncertainty associated with new engineered products cannot be completely eliminated prior to introduction, but ongoing environmental assessments of the technologies as they advance can serve to reduce unforeseen risks. Given the pace at which tissue engineering is advancing, systemic assessments of the technology will be pivotal in mitigating unintended environmental consequences.

What is artificial meat and what does it mean for the future of the meat industry?

Sarah P F Bonny, Graham E Gardner, David W Pethick, Jean-Fran?ois Hocquette

2015, 14(2): 255-263. DOI: 10.1016/S2095-3119(14)60888-1

Abstract ( ) PDF in ScienceDirect

The meat industry cannot respond to increases in demand by ever increasing resource use. The industry must find solutions to issues regarding animal welfare, health and sustainability and will have to do so in the face of competition from emerging non-traditional meat and protein products in an increasingly complex regulatory environment. These novel meat and protein products, otherwise known as ‘artificial meat’ are utilising ground breaking technologies designed to meet the issues facing the conventional meat industry. These artificial meats, in vitro or cultured meat and meat from genetically modified organisms have no real capacity to compete with conventional meat production in the present environment. However, meat replacements manufactured from plant proteins and mycoproteins are currently the biggest competitors and are gaining a small percentage of the market. Manufactured meats may push conventional meat into the premium end of the market, and supply the bulk, cheap end of the market if conventional meat products become more expensive and the palatability and versatility of manufactured meats improve. In time the technology for other artificial meats such as meat from genetic modified organisms or cultured meat may become sufficiently developed for these products to enter the market with no complexity of the competition between meat products. Conventional meat producers can assimilate agroecology ecology concepts in order to develop sustainable animal production systems. The conventional meat industry can also benefit from assimilating biotechnologies such as cloning and genetic modification technologies, using the technology to adapt to the changing environment and respond to the increasing competition from artificial meats. Although it will depend at least partly on the evolution of conventional meat production, the future of artificial meat produced from stem cells appears uncertain at this time.

Cultured meat in western media: The disproportionate coverage of vegetarian reactions, demographic realities, and implications for cultured meat marketing

Patrick D Hopkins

2015, 14(2): 264-272. DOI: 10.1016/S2095-3119(14)60883-2

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This paper examines the media coverage of the 2013 London cultured meat tasting event, particularly in the United States, Canada, and the United Kingdom. Using major news outlets, prominent magazines covering food and science issues, and advocacy websites concerning meat consumption, the paper characterizes the overall emphases of the coverage, the tenor of the coverage, and compares the media portrayal of the important issues to the demographic and psychological realities of the actual consumer market into which cultured meat will compete. In particular, the paper argues that Western media gives a distorted picture of what obstacles are in the path of cultured meat acceptance, especially by overemphasizing and overrepresenting the importance of the reception of cultured meat among vegetarians. Promoters of cultured meat should recognize the skewed impression that this media coverage provides and pay attention to the demographic data that suggests strict vegetarians are a demographically negligible group. Resources for promoting cultured meat should focus on the empirical demographics of the consumer market and the empirical psychology of mainstream consumers.

Educated consumers don’t believe artificial meat is the solution to the problems with the meat industry

Aurélie Hocquette, Carla Lambert, Clémentine Sinquin, Laure Peterolff, Zoé Wagner, Sarah P F Bonny, André Lebert, Jean-Fran?ois Hocquette

