Barley Shoots Research Articles

Sporidial mating and infection process of the smut fungus,Ustilago hordei, in susceptible barley

Ustilago hordei (Pers.) Lagerh. causes covered smut of barley and oats. Sporidial mating and the infection process on compatible barley plants, cv. Hannchen, were investigated using light microscopy and scanning and transmission electron microscopy. Within 2 h after mixing of sporidia of opposite mating types on water agar, polar conjugation tubes emerged that subsequently fused, producing infection hyphae at the junctions. Similar events occurred on germinated barley shoots, although sporidia regularly produced several conjugation tubes, of which only one was involved in mating. Tubes emerging from the sides of cells were also observed. Infection hyphae emerged from either the conjugation tube or conjugated cell body. Hyphae elongated along the shoot surface until characteristic crook and appressorium-like structures were formed. An invading hypha emerged beneath this structure and directly penetrated the underlying epidermal cell. Hyphae extended both intra- and inter-cellularly into tissues, without much branching, before becoming established in the shoot meristematic region. Plant plasma membranes remained intact during pathogen ingress and an electron-dense matrix of unknown origin appeared in the interface between plant plasma membrane and invading hypha. A large fungal biomass was generated in the host spike tissue at 42–63 days postinoculation during the development of the floral meristem.Key words: Hordeum vulgare, pathogen, sporidia, teliospores, ultrastructure, Ustilaginales.

Differential cysteine synthase activity and alachlor susceptibility in five crops and six weed species

Cysteine synthase (CS; EC 4.2.99.8) activities were compared among crops and grass weeds having different susceptibilities to alachlor. The order of alachlor tolerance of 11 grass species from most to least was: corn ≫ barley=rice=wheat > sorghum=johnsongrass=broadleaf signalgrass > barnyardgrass=large crabgrass > green foxtail=goosegrass, suggesting that corn was tolerant and all other species were susceptible to alachlor. In shoots, rice had the highest extractable CS activity ( 44.3 μmol/min/g fresh weight), and corn, barley, wheat, sorghum, johnsongrass, and broadleaf signalgrass had the second highest activity ranging between 20.6 and 26.4 μmol/min/g fresh weight. CS activity of large crabgrass, green foxtail, and goosegrass was relatively lower (15.5– 18.1 μmol/min/g fresh weight), and barnyardgrass had the lowest CS activity ( 10.9 μmol/min/g fresh weight). Generally, levels of CS activities in roots were similar to those in shoots in each grass species. However, barley had root CS activity lower than that in shoots and green foxtail had root CS activity higher than that in shoots. Alachlor treatment (GR 50 concentrations) had no effect on extractable CS activity in shoots of corn, barley, sorghum, and barnyardgrass. Content of non-protein cysteine in shoots ranged between 60.1 and 131.5 nmol/g fresh weight, and was not largely different among the grass species except for green foxtail where it was high, i.e., 334.6 nmol/g fresh weight. Content of other non-protein thiols was highest in corn (574.7 nmol/g fresh weight), which was tolerant to alachlor, and the contents were relatively low in other grass species which were susceptible. Alachlor susceptibility was more highly correlated to CS activity ( R 2=0.514) in shoots than to the contents of cysteine ( R 2=0.309) and to other thiols ( R 2=0.025) in grass species susceptible to alachlor. In addition, CS activity in roots ( R 2=0.159) was less correlated to the selectivity than shoots. These results indicate that CS activity in shoots could contribute to alachlor selectivity in grass species.

Salt tolerance of grain crops in relation to ionic balance ability to absorb microelements

A greenhouse experiment was conducted to investigate the effect of exchangeable Na on the growth and absorption of metal elements in barley, rye, and maize. The plants were cultivated in soils whose exchangeable sodium percentages (ESP) were 6.6 (saline soil: Saline), 17.4 (saline-sodic soil: Sodic 1), and 39.6 (sodic soil: Sodic 2), which were prepared from Tottori sand dune soil (Control). The dry weight (DW) and concentrations of metal elements Ca, Mg, Mn, Zn, and Cu) in shoots were analyzed. The shoot DW was smaller with higher ESP, but in barley the difference between all the treatments was no longer observed with time. In Sodic soils, the growth of barley was vigorous, whereas rye growth was poor, and maize plants died by 5 weeks after planting. The Na concentration in shoots of all the species was higher with higher ESP. The K concentration in shoots was low at the early growth stage, but in barley it was higher in the Saline and both Sodic soils than in the Control at the subsequent stages. The concentrations of Ca and Mg in shoots of barley and maize in the Saline and both Sodic soils were higher than those in the Control, but in rye the concentrations were lowest in Sodic 2. The concentrations of Mn, Zn, and Cu in barley shoots in the Saline and bothSodic soils tended to be higher than those in the Control, whereas in rye they were lower than in the Control in both Sodic soils. Barley showed a higher ability to absorb low available microelements than rye and maize. These results indicate that barley is tolerant to sodicity as well as salinity, maize is tolerant to salinity, but is very sensitive to sodicity, and rye is moderately sensitive to both stresses. We suggest that the tolerance of grain crops to ESP involves a tolerance to a high Na concentration in shoots, the ability to keep suitable concentrations of essential cations in the presence of a high concentration of Na in shoots and the ability to absorb low available microelements.

