摘要
摘要:耐盐能力评价是小麦引种、筛选和育种的研究基础。为利用离子流检测技术快速筛选耐盐小麦品种提供依据，本文以普通小麦耐盐品种‘德抗961’和‘薛早’、中度耐盐材料3D232、盐敏感品种‘辽春10号’和‘京411’为试验材料，利用动态离子流检测技术对250 mmol·L^-1 NaCl胁迫下小麦苗期根部对K⁺、Na⁺、Cl^-的吸收情况进行检测，并对小麦生长性状及离子浓度变化进行测定，以确立离子吸收与小麦耐盐性的关系。研究结果表明：1）与无盐胁迫（CK）相比，250 mmol·L^-1 NaCl胁迫24 h后，盐敏感小麦品种‘辽春10’和‘京411’的K⁺由内流转变为外流，中等耐盐材料3D232表现出K⁺外流速度减少，耐盐品种‘德抗961’和‘薛早’则表现出维持K⁺的内流或K⁺外流变为内流；Na⁺均表现为胁迫后外排速度增大，速度值区间由13.86~46.88 pmol·cm^-2·s^-1变为61~150 pmol·cm^-2·s^-1；相较Na⁺，Cl^-外排速度升高幅度较大，其中‘辽春10号’外排量变化最大，外排速度是胁迫前的10倍，Na⁺、Cl^-外排速度变化与品种耐盐性无明显相关性。2）高盐胁迫下，盐敏感小麦的根苗比降低，耐盐小麦根苗比升高；盐敏感小麦品种鲜重较CK显著下降，耐盐小麦品种变化不显著。3）盐胁迫条件下，耐盐及中等耐盐小麦品种，根部及地上部K⁺含量较CK分别增加57%~88%和18%~112%，盐敏感小麦则分别降低40%~44%和24%~42%；耐盐小麦地上部Na⁺增加倍数小于盐敏感材料，将更多的Na⁺阻隔在根部，表现出了较好的区隔Na⁺能力。4）盐胁迫后K⁺流速与耐盐性评价指标根冠比变化量、鲜重变化率均呈高度的相关，其拟合度分别为0.972和0.832。250 mmol·L^-1 NaCl胁迫24 h后小麦根部成熟区K⁺流速可以作为小麦耐盐性筛选的重要生物标记。
关键词:小麦/
盐胁迫/
离子流/
耐盐性/
动态离子流检测/
非损伤微测技术
Abstract:Salt tolerance evaluation is the basis of wheat introduction, screening, and breeding. Salt stress damages plants mainly through osmotic stress, ion toxicity, and other processes. In this study, salt-sensitive varieties 'Liaochun10' and 'Jing411', moderately salt-tolerant breeding material 3D232, and highly salt-tolerant varieties 'DK961' and 'Xuezao' of common wheat were used to analyze ion absorption, growth, and ion concentrations in seedlings under salt concentrations of 0 mmol·L^-1 (CK) and 250 mmol·L^-1 sodium chloride (NaCl). The ion flux and direction of potassium (K⁺), sodium (Na⁺), and chlorine (Cl^-) around the roots of five wheat lines with different salt tolerances were measured by applying dynamic ion detection techniques. The relationship between ion flux and wheat salt tolerance was established by studying the mechanism of wheat salt tolerance, which provided a scientific basis for the rapid selection of salt-tolerant varieties using dynamic ion detection technology. The main results were: 1) the detection of dynamic flux demonstrated that the circulation of K⁺ changed from influx to efflux in the salt-sensitive wheat varieties ('Liaochun10' and 'Jing411') under salt treatment, whereas in the medium salt-tolerant variety (3D232), the efflux of K⁺ decreased. For the salt-resistant varieties, K⁺ efflux changed to influx ('Xuezao') or maintained K⁺ influx ('DK961'). Na⁺ efflux increased after stress, and the velocity range changed from 23-47 pmol·cm^-2·s^-1 to 61-150 pmol·cm^-2·s^-1. Compared with Na⁺, the Cl^- efflux increased, and 'Liaochun10' showed the largest change; the efflux was 10 times higher than that under CK. Na⁺ and Cl^- efflux were not significantly correlated with salt tolerance. 2) Under salt stress, the root-seedling ratio of salt-sensitive wheat decreased, whereas that of salt-tolerant and mid-salt-tolerant wheat increased. The fresh weight of salt-sensitive wheat decreased significantly compared to CK, but the changes in salt-tolerant and mid-salt-tolerant wheat were not significant. 3) After salt stress, the content of K⁺ in the roots and shoots of salt-tolerant and mid-salt-tolerant wheat increased by 57%-88% and 18%-112%, respectively, whereas in salt-sensitive wheat, it decreased by 40%-44% and 24%-42%, respectively. However, the Na⁺ increase in the shoots of salt-tolerant wheat was less than that of salt-sensitive wheat, and more Na⁺ was blocked in the roots. Salt-tolerant wheat was better able to separate Na⁺. 4) Under salt stress, the K⁺ flux was highly correlated with changes in the root-seedling ratio and the rate change of fresh weight, with correlation coefficients of 0.972 and 0.832, respectively. In conclusion, under high salt environments, salt-tolerant lines have a stronger ability to protect K⁺, but K⁺ can also be protected by regional Na⁺ application and salt rejection mechanisms to enhance salt tolerance. The results of this study showed that K⁺ flux in the mature zone of wheat roots can be used as a biomarker for wheat salt tolerance screening after 24 h of 250 mmol·L^-1 NaCl stress.
Key words:Wheat/
Salt stress/
Ion flux/
Salt tolerance/
Dynamic ion detection/
Non-invasive micro-test technique (NMT)



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