氮浓度对盐胁迫下嫁接西瓜幼苗离子累积与平衡的影响

孙晶晶; 李雪芳; 王西娜; 李惠霞; 尚倩; 唐祉怡; 谭军利

文章摘要

氮浓度对盐胁迫下嫁接西瓜幼苗离子累积与平衡的影响

Effects of nitrogen concentration on ion accumulation and balance in grafted watermelon seedlings under salt stress

Received:April 28, 2025

DOI：10.13254/j.jare.2025.0379

中文关键词: 盐胁迫，氮浓度，西瓜幼苗，离子累积量，离子平衡

英文关键词: salt stress, nitrogen concentration, watermelon seedling, ion accumulation, ion balance

基金项目:宁夏自然科学基金项目（2024AAC03128）；宁夏高等学校科学研究项目（NYC-2024-012）；国家自然科学基金项目（52369010，31860590）

Author Name	Affiliation	E-mail
Sun Jingjing	School of Agriculture, Ningxia University, Yinchuan 750021, China
Li Xuefang	School of Agriculture, Ningxia University, Yinchuan 750021, China
Wang Xina	School of Agriculture, Ningxia University, Yinchuan 750021, China	eunicexina-w@163.com
Li Huixia	School of Agriculture, Ningxia University, Yinchuan 750021, China
Shang Qian	School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China
Tang Zhiyi	School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China
Tan Junli	School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China

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中文摘要:

为探究不同氮素用量对西瓜盐胁迫的调控机制，本试验以嫁接西瓜幼苗为试验材料，以霍格兰营养液为基础，采用基质培养方法，在轻度（3.0 g·L^-1）、中度（4.0 g·L^-1）、重度（4.5 g·L^-1）三种盐浓度下设置0、5、10、15、20 mmol·L^-1 5个氮浓度处理，研究盐胁迫下氮浓度对西瓜幼苗生物量及根、茎、叶中Na⁺、K⁺、Ca²⁺、Mg²⁺、Cl^-、NO₃^-累积量变化及离子平衡的影响，以期揭示氮素缓解盐胁迫的机理。结果表明：盐胁迫抑制西瓜生长，使幼苗生物量减少。轻度、中度、重度三种盐胁迫下，西瓜幼苗整株干质量以氮浓度10 mmol·L^-1处理的最高，分别较不施氮处理显著增加11.88%、14.26%、25.00%。同时，随着盐胁迫浓度的增加，西瓜幼苗根、茎、叶中Na⁺、Cl^-累积量增加，而K⁺、Ca²⁺、Mg²⁺、NO₃^-累积量减少。与不施氮相比，三种盐胁迫下西瓜幼苗根、茎、叶Cl^-和NO₃^-累积量均在20 mmol·L^-1氮浓度处理下显著变化，Cl^-降幅分别为26.88%~42.42%、16.29%~20.12%、13.34%~15.87%；NO₃^-累积量显著增加68.03%~211.42%、121.49%~222.02%、121.06%~283.60%；Na⁺累积量在10 mmol · L^-1氮处理下降幅最为显著，分别为4.55%~30.73%、6.32~14.18%、10.47%~18.57%；K⁺、Ca²⁺、Mg²⁺累积量在15 mmol·L^-1氮浓度下显著增加，其中根系中的增幅分别为39.91%~84.63%、21.08%~63.17%、28.14%~55.42%，茎中分别为40.93%~75.83%、35.85%~54.15%、28.60%~60.81%，叶片分别为69.09%~108.61%、45.85%~111.14%、35.40%~119.62%。从离子平衡来看，3.0、4.0、4.5 g·L^-1三种盐胁迫下，K⁺/Na⁺、Ca²⁺/Na⁺和Mg²⁺/Na⁺值均随盐胁迫浓度的增加而降低，Cl^-/NO₃^-值随盐胁迫浓度的增加而增加。与不施氮处理相比，3.0 g·L^-1盐胁迫下根、茎、叶的K⁺/Na⁺、Ca²⁺/Na⁺和Mg²⁺/Na⁺值在15 mmol·L^-1氮处理时分别显著增加69.71%~138.81%、46.86%~110.50%和52.23%~100.53%；4.0 g·L^-1胁迫下显著增加57.13%~86.38%、51.16%~66.72%和43.10%~70.65%；4.5 g·L^-1盐胁迫下增加了94.90%~118.05%、57.93%~120.67%和48.23%~129.58%；而Cl^-/NO₃^-值在20 mmol·L^-1氮处理时显著减少75.57%~84.97%、50.34%~63.91%、69.79%~74.27%。相关性分析及PCA结果显示，幼苗干质量与西瓜幼苗离子累积量具有一定的相关性，Ca²⁺和Na⁺在第一主成分（PC1）上具有较高载荷，Cl^-和NO₃^-在第二主成分（PC2）上承载了主要信息，两者累计方差贡献率为94.2%。可见，盐胁迫下适宜的氮素浓度可调节西瓜幼苗体内养分离子和盐分离子之间的平衡，促进营养吸收，维持植株的正常生长。综合各指标来说，本试验轻度、中度、重度盐胁迫下西瓜幼苗生长的适宜氮浓度分别为10.69~11.86、10.70~12.92 mmol·L^-1和11.41~12.50 mmol·L^-1。

