Zhong Shangzhi, Hou Pengxin, Zheng Congcong, Yang Xuechen, Tao Qibo, Sun Juan
College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China.
Shandong Key Laboratory for Germplasm Innovation of Saline-Alkaline Tolerant Grasses and Trees, College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China.
Plants (Basel). 2025 Jun 26;14(13):1954. doi: 10.3390/plants14131954.
Salinity stress is a major environmental challenge that adversely impacts the physiological and biochemical processes of pasture, consequently resulting in reduced yields and compromised quality. Biochar amendment has recently emerged as a promising strategy to alleviate the deleterious effects of salinity stress. However, the interactive influences of salinity stress and wheat straw biochar on the physiological, biochemical, and growth characteristics of alfalfa ( L.) remain underexplored. A factorial experiment was conducted using a randomized complete design with five salinity levels (0, 25, 50, 75, and 100 mM NaCl) and three application rates of biochar (0, 25, and 50 g kg) to evaluate wheat straw biochar's potential in alleviating salinity stress in alfalfa. Results showed that salinity stress increased oxidative stress (hydrogen peroxide and malondialdehyde) and reduced chlorophyll fluorescence (maximum quantum efficiency of photosystem II by 1-27%), leading to decreasing photosynthetic parameters, thereby constraining biomass accumulation by 9-77%. Wheat straw biochar amendment under the highest salinity stress, particularly at 25 g kg, mitigated oxidative stress by reducing HO and MDA levels by 35% and 33%, respectively, while decreasing the antioxidant enzymes activities of CAT, POD, and SOD by 47%, 42%, and 39%, respectively, compared to the control (non-biochar addition). Concurrently, biochar restored the osmoregulatory substance concentrations of proline and soluble sugar by 59% and 33%, respectively, compared to the control. Furthermore, wheat straw biochar amendment increased the net CO assimilation rate by 98%, thereby increasing biomass by 63%. Our study demonstrates that wheat straw biochar can contribute to protecting alfalfa against salinity stress by modulating physiological and biochemical responses. These findings demonstrate that the 25 g kg wheat straw biochar application had the best performance, suggesting this amendment could be a viable strategy for improving alfalfa productivity in salt-affected soils. Future research should explore long-term field applications and the underlying mechanisms of biochar-plant-soil-plant interactions under diverse saline-alkali environments.
盐胁迫是一项重大的环境挑战，会对牧草的生理和生化过程产生不利影响，从而导致产量下降和品质受损。生物炭改良最近已成为一种有前景的策略，可减轻盐胁迫的有害影响。然而，盐胁迫和小麦秸秆生物炭对紫花苜蓿生理、生化及生长特性的交互影响仍未得到充分研究。采用随机完全区组设计进行了一项析因试验，设置了五个盐度水平（0、25、50、75和100 mM NaCl）和三个生物炭施用量（0、25和50 g/kg），以评估小麦秸秆生物炭缓解紫花苜蓿盐胁迫的潜力。结果表明，盐胁迫增加了氧化应激（过氧化氢和丙二醛），降低了叶绿素荧光（光系统II的最大量子效率降低了1%-27%），导致光合参数下降，从而使生物量积累减少了9%-77%。在最高盐胁迫下，尤其是25 g/kg的小麦秸秆生物炭改良，通过分别将过氧化氢和丙二醛水平降低35%和33%来减轻氧化应激，同时与对照（不添加生物炭）相比，过氧化氢酶、过氧化物酶和超氧化物歧化酶的抗氧化酶活性分别降低了47%、42%和39%。同时，与对照相比，生物炭分别使脯氨酸和可溶性糖的渗透调节物质浓度恢复了59%和33%。此外，小麦秸秆生物炭改良使净二氧化碳同化率提高了98%，从而使生物量增加了63%。我们的研究表明，小麦秸秆生物炭可通过调节生理和生化反应来帮助保护紫花苜蓿免受盐胁迫。这些结果表明，施用25 g/kg的小麦秸秆生物炭表现最佳，表明这种改良可能是提高盐碱地紫花苜蓿生产力的可行策略。未来的研究应探索生物炭在不同盐碱环境下的长期田间应用以及生物炭-植物-土壤-植物相互作用的潜在机制。
