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不同胁迫处理对青葙种子萌发和幼苗生长的影响
Responses of seed germination and seedling growth of Celosia argentea to acid, drought and NaCl stresses
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摘要: 以青葙种子为材料,采用水培法研究了5个pH水平、5个聚乙二醇(PEG-6000)胁迫水平、5个NaCl胁迫水平对种子萌发和幼苗生长的影响。结果表明:pH为 3~5时对种子萌发率和发芽势无显著抑制作用,两者分别在79%%~81%和73%~79%之间,但可显著促进萌发初期的种子萌发。PEG胁迫对萌发率和发芽势的抑制作用随浓度升高而升高,仅20% PEG处理时种子的萌发被显著抑制,但仍有超过60%的种子萌发。50 mmol/L NaCl对种子萌发的抑制作用不显著,100~200 mmol/L NaCl显著抑制种子萌发。解除胁迫后种子恢复萌发率和休眠率总体表现为随原胁迫浓度增加而显著增加趋势,第21 d时累计萌发种子数分别在69%~84%之间,高浓度盐胁迫表现出一定的离子毒害作用。幼苗胚根和下胚轴长表现出较大的生态可塑性,胚根长、下胚轴长与苗高间总体上呈幂函数形式的异速增长关系,青葙通过改变个体形态特征适应环境胁迫。Abstract: Using by hydroponic method, Celosia argentea was utilised to investigate the response of seed germination and seedling growth to soil acidity, drought and NaCl stresses. Five pH levels(3, 3.5, 4, 5, 7), five PEG-
6000 levels(0, 5, 10, 15 and 20%), and five NaCl levels(0, 50, 100, 150 and 200 mmol/L) were assessed, and to provide basic information for the application of C. argentea in soil restoration of paddy field transformed from dryland. The results indicated that: 1) Seed could germinate over the range of pH 3 to 5, and the germination percentage and germination potential were between 79% to 81% and 73% to 79% respectively, and significantly promoted seed in the early stage of germination. Germination percentage and seed potential decreased with increasing concentration ofPEG-6000, the seed germination was significantly inhibited only under high concentration(20%) PEG stress, but the germination percentage was more than 60%. The seed germination was not significantly inhibited under 50 mmol/L NaCl stress, and significantly inhibited under 100~200 mmol/L NaCl stresses. 2) The non-germinated seeds did not lose vitality under acid, drought and salt stress, recovery percentage and dormancy percentage increased significantly with increasing primary stress concentration, after 21 days, the number of accumulative seed germination were between 69% to 84%, high salt stress showed some iron toxic action. 3) Radicle and hypocotyl length of seedling had great ecological plasticity in acid, drought and salt stresses, the relationship between radical length, hypocotyl length and seedling height was a power function allometric scaling relationship, C.argentea adapted to the different environmental stresses by changing morphological traits. This study clarified seed germination and seedling growth strategy of C.argentea under different stresses, it was of strong acid-, drought-, and salt-tolerance and the capability coping with environmental changes, the results provided theoretical basis for soil restoration of Paddy field transformed from dryland.