英文摘要:

To investigate the regulatory mechanisms of different nitrogen levels on watermelon under salt stress, this experiment utilized grafted watermelon seedlings as experimental materials. Employing a substrate culture method with Hoagland ′ s nutrient solution as the base, five nitrogen concentration treatments（0, 5, 10, 15, and 20 mmol·L^-1）were established under three salinity levels：mild（3.0 g·L^-1）, moderate（4.0 g·L^-1）, and severe（4.5 g·L^-1）. The study aimed to examine the effects of nitrogen concentration on seedling biomass and the accumulation dynamics of Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^-, and NO₃^- in roots, stems, and leaves under salt stress, as well as their impact on ion homeostasis, thereby elucidating the mechanism by which nitrogen alleviates salt stress. The results showed that salt stress inhibited watermelon growth and reduced seedling biomass. Under mild, moderate, and severe salt stress conditions, the highest dry mass of whole watermelon seedlings was observed under trentment with a nitrogen concentration of 10 mmol·L^-1, increasing significantly by 11.88%, 14.26% and 25.00%, respectively, compared with the nitrogen-free treatment. Additionally, as salt stress increased, the accumulation of Na⁺ and Cl^- in roots, stems, and leaves increased, while K⁺, Ca²⁺, Mg²⁺, and NO₃^- accumulation decreased. Compared with the nitrogen-free treatment, under all three salt stress levels, the Cl^- accumulation in roots, stems, and leaves significantly decreased at 20 mmol·L^-1 nitrogen, with reductions of 26.88%-42.42%, 16.29%-20.12% and 13.34%-15.87%, respectively while NO₃^- accumulation significantly increased by 68.03%-211.42%, 121.49%-222.02%, and 121.06%-283.60%, respectively. Na⁺ accumulation decreased most significantly at 10 mmol·L^-1 nitrogen, with reductions of 4.55%-30.73%, 6.32-14.18% and 10.47%-18.57%, respectively but K⁺, Ca²⁺, and Mg²⁺ accumulation increased significantly at 15 mmol·L^-1 nitrogen concentration, among which the increase in root were 39.91%-84.63%, 21.08%-63.17%, 28.14%-55.42%, in stem were 40.93%-75.83%, 35.85%-54.15%, 28.60%-60.81%, and in leaf were 69.09%-108.61%, 45.85%-111.14%, 35.40%-119.62%. From the perspective of ion balance, under 3.0, 4.0, and 4.5 g·L^-1 salt stress, the K⁺/Na⁺, Ca²⁺/Na⁺, and Mg²⁺/Na⁺ ratios decreased with increasing salt stress, while the Cl^-/NO₃^- ratio increased. Compared with the nitrogen-free treatment, under 3.0 g·L^-1 stress, the K⁺/Na⁺, Ca²⁺/Na⁺, and Mg²⁺/Na⁺ ratios in roots, stems, and leaves significantly increased by 69.71%- 138.81%, 46.86%-110.50%, and 52.23%-100.53%, respectively, at 15 mmol·L^-1 nitrogen. Under 4.0 g·L^-1 stress, they increased by 57.13%-86.38%, 51.16%-66.72%, and 43.10%-70.65%, respectively, and under 4.5 g·L^-1 stress, by 94.90%-118.05%, 57.93%-120.67%, and 48.23%-129.58%, respectively. Meanwhile, the Cl^-/NO-3 ratio significantly decreased by 75.57%-84.97%, 50.34%-63.91%, and 69.79%-74.27% at 20 mmol·L^-1 nitrogen. The results of correlation analysis and PCA revealed a certain correlation between seedling dry mass and ion accumulation in watermelon seedlings. Ca²⁺ and Na⁺ exhibited high loadings on the first principal component（PC1）, while Cl^- and NO₃^- carried primary information on the second principal component（PC2）. The cumulative variance contribution rate of these two components reached 94.2%. Appropriate nitrogen concentrations under salt stress may regulate the balance between nutrient ions and salt ions in watermelon seedlings, promoting nutrient absorption and maintaining normal plant growth. In this experiment, the optimal nitrogen concentrations for watermelon seedling growth under mild, moderate, and severe salt stress are 10.69-11.86 mmol·L^-1, 10.70-12.92 mmol·L^-1, and 11.41-12.50 mmol·L^-1, respectively.

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