Plants differ in their ability to use different nitrogen (N) chemical forms, these differences can be related to their ecology and drive community structure. The capacity to uptake intact organic N has been observed in plants of several ecosystems. However, soil organic N uptake by Mediterranean plants is unknown despite organic N being abundant in Mediterranean ecosystems. We compare the uptake of different N forms in two widespread coexisting Mediterranean forest trees with contrasting ecophysiological characteristics: Quercus ilex and Pinus halepensis.
MethodsTo estimate root uptake rate of each N form we used equimolar solutions (1 mM N) of 15NO3 ?, 15NH4 + and 15N-13C glycine.
ResultsNH4 + and glycine were taken up at a similar rate, but faster than NO3 ? in both species. Intact dual labeled glycine was found in both species, demonstrating that both species can absorb intact organic N.
ConclusionsDespite their ecological differences, both species had similar preference for N forms suggesting no fundamental niche complementarity for N uptake. The higher preference for NH4 + and glycine over NO3 ? possibly reflects adaptation to the differing proportions of N forms in Mediterranean soils.
相似文献Arsenate (AsV) and chromate (CrVI) inhibit each other’s uptake and translocation in As-hyperaccumulator Pteris vittata. In the present study, we extended the research to As-sensitive plant Pteris ensiformis to better understand the mechanism of their interactions.
MethodsPlants were exposed to 0, 0.75 or 7.5 mg L?1 AsV and 0, 0.52, or 5.2 mg L?1 CrVI for 7 d in hydroponics. Arsenic and Cr speciation were determined in nutrient solutions and plant biomass.
ResultsP. ensiformis accumulated high levels of As and Cr in the rhizomes and roots with low levels in the fronds. However, P. ensiformis was much more effective in taking up Cr than As, as much more Cr was accumulated in the roots (306–6015 vs. 87–642 mg kg?1). AsV and CrVI increased each other’s uptake in the rhizomes and roots when co-present. The AsV and CrVI taken up by P. ensiformis were reduced to arsenite (AsIII) and chromite (CrIII), possibly serving as detoxification mechanism.
ConclusionsUptake of As and Cr induced oxidative stress as indicated by increased lipid peroxidation and electrical conductivity. Arsenic and Cr increased each other’s uptake by P. ensiformis.
相似文献The wild barley Hordeum chilense fulfills some requirements for being a useful tool to investigate the endosperm yellow pigment content (YPC) in the Triticeae including its diploid constitution, the availability of genetic resources (addition and deletion stocks and a high density genetic map) and, especially, its high seed YPC not silenced in tritordeums (amphiploids derived from H. chilense and wheat). Thus, the aim of this work was to test the utility of the H. chilense genome for investigating the YPC in the Triticeae.
ResultsTwelve genes related to endosperm carotenoid content and/or YPC in grasses (Dxr, Hdr [synonym ispH], Ggpps1, Psy2, Psy3, Pds, Zds, e-Lcy, b-Lcy, Hyd3, Ccd1 and Ppo1) were identified, and mapped in H. chilense using rice genes to identify orthologs from barley, wheat, sorghum and maize. Macrocolinearity studies revealed that gene positions were in agreement in H. vulgare and H. chilense. Additionally, three main regions associated with YPC were identified in chromosomes 2Hch, 3Hch and 7Hch in H. chilense, the former being the most significant one.
ConclusionsThe results obtained are consistent with previous findings in wheat and suggest that Ggpps1, Zds and Hyd3 on chromosome 2Hch may be considered candidate genes in wheat for further studies in YPC improvement. Considering the syntenic location of carotenoid genes in H. chilense, we have concluded that the Hch genome may constitute a valuable tool for YPC studies in the Triticeae.
相似文献Subsoil acidity with a high aluminium (Al3+) soil content inhibits root growth and proliferation of durum wheat (tetraploid AABB, Triticum turgidum) leading to poor nutrient and water uptake. This study evaluated the impact of Al3+-tolerantTaMATE1B allele on root and shoot traits of durum wheat grown in an acidic soil with a high Al3+concentration.
MethodsTwo durum wheat lines, Jandaroi–TaMATE1B with the TaMATE1B gene introgressed from Al3+-tolerant bread wheat and Jandaroi–null (a sister line lacking the Al3+-tolerant TaMATE1B allele), were grown in rhizoboxes in a glasshouse. We mapped root growth and proliferation over time and measured shoot traits and grain yield.
