Abstract:

Effects of NaHCO₃ and Na₂CO₃ on the seed germination and physiological responses of Agropyron cristatu'Tawukumu' were investigated in order to provide a theoretical reference for the promotion and planting of the new varieties by petri-dishes and pot methods. The seeds of Tawukumu were germinated under the NaHCO₃+Na₂CO₃ (9:1) of six levels (0, 10, 30, 60, 90, 120 mM). The results showed that seed germination rate, shoot length, radical length, seed vigor index and chlorophyll content reduced significantly with an increase of alkali stress. Meanwhile, the percentage of cumulative germination was also delayed. However, the content of MDA increased, the contents of soluble sugar, Pro and SOD were increased first and then decreased. Tawukumu had a good tolerance to alkali stress below the level of 30 mM (pH≤9.1), whereas both seed germination and growth of Tawukumu are significantly inhibited at the alkali treatment of 90 mM (pH≥10.1). Therefore, the maximum threshold of alkali concentration is 60 mM (pH≤9.8) that does not affect the seed germination and growth of Tawukumu.

Key words: Agropyron cristatum‘Tawukumu’, Alkali Stress, Seed Germination, Physiology responses

摘要：

以塔乌库姆冰草（Agropyron cristatum‘Tawukumu’）种子为材料，将NaHCO₃和Na₂CO₃碱溶液以9：1混合，设0，10，30，60，90，120mM共6个处理浓度，采用培养皿法及盆栽法分别研究碱胁迫下种子萌发和幼苗的生理表现，为其推广及在盐碱地生产提供依据。结果表明：随着处理液浓度的升高，种子萌发率下降，萌发时间延迟；胚芽长、胚根长、种子活力指数以及叶绿素含量显著下降；丙二醛（MDA）含量上升；可溶性糖、脯氨酸和超氧化物歧化酶（SOD）含量均表现出先升高后降低的趋势。塔乌库姆冰草对碱胁迫具有一定的耐受性，在胁迫浓度≤30mM，即pH≤9.1时，萌发和生长不会受到影响；当胁迫浓度≥90mM，即pH≥10.1时，萌发和生长会受到明显抑制。因此，碱胁迫浓度≤60mM，即pH≤9.8是塔乌库姆冰草能够萌发和生长的最大耐碱性范围。

关键词: 冰草, 碱胁迫, 种子萌发, 生理响应