2015, 14(2): 273-284. DOI: 10.1016/S2095-3119(14)60886-8

Abstract ( ) PDF in ScienceDirect

The production of in vitro meat by cell culture has been suggested by some scientists as one solution to address the major challenges facing our society. Firstly, consumers would like the meat industry to reduce potential discomfort of animals on modern farms, or even to avoid killing animals to eat them. Secondly, citizens would like meat producers to reduce potential environmental deterioration by livestock and finally, there is a need to reduce world hunger by increasing protein resources while the global population is predicted to grow rapidly. According to its promoters, artificial meat has a potential to make eating animals unnecessary, to reduce carbon footprint of meat production and to satisfy all the nutritional needs and desires of consumers and citizens. To check these assumptions, a total of 817 educated people (mainly scientists and students) were interviewed worldwide by internet in addition to 865 French educated people. We also interviewed 208 persons (mainly scientists) after an oral presentation regarding artificial meat. Results of the three surveys were similar, but differed between males and females. More than half of the respondents believed that “artificial meat” was feasible and realistic. However, there was no majority to think that artificial meat will be healthy and tasty, except respondents who were in favour of artificial meat. A large majority of the respondents believed that the meat industry is facing important problems related to the protection of the environment, animal welfare or inefficient meat production to feed humanity. However, respondents did not believe that artificial meat will be the solution to solve the mentioned problems with the meat industry, especially respondents who were against artificial meat. The vast majority of consumers wished to continue to eat meat even they would accept to consume less meat in a context of increasing food needs. Only a minority of respondents (from 5 to 11%) would recommend or accept to eat in vitro meat instead of meat produced from farm animals. Despite these limitations, 38 to 47% of the respondents would continue to support research on artificial meat, but a majority of them believed that artificial meat will not be accepted by consumers in the future, except for respondents who were in favour of artificial meat. We speculated that the apparent contradictory answers to this survey expressed the fact that people trust scientists who are supposed to continuously discover new technologies potentially useful in a long term future for the human beings, but people also expressed concern for their health and were not convinced that artificial meat will be tasty, safe and healthy enough to be accepted by consumers.

Challenges and prospects for consumer acceptance of cultured meat

Wim Verbeke, Pierre Sans, Ellen J Van Loo

2015, 14(2): 285-294. DOI: 10.1016/S2095-3119(14)60884-4

Abstract ( ) PDF in ScienceDirect

Consumer acceptance of cultured meat is expected to depend on a wide diversity of determinants ranging from technologyrelated perceptions to product-specific expectations, and including wider contextual factors like media coverage, public involvement, and trust in science, policy and society. This paper discusses the case of cultured meat against this multitude of possible determinants shaping future consumer acceptance or rejection. The paper also presents insights from a primary exploratory study performed in April 2013 with consumers from Flanders (Belgium) (n=180). The concept of cultured meat was only known (unaided) by 13% of the study participants. After receiving basic information about what cultured meat is, participants expressed favorable expectations about the concept. Only 9% rejected the idea of trying cultured meat, while two thirds hesitated and about quarter indicated to be willing to try it. The provision of additional information about the environmental benefits of cultured meat compared to traditional meat resulted in 43% of the participants indicating to be willing to try this novel food, while another 51% indicated to be ‘maybe’ willing to do so. Price and sensory expectations emerged as major obstacles. Consumers eating mostly vegetarian meals were less convinced that cultured meat might be healthy, suggesting that vegetarians may not be the ideal primary target group for this novel meat substitute. Although exploratory rather than conclusive, the findings generally underscore doubts among consumers about trying this product when it would become available, and therefore also the challenge for cultured meat to mimic traditional meat in terms of sensory quality at an affordable price in order to become acceptable for future consumers.

Molecular mapping of a stripe rust resistance gene in Chinese wheat cultivar Mianmai 41

REN Yong, LI Sheng-rong, WEI Yu-ming, ZHOU Qiang, DU Xiao-ying, HE Yuan-jiang, ZHENG You-liang

