关键词: 菊芋, 盐碱胁迫, Na⁺, K⁺, 离子分布

Abstract: In order to explore K⁺ and Na⁺ contents of Helianthus tuberosus under different salinity stress, Helianthus tuberosus was planted in three plots classified as light, moderate, and heavy in saline-alkali grasslands. Ion distributions of Helianthus tuberosus in different growing periods were determined. Results showed that Na⁺ contents of whole plants increased significantly, and both K⁺ contents and K⁺/Na⁺ ratio decreased significantly with the degree of soil saline-alkali increasing (P<0.05). The K⁺/Na⁺ ratios in different organs were ranked as leaves>stems>roots. K⁺ and Na⁺ absorption of selectivity ratios (AS_K,Na) in roots increased significantly with the degree of soil saline-alkali increasing. Transportation of selectivity ratio (TS_K,Na) in stems and leaves of Helianthus tuberosus increased under moderate salinity stress in bud stage, but decreased under heavy salinity stress. In the same salinity stress levels, TS_K,Na were higher in leaves than in stems, while the contents of K⁺, Ca²⁺, Mg²⁺ and K⁺/Na⁺ were higher in aboveground parts than in underground parts. Na⁺ contents were higher in underground parts than in aboveground parts. Na⁺ content was the lowest, K⁺/Na⁺ was the highest, as K⁺ contents decreased slightly in bud stages compared with other growing stages.

Key words: Helianthus tuberosus, Salinity stress, Na⁺, K⁺, Ion distribution