Effects of humic acids derived from lignite and cattle manure on antioxidant enzymatic activities of barley root

To investigate the effects of humic acids (HAs) on the ability of plants to defend themselves against oxidative stress, barley was hydroponically cultured in the absence and presence of HAs, and the antioxidant enzymatic activities (catalase, superoxide dismutase, ascorbate and glutathione peroxidases) of root tissue were evaluated. Auxin-like structures in HAs, which were extracted from an oxidation product of lignite (LHA) and compost derived from cattle manure (CHA), were identified by pyrolysis-gas chromatography/mass spectrometry (GC/MS) with tetramethylammonium hydroxide. The LHA, which had the lower molecular weight, was more effective in promoting the growth of barley root than CHA. However, the amounts of auxin-like structures in the CHA were much higher than those for LHA. The antioxidant enzymatic activities were initially decreased in the presence of LHA and CHA at the first day after refreshing the culture solution, but were significantly increased on the second day. The CHA sample, which contained relatively high levels of phenolic acids that contained auxin-like structures, was effective in increasing four types of enzymatic activities, while the activities of catalase and ascorbate peroxidase were increased in the presence of LHA, which contains naphthalene derivatives. These results indicate that using HAs as a supplement can be effective in enhancing antioxidation enzymatic activities, while the appearance of the effects is retarded because of the decomposition and release of auxin-like compounds from HAs by organic acids from the plant roots.     

西藏地区春青稞耗水特征及适宜灌溉制度探讨

以中科院拉萨高原生态试验站为依托,通过开展春青稞生长与土壤水分定位观测实验,利用SHAW模型实现对春青稞农田蒸散发与土壤水深层渗漏与补给过程模拟,分析了春青稞的耗水特征,并对其适宜的灌溉制度进行了初步探讨:①春青稞生长期间,耗水450 mm左右,其中,分蘖—拔节、拔节—抽穗、抽穗—蜡熟这3个阶段是春青稞的耗水旺期,耗水量占整个生长期的72%。把握住该时期的水分供应,对提高作物产量十分重要。②在春青稞的需水关键期降水量仅能满足作物需水的58%,必须补充人工灌溉;但现行的灌溉制度由于灌溉量较大,不仅加大土壤蒸发,更造成较大的深层渗漏。③在播种—出苗、拔节—抽穗期分别灌溉50 mm,抽穗—蜡熟期灌溉60 mm,共减少灌溉用水125 mm后,深层渗漏减少了81%(131 mm);深层土壤水向上补给量增加了55%(44 mm)。节水灌溉不仅减少了土壤蒸发与深层渗漏也促使深层土壤水向上补给根系层,应该大力推广这一灌溉制度。     

Effect of different pearling times on the quality of hull-less barley rice北大核心CSCD

Hull-less barley is a special food crop rich in various nutrients in Qinghai-Tibet Plateau. Six-pearling is often used to produce commercial hull-less barley rice in order to improve its rough taste and inferior cooking quality. This study evaluated the differences in the nutritional, cooking, sensory, and storage qualities of hull-less barley rice with different pearling times to obtain suitable processing conditions for the production of high-quality hull-less barley rice. With increasing pearling time, the contents of vitamin B6, vitamin E, dietary fiber, iron, zinc, phenols, and flavonoids significantly decreased to a large extent, protein and vitamin B3 decreased slightly, the contents of total starch and β-glucan increased significantly, and γ-aminobutyric acid (GABA) initially increased and then decreased. The peak, trough, and final viscosity of whole grain barley were 1 860.50 cP, 914.50 cP, and 2 150.00 cP, respectively, and increased after six-pearling to 4 219.00 cP, 2 628.00 cP, and 5 074.00 cP, respectively. At the same time, the water absorption and volume expansion of the pearled hull-less barley increased significantly. The hardness of pearled hull-less barley reduced from 4 708.50 g to 2 282.00 g, its adhesiveness increased from 0.00 to -7.33, and its taste and sensory quality exhibited better. The activities of α-amylase, polyphenol oxidase, lipase, and catalase in pearled hull-less barley slightly decreased. Hull-less bran flour is rich in a variety of nutritional components and could be a potential resource with great developmental value. In general, hull-less barley rice obtained from three-pearling has high nutritional value, high cooking quality, low enzyme activity, and low energy consumption; therefore, it can be used to produce high-quality barley rice. This study provides important information for high-quality pearled hull-less barley and further utilization of barley bran flour. © 2022 Science Press. All rights reserved.     