Developmental responses to sowing date in wheat, barley and rapeseed

Two cultivars of each bread wheat ( Triticum aestivum L.), malting barley ( Hordeum vulgare L.) and spring rapeseed ( Brassica napus L.), were grown in a wide range of different sowing dates in Buenos Aires, Argentina. The aims of this study were (i) to analyse how the number of leaf primordia and the rate of leaf emergence interact to modify the duration of different pre-flowering phases and (ii) to establish how different yield components initiated during those phases are affected when the duration of these phases are modified by wide range of sowing dates. The results showed interactions between photoperiod and temperature for wheat and rapeseed producing different combination for the length of the pre-flowering phases. Barley reached floral initiation earlier than wheat and rapeseed and had a shorter ‘intrinsic earliness’. Plastochron and phyllochron varied among different sowing dates in the three species. In most cases the relationship between the cumulative number of leaves on the main shoot of wheat and barley and thermal time was describe by a bilinear model with the earlier leaves emerging faster than the later ones. However, the opposite pattern was observed for rapeseed which showed a slower rate of leaf emergence for the first than for the lasts leaves. The changes observed in the rate of leaf emergence throughout plant ontogeny, might delay or hasten the duration of the later reproductive phase during which the spikes grow and some of the initiated floret primordia becoming fertile. Extending the duration of the stem elongation phase in wheat and barley produced more fertile florets per spikelets.

Is carbonyl sulfide a precursor for carbon disulfide in vegetation and soil? Interconversion of carbonyl sulfide and carbon disulfide in fresh grain tissues in vitro.

The interconversion of carbonyl sulfide (COS) and carbon disulfide (CS(2)) was studied in the roots and shoots of barley and chickpeas. Ratios of conversion gases, K, 40 h after the addition of COS or CS(2) are recorded. The proportion of COS converted to each of CS(2), CO, and H(2)S and the proportion of CS(2) converted to COS were greater in roots than in shoots. More COS was converted to CS(2) than CS(2) to COS in roots and shoots of barley and chickpeas. The amount of COS converted to H(2)S and CO was 8 times the amount converted to CS(2) in barley and 3-4 times the amount in chickpeas. Carbonyl sulfide may be a precursor for CS(2) in vegetation and soil, just as the reverse is true in the atmosphere. These two different results might form a cycle of COS and CS(2).

Clonal analysis of the development of the barley ( Hordeum vulgare L.) leaf using periclinal chlorophyll chimeras

Barley seedlings that show mosaic expression of chlorophyll were selected from the progenies of mutagenized seeds. The sectored plants were grown under conditions that lead to the formation of lateral tillers, and a fraction of these had different kinds of leaf variegation. These sectorially and periclinally chimeric shoots were used to analyze the cellular organization of the barley shoot apex and the clonal development of the leaf. The shoot apex is organized in two cell lineages, L1 and L2. As well as giving rise to the epidermis, the L1 layer contributes to leaf mesophyll, particularly at the margins, but, on the adaxial side of leaf laminae, also in more central positions. The L1 layer alone is responsible for the formation of the hood, a flower homologue structure present in strains homozygoous for the dominant allele at the K (hooded ) locus. The relative contribution of L2 to leaf formation decreases in younger tillers and during tiller development from the basal to the flag leaf. Chimerism of the plants was generated by non-transmissible somatic events or by nuclear mutations.

