Identification and selection of low-phosphate-tolerant germplasm in barley (Hordeum vulgare L.)

Phosphorus (P) deficiency is one of the major constraints to crop yield worldwide, and genotypes or cultivars with high phosphate use efficiency (PUE) sustain growth when exposed to phosphate stress. Therefore, it is imperative to develop the genotypes or cultivars with high PUE. A pot experiment was conducted to evaluate the PUE among 150 barley (Hordeum vulgare L.) genotypes. Two high-tolerant and -sensitive accessions were selected. These two candidate materials were used to investigate the differences among the root morphology characteristics, antioxidant enzyme activity, inorganic phosphate (Pi) content and gene expression of HvPT5 under P-deficiency and P-sufficiency conditions. The values of these parameters were higher in the low-P-tolerant genotype than in the sensitive one. In pot experiment 1, all genotypes showed a significant difference in low-P tolerance, with variety GN121 achieving the highest tolerance, and GN42 being most sensitive. The results of this study may provide elite genetic germplasms for future work on isolation of P-related genes, and the improvement of PUE in barley.

Abbreviations: PUE: phosphate use efficiency; CAT: catalase; POD: peroxidase; SOD: superoxide dismutase; DMSO: dimethyl sulphoxide; MDA: malondialdehyde; TOPSIS: technique for order preference by similarity to an ideal solution; MCDM/MADM: multi-criteria (or attribute) decision making     

The barley (Hordeum vulgare L.) of Sardinia, Italy

Since ancient times, barley has been an important food resource for the people of Sardinia. The oldest traces of its cultivation are from the mid-Neolithic (fourth millennium B.C.). Archaeological, historical and anthropological aspects of barley cultivated in Sardinia are discussed in this paper. We describe the traditional process for making barley bread (orgiathu) in Sardinia, where a special starter called ghimisone was prepared. Today, barley is cultivated only as animal feed, with two uses, grain yield and grazing. Many farmers prefer to grow local populations belonging to landrace locally known as S' orgiu sardu. Local Sardinian populations of barley evolved in diverse environments, being cultivated from sea-level up to 1000 m elevation, on various soil types at different intensities of abiotic stresses, and with climates and environments associated with various agricultural practices, depending both on production strategies and climatic conditions. These barley materials are thought to be valuable genetic and cultural inheritance which must be preserved and used for both productive and research purposes.     

施磷量对小麦物质生产及吸磷特性的影响

在低磷土壤条件下,以中筋小麦扬麦12号和弱筋小麦扬麦9号为材料,研究了施磷量对小麦物质生产和吸磷特性的影响。结果表明,在施磷量(P2O5)0～180.kg/hm2范围内,植株对磷的吸收量、吸收速率和磷的积累量随施磷量增加而上升;以施磷量108.kg/h2处理的叶面积指数(LAI)、植株茎蘖数、茎蘖成穗率、干物质积累量、花后干物质积累量和子粒产量最高。当施磷量超过108.kg/hm2时,相关物质生产指标则呈下降趋势,说明即使在缺磷土壤上,施磷量有其适宜值。小麦一生对磷的吸收存在两个高峰,出苗至越冬始期为第一个吸收高峰,拔节至孕穗期为第二个吸收高峰。植株磷素积累量的70%～75%是在拔节后吸收,表明拔节期施磷对满足小麦第二个吸磷高峰和磷的最大积累期需磷有重要意义。     

Regrowth in barley (Hordeum vulgare L.) and rye (Secale cereale L.)

Regrowth after cutting at four development stages, from heading to grain maturity, was investigated in a pot experiment containing three rye and four barley varieties. Regrowth in the barley varieties decreased strongly from heading to grain maturity. Rye generally showed stronger regrowth than barley after late cutting, but only the perennial variety ‘Soperta’ regenerated as many tillers at cutting as formed when harvested at the ripe grain stage. In both species, significant differences were found between varieties. The level of soluble carbohydrates reached a maximum between heading and maturity, but differences in regrowth could not be explained by such differences. Total N decreased from heading to maturity, except for perennial rye, where an increase was observed towards ripening. It is, however, uncertain whether this was an effect rather than a cause of the regrowth.     

