夜间增温与农田铜污染对小麦吸持铜的影响

Effects of night warming and soil copper contamination on copper retention in wheat

  • 摘要: 当前部分农业土壤铜(Cu)富集与非对称气候变暖潜在地影响我国小麦生产,理解夜间增温与土壤Cu污染对小麦吸持利用Cu的影响有助于确保小麦的安全优质生产。本研究利用田间被动式夜间增温系统,设置土壤Cu污染与对照对比盆栽试验,研究小麦地上部物质积累、不同组织Cu含量与积累量、Cu迁移系数对增温的响应。结果表明,夜间增温显著增加小麦茎叶(增幅为25.1%)、穗(增幅为221.3%)、地上部(增幅为22.7%)和全株(增幅为22.3%)的生物量,能缓解土壤Cu污染对小麦生长的抑制。夜间增温使对照处理小麦茎叶、穗、地上部与全株的Cu积累量显著增加14.7%~56.5%;使Cu污染下小麦根、穗和全株的Cu积累量显著增加12.1%~22.8%,却使Cu污染下小麦茎叶Cu含量显著降低13.9%。夜间增温和Cu污染胁迫影响Cu在不同小麦组织间的迁移和利用,夜间增温显著增加了对照处理下Cu由根向茎的迁移系数,但由茎向叶、茎向穗的迁移系数显著降低;Cu污染胁迫下,夜间增温显著降低了由根向茎的转运,且未显著影响Cu由茎向叶的转运,却增加了茎向穗的转运利用。Cu污染胁迫改变了小麦吸收利用Cu对夜间增温的响应规律。夜间增温有利于小麦生物产量、缓解Cu胁迫生长危害,但增加了Cu胁迫农田粮食遭受Cu污染的潜在风险。

     

    Abstract: Grain production in China is subject to the stresses of copper (Cu) contamination in agricultural soils and asymmetric climate warming; it is vital to understand the effects of these dual pressures on crop growth and production. Since asymmetric climate warming and soil Cu accumulation potentially affect wheat production in China, it is important to analyze the effects of night warming on the uptake and distribution of Cu in wheat under Cu pollution stress. A pot experiment was conducted during the 2018-2019 wheat growth season on the Experimental Farm of the Henan University of Science and Technology (34°35N, 112°24E), an agricultural area with an annual average temperature of 14.86℃ and annual average precipitation of 600 mm. The experiment had two temperature treatments (a control group and night warming under a passive night warming system) and two levels of Cu pollution (6 mg·kg-1control and 155 mg·kg-1Cu pollution). The Cu-polluted soils in the pots were collected from a Cu single factor contaminated site at the Kaiyuan Campus Farm of Henan University of Science and Technology. The crop responses (vs. Luohan 11) to night warming and Cu contamination with respect to yield, biomass of different aboveground tissues, and content, accumulation, and translocation coefficients of Cu in the aboveground tissues were investigated. The results showed that night warming significantly increased the crop straw, spike, aboveground, and total biomasses by 25.1%, 21.3%, 22.7%, and 22.3%, respectively, and could alleviate the inhibition of Cu pollution on wheat growth. Night warming significantly increased the straw Cu content by 26.3% in the control group, but significantly decreased the straw Cu content by 13.9% in the Cu pollution groups. In the control group, night warming significantly increased Cu accumulation by 14.7%-56.5% in the straw, spike, aboveground, and whole plant. In the Cu pollution groups, night warming increased Cu accumulation by 12.1%-22.8% in the roots, spikes, and whole plant. Night warming and Cu pollution affected the migration and utilization of Cu in different tissues. Night warming significantly increased the Cu translocation coefficient from root to stem and decreased the stem to leaf and stem to spike Cu translocation coefficients in the control. Night warming significantly decreased Cu transport from root to stem, did not affect Cu transport from stem to leaf, and increased Cu transport from stem to spike in the Cu pollution groups. Cu pollution changed the response law of wheat Cu absorption and utilization as it related to night warming. This study illustrated that night warming improved wheat production and alleviated the harmful growth-related effects of Cu stress, however, if increased potential risk of Cu pollution on grain crop quality.

     

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