2015, 14(2): 295-304. DOI: 10.1016/S2095-3119(14)60781-4

Abstract ( ) PDF in ScienceDirect

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most damaging diseases of wheat. Chinese wheat cultivar Mianmai 41 showed high resistance against most of the prevailing Pst races in China. Genetic analysis of the F1, F2 and F2:3 populations from a cross between Mianmai 41 and a susceptible line Mingxian 169 indicated that resistance to Pst race CYR32 was conferred by a single dominant gene, temporarily designated as YrMY41. Molecular marker analysis placed the gene on chromosome 1B near the centromere. Six co-dominant genomic SSR markers Xwmc329, Xwmc406, Xgwm18, Xgwm131, Xgwm413, and Xbarc312, and one STS marker Xwe173 linked with the resistance gene. The two closest flanking SSR markers were Xgwm18 and Xwmc406, with genetic distances of 2.0 and 4.9 cM, respectively. A seedling test with 29 Pst isolates indicated the reaction patterns of Mianmai 41 were different from those of lines carrying Yr3, Yr9, Yr10, Yr15, Yr26, and YrCH42 on chromosome 1B. Allelic tests indicated that YrMY41 is likely a new allele at Yr26 locus.

Developing transgenic maize (Zea mays L.) with insect resistance and glyphosate tolerance by fusion gene transformation

SUN He, LANG Zhi-hong, LU Wei, ZHANG Jie, HE Kang-lai , ZHU Li, LIN Min, HUANG Da-fang

2015, 14(2): 305-313. DOI: 10.1016/S2095-3119(14)60855-8

Abstract ( ) PDF in ScienceDirect

Using linker peptide LP4/2A for multiple gene transformation is considered to be an effective method to stack or pyramid several traits in plants. Bacillus thuringiensis (Bt) cry gene and epsps (5-enolpyruvylshikimate-3-phosphate synthase) gene are two important genes for culturing pest-resistant and glyphosate-tolerant crops. We used linker peptide LP4/2A to connect the Bt cry1Ah gene with the 2mG2-epsps gene and combined the wide-used manA gene as a selective marker to construct one coordinated expression vector called p2EPUHLAGN. The expression vector was transferred into maize by Agrobacterium tumefaciens-mediated transformation, and 60 plants were obtained, 40% of which were positive transformants. Molecular detection demonstrated that the two genes in the fusion vector were expressed simultaneously and spliced correctly in translation processing; meanwhile bioassay detection proved the transgenic maize had preferable pest resistance and glyphosate tolerance. Therefore, linker peptide LP4/2A provided a simple and reliable strategy for producing gene stacking in maize and the result showed that the fusion gene transformation system of LP4/2A was feasible in monocot plants.

G-protein β subunit AGB1 positively regulates salt stress tolerance in Arabidopsis

MA Ya-nan, CHEN Ming, XU Dong-bei, FANG Guang-ning, WANG Er-hui, GAO Shi-qing, XU Zhao-shi, LI Lian-cheng, ZHANG Xiao-hong, MIN Dong-hong, MA You-zhi

2015, 14(2): 314-325. DOI: 10.1016/S2095-3119(14)60777-2

Abstract ( ) PDF in ScienceDirect

The heterotrimeric GTP-binding proteins (G-proteins) in eukaryotes consisted of α, β and γ subunits and are important in molecular signaling by interacting with G-protein-coupled receptors (GPCR), on which to transduce signaling into the cytoplast through appropriate downstream effectors. However, downstream effectors regulated by the G-proteins in plants are currently not well defined. In this study, the transcripts of AGB1, a G protein β subunit gene in Arabidopsis were found to be down-regulated by cold and heat, but up-regulated by high salt stress treatment. AGB1 mutant (agb1-2) was more sensitive to high salt stress than wild-type (WT). Compared with WT, the cotyledon greening rates, fresh weight, root length, seedling germination rates and survival rates decreased more rapidly in agb1-2 along with increasing concentrations of NaCl in normal (MS) medium. Physiological characteristic analysis showed that compared to WT, the contents of chlorophyll, relative proline accumulation and peroxidase (POD) were reduced, whereas the malonaldehyde (MDA) content and concentration ratio of Na+/K+ were increased in agb1-2 under salt stress condition. Further studies on the expression of several stress inducible genes associated with above physiological processes were investigated, and the results revealed that the expressions of genes related to proline biosynthesis, oxidative stress response, Na+ homeostasis, stress- and ABAresponses were lower in agb1-2 than in WT, suggesting that those genes are possible downstream genes of AGB1 and that their changed expression plays an important role in determining phenotypic and physiologic traits in agb1-2. Taken together, these findings indicate that AGB1 positively regulates salt tolerance in Arabidopsis through its modulation of genes transcription related to proline biosynthesis, oxidative stress, ion homeostasis, stress- and ABA-responses.