The Influence of Mycorrhiza on Uranium and Phosphorus Uptake by Barley Plants from a Field-contaminated Soil (7 pp)

Background Recent studies indicated that arbuscular mycorrhizal fungi (AMF) play important roles in plant accumulation of uranium (U) from contaminated environments, but the impacts of fertilization practices on functioning of the symbiotic associations, which are crucial factors influencing plant nutrition and growth responses to mycorrhiza, have rarely been considered. Materials and Methods In a greenhouse experiment, a bald root barley mutant (brb) together with the wild type (wt) were used to test the role of root hairs and AMF in uranium (U) uptake by host plants from a U contaminated soil. Nil, 20 and 60 mg KH2PO4-P kg–1 soil were included to investigate the influences of phosphorus (P) fertilization on plant growth and accumulation of U. Results Dry matter yield of barley plants increased with increasing P additions and wt produced significantly higher dry weight than brb. Mycorrhiza markedly improved dry matter yield of both genotypes grown at nil P, whereas only brb responded positively to mycorrhiza at 20 mg P kg-1. At the highest P level, mycorrhiza resulted in growth depressions in both genotypes, except for the roots of wt. In general, plant P concentrations increased markedly with increasing P additions and in response to mycorrhiza. Mycorrhiza and P additions had no significant effects on shoot U concentrations. However, root U concentrations in both genotypes were significantly increased by mycorrhiza. On the other hand, shoot U contents increased with increasing P levels, while 20 mg P kg-1 stimulated, but 60 mg P kg-1 marginally affected the U accumulation in roots. Root length specific U uptake was moderately enhanced both by root hairs and strongly enhanced by mycorrhiza. Moreover, non-inoculated plants generally had higher shoot-root ratios of U content than the corresponding inoculated controls. Conclusion Our study shows that AMF and root hairs improves not only P acquisition but also the root uptake of U, and mycorrhiza generally decreases U translocation from plant root to shoot. Hence, mycorrhiza is of potential use in the phytostabilization of U contaminated environments. Perspectives The complex impacts of P on U accumulation by barley plants suggested that U behavior in mycorrhizosphere and translocation along the soil-fungi-plant continuum as affected by fertilization practices deserve extensive studies for optimizing the function of mycorrhizal associations for phytoremediation purposes.     

How Plants Cope with Foreign Compounds. Translocation of xenobiotic glutathione conjugates in roots of barley (Hordeum vulgare) (9 pp)