Potassium placement effect on dynamics of barley (Hordeum vulgare L.) nutrition

The effects of local placement of potassium (K) on mineral nutrition dynamics of barley (Hordeum vulgare L.) in fertile Сhernozem were studied. A pot experiment with local K-placement at 4–5 cm soil depth was carried out and the dynamics of nitrogen, phosphorus, potassium (NPK) concentrations in tillers, organs and parts of spring barley was measured. K-placement increased the productivity index from 0.49 to 0.54, despite optimal and slightly varying NPK concentrations during the second half of the vegetation period (60–100 d). This occurs due to partitioning of assimilates, N, K, and especially P in generative organs of primary and secondary tillers forming quality grains. Nutrient concentrations in certain primary tiller parts of a 60-d plant (senescing leaves and the main spike axis) proved to be more sensitive indicators of the K-placement effect than average whole-plant characteristics. While being beneficial, K-placement had little impact on the overall NPK removal in barley, which shows a significant role of factors related to K uptake kinetics. Thus, the chosen parameters in the soil–plant system (the high content of available K in Chernozem, in the second part of the vegetation period) have for the first time allowed the evaluation of the impact of local K-placement on mineral nutrition dynamics in barley.     

Bacteria and fungi on roots of different barley varieties (Hordeum vulgare L.)

Summary We investigated the abundance of bacteria and fungi on roots of different barley varieties grown in soil and in a nutrient solution. Measurements were made on the rhizoplane and, for soil-grown plants, also in the rhizosphere soil. Further, the influence of plant age was investigated. Barley variety, had a significant influence both for plants grown in soil and in the nutrient solution, and the effects were most pronounced on the rhizoplane. There were no significant differences among varieties in fungal hyphal lengths on the roots. Bacterial abundance on the rhizoplane was significantly decreased with increasing plant age. Varietal differences were maintained over different plant ages.     

Physiological response of culture media-grown barley (Hordeum vulgare L.) to titanium oxide nanoparticles

Since the fate of nanoparticles after their release in the environment and their possible transfer in plants and subsequent impacts is still largely unknown, this paper evaluates the potential phytotoxic effects of up to 20% w/w TiO₂ nanoparticles (nTiO₂) on barley cultivated in hydroponics and agar media. The X-ray diffraction analysis confirmed that nTiO₂ powder corresponds to anatase phase. On agar medium only high concentrations of nTiO₂ (10% and 20% w/w) induced significant inhibition of shoot growth. However, hydroponics treatment with nTiO₂ up to 1000?mg?L^?1 did not show any adverse effect on the shoot growth. In both experiments, (i) root growth inhibition effects became visible with increasing concentration of nTiO₂, (ii) plants treated with nTiO₂ showed no change in chlorophyll a and b content, even though the plants absorbed nTiO₂, (iii) weight of biomass treated with nTiO₂ was not significantly different compared to control. Therefore, we assume that transport of nTiO₂ into the aerial parts is limited due to the presence of effective mechanical or physiological barriers in roots. Overall, it appears that early root growth is a relevant indicator of potential effects of nTiO₂ exposure. Our results also indicate that synthesized nTiO₂ are not significantly toxic to the barley when applied at the concentrations used in this work, even though plants absorb titanium.     

Shoot,root, soil and microbial nitrogen dynamics in two contrasting soils cropped to barley (Hordeum vulgare L.)

Summary Dynamics of barley N, mineral N, and organic N were compared at Ellerslie (Black Chernozem, Typic Cryoboroll) and Breton (Gray Luvisol, Typic Cryoboralf) in central Alberta, using ¹⁵N-urea. On average, shoot N and shoot ¹⁵N recoveries at Ellerslie (14.1 g m^–2, 36%) were greater than at Breton (4.5 g m^–2, 17%). Root N (g m^–2) did not significantly differ between sites (0–30 cm) but root ¹⁵N recovery was greater at Breton (3.4%) than Ellerslie (1.8%). Low levels of shoot N and shoot ¹⁵N at Breton were partly due to very wet soil conditions in July, which resulted in premature shoot senescence and low plant N uptake. Although the total ¹⁵N recoveries from the system (to 30 cm depth) at Ellerslie (63%) and Breton (56%) were similar, soil ¹⁵N was greater at Breton (35%) than at Ellerslie (26%). There were no differences in mineral N between sites but the average ¹⁵N recovery in the mineral-N pool was significantly greater at Ellerslie (3.3%) than at Breton (1.6%). There was no difference in ¹⁵N recovery in the microbial biomass (3%) between sites, although non-microbial organic ¹⁵N was greater at Breton (31 %) than at Ellerslie (20%). The two soils showed differences in the relative size of kinetically active N pools and in relative mineralization rates. Microbial N (0–30 cm) was greater at Ellerslie (13.3 g m^–2) than at Breton (9.9 g m^–2), but total microbial N made up a larger proportion of total soil N at Breton (1.6%) than at Ellerslie (0.9%). In the 0–10 cm interval, microbial N was 1.7-fold greater and non-microbial active N was 3-fold greater at Breton compared to Ellerslie, when expressed as a proportion of total soil N. Net N mineralization in a 10-day laboratory incubation was 1.4-fold greater in the Black Chernozem (0–10 cm interval) from Ellerslie, compared to the Gray Luvisol from Breton, when expressed per gram of soil. Net N mineralization in the soil from Breton was double that of the soil from Ellerslie, when expressed as a proportion of soil N. Although soil N (g m^–2) was 2.5-fold greater at Ellerslie compared to Breton, it was cycled more rapidly at Breton.     

