Zhang Minghui, Ma Changming, Qiao Shenqi, Li Hongjiao, Zhao Wenhao, Liu Bingxiang
Department of Forest Cultivation, College of Forest, Hebei Agricultural University, Baoding, 071000, China.
Hebei Urban Forest Health Technology Innovation Center, Baoding, 071000, China.
BMC Plant Biol. 2025 Feb 20;25(1):231. doi: 10.1186/s12870-025-06252-z.
Investigating the responses of Salix matsudana to homogeneous and heterogeneous salt concentrations is crucial for the development and optimal use of saline-alkali lands. This study utilized a split-root experiment, positioning the roots of Salix matsudana in both low-salinity and high-salinity areas. Using a salt-free treatment (0/0) as a control, we applied two homogeneous salt treatments (171/171, 342/342 mmol L NaCl) and two heterogeneous salt treatments (0/342, 171/513 mmol L NaCl) to assess growth characteristics, photosynthesis, ion distribution, root vigor, and water uptake under salt stress.
The results showed that leaf biomass under heterogeneous salt treatments (0/342 and 171/513 mmol L NaCl) was 1.2 and 1.7 times greater, respectively, than under homogeneous treatments (171/171 and 342/342 mmol L NaCl). Root biomass in the low-salinity areas of the heterogeneous treatments was 2.1 and 1.3 times higher than in the high-salinity areas, with water uptake 1.6 and 1.5 times greater. This improvement was attributed to significantly enhanced root vigor in the low-salinity areas, which promoted water uptake and mitigated the inhibitory effects of salt concentration on aboveground growth and stomatal limitation. Consequently, this resulted in higher net photosynthesis rates, elevated levels of K, Ca, and Mg, and reduced Na content in the leaves. Moreover, micro-area X-ray fluorescence imaging revealed that, under salt stress, Na was uniformly distributed across the leaves, while K accumulated in the main veins and, under heterogeneous salt stress, was translocated downward and redistributed to the roots in the low-salinity areas, further promoting ion balance. Compensatory growth occurred in the roots of the low-salinity areas, supporting normal plant growth.
Compared to homogeneous salt stress, heterogeneous salt stress significantly alleviated the growth and physiological damage in Salix matsudana. Reducing salt concentrations in localized areas of saline-alkali soils may help mitigate the detrimental effects of salt stress, offering a theoretical basis for adaptive cultivation in saline-alkali regions.
研究旱柳对均匀和非均匀盐浓度的响应对于盐碱地的开发和优化利用至关重要。本研究采用分根实验，将旱柳的根系置于低盐度和高盐度区域。以无盐处理（0/0）作为对照，我们施加了两种均匀盐处理（171/171、342/342 mmol L NaCl）和两种非均匀盐处理（0/342、171/513 mmol L NaCl），以评估盐胁迫下的生长特征、光合作用、离子分布、根系活力和水分吸收。
结果表明，非均匀盐处理（0/342和171/513 mmol L NaCl）下的叶片生物量分别比均匀处理（171/171和342/342 mmol L NaCl）下高1.2倍和1.7倍。非均匀处理低盐度区域的根系生物量比高盐度区域高2.1倍和1.3倍，水分吸收高1.6倍和1.5倍。这种改善归因于低盐度区域根系活力的显著增强，这促进了水分吸收并减轻了盐浓度对地上部生长和气孔限制的抑制作用。因此，这导致了更高的净光合速率、叶片中K、Ca和Mg含量的升高以及Na含量的降低。此外，微区X射线荧光成像显示，在盐胁迫下，Na在叶片中均匀分布，而K在主脉中积累，并且在非均匀盐胁迫下向下转运并重新分布到低盐度区域的根系中，进一步促进了离子平衡。低盐度区域的根系发生了补偿性生长，支持了植物的正常生长。
与均匀盐胁迫相比，非均匀盐胁迫显著减轻了旱柳的生长和生理损伤。降低盐碱土局部区域的盐浓度可能有助于减轻盐胁迫的有害影响，为盐碱地区的适应性栽培提供了理论依据。