Effects of silicon on enzyme activity and sodium, potassium and calcium concentration in barley under salt stress

Two contrasting barley (Hordeum vulgare L.) cultivars: Kepin No.7 (salt sensitive), and Jian 4 (salt tolerant) were grown in a hydroponics system containing 120 mol m-3 NaCl only and 120 mol m-3 NaCl with 1.0 mol m-3 Si (as potassium silicate). Compared with the plants treated with salt alone, superoxide dismutase (SOD) activity in plant leaves and H+-ATPase activity in plant roots increased, and malondialdehyde (MDA) concentration in plant leaves decreased significantly for both cultivars when treated with salt and Si. The addition of Si was also found to reduce sodium but increase potassium concentrations in shoots and roots of salt-stressed barley. Sodium uptake and transport into shoots from roots was greatly inhibited by added Si under salt stress conditions. However, Si addition exhibited little effect on calcium concentrations in shoots of salt-stressed barley. Thus, Si-enhanced salt tolerance is attributed to selective uptake and transport of potassium and sodium by plants. The results of the present study suggest that Si is involved in the metabolic or physiological changes in plants.

Settling behaviour of Rhopalosiphum padi (L.) in relation to cyanogenic glycosides and gramine contents in Barley

In order to examine whether the content of cyanogenic glycosides or gramine in barley affects the host plant preference of the aphid Rhopalosiphum padi (L.), two‐choice settling tests were performed with R. padi on different barley varieties with varying amounts of these compounds. The total concentration of cyanogenic glycosides in barley shoots, as determined in 59 varieties, varied between 20 and 1200 nmol (g fw)−1. Of the 59 varieties, six with high [>700 nmol (g fw)−1], six with intermediate [450–650 nmol (g fw)−1] and six with low [<200 nmol (g fw)‐l] content of cyanogenic glycosides were chosen for preference tests with R. padi. The content of gramine was determined in these 18 chosen varieties and was generally either low (close to 0) or high [about 2 μmol (g fw)−1]. There was no correlation between cyanogenic glycoside and gramine content. The aphids did not discriminate between varieties with high, intermediate or low content of cyanogenic glycosides in combinations with high or low gramine content. The results indicate that the concentration of neither of these compounds affected the settling preference of R. padi.

Effect of Glomus etunicatum inoculation on aluminum, phosphorus, calcium, and magnesium uptake of two barley genotypes with different aluminum tolerance

This study was conducted to evaluate the effect of vesicular‐arbuscular mycorrhizal (VAM) fungus Glomus etunicatum on growth, absorption, and distribution of calcium (Ca), magnesium (Mg), phosphorus (P), and aluminum (Al) in one Al‐tolerant and one Al‐sensitive barley cultivar. The plants were grown in sand daily irrigated with nutrient solution containing 0 or 600 μM Al at pH 4.8. Significant interaction (P=0.05) among variety, mycorrhiza, and aluminum (VxMxAl) were noted for both shoot and root dry matter (DM); shoot concentration and content of Al, P, Ca, and Mg; root concentration of Al, P, and Mg; and root content of Al, P, Ca, and Mg. With VAM inoculation: i) root colonization degree was about 50% in all treatment, ii) shoot DM yield increased between 30 and 70%, iii) Al concentration and content decrease down to a half both in shoots and roots of sensitive barley, iv) Ca concentration in shoots of sensitive barley showed a high increase at 600 μM Al, and v) P concentration and content in shoots of both varieties increased significantly.

Bioavailability of Copper and Zinc in Soils Treated with Alkaline Stabilized Sewage Sludges

AbstractA glasshouse experiment was conducted to determine the bioavailability of Cu and Zn in a sandy loam and a clay loam. Spring barley (Hordeum vulgare L. cv. Forrester) was grown for 40 d in the two soils following application of alkaline‐stabilized sewage sludge. The soils were mixed with sludge product to give mixtures equivalent to fresh sludge cake application rates of 30, 90, and 120 Mg/ha. Unamended controls and all sludge‐treated soils except those receiving 90 Mg/ha were sequentially extracted to fractionate Cu and Zn into five operationally defined chemical forms. About 74% of total Cu and 80% of total Zn remained in the RESD fraction of the sludge‐amended soils. The largest extractable Cu fraction was OM‐Cu while the largest extractable Zn fraction was FeMnOX‐Zn in both types of sludge product and in both soils. The EXCH and CARB fractions together comprised &lt;2% of total Cu and Zn in sludge‐amended soils. The sludge product raised soil pH and, except for EXCH‐Zn, increased the concentrations of both metals in the four extractable soil fractions. The sludge product increased barley shoot uptake of Cu by 112% and of Zn by 67% on average. However, sludge application decreased the shoot Zn concentration by 39% in the clay loam. This may be due to a decrease in EXCH‐Zn in the soil together with a dilution effect in the shoots resulting from a positive yield response to the sludge cake. Plant metal uptake was correlated (P &lt; 0.05) with the various soil fractions, particularly EXCH‐Cu and CARB‐Zn.