SlSOM inhibits seed germination by regulating the expression of ABA/GA metabolic genes and SlABI5 in Solanum lycopersicum

SUN Xiao-chun, GAO Yong-feng, ZHANG Ning, LI Hui-rong, YANG Shu-zhang, LIU Yong-sheng

2015, 14(2): 326-336. DOI: 10.1016/S2095-3119(14)60859-5

Abstract ( ) PDF in ScienceDirect

SOM encodes a nucleus-localized CCCH-type zinc finger protein and negatively regulates seed germination in Arabidopsis thaliana. We have previously demonstrated that ectopic expression of SlABI3, an important transcription factor in abscisic acid (ABA) signaling pathway, resulted in alteration of SlSOM expression patterns in both leaf and seed of tomato. In this study, we aimed to elucidate the function of tomato SlSOM in regarding to seed germination and seedling development. Here, we constructed SlSOM over-expression vector pBI121-SOM driven by CaMV 35S promoter, and the recombinant plasmid was incorporated into wild-type tomato by the method of Agrobacterium tumefaciens-mediated transformation. The result showed that over-expression of SlSOM conferred enhanced responses to exogenous ABA application during seed germination and seedling development. In addition, ectopic expression of SlSOM resulted in the alteration of expression level of ABA/GA (gibberellins) metabolic genes, such as SlABA1, SlCYP707A1, SlGA3ox2, and SlGA2ox4, in both leaf and seed. The ABA anabolic gene SlABA1 and the GA catabolic gene SlGA2ox4 were up-regulated while the ABA catabolic gene SlCYP707A1 and the GA anabolic gene SlGA3ox2 were down-regulated. Compared to wild type, the expression level of SlABI5 was increased by about 40–50% in transgenic seeds while adding exogenous ABA treatment. These results support the notion that SlSOM inhibits seed germination by regulating ABA/GA metabolic genes and SlABI5 expression in Solanum lycopersicum.

Characterization and functional analysis of β-1,3-galactosyltransferase involved in Cry1Ac resistance from Helicoverpa armigera (Hübner)

ZHANG Li-li, LIANG Ge-mei, GAO Xi-wu, CAO Guang-chun, GUO Yu-yuan

2015, 14(2): 337-346. DOI: 10.1016/S2095-3119(14)60771-1

Abstract ( ) PDF in ScienceDirect

Carbohydrate chains are the principal antigens by which Bacillus thuringiensis (Bt) identify receptor proteins. The interaction between the antigen and Bt causes a pore in the membrane of midgut epithelial cells of insects. Receptor proteins, such as aminopeptidase N and alkaline phosphatase, are glycoproteins. Cadherin is another cell surface receptor protein which has potential glycosylation sites. Glycosyltransferase is very important for the synthesis and modification of receptor proteins. It can indirectly influence the function of Bt. The 1 950 bp full-length cDNA encoding β-1,3-galactosyltransferase was cloned from the the midgut of Helicoverpa armigera by degenerative PCR combined with RACE techniques (GAL-Harm, GenBank accession no.: GQ904195.1) with two potential N-glycosylation sites (157NNTI160 and 272NKTL275). Protein sequence alignments revealed that H. armigera β-1,3-galactosyltransferase shared high identity with β-1,3-galactosyltransferase in other insect species. The expression level of the β-1,3-galactosyltransferase gene in Cry1Ac-resistant H. armigera larvae was 9.2-fold higher than that in susceptible strain. The function of β-1,3-galactosyltransferase was investigated using RNAi technique. The result showed Cry1Ac enhanced the toxicity against the siRNA-treated larvae compared with non-siRNA-treated ones, which indicated β-1,3-galactosyltransferase played an important role for the insecticidal toxicity of Cry1Ac in H. armigera.