Background, Aim and Scope Numerous herbicides and xenobiotic organic pollutants are detoxified in plants to glutathione conjugates. Following this enzyme catalyzed reaction, xenobiotic GS-conjugates are thought to be compartmentalized in the vacuole of plant cells. In the present study, evidence is presented for long range transport of these conjugates in plants, rather than storage in the vacuole. To our knowledge this is the first report about the unidirectional long range transport of xenobiotic conjugates in plants and the exudation of a glutathione conjugate from the root tips. This could mean that plants possess an excretion system for unwanted compounds which give them similar advantages as animals. Materials and Methods: Barley plants (Hordeum vulgare L. cv. Cherie) were grown in Petri dishes soaked with tap water in the greenhouse. - Fluorescence Microscopy. Monobromo- and Monochlorobimane, two model xenobiotics that are conjugated rapidly in plant cells with glutathione, hereby forming fluorescent metabolites, were used as markers for our experiments. Their transport in the root could be followed sensitively with very good temporal and spatial resolution. Roots of barley seedlings were cut under water and the end at which xenobiotics were applied was fixed in an aperture with a thin latex foil and transferred into a drop of water on a cover slide. The cover slide was fixed in a measuring chamber on the stage of an inverse fluorescence microscope (Zeiss Axiovert 100). - Spectrometric enzyme assay. Glutathione S-transferase (GST) activity was determined in the protein extracts following established methods. Aliquots of the enzyme extract were incubated with 1-chloro-2,4-dinitrobenzene (CDNB), or monochlorobimane. Controls lacking enzyme or GSH were measured. - Pitman chamber experiments. Ten days old barley plants or detached roots were inserted into special incubation chambers, either complete with tips or decapitated, as well as 10 days old barley plants without root tips. Compartment A was filled with a transport medium and GSH conjugate or L-cysteine conjugate. Compartments B and C contained sugar free media. Samples were taken from the root tip containing compartment C and the amount of conjugate transported was determined spectro-photometrically. Results: The transport in roots is unidirectional towards the root tips and leads to exsudation of the conjugates at rates between 20 and 200 nmol min-1. The microscopic studies have been complemented by transport studies in small root chambers and spectroscopic quantification of dinitrobenzene-conjugates. The latter experiments confirm the microscopic studies. Furthermore it was shown that glutathione conjugates are transported at higher rates than cysteine conjugates, despite of their higher molecular weights. This observation points to the existence of glutathione specific carriers and a specific role of glutathione in the root. Discussion: It can be assumed that long distance transport of glutathione conjugates within the plant proceeds like GSH or amino acid transport in both, phloem and xylem. The high velocity of this translocation of the GS-X is indicative of an active transport. For free glutathione, a rapid transport-system is essential because an accumulation of GSH in the root tip inhibits further uptake of sulfur. Taking into account that all described MRP transporters and also the GSH plasmalemma ATPases have side activities for glutathione derivatives and conjugates, co-transport of these xenobiotic metabolites seems credible. - On the other hand, when GS-B was applied to the root tips from the outside, no significant uptake was observed. Thus it can be concluded that only those conjugates can be transported in the xylem which are formed inside the root apex. Having left the root once, there seems to be no return into the root vessels, probably because of a lack of inward directed transporters. Conclusions: Plants seem to possess the capability to store glutathione conjugates in the vacuole, but under certain conditions, these metabolites might also undergo long range transport, predominantly into the plant root. The transport seems dependent on specific carriers and is unidirectional, this means that xenobiotic conjugates from the rhizosphere are not taken up again. The exudation of xenobiotic metabolites offers an opportunity to avoid the accumulation of such compounds in the plant. Recommendations and Perspectives: The role of glutathione and glutathione related metabolites in the rhizosphere has not been studied in any detail, and only scattered data are available on interactions between the plant root and rhizosphere bacteria that encounter such conjugates. The final fate of these compounds in the root zone has also not been addressed so far. It will be interesting to study effects of the exuded metabolites on the biology of rhizosphere bacteria and fungi.     

我国土壤中重金属铜的生物配体模型的建立与应用

关于重金属污染的风险评价及其预测模型日益成为环境领域的研究热点。近年来,一种用于预测和评价环境中重金属生物毒性的机理性模型一生物配体模型(BLM)被广泛应用于水体及陆地生态系统。本研究以我国土壤的陆地生物配体模型(TBLM)建构为目标,以土壤溶液系统为媒介,通过17种土壤上重金属铜离子与大麦根长的相互作用关系,发现了土壤中Cu-TBLM的主要影响因素为Cu~(2+)、CuOH~+、Mg~(2+)以及铜离子与大麦根系表面的专性结合能力。基于模型大麦根长预测值与实测值之间的相关关系,通过数学拟合功能求得TBLM中各参数值为logK_(CuBL)=4.87、logK_(CuOH)+=7.62、logK_(MgBL)=1.91、f~(50%)=0.103、β=1.09。本研究所得到的TBLM模型能很好地预测我国土壤中铜对大麦根长的毒害程度,预测值与实测值的相关性达到了90%。本研究结果不仅可以为我们降低重金属离子生物有效性提供有力的理论借鉴,更对我国土壤环境质量保护和长期良性可持续发展具有重要意义。文160余篇。     

Progress of the scientific expedition and research on farmland ecosystem and food security in Qinghai-Tibet Plateau北大核心CSCD

介绍第二次青藏高原综合科学考察研究任务三生态系统与生态安全专题三“农田生态系统与粮食安全”科学考察背景、总体思路、研究内容、研究目标和取得的阶段性进展.该专题针对青藏高原地区农业生产中逐渐出现的局部农田生态系统结构失稳、功能失衡、地力衰退、作物品质下降、农残渐增等问题,在区域尺度上,从耕地肥力和土壤生物、农田植被、农业生产经营管理、作物产量品质和利用、农业气象条件等方面开展科学考察研究,在青藏高原农田生态系统相关生态环境参数的时空特征、分布规律与作物开发利用等考察研究方面取得阶段性重要进展,可为青藏高原农业生态系统可持续经营管理和粮食安全提供数据及科技支撑.(图1参90)     

Identification and expression analysis of the HvENOD93 gene family in barley北大核心CSCD

