Abstract:

To study the effect of seed priming under alkali stress on germination and seedling growth, seeds of sweet sorghum hybrid combinations of ‘Tongtian No.1’ were primed with 500 μmol/L γ-aminobutyric acid (GABA). The primed seeds were subjected to mixed alkalis (NaHCO₃:Na₂CO₃=5:1) stress of 3 levels (0, 50 and 100 mmol/L) in a pot culturing experiment. The effects of the seed priming and alkalis stress on seed, germination and seedling growth were then investigated. The results showed that with the alkali stress concentration increased, whether the seeds were primed or not, the amount of water absorbed by seeds, the germination index, the rate of seed emergence and the seedling survival rate dropped significantly, while the seedling growth was inhibited, and biomass accumulation decreased. Compared with unprimed seeds under the same alkalis concentration, the amount of water absorbed by seeds, the germination index, the growth of the embryo and the leaf area of seedlings of the primed seeds all significantly increased. Compared with unprimed seeds under low alkali stress, the primed seeds had higher emergence rate and seedling survival rate, and the plant height and stem thickness up to 7 d and the total biomass all significantly increased. The results suggest that seed priming could promote sorghum seed germination under alkalis stress, alleviate seedling damage by alkalis stress, accelerate seedling growth and increase seedling alkalis tolerance.

Key words: γ-aminobutyric acid (GABA);, seed priming, alkaline stress, alkali-resistant, germination and growth