State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
Environ Pollut. 2021 Jul 15;281:116993. doi: 10.1016/j.envpol.2021.116993. Epub 2021 Mar 23.
To explore the relationship between Al phytotoxicity and the electrochemical characteristics of wheat root surfaces, a new chemical mechanism for tolerance of wheat to Al toxicity was initially proposed by conducting acute root elongation experiment, adsorption/desorption experiment, streaming potential determination, and infrared spectroscopy (ATR-FTIR) analysis respectively to classify the grade of Al tolerance of 92 wheat cultivars and quantitatively characterize the electrochemical properties of their root surfaces. Then a pot experiment was conducted with the screened wheat cultivars with different Al resistance grown on acid soils to verify their tolerance to Al toxicity. Results show that zeta potentials of the roots of 67 wheat cultivars at pH4.46 were significantly negatively correlated with Al(Ⅲ) adsorbed on the roots and their relative root elongation (P < 0.05), indicating that wheat roots with less negative charges is more tolerant to Al toxicity. Based on the mechanism, 14 Al-tolerant, 23 medium Al-tolerant and 30 Al-sensitive wheat cultivars were classified. The pot experiment reveals that the relative dry weight of Al-tolerant wheat cultivars was generally greater than that of medium Al-tolerant and Al-sensitive wheat cultivars and Al-tolerant wheat cultivars accumulate less Al in their shoots, which further verifies the relationship among charge characteristics, tolerance of wheat to Al toxicity, and Al uptake by wheat. The negative charges derived from organic functional groups on root surfaces could influence the exchangeable and complexed Al(Ⅲ) adsorbed on wheat roots and thereby affect Al tolerance of wheat cultivars. This finding not only provides a new perspective to screen Al-tolerant wheat cultivars and explain the mechanism of tolerance of wheat to Al toxicity, but is also useful for the prediction of differences in the uptake of Al in the shoots between Al-tolerant and Al-sensitive wheat cultivars, and finally contributes to the prevention of food security risk caused by Al in acid soils.
为了探究铝的植物毒性与小麦根表面电化学特性之间的关系，本研究通过急性根伸长实验、吸附/解吸实验、流动电势测定和傅里叶变换衰减全反射红外光谱（ATR-FTIR）分析，分别对 92 个小麦品种的耐铝性进行分级，并定量描述其根表面的电化学特性，从而初步提出了小麦耐铝性的一种新的化学机制。然后，在酸性土壤上用筛选出的具有不同耐铝性的小麦品种进行盆栽实验，以验证其对铝毒性的耐受性。结果表明，在 pH4.46 时，67 个小麦品种的根zeta 电位与根吸附的 Al(Ⅲ)和相对根伸长显著负相关（P<0.05），表明带较少负电荷的小麦根更耐铝毒性。基于这一机制，将 14 个耐铝、23 个中耐铝和 30 个敏感的小麦品种进行了分类。盆栽实验表明，耐铝小麦品种的相对干重一般大于中耐铝和敏感小麦品种，耐铝小麦品种在地上部积累的铝较少，这进一步验证了电荷特性、小麦对铝毒性的耐受性和小麦对铝的吸收之间的关系。根表面有机官能团产生的负电荷可能会影响小麦根上吸附的可交换和络合的 Al(Ⅲ)，从而影响小麦品种的耐铝性。这一发现不仅为筛选耐铝小麦品种和解释小麦耐铝毒性的机制提供了新的视角，而且有助于预测耐铝和敏感小麦品种在地上部吸收铝的差异，最终有助于防止酸性土壤中铝对食品安全造成的风险。