早期结瘤素93(ENOD93)蛋白在植物根瘤形成初期扮演着重要的角色.基于大麦基因组信息鉴定大麦ENOD93基因家族成员,分析其理化特性、进化关系、基因结构、蛋白质结构和启动子顺式作用元件;并分析ENOD93家族在不同组织和不同基因型(籽粒大小)的表达情况.结果显示,大麦ENOD93基因家族有16个成员,均含有ENOD93基因家族特有的保守结构域;编码区长度在207-627 bp之间,外显子数量有1-4个,平均2.75个,且大部分位于细胞膜上;进化树结果表明与水稻、小麦和玉米等禾本科植物ENOD93基因的亲缘关系较近;启动子顺式元件主要有植物生长发育响应元件、胁迫响应元件以及激素响应元件;大部分HvENOD93基因在灌浆期籽粒和大粒材料中表达量较高.推测大麦HvENOD93基因在籽粒大小形成中起关键性作用;另外,结合其他物种相关基因研究结果,共筛选出3个同源基因.(图4表2参45)     

Potential Methods for Managing Prymnesium parvum Blooms and Toxicity,With Emphasis on Clay and Barley Straw: A Review1

Hagström, Johannes A., Mario R. Sengco, and Tracy A. Villareal, 2010. Potential Methods for Managing Prymnesium parvum Blooms and Toxicity, With Emphasis on Clay and Barley Straw: A Review. Journal of the American Water Resources Association (JAWRA) 46(1):187-198. DOI: 10.1111/j.1752-1688.2009.00402.x Abstract: Harmful algal bloom (HAB) control and mitigation is a complex problem in ecosystem management. Phytoplankton play an important role in aquatic ecosystems as primary producers and food sources for many commercially important shellfish and there are limited options for targeting just a single species within the community. Chemical treatments (e.g., algaecides), rotting barley straw, nitrogen and phosphorus manipulation, and clay and/or flocculants are but a few techniques tested or used to reduce fish kills or shellfish contamination during a HAB event. Prymnesium parvum control has focused on the use of chemicals, nutrient manipulation, and clay flocculation. However, many HAB control methods have been rejected due to their effects on ecosystems, high costs, or limited effects on target organisms. For example, rotting barley straw (Hordeum vulgare) is considered to be an environmentally friendly alternative, but has been found to have very different results on the phytoplankton community depending on the dominating taxa and is ineffective against P. parvum and dinoflagellate blooms. Clay flocculation is a useful control/mitigation technique during fish kills in marine aquaculture sites in South Korea and can be effective in freshwater if the correct combination of clay and flocculent is used. Toxins produced by P. parvum and Karenia brevis also bind to phosphatic clay, thereby removing and/or neutralizing the toxins, but there is concern that the clay will have a negative effect on sessile organisms. Some shellfish suffer high mortalities and significant impacts on somatic and reproductive tissue growth at high clay loads; however, benthic communities appear to be unchanged after five years of clay treatment in South Korea. There are likely site-specific and ecosystem-specific characteristics that make generalizations about control options difficult and require careful assessment of options at each location.     

Mapping loci that control lateral spike development in Tibetan barley by bulked segregant analysis (BSA)北大核心CSCD

Fertility of lateral spikelets determines the two-rowed or six-rowed spikes of barley (Hordeum vulgare L.), which results in significantly different grain yields. The change in row type from two-rowed to six-rowed shows remarkable domestication characteristics. The Qinghai-Tibet plateau has abundant resources of wild and cultivated barley, and is considered one of the centers of domestication and genetic diversity of cultivated barley. In order to obtain a primary understanding of the genetic basis of lateral spike development regulation and the domestication process in cultivated Tibetan barley, an F2 segregation population was constructed by crossing the two-rowed wild barley accession ZYM0083 with the six-rowed landraces Linzhiheiliuleng. Genetic analysis showed that the row type was controlled by a single gene. Using the specific-locus amplified fragment sequencing (SLAF-seq) technology and bulked segregant analysis (BSA), two DNA pools from 22 two-rowed spike individuals and 22 six-rowed spike individuals of the F2 population were constructed and sequenced. A total of 456 691 SLAF tags were obtained. By adopting the ED and SNP index for association analysis, three candidate regions with a 53.84-Mb interval and containing 536 genes were obtained. Four-hundred thirteen, 189, and 160 annotated genes were acquired by GO, KEGG, and COG libraries, respectively. Loci that control lateral spike development in Tibetan barley were primarily mapped by SLAF-seq, and the results presented in this study will facilitate the fine mapping and cloning of target genes. © 2018 Science Press. All rights reserved.