Toxicity and binding analyses of Bacillus thuringiensis toxin Vip3A in Cry1Ac-resistant and -susceptible strains of Helicoverpa armigera (Hübner)

ZHANG Qian, CHEN Li-zhen, LU Qiong, ZHANG Yan, LIANG Ge-mei

2015, 14(2): 347-354. DOI: 10.1016/S2095-3119(14)60770-X

Abstract ( ) PDF in ScienceDirect

The Bacillus thuringiensis vegetative insecticidal protein, Vip3A, represents a new family of Bt toxin and is currently applied to commercial transgenic cotton. To determine whether the Cry1Ac-resistant Helicoverpa armigera is cross-resistant to Vip3Aa protein, insecticidal activities, proteolytic activations and binding properties of Vip3Aa toxin were investigated using Cry1Ac-susceptible (96S) and Cry1Ac-resistant H. armigera strain (Cry1Ac-R). The toxicity of Vip3Aa in Cry1Ac-R slightly reduced compared with 96S, the resistance ratio was only 1.7-fold. The digestion rate of full-length Vip3Aa by gut juice extracts from 96S was little faster than that from Cry1Ac-R. Surface plasmon resonance (SPR) showed there was no significant difference between the binding affinity of Vip3Aa and BBMVs between 96S and Cry1Ac-R strains, and there was no significant competitive binding between Vip3Aa and Cry1Ac in susceptible or resistant strains. So there had little cross-resistance between Vip3Aa and Cry1Ac,Vip3A+Cry proteins maybe the suitable pyramid strategy to control H. armigera in China in the future.

Response dynamics of three defense related enzymes in cotton leaves to the interactive stress of Helicoverpa armigera (Hübner) herbivory and omethoate application

SHA Pin-jie, FAN Yin-jun, WANG Zhi-chao, SHI Xue-yan

2015, 14(2): 355-364. DOI: 10.1016/S2095-3119(14)60793-0

Abstract ( ) PDF in ScienceDirect

In order to explore the response dynamics of the activities of defense related enzymes in cotton leaves towards the interactive stress of Helicoverpa armigera herbivory and omethoate application, the activities of phenylalanine ammonia-lyase (PAL), lipoxygenase (LOX), and polyphenol oxidase (PPO) were examined from 6 to 126 h after cotton leaves were treated 12 h of H. armigera herbivory, and then sprayed with 800 mg L–1 omethoate. The results showed that the changes in the activities of PAL, LOX and PPO that occured under the interactive stress of H. armigera herbivory and omethoate application reflected the interactive effects of the two stresses on cotton defense. The similarity between the response dynamics of PAL, LOX, and PPO activities in cotton leaves under the interactive stress and that under H. armigera herbivory treatment alone showed that the induction of H. armigera herbivory on the activities of PAL, LOX and PPO in cotton leaves played a leading role in the interactive effects, and the effect of omethoate application played only a minor role. A joint factor analysis was performed according to a method which has been used to analyze the joint toxicity of pesticides; this analysis sought to clarify if there was a synergistic, antagonistic, or additive effect on PAL, LOX, and PPO activity in cotton leaves resulting from the interactive H. armigera herbivory and omethoate treatment. In the interactive effect on the response of PAL activity in cotton leaves, antagonistic effects of the omethoate application towards H. armigera herbivory were observed at 6 and 12 h. Synergistic effects were then observed at 18 and 30 h. Antagonistic effects were observed from 54 to 78 h and synergistic effects were finally observed at 126 h. The correlation between H. armigera herbivory and omethoate application in the interactive effect on cotton defense responses of LOX activity also fluctuated from synergism to antagonism during the time course. In the interactive effect on PPO activity, only antagonism was observed between H. armigera herbivory and omethoate application. In the interactive stress of H. armigera herbivory and omethoate application on cotton defense responses, omethoate affected the defense responses of cotton to H. armigera herbivory by producing antagonistic and synergistic effects. These results will be useful to understand the relationship between host plant and herbivorous pest.

