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作 者 ：马红媛,梁正伟*,孔祥军,闫超,陈渊

期 刊 ：生态学报 2008年 28卷 10期 页码：4710~4717

关键词：羊草；NaCl；温度；发芽率；幼苗；

Keywords:Leymus chinensis, NaCl, temperature, germination percentage, seedling,

摘 要 ：羊草是多年生优质牧草，也是中国松嫩平原的优势建群植物。研究了羊草种子在8种浓度(0、50、100、150、200、300、400和500 mmol/L) NaCl胁迫及将胁迫解除后在3种变温(16/28℃、5/28℃和5/35℃)条件下的发芽率以及幼苗的生长变化。双因素方差分析表明，NaCl胁迫解除前后盐浓度、温度及其互作均极显著影响羊草种子萌发和幼苗生长。胁迫解除前，在3种温度下，羊草种子发芽率最高出现在没有盐胁迫的条件下，随着NaCl浓度的增加，发芽率呈下降趋势。5/28℃下，NaCl溶液对种子萌发抑制最小，浓度达到200 mmol/L时，仍有25.3%的种子萌发；在5/35℃下，对种子萌发抑制作用最大，浓度超过100 mmol/L时，种子萌发被完全抑制；16/28℃的处理介于二者之间。胁迫解除后，羊草种子在3种温度下发芽趋势不同。16/28℃下表现为NaCl浓度较大的处理发芽率较高，5/28℃下则呈先上升(0~150 mmol/L)后基本保持不变趋势；5/35℃下则呈先上升后下降趋势。盐胁迫下，羊草幼苗在16/28℃变温下生长最好，其次为5/28℃，5/35℃生长最差。盐胁迫解除后，16/28℃和5/28℃下，0~100 mmol/L NaCl处理的幼苗根长和苗长随浓度增加而显著上升，大于此浓度变化较小；在5/35℃下，100 mmol/L NaCl处理的幼苗根长和苗长最大，而浓度大于100mmol/L时,则随着NaCl浓度增加呈下降趋势。

Abstract:Leymus chinensis (Trin.) Tzvel. (Poaceae) is a perennial, high quality grass and is the dominant species in Songnen plain, China. Seed germination and seedling growth of Leymus chinensis were investigated under eight levels of salinity stress (0, 50, 100, 150, 200, 300, 400, 500 mmol/L NaCl) and three temperature regimes (16/28℃, 5/28℃, and 5/35℃) and then after the salinity stress was removed. The results of a two-way ANOVA showed that salinity (including when the salinity stress was removed), temperature and their interaction significantly affected the seed germination and seedling growth of L. chinensis. The highest germination percentage was obtained under non-saline conditions, and with an increase of NaCl concentration, germination significantly decreased. Seed germination at the moderate temperature regime of 5/28℃ was optimal, with 25.3% of seeds germinating in 200 mmol/L NaCl. The salinity inhibition for seed germination was greatest at 5/35℃ when no seeds germinated above a concentration of 100 mmol/L NaCl while the salinity inhibition was lightest at 5/28℃. After 18 days, seeds were transferred from salt solutions to distilled water and those from high salinities (≥150 mmol/L), the seed germination recovered most quickly at 5/28℃, and slowest at 5/35℃. At 16/28℃, germination percentage increased with the pre-treatment NaCl concentration. At 5/28℃, germination increased between 0 to 150 mmol/L and then changed little when NaCl was more than 150 mmol/L. However, seed germination percentage increased from 0 to 100 mmol/L and then decreased from 100 to 500 mmol/L. Seedling growth was also significantly inhibited by salinities. Under NaCl stress, seedlings grew best at 16/28℃, moderately well at 5/28℃ and seedling growth was significantly inhibited at 5/35℃. Seedlings which germinated after being transferred to distilled water showed different growth patterns with different pre-treatment salinity and temperature regimes. At 16/28℃ and 5/28℃, root and shoot length increased with a pre-treatment NaCl concentration of 0-100 mmol/L but changed little when it was more than 100 mmol/L. At 5/35℃, the maximum values of shoot and root length occurred at 100 mmol/L NaCl, and then decreased when the concentration was over 100 mmol/L.

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