EEB：廣東農科院丨提升銨營養有助于抑制水稻鎘積累?

期刊：Environmental and Experimental Botany（EEB）

主題：提升銨營養有助于抑制水稻鎘積累

標題：Increasing ammonium nutrition as a strategy for inhibition of cadmium uptake and xylem transport in rice (Oryza sativa L.) exposed to cadmium stress

影響因子：3.666

檢測指標：Cd2+流速

檢測部位：距根尖700μm

作者：廣東農科院王旭、王富華、吳志超

英文摘要

Nitrogen (N) speciation could in?uence the e?ciency of Cd accumulation by plants grown in Cd-contaminated areas. However, limited information has been reported on how the application of N speciation to rice a?ects the Cd accumulation. Here, we investigated the physiological and genetic mechanisms involved in Cd uptake by roots, xylem translocation and subsequent Cd accumulation in rice (Oryza sativa L.) a?ected by di?erent NO3?/ NH4+ ratios under low-and-high Cd stress.
 
Results showed that both N speciation and Cd stress a?ected plant growth, with high NH4+-N ratios treatments having higher tissue biomass, and high Cd treatment reducing tissue biomass. The Cd concentrations in shoots and roots were reduced with the increasing NH4+-N ratios (except for the full NO3?-N treatment), but did not a?ect the Cd translocation factor (TF). The total Cd accumulation of the whole plant were also reduced with the high NH4+-N ratios (NO3?/NH4+, 1:2 and 0:1) on the low Cd treatment due to the decline both in the Cd accumulation of shoots and roots.
 
A Non-invasive Micro-test Technology (NMT) showed that the net Cd2+ in?uxes at the root hair zone were inhibited with the increasing NH4+-N ratios in absence or pretreatment with di?erent NO3?/NH4+ ratios. Additionally, the Cd concentrations in xylem sap were also displayed a decline trend with the increasing NH4+-N ratios under two dose Cd treatments.Furthermore, the gene expression related to Cd uptake (OsIRT1 and OsNRAPM5) and transport (OsHMA2) in roots showed the familiar tendencies with those of Cd uptake and transport at the physiological level treated with di?erent NO3?/NH4+ ratios under two dose Cd treatments.

It is concluded that increasing ammonium nutrition contributes to the inhibition of Cd uptake, xylem transport and subsequent accumulation in rice.

中文摘要（谷歌機翻）

氮（N）物種形成可能影響鎘污染地區生長的植物對Cd積累的影響。然而，關于如何將N形態應用于水稻以影響Cd積累的報道有限。在這里，我們研究了在低和高Cd脅迫下由不同NO3-/NH4+比例影響的水稻（Oryza sativa L.）根系吸收Cd，木質部易位和隨后Cd積累所涉及的生理和遺傳機制。
 
結果表明，N形態和Cd脅迫均影響植物生長，高NH4+-N比處理具有較高的組織生物量，高Cd處理降低組織生物量。隨著NH4+-N比值的增加，芽和根中的Cd濃度降低（除了完全的NO3-N處理），但不影響Cd轉運因子（TF）。由于芽和根中Cd積累量的下降，低Cd處理的NH4+-N比值（NO3-/NH4+，1：2和0：1）也降低了整株植物的總Cd積累量。
 
非損傷微測技術（NMT）顯示，在不存在或預處理不同的NO3-/NH4+比率時，NH4+ -N比率增加時，根毛區的流體中的凈Cd2+受到抑制。此外，在兩劑Cd處理下，隨著NH4+-N比值的增加，木質部汁液中的Cd濃度也呈下降趨勢。此外，與Cd吸收（OsIRT1和OsNRAPM5）和轉運（OsHMA2）相關的基因表達顯示了在兩種劑量Cd處理下用不同的NO3-/NH4+比率處理的生理水平的Cd攝取和轉運的熟悉趨勢。
 
結論是，增加銨營養有助于抑制水稻的Cd吸收，木質部運輸和隨后的積累。

Fig. 1. E?ect of di?erent NO3-/NH4+ ratios (A and B) or pretreatment with di?erent ratios of NO3-/NH4+ (C and D) on net Cd2+ in?ux at root hair zone by Non-invasive Micro-test Technology(NMT). Each point represents the mean values of Cd2+ in?ux of six roots from six individual plants during the time of 6th-10th minutes. Bars with di?erent letters mean signi?cantly statistical di?erences followed by one-way ANOVA analysis (LSD test, P < 0.05, n=6). 'preCK' indicates 'pretreatment of the rice seedlings with NO3-/NH4+ (1:1)'.

文章鏈接：

https://www.sciencedirect.com/science/article/abs/pii/S0098847218307871?via%3Dihub