Effects of long-term phosphorus fertilization and straw incorporation on phosphorus fractions in subtropical paddy soil

LI Yu-yuan, YANG Rui, GAO Ru, WEI Hong-an, CHEN An-lei, LI Yong

2015, 14(2): 365-373. DOI: 10.1016/S2095-3119(13)60684-X

Abstract ( ) PDF in ScienceDirect

Study on soil phosphorus (P) fraction is an important aspect in probing the mechanisms of soil P accumulation in farmland and mitigating its losing risk to the environment. We used a sequential extraction method to evaluate the impacts of long-term fertilization and straw incorporation on inorganic, organic, and residual P (Pi, Po, and Pre) fractions in the plow layer (0–20 cm) of acidic paddy soil in southern China. The experiment comprised of six treatments: (i) no fertilizer control (CK); (ii) straw incorporation and green manure (SG); (iii) nitrogen and P fertilizer (NP); (iv) NP+SG; (v) NP+K fertilizer (NPK); and (vi) NPK+SG. The results showed that, compared to the initial total soil P content (TSP, 600 mg kg–1 in 1990), long-term (20 years) combined continuous P fertilizer and SG significantly increased P accumulation (by 13–20%) while single fertilization (39.3 kg P ha–1 yr–1) could maintain soil P status at the most. The average soil P fractions comprised of extractable Pi, Po, and Pre by 51.7, 33.4, and 14.9% in total soil P, respectively. With comparison of no fertilizer addition (CK), long-term single fertilization significantly (P<0.05) increased the accumulation of NaHCO3 –, NaOH–, and HCl– extractable Pi fractions accounting for two- to three-fold, while SG increased the accumulation of NaHCO3 – and NaOH– extractable Pi and Po accounting for 12–60%. Though the mobilization of Pre fractions was not significant (P>0.05), our data indicate that SG may partially substitute for fertilizer P input and minimizing soil P accumulation and subsequent environmental risk in the subtropical paddy soil.

Nitrate leaching of winter wheat grown in lysimeters as affected by fertilizers and irrigation on the North China Plain

GU Li-min, LIU Tie-ning, ZHAO Jun, DONG Shu-ting, LIU Peng, ZHANG Ji-wang, ZHAO Bin

2015, 14(2): 374-388. DOI: 10.1016/S2095-3119(14)60747-4

Abstract ( ) PDF in ScienceDirect

Proper application of nitrogen (N) fertilizers and irrigation management are important production practices that can reduce nitrate leaching into groundwater and improve the N use efficiency (NUE). A lysimeter/rain shelter facility was used to study effects of the rate of N fertilization, type of N fertilizer, and irrigation level on key aspects of winter wheat production over three growing seasons (response variables were nitrate transport, N leaching, and NUE). Results indicated that nitrate concentration in the soil profile and N leaching increased with the rate of N fertilization. At the end of the third season, nitrate concentration in the top 0–75 cm layer of soil was higher with manure treatment while urea treatments resulted in higher concentrations in the 100–200 cm layer. With normal irrigation, 3.4 to 15.3% of N from applied fertilizer was leached from the soil, yet no leaching occurred under a stress irrigation treatment. The manure treatment experienced less N leaching than the urea treatment in all cases except for the 180 kg N ha-1 rate in 2011–2012 (season 3). In terms of grain yield (GY), dry matter (DM) or NUE parameters, values for the manure treatment were lower than for the urea treatment in 2009–2010 (season 1), yet were otherwise higher for urea treatment in season 3. GY and crop nitrogen uptake (NU) were elevated when the rate of N fertilizer increased, while the NUE decreased; GY, DM, and NU increased with the amount of irrigation. Data indicated that reduced rates of N fertilization combined with increased manure application and proper irrigation management can lower nitrate levels in the subsoil and reduce potential N leaching into groundwater.

