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南農(nóng)：銅抑制水稻硝酸鹽吸收 | NMT植物氮營養(yǎng)創(chuàng)新科研平臺(tái)
NMT作為生命科學(xué)底層核心技術(shù)，是建立活體創(chuàng)新科研平臺(tái)的*技術(shù)。2005年~2020年，NMT已扎根中國15年。2020年，中國NMT銷往瑞士蘇黎世大學(xué)，正式打開歐洲市場。
研究使用平臺(tái)：NMT植物氮營養(yǎng)創(chuàng)新科研平臺(tái)
期刊：Ecotoxicology and Environmental Safety
主題：銅抑制水稻**鹽吸收
標(biāo)題：Excess copper inhibits the growth of rice seedlings by decreasing uptake of nitrate
影響因子：4.527
檢測指標(biāo)：NO3-流速
檢測樣品：根
NO3-流實(shí)驗(yàn)處理方法：
水稻幼苗在氮環(huán)境中培養(yǎng)7天后，在0.2μmolL-1 CuSO4和10μmolL-1 CuSO4的無氮環(huán)境中處理15天
NO3-流實(shí)驗(yàn)測試液成份：
0.1mM **銨及氯化鈣，pH5.5
作者：南京農(nóng)業(yè)大學(xué)陳晨、霍塏
中文摘要（谷歌機(jī)翻）
銅（Cu）的毒性對(duì)植物的生長具有有害作用，而不同的氮（N）形式對(duì)植物對(duì)重金屬的吸收和積累的影響也大不相同。然而，目前尚不清楚過量的銅如何抑制不同氮素形態(tài)下水稻幼苗的生長。在這里，我們研究了銅毒性抑制不同形式氮素供應(yīng)的水稻生長的機(jī)理。
在0.2μmolL-1 CuSO4或0.2μmolL-1的養(yǎng)分溶液中，水稻幼苗生長在含有0.81 mmol L-1 N的營養(yǎng)液中，如銨鹽（NH4+），**鹽（NO3-）和NH4++ NO3--或無氮（0 N）。10μmolL-1 CuSO4。在供給有NO3-的植物中，在過量的Cu下對(duì)芽生長的抑制作用比NH4 +更為明顯。芽中較高的Cu濃度不會(huì)誘導(dǎo)這種抑制作用。單獨(dú)施用NO3-可使溶液的pH值增加到6.2，但單獨(dú)施用NH4+和NH4++ NO3-可以將溶液的pH值分別降低到4.0和4.2。
溶液pH值的增加降低了單獨(dú)添加NO3-的水稻芽中的Cu濃度。銅的毒性降低了單獨(dú)提供NO3-的水稻幼苗中的NO3-濃度，但增加了提供NH4+或NH4+ + NO3-的植物中NH4+的濃度。通過對(duì)凈NO3-通量和NO3-同化酶活性的分析，高Cu水平降低了根部對(duì)NO3-的吸收。在過量的銅下，OsNPF6.5，OsNPF2.2和OsNPF2.4基因的轉(zhuǎn)錄水平受到抑制，而OsNRT2.1，OsNRT2.2和OsNAR2.1的根部升高。
總之，銅毒性通過調(diào)節(jié)NO3-轉(zhuǎn)運(yùn)蛋白基因的表達(dá)水平來抑制NO3-的吸收和向上移位。當(dāng)?shù)訬O3-的形式供應(yīng)時(shí)，NO3-和總氮濃度的降低會(huì)降低水稻幼苗的莖生長。因此，在銅脅迫下，供應(yīng)有NO3-的水稻幼苗的莖生物量要低于含有NH4 +的水稻。
Effect of Cu on the net NO3− fluxes at the root hair zone of rice. Plants were grown under hydroponic conditions supplied with N as NO3− for 7 days, and then were incubated in s lution without N in the presence of 0.2 μmol L−1 CuSO4 (CK) and10 μmol L−1 CuSO4 (Cu). Photographs of the measuring point (A, B) and the mean fluxes of NO3− within the measu ing period (C) are shown. Data are means of at least 6 replicates.
英文摘要
Copper (Cu) toxicity has a deleterious effect on plant growth, and different nitrogen (N) forms have significantly different impacts on the uptake and accumulation of heavy metals by plants. However, it remains unclear how excess Cu inhibits the growth of rice seedlings under different N forms. Here, we examined the mechanism of Cu toxicity inhibiting the growth of rice supplied with different N forms.
Rice seedlings were grown in a nutrient solution with 0.81 mmol L−1 N, as ammonium (NH4+), nitrate (NO3−) and NH4++ NO3−, or without N (0 N) in the presence of 0.2 μmol L−1 CuSO4 or 10 μmol L−1 CuSO4. The inhibition of shoot growth under excess Cu was more pronounced in plants that were supplied with NO3− than NH4+; such inhibition was not induced by higher Cu concentration in shoots. Applied with NO3− alone increased solution pH value up to 6.2, but supplied with NH4+ alone and NH4++NO3− decreased solution pH value to 4.0 and 4.2, respectively.
The increment of solution pH reduced Cu concentration in shoots of rice supplied with NO3 − alone. Copper toxicity decreased NO3− concentrations in rice seedlings that were supplied with NO3− alone but increased the NH4+ concentrations in plants that were supplied with NH4+ or NH4+ + NO3−. High Cu levels reduced the uptake of NO3− in roots by the analysis of net NO3− flux and NO3− assimilation enzymes activity. Under excess Cu, the transcript levels of OsNPF6.5, OsNPF2.2 and OsNPF2.4 genes were suppressed, while OsNRT2.1, OsNRT2.2 and OsNAR2.1 were raised in roots.
In conclusion, Cu toxicity inhibits NO3− uptake and upward translocation by modulating the expression level of NO3− transporter genes. The reduction in the concentrations of NO3− and total N decreased shoot growth of rice seedlings when N was supplied as NO3−. Hence, rice seedlings supplied with NO3− had lower shoot biomass than those with NH4+ under Cu stress.