D-33 Endogenous brasslnosterclds in the shoots of barley and whet.

D-33 Endogenous brasslnosterclds in the shoots of barley and whet.

Methylcrotonyl-CoA carboxylase from barley ( Hordeum vulgare L): Purification, kinetic characterization and senescence-related induction of activity

Summary 3-Methylcrotonyl-CoA carboxylase (MCC, 3-methylcrotonyl-CoA: carbondioxide ligase, (ADP-forming), EC 6.4.1.4) from barley shoots ( Hordeum vulgare L.) was purified to homogeneity with a 5340-fold purification factor. MCC from barley consists of two subunits with a molecular weight of 60 and 85 kDa, and thus is a type II biotin-containing carboxylase. The larger polypeptide contains the biotin. Barley MCC has a native molecular weight of about 660 kDa. It exhibits maximum activity at 45 °C and at a pH of 8.0–8.3. Carboxylation of methylcrotonyl-CoA by barley MCC is Mg 2+ -dependent. Exchange of Mg 2+ by Mn 2+ or Fe 2+ resulted in only 13 % or 20 % of the original activity. Barley MCC was inhibited to 95 % by 1 mM acetoacetyl-CoA and to 25 % by 1 mM palmitoyl-CoA. K m -values for methylcrotonyl-CoA, ATP, and hydrogencarbonate were 31 μM, 21 μM and 2.8 mM, respectively. Kinetic measurements revealed an independent binding of methylcrotonyl-CoA and ATP to the enzyme, as well as sequential binding of methylcrotonyl-CoA vs. hydrogencarbonate, and hydrogencarbonate vs. ATP. MCC-activity was low in young leaf tissue, but strongly increased with increasing age of the plants. For barley seedlings an age of 21 days was found to be the optimum for enzyme isolation. In young barley shoots MCC-activity could be stimulated by treating the plants with leucine or senescence-inducing substances such as jasmonic acid. Apparent MCC-activity was also stimulated by continuous darkness.

Identification of promoter elements in a low-temperature-responsive gene (blt4.9) from barley (Hordeum vulgare L.).

The blt4 barley gene family encodes non-specific lipid transfer proteins and has been shown, by in situ localisation, to be expressed in the epidermal cells of leaves. The transcriptionally controlled, low-temperature-responsive member of this gene family, blt4.9, is predominantly expressed in shoot meristems. The promoter region (1938 bp) of blt4.9 contains sequence motifs which have been implicated in responses to low temperature, abscisic acid and other environmental factors. Deletion analysis showed that a 42 bp sequence proximal to, but not including, the CAAT and TATA boxes, confers enhanced low-temperature response to a reporter gene in a barley shoot explant transient expression system. Other promoter regions were shown to contain negative and positive regulatory regions. Electrophoretic mobility shift analysis (EMSA) was used with nuclear proteins from either low-temperature- or control-temperature-treated plants to further investigate the blt4.9 promoter. Synthetic oligonucleotides were used to identify a hexanucleotide, CCGAAA, within the 42 bp, low-temperature-responsive promoter region, as the binding site of a low-mobility nuclear protein complex. This complex was present in nuclear extracts from both low-temperature-treated and control plants and was the only complex formed within this region. Mutation of the CCGAAA motif within the low-temperature-responsive 42 bp promoter sequence reduced low-temperature responsiveness to basal levels. A related upstream element, CCGAC, known to be a low-temperature-responsive element in other plants, did not bind to nuclear proteins in this study. It is proposed that the hexanucleotide CCGAAA, at -195 from the first ATG, is involved in the low-temperature response of blt4.9 in barley.