Inoculation with chlamydospores of Trichoderma asperellum SM- 12F1 accelerated arsenic volatilization and influenced arsenic availability in soils

WANG Xiu-rong, SU Shi-ming, ZENG Xi-bai, BAI Ling-yu, LI Lian-fang, DUAN Ran, WANG Ya-nan, WU Cui-xia

2015, 14(2): 389-397. DOI: 10.1016/S2095-3119(14)60772-3

Abstract ( ) PDF in ScienceDirect

Fungi capable of arsenic (As) accumulation and volatilization are hoped to tackle As-contaminated environment in the future. However, little data is available regarding their performances in field soils. In this study, the chlamydospores of Trichoderma asperellum SM-12F1 capable of As resistance, accumulation, and volatilization were inoculated into As-contaminated Chenzhou (CZ) and Shimen (SM) soils, and subsequently As volatilization and availability were assessed. The results indicated that T. asperellum SM-12F1 could reproduce well in As-contaminated soils. After cultivated for 42 days, the colony forming units (cfu) of T. asperellum SM-12F1 in CZ and SM soils reached 1010–1011 cfu g–1 fresh soil when inoculated at a rate of 5.0%. Inoculation with chlamydospores of T. asperellum SM-12F1 could significantly accelerate As volatilization from soils. The contents of volatilized As from CZ and SM soils after being inoculated with chlamydospores at a rate of 5.0% for 42 days were 2.0 and 0.6 μg kg–1, respectively, which were about 27.5 and 2.5 times higher than their corresponding controls of no inoculation (CZ, 0.1 μg kg–1; SM, 0.3 μg kg–1). Furthermore, the available As content in SM soils was decreased by 23.7%, and that in CZ soils increased by 3.3% compared with their corresponding controls. Further studies showed that soil pH values significantly decreased as a function of cultivation time or the inoculation level of chlamydospores. The pH values in CZ and SM soils after being inoculated with 5.0% of chlamydospores for 42 days were 6.04 and 6.02, respectively, which were lowered by 0.34 and 1.21 compared with their corresponding controls (CZ, 6.38; SM, 7.23). The changes in soil pH and As-binding fractions after inoculation might be responsible for the changes in As availability. These observations could shed light on the future remediation of As-contaminated soils using fungi.

Adaptation of potato production to climate change by optimizing sowing date in the Loess Plateau of central Gansu, China

WANG Chun-ling, SHEN Shuang-he, ZHANG Shu-yu, LI Qiao-zhen, YAO Yu-bi

2015, 14(2): 398-409. DOI: 10.1016/S2095-3119(14)60783-8

Abstract ( ) PDF in ScienceDirect

Potato grows in most part of China, it achieves higher yield and better quality in Gansu Province than in others. With global warming, its growth duration has been prolonged and sowing date become earlier than before. Therefore, to regulate its sowing date and growing period is of great significance for better harvest. In this study, experiments were conducted with six sowing-date treatments of potato in Dingxi, which is in the Loess Plateau of central Gansu Province in Northwest China in 2010. The growth period, morphological index and change in yield and their relationships with temperature, precipitation, and other climatic factors were investigated for each treatment. Results show that the crop with different sowing dates experienced different climate conditions, leading to distinct growth duration, plant height, and leaf area index. The growth duration was shortened due to a delay in sowing date. For each 15-day delay in sowing, the growth duration was reduced by 12 days on average. A significant linear relationship was found between numbers of days either from seeding to emergence or from flowering to harvest and mean temperature over the corresponding period. Dry matter accumulation, tuber fresh weight, and final yield were all decreased because of insufficient cumulative temperature over the shorter growing periods. Marked differences in tuber yield were discovered among the six treatments of sowing date, the potato planted on May 27 giving the highest yield. The potato planted either earlier or later would produce invariably lower yield than the treatment of May 27. Late May therefore can be taken as the optimum sowing time of potato in this region because the crop can fully utilize thermal resource. We conclude that to postpone sowing time is a good practice for potato production to adapt to climate warming in the Loess Plateau of central Gansu, China.

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