Soil compaction effects on soil bulk density and penetration resistance and growth of spring barley (Hordeum vulgare L.)

Abstract

The weight of the tractor is not the only factor affecting soil compaction. Soil-management practices, such as the use of fertilizers and pesticides, also affect soil properties through an increased number of overriding. The aim of the current study was to investigate compaction effects on soil physical properties, such as dry bulk density and penetration resistance, and the growth of spring barley (Hordeum vulgare L.) as a monoculture. The five-year experiment was conducted on the Estonian University of Life Sciences’ research field at Eerika, near Tartu in 2001–2005. The soil of the experimental site is sandy loam Stagnic Luvisol. The treatments included were no compaction, one pass, three passes, and six passes. All passes were track-by-track. Measurements of soil and plant were made in the earing phase of barley and measurements of yield in the maturity phase of barley. The compaction treatment was conducted using an MTZ-82 tractor (total weight 4.84 Mg). Neither fertilizers nor herbicides were used. 5 years after compaction distinguishable subsoil and topsoil compaction was detected. Soil deformation increases with the number of passes; in the case of six passes soil bulk density increased by 0.15 Mg m^?3 and penetration resistance by 3 MPa. However, there were no significant differences in the soil bulk density and penetration resistance between treatments compacted with one and three passes. The effect of compaction on soil bulk density was higher when the soil was compacted under wet conditions. Compaction decreased the quantity of barley shoots, their phytomass, and grain yield by more than 80%. In the second year of the experiment the dry weight of above ground biomass decreased by almost three times and shoots’ density by 1.5 times, compared with the first year results. In the third year of the experiment the biomass, plant density, and grain yield of barley were stabilized and no further decreases were detected in the following two experimental years. The results from the experiment revealed that even a low weight tractor can induce subsoil compaction and a high decrease of plant productivity by repeated passes over time.     

Crop stand density enhances competitive ability of spring barley (Hordeum vulgare L.)

Abstract

The aim of the research was to establish weediness, competitive ability and productivity of the crop. The experimental object was agrophytocenoses of spring barley – Hordeum vulgare L. – crop of spring barley ‘Aura’ and unsown soil, and weeds growing in them. The crop was formed sowing 0, 120, 200 and 280 kg ha^?1 (0, 2.7, 4.5 and 6.2 million seeds per ha^?1 respectively) seeds of spring barley ‘Aura’. Spring barley crop was not harrowed and herbicides were not applied. In the field experiment estimates were made of changes of weeds and spring barley inter- and within- species competition optimizing crop density. During three years of field experiment in the crop of spring barley annual weeds prevailed at 88–99%, such as Chenopodium album, Stellaria media, Erysimum cheiranthoides. Perennial weeds formed 1–12% of the crop weeds, such as Sonchus arvensis, Cirsium arvense, Equisetum arvense. General number of weed species in spring barley crops varied from 13 to 21. Weed abundance proportionally declined in the crops of higher density, hence, higher seed rate should be recommended for organic agriculture where weeds are controlled in non-chemical ways. Consistently increasing barley stand density, the competition between species (spring barley with weeds) gradually turned into competition within species (between barley plants) when a higher number of weaker and non-productive stems started forming. Spring barley yield did not significantly depend on the stand density. Increasing stand density enhanced cultivated crop yield to a certain level (200 kg ha^?1), since an increase in spring barley plant number resulted in the reduction in weight per plant and 1000 grain weight, which was compensated by an increase in the number of spring barley plants. Different spring barley density had an essential influence on the chemical composition of weeds which was similar to that of spring barley. Weeds accumulated the greatest amount of crude proteins, crude fat and crude fibre growing without spring barley.     

