The genetic relationship between Habo alkaline intrusion and its surrounding deposits, Yunnan Province, China: geological and S–Pb isotopic evidences

The Habo alkaline intrusion, which is located in the south of the Sanjiang area, Yunnan Province, China, is a typical Cenozoic alkaline intrusion. There are a series of small to medium-sized Au and Pb-（Zn） deposits around this intrusion. Those deposits are spatially associated with the Habo alkaline intrusion. （1） The δ^34S values of sulfides from Au deposits range from -1.91‰ to 2.69 ‰, which are similar to those of Pb-（Zn） deposits （-3.82 ‰ to -0.05 ‰） and both indicate a much greater contribution from magma. （2） The Habo alkaline intrusion has relatively homogeneous Pb isotopic compositions with ^206pb/^204pb ranging from 18.608 to 18.761, ^207pb/^204pb from 15.572 to 15.722 and ^20spb/^204pb from 38.599 to 39.110. These Pb isotope ratios are similar to those of Au deposits, whose ^206pb/^204pb range from 18.564 to 18.734, ^20Tpb/^20apb from 15.582 to 15.738 and ^208pb/^204pb from 38.592 to 39.319. Pb ratios in both the intrusion and Au deposits suggest that Pb mainly derived from the depth, probably represents a mixture of mantle and crust. Pb-（Zn） deposits, however, show a decentralized trait, and most of them are similar to that of the alkaline intrusion with ^206pb/^204pb ranging from 18.523 to 18.648, ^207pb/^204pb from 15.599 to 15.802, and ^20spb/^204pb from 38.659 to 39.206. （3） In the plumbotectonic diagram ^20Tpb/^204pb versus ^206pb/^204pb, almost all of Au and Pb-（Zn） deposits have the same projection area with the Habo alkaline intrusion, which indicates that those deposits almost share the same source with the alkaline intrusion. （4） Isotopic age of the Habo alkaline intrusion is 36-33 Ma, which is similar to that of Beiya, whose ore- related alkaline porphyries age is 38-31 Ma and molybdenite Re-Os age is 36.9 Ma. Therefore, along with S-Pb isotope traits, we suggest that the Habo Au and Pb-（Zn） deposits should be typically Ailaoshan-Red RiverCenozoicalkaline-related deposits and ore-forming ages of these deposits should be later than that of the Habo alkaline intrusion.

Effects of arbuscular mycorrhizal fungi on zinc uptake,translocation and accumulation in winter wheat during whole plant growth stages

Although arbuscular mycorrhizal fungi(AMF)could play important roles in zinc(Zn)uptake in host plants,the effects of AMF on Zn uptake and transport in winter wheat during the whole growth stages remain unclear.A pot experiment was conducted to investigate the effects of Funneliformis mosseae(Fm)and Claroideoglomus etunicatum(Ce)on Zn absorption,transport,and accumulation in winter wheat growing in soils spiked with different Zn levels(0,2.5,and 25 mg kg^(-1)).The results showed that there was a significant correlation between mycorrhizal colonization rate and Zn absorption efficiency in winter wheat roots during the post-anthesis period,but there was no significant correlation during the pre-anthesis period.Arbuscular mycorrhizal fungi significantly increased Zn concentrations(0.56–1.58 times)in wheat grains under 0 mg kg^(-1)Zn level,but decreased Zn concentrations in wheat grains under 25 mg kg^(-1)Zn level.Additionally,at the filling and maturity stages,AMF increased Zn absorption rate and the contribution of root Zn uptake to grain Zn by 3–14 and 0.36–0.64 times,respectively,under 0 mg kg^(-1)Zn level and 0.21–1.02 and 0.27–0.37 times,respectively,under 2.5 mg kg^(-1)Zn level.However,AMF decreased root Zn absorption rate(0.32–0.61 times)and increased the contribution of Zn remobilization in vegetative tissues to grain Zn(1.69–2.01 times)under 25 mg kg^(-1)Zn level.This study would complement the mechanisms and effects of AMF on Zn absorption and transport in winter wheat and provide a potential method for the application of AMF to enrich wheat grain Zn.

Efficiency of soil-applied ^(67)Zn-enriched fertiliser across three consecutive crops

A very small amount of applied zinc(Zn) is taken up by crops, resulting in low recovery by plants. Adding elemental sulphur to zinc oxide(ZnO) fertiliser could improve Zn solubilisation and exert a higher residual effect on crops than soluble Zn sources. We produced an isotopically labelled Zn-elemental sulphur fertiliser and evaluated its performance in comparison to traditional Zn sources during sequential crop cultivation. Three ^(67)Zn-labelled fertilisers,ZnO, zinc sulphate(ZnSO_(4)), and ZnO co-granulated with elemental sulphur(ZnOS^(0)), were soil applied, and their contributions to the uptake of Zn by three consecutive crops, wheat, ryegrass, and corn, were assessed in a 294-d pot experiment. The contributions of Zn fertilisers followed the order: ZnSO_(4) > ZnO= ZnOS^(0). The relative contributions of Zn fertilisers were lower in the first crop than in the subsequent crops. The overall recovery of applied Zn by the three crops was higher for ZnSO_(4) than for ZnO and ZnOS^(0), reaching 1.56%, 0.45%, and 0.33% of the applied Zn, respectively. Zinc recovery by plants was very low, regardless of the source of Zn. Adding elemental sulphur to ZnO did not increase its effectiveness up to 294 d after application. Fertiliser contribution was higher for the subsequent crops than for the initial crop, indicating the importance of assessing the residual effects of Zn fertilisers.

Effect of Zn binding to phytate and humic substances on its uptake by wheat(Triticum durum L.)as affected by carbonates and Fe oxides

Although complexation with soil organic matter may improve zinc(Zn)bioavailability to plants,the effect of Zn sorbent surface on the use of complexed Zn by plants remains unknown.The objective of this research was to elucidate how Zn complexation with humic substances(HS)and phytate affects the uptake of Zn by wheat plants depending on the main sorbent surface in growth media,i.e.,carbonates and Fe oxides.To this end,two pot experiments were performed,one using Fe oxide-coated siliceous as the siliceous growth medium sand and the other using a mixture of calcareous sand and siliceous sand as the calcareous growth medium.Each experiment involved three Zn sources,Zn-HS complex,Zn phytate,and ZnSO_(4).All sources were applied with surface irrigation at two Zn rates(0.25 and 2 mg kg^(-1) growth medium).The Zn-HS complex significantly increased Zn uptake by plants in both media,relative to the other two Zn sources,but no significant difference was observed between Zn phytate and ZnSO_(4).In the calcareous medium,Zn-HS complex and Zn phytate resulted in significantly higher dry biomass yields of wheat than ZnSO_(4).In the siliceous medium,spike and shoot dry biomass yields with Zn-HS complex at the low rate and Zn phytate at both rates were not significantly different from those with ZnSO_(4) at the high rate.After harvest,approximately 50%of the Zn applied as Zn-HS complex remained extractable by diethylenetriaminepentaacetic acid(DTPA),while this proportion was less than 20%for the other Zn sources.Thus,Zn-HS complex and Zn phytate are sources of available Zn for plants,and they are more effective than ZnSO_(4) in increasing plant growth,particularly when carbonates are the main Zn sorbent surface.