The relationship between leaf growth and ABA accumulation in the grass leaf elongation zone

ABSTRACTDetached barley (Hordeum vulgare L.) shoots, maintained at different air temperatures and VPDs, were fed ABA via the sub‐crown internode in a leaf elongation assay. Analysis of variance of leaf elongation rate (LER) showed significant effects of temperature (T), fed [ABA] and the interaction T × [ABA]. However, the interaction became non‐significant when LER was modelled against the [ABA] of the elongation zone, [EZ‐ABA]When detached barley shoots were fed sap from droughted maize (Zea mays L.) plants, sap [ABA] could not explain the growth inhibitory activity. Measurement of [EZ‐ABA] accounted for this ‘unexplained’ growth inhibition.The detached shoot experiments indicated that [EZ‐ABA], and not xylem sap [ABA], was an appropriate explanatory variable to measure in droughted plants. However, ABA accumulation in the elongation zone could not explain a 35% growth reduction in intact droughted plants; thus we considered an interaction of water status and ABA.Using a coleoptile growth assay, we applied mild osmotic stresses (ψ=0 to −0.06 MPa) and 10−4 mol m−3 ABA. Individually, these treatments did not inhibit growth. However, osmotic stress and ABA applied together significantly reduced growth. This interaction may be an important mechanism in explaining leaf growth inhibition of droughted plants.

Barley uptake of N deposited in the rhizosphere of associated field pea

N deposited in the rhizosphere of a legume may contribute to the N-nutrition of an intercropped non-legume. The process of deposition and subsequent uptake by a neighbouring plant is often termed N-transfer. The N-transfer from field pea ( Pisum sativum L.) to associated spring barley ( Hordeum vulgare L.) was determined in three pot experiments using a direct split-root 15N-labelling technique. The donor (pea) and receiver (barley) plants were grown with their root systems either mixed within the same soil compartment or separated by a 20 μm mesh bag. Pea-derived N was detected in barley after 4 weeks of growth, but in most associations <1% of total pea N was recovered in barley. N-transfer from barley to pea was not detected when barley was grown as the donor. The amount of pea-derived N in barley increased markedly with time, probably due to the accelerated turnover of root and nodule debris. Separating the root systems reduced the barley recovery of pea-derived N to about half the amount recovered in the association where root systems grew in the same compartment. The death of pea, caused by spraying with a herbicide, increased the amount of N recovered in barley, whereas shading the pea plant had no effect on the amount of pea-derived N taken up in barley. The N deposited up to 45 days of growth contributed <5% of the barley shoot N in most treatments. However, at 70 days, 19% of the N in barley was derived from pea. It is concluded that field pea rhizodeposition of N may be a significant source of N to intercropped barley, especially at low rates of N-fertilization.

Diamine oxidase from millet catalyzes the oxidation of 1, 3-diaminopropane

Diamine oxidase was purified sixty-fold from millet shoots. The partially purified enzyme of 150 kDa oxidized 1, 3-diaminopropane (1, 3-DAP) to 3-aminopropionaldehyde. The Km values were 9.1×10−5M for 1, 3-DAP and 6.3×10−4M for putrescine. Extracts of shoots of prosomillet, maize and barley also contained an activity that oxidized 1, 3-DAP.

The influence of cytokinins in nitrate regulation of nitrate reductase activity and expression in barley

The responses of nitrate reductase (NR) activity and levels of NR‐mRNA to environmental nitrate and exogenous cytokinins are characterised in roots and shoots of barley (Hordeum vulgare L., cv. Golf), using a chemostate‐like culture system for controlling nitrate nutrition. Experiments were mainly performed with split root cultures where nitrate‐N was supplied at a constant relative addition rate of 0.09 day−1, and distributed between the subroots in a ratio of 20%:80%. The subroot NR‐mRNA level and NR activity, as well as the endogenous level of zeatin riboside (ZR), increased when the local nitrate supply to one of the subroots was increased 4‐fold by reversing the nitrate addition ratio (i.e. from 20%:80% to 80%:20%). Also shoot levels of ZR, NR‐mRNA and NR activity increased in response to this treatment, even though the total nitrate supply remained unaltered. External supply of ZR at 0.1 μM caused an approximately 3‐fold increase in root ZR levels within 6 h. which is comparable to the nitrate‐induced increase in root ZR. External application of ZR. zeatin. isopentenyl adenine or isopentenyl adenosine at 0.1 μM caused from insignificant to 25% increases in NR‐mRNA and activity in roots and up to 100% stimulation in shoots, whereas adenine or adenosine had no effect. No synergistic effects of perturbed nitrate supply and cytokinin application were detected in either roots or shoots. The translocation of nitrate from the root to the shoot was unaffected by application of ZR or switching the nitrate distribution ratio between subroots. The data give arguments for a physiological role of cytokinins in the response of root and shoot NR to environmental nitrate availability. The nature and limitations of the physiological role of cytokinins are discussed.