Root Plasticity Not Evident in N-Enriched Soil Volumes for Wheat (Triticum aestivum L.) and Barley (Hordeum vulgare L.) Varieties

Root plasticity is a unique characteristic of root systems that may enhance the nutrient foraging capacity of plants. Here we investigated the effect of localized high nitrogen (N) concentration on plasticity of wheat and barley roots in soil. We conducted a series of experiments to maintain localized high concentration of N in soil and to evaluate any root morphological variation in the enriched N zone. Wheat and barley seedlings were grown in N responsive Red Ferrosol with an enriched subsurface N band for 12 days. Wheat and barley roots did not proliferate in N-enriched soil volumes. Rather, higher root length density (~1.6 times) was observed in low N surface soil. Shoot dry matter and shoot N uptake of banded N treatment was statistically similar between uniform and low N treatments. Results indicated the absence of plastic root response of the wheat and barley seedlings in subsurface N band.     

Aspects of the phosphorus nutrition of white clover populations. IV root growth and morphology

Most studies using split root or single isolated roots have demonstrated that root systems proliferate in regions of high nutrient supply, though it is not clear whether tne whole root system responds by producing more roots or by greater elongation of existing roots.

The effect of pretreatment and subsequent treatment at high and low phosphorus (P) supply on the rate of production and rate of elongation of roots was determined for 10 white clover populations, grown in nutrient solution. External P supply was shown to have a greater effect on root elongation rate than on root production rate.

Populations with many small roots (i.e. a low root weight/number ratio) were generally the most responsive to P, measured by shoot weight. Populations collected from low‐P soils had lower root elongation rates, shorter average root lengths and their root production rates were more responsive to P than populations from high‐P soils.     

Effects of late-terminal drought stress on seed germination and vigor of barley (Hordeum vulgare L.)

Late-terminal drought stress during grain filling has recently become more common in the semi-arid Mediterranean region, where barley (Hordeum vulgare L.) is grown as an important winter cereal crop. Little information is available in the literature about the effect of late-terminal drought stress on seed germination and vigor of barley. The objective of this experiment was to study the effect of late-terminal drought stress on seed germination and vigor of barley as estimated by the germination after accelerated aging test. Drought stress reduced grain yield of barley. Grain yield was correlated positively with leaf gross photosynthetic rate and negatively with leaf osmotic potential. Late-drought stress had no effect on standard germination, but reduced the germination after the accelerated aging test. These data suggested that late-terminal drought stress had a greater effect on seed vigor than standard germination in barley.     

Multiple element concentration in the grain of spring barley (Hordeum vulgare L.) collection

Multiple element analyses were carried out to investigate variation in element concentrations in barley grains of 336 genotypes. Of 13 elements analyzed, Ba ranged from 0.2 to 8.9?mg kg^?1, Ca from 186.4 to 977.5?mg kg^?1, Cu from 1.5 to 9.8?mg kg^?1, K from 353.2 to 7721.5?mg kg^?1, Mg from 1049.8 to 2024.2?mg kg^?1, Mn from 8.1 to 22.9?mg kg^?1, Na from 55.9 to 627.9?mg kg^?1, P from 2272.9 to 5428.8?mg kg^?1, S from 880.7 to 1898.0?mg kg^?1, Si from 19.1 to 663.2?mg kg^?1, and Sr from 0.35 to 2.62?mg kg^?1 in the barley grain. The least square means showed high Zn, Fe, Mg, P, and S concentration in AM-64 and AM-228 genotypes. The principal component analysis of element concentration showed four PCs explained 64.3% total variance. Strong positive correlations (p?<?0.001) of Fe-Mn, Fe-S, S-Mn, Zn-P, Zn-Mg, Mg-P, Mg-Mn, and Ca-Sr were found. The identification barley genotypes that showed high elements concentration furnish valuable genetic resources for biofortification in future.     

Interactions of malt and barley (Hordeum vulgare L.) endoproteinases with their endogenous inhibitors.

For producing worts that are optimal for beer production, some, but not all, of the barley proteins must be degraded during malting and mashing. This protein hydrolysis is controlled by endoproteinases, and, in turn, is partially regulated by the presence of low-molecular-weight (LMW) proteinaceous inhibitors. This paper reports studies of the interactions between the proteinases and inhibitors and an "affinity" method for concentrating the inhibitors. The malt inhibitors (I) and proteinases (E) quickly formed strong (E-I) complexes when dissolved together, and all of the I was complexed. Heating at 100 degrees C, but not 70 degrees C, dissociated the complex, even though the enzyme activities were destroyed at 70 degrees C. The released I readily recomplexed with fresh E. Barley, however, contained insufficient E to complex all of its I complement. The E-I complex was treated with salts, detergents, and reducing agents to release active E molecules, but none disrupted the complex. By removing the LMW proteins from a malt E-I extract and dissociating the complex by heating, the concentration of I molecules was greatly increased. This "affinity" method can thus be used to concentrate the I molecules for further purification.     

