The growth and yield of essential crops, including maize, are significantly endangered by drought. Closing stomata, limiting water dissipation, and improving water use efficiency are important ...components of plant drought responses. In our study, the MYB-like transcription factor ZmMYB56, expressed in maize guard cells, played important roles in regulating stomatal closure and drought tolerance. Mutations in ZmMYB56 triggered elevated stomatal conductance, rapid water loss in isolated leaves, and severe drought sensitivity in plants. ZmMYB56 possesses transcriptional activation activity, and is expressed specifically in stomatal guard cells. As an R2R3 transcription factor, ZmMYB56 can bind the cis-acting element on the ZmTOM7 promoter sequence, activating its expression. Correspondingly, the ZmTOM7 transcript level is downregulated in Zmmyb56 seedlings. Transgenic Arabidopsis plants overexpressing ZmTOM7 exhibit limited stomatal conductance and elevated drought tolerance, while the ZmTOM7 mutation is linked to higher stomatal conductance and substantial drought sensitivity in maize seedlings. According to these findings, we conclude that ZmTOM7 operates as a key target gene of ZmMYB56 and is involved in ZmMYB56-regulated stomatal closure and maize drought tolerance. Our findings regarding the functional mechanisms of maize ZmMYB56 transcription factors in stomatal closure and drought stress enable a potential genetic resource for improving the drought resistance of maize.
C60 fullerene-bonded-CNTs (CNBs) were successfully synthesized by radio frequency plasma (RF plasma) treatment for the first time. High-resolution transmission electron microscopy (HRTEM) and Raman ...spectroscopy were used to confirm the formation of the CNB structure. A possible mechanism was also proposed to explain the formation of CNBs. This RF plasma treatment may inspire a novel method to potentially overcome the synthetic difficulty of CNBs.
In this study, graphene was functionalized with furfuryl alcohol (FA) through the Diels–Alder reaction. The as-prepared FA functionalized graphene (FAG) was characterized by XRD, Raman, TEM, AFM, ...FT-IR and TG. The sorption performance of the obtained FAG toward radionuclides was evaluated. The maximum sorption capacities from the Langmuir model were calculated to be 1.178, 1.947, 1.431 and 1.608mmolg−1 for U(VI), Eu(III), Sr(II), and Co(II), respectively, at T=303K and pH=3.0, indicating the hierarchical binding affinity of the FAG surface toward the radionuclides in the order Eu(III)>Co(II)>Sr(II)>U(VI). Based on the experimental results presented in this study, it is clear that FAG can be potentially used as a promising candidate for the sorption of radionuclides.
The thermoresponsive poly(N-isopropylacrylamide) and matching thermal-liftoff method are widely employed for cell culture. There is already growing evidence that this special cell culture system not ...only provides an appropriate growth environment for anchorage-dependent cells at physiologic conditions, but also supports mild and efficient cell harvesting by cooling treatment. This review elaborates the internal and external factors affecting two-dimensional surface thermosensitivity and cell behavior, and then briefly discusses three-dimensional cell culture systems involved in thermosensitive microcarriers, scaffolds, hydrogels, and hollow fiber membranes, and finally presents their potential applications including large-scale cell expansion as well as tissue repair and reconstruction.
Ozone was used to oxidize graphene oxides （GO） to generate ozonated graphene oxides （OGO） with higher oxygen-containing functional groups. The as-prepared OGO was characterized by Fourier transformed ...infrared spectroscopy （FTIR）, scanning electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS）. Based on the results of potentiometric acid-base ti- trations, the total carboxylic acid concentration on OGO surface was calculated to be 3.92 retool/g, which was much higher than that on GO surface. The results of adsorption experiments indicated that the adsorption capacities of OGO for Sr（II） and U（VI） removal were improved significantly after ozonization.
Interest has developed in the potential of mulberry (
Morus alba
), a woody perennial, for revegetating the hydro-fluctuation belt of the Three Gorges Reservoir due to its resistance to water-logging ...stress. To be useful, the trees must also be able to withstand dry conditions in summer when temperatures can be very high and droughts become severe quickly. Here, we report a study in which mulberry seedlings were grown in a greenhouse under a variety of simulated soil water conditions reflecting potential summer scenarios in the hydro-fluctuation belt of the Three Gorges Reservoir Area. We compared the responses of two pretreatment groups of mulberry seedlings to different levels of drought stress. The pretreatment groups differed with respect to drought hardening: the daily-managed (DM) group had relative soil moisture held constant in the range 70–80 %, while the drought-hardened (DH) group had relative soil moisture held constant at 40–50 %. Following the month-long pretreatment of seedlings, the two groups of young trees (DM and DH) were then respectively subjected to three levels of drought stress for a month: normal watering, moderate drought stress, and severe drought stress. A series of measurements comparing the physiological status of the plants in the two groups were then made, and the following results were obtained: (1) As drought stress increased, the heights, base diameters, root surface areas, photosynthetic rates (Pn), stomatal conductances (Gs), and transpiration rates (Tr) of the mulberry trees in both groups (DM and DH) decreased significantly, while the specific root area and abscisic acid (ABA) contents had increasing trends. Root activity and instantaneous water use efficiency of mulberry trees in both groups (DM and DH) were all raised under drought stress conditions than under normal watering, but the root/shoot ratio and leaf water potential were lowered. (2) At the same level of soil water content, the heights, base diameters, root/shoot ratios, root surface areas, specific root areas, photosynthetic rates (Pn), stomatal conductances (Gs), and transpiration rates (Tr) of the young mulberry trees in the DH were all significantly higher than those of the control group (DM). Leaf water potential, instantaneous water use efficiency, and abscisic acid content of DH were all significantly lower than DM. Under different degrees of drought stress, the growth of mulberry trees will be inhibited, but the trees can respond to the stress by increasing the root absorptive area and enhancing capacity for water retention. Mulberry trees demonstrate strong resistance to drought stress, and furthermore drought resistance can be improved by drought hardening during the seedling stage.
In this study, polyacrylamide was coated onto Fe sub(3)O sub(4) to prepare novel polyacrylamide coated-Fe sub(3)O sub(4) magnetic composites (denoted as Fe sub(3)O sub(4)atPAM). The as-prepared ...composites were characterized by Fourier transferred infrared spectroscopy, X-ray diffraction, and thermo gravimetric analysis, and the results indicated that polyacrylamide was successfully coated on the surface of Fe sub(3)O sub(4). And Fe sub(3)O sub(4)atPAM composites were applied as adsorbents to remove U(VI) from aqueous solutions and it could be separated by a simple magnetic separation method. The sorption isotherms were well fitted by the Langmuir sorption isotherms, and the maximum sorption capacity of Fe sub(3)O sub(4)atPAM for U(VI) at pH 5.0 was calculated to be 220.9 mg/g. According to the XPS analysis of Fe sub(3)O sub(4)atPAM before and after U(VI) sorption, the nitrogen-containing functional groups on the surface of Fe sub(3)O sub(4)atPAM were responsible for U(VI) sorption. The U(VI) sorbed onto Fe sub(3)O sub(4)atPAM could be desorbed effectively in acid solutions, and the sorption capacity of regenerated sorbents could still maintain high level even after five cycles. The results showed that the Fe sub(3)O sub(4)atPAM composites were promising materials for the separation and enrichment of radionuclides from aqueous solution in environmental pollution cleanup.
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