Silicon Mitigates Aluminum Toxicity of Tartary Buckwheat by Regulating Antioxidant Systems

Aluminum (Al) toxicity is a considerable factor limiting crop yield and biomass in acidic soil. Tartary buckwheatgrowing in acidic soil may suffer from Al poisoning. Here, we investigated the influence of Al stress on the growthof tartary buckwheat seedling roots, and the alleviation of Al stress by silicon (Si), as has been demonstrated inmany crops. Under Al stress, root growth (total root length, primary root length, root tips, root surface area, androot volume) was significantly inhibited, and Al and malondialdehyde (MDA) accumulated in the root tips. At thesame time, catalase (CAT) and ascorbate peroxidase activities, polyphenols, flavonoids, and 1,1-diphenyl-2-picrylhydrazyl(DPPH) and 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) free-radical scavenging abilitywere significantly decreased. After the application of Si, root growth, Al accumulation, and oxidative damage wereimproved. Compared to Al-treated seedlings, the contents of ·O2− and MDA decreased by 29.39% and 25.22%,respectively. This was associated with Si-induced increases in peroxidase and CAT enzyme activity, flavonoidcompounds, and free-radical scavenging (DPPH and ABTS). The application of Si therefore has positive effectson Al toxicity in tartary buckwheat roots by reducing Al accumulation in the roots and maintaining oxidationhomeostasis.

Polysaccharide Elicitor from the Endophyte Bionectria sp.Fat6 Improves Growth of Tartary Buckwheat under Drought Stress

Drought can limit the growth and reduce the yield of crops,but the safe and effective bio-approach to improve the drought resistance of crops is very little.We conducted an experiment in which we monitored the effects of polysaccharide from the endophyte Bionectria sp.Fat6 on the growth of Tartary buckwheat(Fagopyrum tataricum(L.)Gaertn)seedlings under control and drought-stressed conditions by determining gas exchange,photosynthesis parameters,photosynthetic pigment contents,and metabolite accumulation.Results indicated that the polysaccharide from endophyte stimulated plant growth and increased the aboveground biomass,root mass,and root/shoot ratio of Tartary buckwheat.Application of the polysaccharide to drought-stressed plants resulted in a significant increase in the net photosynthetic rate,stomatal conductance,and transpiration rate of Tartary buckwheat and decreased the intercellular CO_(2) concentration.The contents of chlorophyll a,chlorophyll b,chlorophyll a+b,and carotenoids in leaves were higher in polysaccharide-treated seedlings than that in control.Polysaccharide notably increased the soluble protein and proline content and decreased the malondialdehyde content in Tartary buckwheat leaves.The endophytic polysaccharide may protect Tartary buckwheat against drought by improving leaf gas exchange and photosynthetic capacity,and altering concentrations of protective metabolites.Together,these changes may compensate for the negative impacts of drought stress on the growth of Tartary buckwheat.Thus,the polysaccharide from the endophyte Bionectria sp.Fat6 may be an effective biotic elicitor and a promising bio-approach to improve Tartary buckwheat production worldwide.

Stretchable and environment-resistant doubly crosslinked hydrogel for all-in-one supercapacitor and strain sensors

Despite their importance as components for flexible electronics,most stretchable hydrogels suffer from incomplete recovery after deformation,are prone to failure upon long-term repeated stretching,and cannot be exploited at subzero temperatures because of the freezing of their constituent water.Conse-quently,strategies for circumventing these drawbacks are highly sought after.This study describes the synthesis of a doubly(chemically and physically)crosslinked hydrogel from gelatin and methacrylic acid and demonstrates the suitability of this material for the fabrication of high-performance stretchable and environment-resistant supercapacitors and strain sensors.The performance of this supercapacitor(areal capacitance=1,210.2 mF/cm^(2) at a current density of 1 mA/cm^(2),maximum energy density=158.8μW.h/cm^(-1),maximum power density=659.5μW/cm^(2))was superior to that of most of integrated super-capacitors reported to date and was hardly affected by stretchable,low temperatures,bending,ice-cold water and strong acid/alkali solutions or long-term storage.Additionally,a strain sensor based on the above hydrogel was capable of accurately capturing human body motions when affixed to skin and recognising mouse movement(even in humid environments)after implantation into mouse legs.Our work may pave the way to high-performance stretchable and environment-resistant wearable electronics.