野生大豆根系形态对局部磷供应的响应及其对磷吸收的贡献

通过土柱试验模拟局部供磷,定量评价了磷局部供应对野生大豆根系形态参数的影响以及这些根形态参数对植株磷吸收的贡献.磷局部供应明显改变了野生大豆的根形态,使总根长增加了80.5％,比根长增加了32.6％,根表面积扩大了70.7％,根直径减小了27.6％,植株对磷的吸收增加了43.2％,地上干重增加了72.0％;在所有的根形态参数中,总根长、根表面积和比根长对野生大豆植株磷吸收具有较大贡献,其中尤以比根长对植株磷吸收贡献最大,即在根长增加的同时,根直径减小能够明显提高野大豆根系对磷的吸收.结果表明,野生大豆对局部磷供应表现出高度的根系形态可塑性,通过局部养分供应优化根系空间分布和定向调控根系生长能显著提高植物对异质性土壤磷资源的获取能力.     

玉米细根形成和土壤中无机磷分级平衡对缺磷的特异性响应

Plants have diverse strategies to cope with phosphorus (P) deficiency. To better understand how maize responds to P deficiency, a field experiment with two P levels, 0 and 100 kg P2O5 ha-1 (P0 and P100, respectively), was carried out as a part of a long-term Pfertilizer field trial. Plant and soil analyses showed that P-deficient maize reduced its growth rate, increased P use efficiency, and formed more thin roots with the diameter less than 0.6 mm at jointing and silking stages, compared to the plants treated with P100. Further, there were no differences in major inorganic P fractions (Ca 2 -P, Ca 8 -P, Al-P, Fe-P, occluded P and Ca 10 -P) between the rhizospheric and bulk soils at each harvest, even when soil Olsen-P was only 1.38 mg kg-1 . These results suggested that maize responded to P deficiency by reducing the internal P demand for growth and increasing P acquisition ability by favorable root morphological alteration at low carbon cost.     

Distribution of microbial biomass across the rhizosphere of barley (Hordeum vulgare L.) in soils

Summary The microbial activity at the soil-root interface (rhizosphere) of barley was examined using a rhizobox system. In this system, the soil was placed in several compartments separated from each other by a 500-mesh nylon cloth. Plants were grown in the central compartment and after a 2-month growing period the roots were still confined to this compartment. The soil from each compartment was then analyzed for ATP, NO₃ ^/–, total N, total C and CO₂ production. The increase in ATP concentration was found in a range of 4 mm around the roots. The ATP content and CO₂ production across the rhizosphere were correlated in all the soils used, but changes in NO₃ ^– were not correlated with ATP changes. The range of NO₃ ^– change was wider than that of the ATP change, indicating that NO₃ ^– production is not influenced by the biological activity in the rhizosphere.     

Trait phenotyping and molecular marker characterization of barley (Hordeum vulgare L.) germplasm from Western Himalayas

Genetic Resources and Crop Evolution - Barley (Hordeum vulgare L.) is one of the principal cereal crops grown in Western-Himalayas of India. A set of 105 barley&nbsp;genotypes including 38...     

砂培条件下两种磷效率棉花根系形态及根际特征差异

为对比两种磷效率棉花在两种磷水平(0.1和5 mmol/L)的根系形态和根际特征的差异。以磷高效型棉花ZM42和磷低效型棉花XLZ13为研究对象设计砂培花盆分层试验,测定生物量、吸磷量、根系形态数据、分层Olsen－P、 pH值和酸性磷酸酶。结果表明：在砂培条件下两种磷效率棉花生物量和磷素积累量随施磷量的增加均有不同程度增加; ZM42在两种磷处理的根部生物量、吸磷量以及根冠比都优于XLZ13。在两种磷处理下, ZM42根系中根径(0~0.4 mm)的细根长度较XLZ13长,细根在总根长中的比例较高。总根长中细根越多有利于促进植株对磷的吸收。生长介质中磷含量降低时,棉花根际pH值也随之降低,高效品种ZM42的根际pH值降低幅度显著高于XLZ13;两种磷效率棉花在两个时期的根际土壤磷酸酶活性均随着施磷量的减少而增加,磷高效棉花ZM42分泌的土壤磷酸酶活性均高于磷低效棉花XLZ13。由此可见,两种磷效率棉花在相同生长介质中根际机理存在差异,且在低磷胁迫下磷高效棉花根系形态特征改变是根际磷活化主要机理之一。