Field assessment of supernodulating genotypes of soybean for yield, N 2 fixation and benefit to subsequent crops

Development and commercial use of cultivars of soybean with high N 2 fixation activity, even in the presence of moderate to high amounts of soil nitrate, may result in larger inputs of N into the soil-plant system. We report experiments from a 6-year study (1988–93) to evaluate yield, N 2 fixation and effects on subsequent cereal crops of intermediate supernodulating (designated 2 × nodulation phenotype) and extreme supernodulating mutants of Bragg soybean (6 × nodulation phenotype), a non-nodulating mutant of Bragg (0 × nodulation phenotype), genotypes derived from the mutants and commercial cultivars. Plants were grown at two sites in southern Queensland (Norwin and Gatton) in blocks fertilized with N (40 and 180 kg ha −1) or left unfertilized. Seed was inoculated at sowing with commercial peat inoculant containing effective Bradyrhizobium japonicum CB1809. The supernodulating genotypes produced up to 5 times the number of nodules and 8 times the nodule weight of cv. Centaur. Nitrogen fixation, assessed in five site × years using the xylem ureide technique, varied with site, season, genotype and fertilizer N. In some instances, relative ureide-N values of the supernodulators were significantly higher than for commercial cultivars. Results over all experiments indicated that the supernodulators and cv. Manark were similar with values 13–21% above Centaur. In two of three experiments to evaluate the effects of fertilizer N on N 2 fixation, the supernodulators showed higher activity in the N fertilized plots than the commercial cultivars, including Manark. There was good agreement ( r 2=0.81) between assessments of N 2 fixation using ureide and natural 15N abundance techniques. grain yield of the supernodulators, averaged over sites and years, were either the same or up to 25% less than Centaur and Bragg. At the Gatton site in 1989, the dry matter of oats, sown immediately after soybean harvest, was significantly ( P < 0.05) greater after the supernodulators than after commercial cultivars. At Norwin in 1990 and 1991, significant benefits on barley shoot dry matter and grain were recorded for the 2 × nodulation phenotypes only.

Diurnal Variations in Release of Phytosiderophores and in Concentrations of Phytosiderophores and Nicotianamine in Roots and Shoots of Barley

Summary The effects of the iron (Fe) nutritional status and time of the day on the release of phytosiderophores (PS) and on concentrations of PS and their precursor nicotianamine (NA) in roots and shoots were studied over a 24-hour cycle for barley ( Hordeum vulgare L. cv. Europa). Phytosiderophores were released in a diurnal rhythm with maximum rates 5 to 6 hours after onset of the light. Compared with Fe-sufficient plants, PS release rates were up to 250 times higher in Fe-deficient plants. The dominant PS in root exudates and root and shoot extracts was epi -hydroxymugineic acid (HMA). In root extracts of Fe-deficient plants, concomitantly to release of epi -HMA, concentrations of epi -HMA decreased until the end of the highest release rate. Thereafter, epi -HMA concentrations in root extracts increased with time and were as high at the en4 of the light period as at the onset. In root extracts of Fe-sufficient plants, epi -HMA concentrations were up to 10 times lower and diurnal variations in epi -HMA concentrations were not observed. Nicotianamine concentrations were 1.5 times higher in root extracts of Fe-deficient plants than of Fe-sufficient plants and were independent of time of the day. In root extracts of Fe-deficient plants NA concentrations were up to 62 times lower than epi -HMA concentrations. In shoot extracts epi -HMA and NA concentrations were similar in Fe-sufficient and Fe-deficient plants and no consistent diurnal variations were observed. Apparently, depending on Fe nutritional status, PS are synthesized in roots at constant rates over the whole light period. No marked accumulation of NA or other precursors of epi -HMA such as deoxymugineic acid (DMA) or mugineic acid (MA) occurs under Fe deficiency.

Impact of greater sandhill cranes foraging on corn and barley crops

The impact of greater sandhill cranes grazing on corn and barley crops was measured during 1991–1992 in northern Utah and southwestern Wyoming. Fields were selected based on complaints of chronic crane depredation problems received from farmers. Though evidence of depredation was qualitatively documented, it was difficult to document quantitatively. Open field sites in barley fields had a lower density of barley shoots, and significantly longer gaps between plants than areas inside exclosures during the spring. By fall, these differences were no longer detectable. Estimates based on direct measurements in depredated barley fields suggested losses of <3% of grain biomass. Sites open to crane use in corn fields had significantly longer gaps between plants and lower shoot densities than areas in exclosures, but the relationship to corn yield was equivocal. In the face of increasing crane populations, proactive management may ameliorate future crane-crop conflicts.