ResultsIntrogression of the Al3+-tolerant TaMATE1B allele into durum wheat enabled root growth and proliferation below 0.25 m of the soil profile, where the soil pH was low (4.1, CaCl2 extract) with high Al3+ content (16.5 mg kg−1), and increased total root length and biomass at 42 days after sowing (DAS; Z33) by 38.3 and 22%, respectively, relative to the Jandaroi–null. Differences in root growth between the two lines were apparent from tillering stage (Z33) and by 50% anthesis (Z64), respectively. Jandaroi–TaMATE1B had 69.2% greater root biomass, 76.2% greater root length, 5.89% greater leaf area and 18% greater shoot biomass than Jandaroi–null at 50% anthesis (Z64). Time to anthesis and physiological maturity was delayed 6–7 days in Jandaroi–TaMATE1B, compared to Jandaroi–null. Jandaroi–TaMATE1B tended to have relatively greater, but not significantly different, shoot biomass, grain yield and yield components than Jandaroi–null.
ConclusionsIntrogression of the Al3+-tolerant TaMATE1B allele into durum wheat enabled root growth and proliferation down an acidic soil profile with a high Al3+ concentration. We assume that in the field where plants need to acquire water at depth differences in above-ground parameters would be amplified.
相似文献This study was aimed at engineering charged residues on the surface of Thermomyces lanuginosus lipase (TLL) to obtain TLL variant with elevated performance for industrial applications.
ResultsSite-directed mutagenesis of eight charged amino acids on the TLL surface were conducted and substitutions on the negatively charged residues D111, D158, D165, and E239 were identified with elevated specific activities and biodiesel yields. Synergistic effect was not discovered in the double mutants, D111E/D165E and D165E/E239R, when compared with the corresponding single mutants. One TLL mutant, D165E, was identified with increased specific activity (456.60 U/mg), catalytic efficiency (kcat/Km: 44.14 s?1 mM?1), the highest biodiesel conversion yield (93.56%), and comparable thermostability with that of the TLL.
ConclusionsOur study highlighted the importance of surface charge engineering in improving TLL activity and biodiesel production, and the resulting TLL mutant, D165E, is a promising candidate for biodiesel industry.
相似文献Rice (Oryza sativa L.), wheat (Triticum aestivum L.) and common bean (Phaseolus vulgaris L.) are major staple food crops consumed worldwide. Zinc (Zn) deficiency represents a common micronutrient deficiency in human populations, especially in regions of the world where staple food crops are the main source of daily calorie intake. Foliar application of Zn fertilizer has been shown to be effective for enriching food crop grains with Zn to desirable amounts for human nutrition. For promoting adoption of this practice by growers, it is important to know whether foliar Zn fertilizers can be applied along with pesticides to wheat, rice and also common bean grown across different soil and environmental conditions.
MethodsThe feasibility of foliar application of zinc sulphate (ZnSO4.7H2O) to wheat, rice and common bean in combination with commonly used five fungicides and nine insecticides was investigated under field conditions at the 31 sites-years of seven countries, i.e., China, India, Pakistan, Thailand, Turkey, Brazil and Zambia.
ResultsSignificant increases in grain yields were observed with foliar Zn/foliar Zn?+?pesticide (5.2–7.7 % of wheat and 1.6–4.2 % of rice) over yields with no Zn treatment. In wheat, as average of all experiments, higher grain Zn concentrations were recorded with foliar Zn alone (41.2 mg kg?1) and foliar Zn?+?pesticide (38.4 mg kg?1) as compared to no Zn treatment (28.0 mg kg?1). Though the magnitude of grain Zn enrichment was lesser in rice than wheat, grain Zn concentrations in brown rice were significantly higher with foliar Zn (24.1 mg kg?1) and foliar Zn?+?pesticide (23.6 mg kg?1) than with no Zn (19.1 mg kg?1). In case of common bean, grain Zn concentration increased from 68 to 78 mg kg?1 with foliar Zn alone and to 77 mg kg?1 with foliar Zn applied in combination with pesticides. Thus, grain Zn enrichment with foliar Zn, without or with pesticides, was almost similar in all the tested crops.
ConclusionsThe results obtained at the 31 experimental site-years of seven countries revealed that foliar Zn fertilization can be realized in combination with commonly-applied pesticides to contribute Zn biofortification of grains in wheat, rice and common bean. This agronomic approach represents a useful practice for the farmers to alleviate Zn deficiency problem in human populations.
相似文献