不同温度和PEG处理对中华羊茅种子萌发的影响

本文采用不同温度和不同浓度PEG溶液的互作胁迫来模拟中华羊茅种子萌发的水温环境,研究了中华羊茅在不同水热条件下种子的萌发状况,旨在探究中华羊茅种子萌发的最适水温条件。结果表明,中华羊茅种子在不同水温条件下表现出不同的萌发特性,3种温度条件下种子的发芽率在25℃时达到最高,而在15℃时发芽率最低,说明高温条件有利于中华羊茅种子的萌发。其中在15和20℃条件下,-0.2 MPa水势条件下的发芽率、发芽势、发芽指数和种子活力指数均显著高于对照和其他浓度水势处理(P0.05),说明在低温条件下,低浓度的PEG溶液可显著提高中华羊茅种子的活力;而在25℃温度下,其对照处理的发芽率和发芽指数显著高于各渗透势处理(P0.05);表明在较高温度下,PEG对中华羊茅种子的萌发具有抑制作用,且其抑制作用随着PEG浓度的增大而增大;随着PEG浓度的增大,各温度处理种子的发芽率和发芽指数逐渐降低,胚芽长、胚根长和根芽比逐渐减小,幼苗含水量以及种子的萌发抗旱指数和活力抗旱指数也不断降低,表明低浓度PEG溶液对中华羊茅种子具有"引发"作用,高浓度PEG溶液则对其种子活力有抑制作用。

Effects of different temperature and moisture conditions on seed germination of Festuca sinensis

The aim of this study was to determine the most suitable moisture and temperature conditions for seed germination of Festuca sinensis .The germination of F .sinensis seeds was evaluated at 15,20,and 25℃, and under different moisture conditions imposed using various concentrations of polyethylene glycol (PEG). The F .sinensis seeds showed different germination features under different moisture and temperature condi-tions.The highest germination rate was at 25℃ and the lowest was at 15℃,suggesting that higher tempera-tures are beneficial for seed germination.At 15 and 20℃,the seed germination rate,germination potential, germination index,and vigor index of seeds were significantly higher in the -0.2 MPa water treatment than in the control and the other treatments (P <0.05).These results indicated that a low PEG concentration can im-prove F .sinensis seed vigor under low temperatures.However,at 25℃,the germination rate and germination index of seeds were higher in the control than in the PEG treatments (P <0.05)suggesting that PEG inhibited the germination of F .sinensis seeds at higher temperatures.The degree of inhibition increased with increasing PEG concentrations.As the PEG concentration increased,there were decreases in the seed germination rate, germination index,plumule length,radicle length,shoot ratio of seeds,seedling moisture content,and drought resistance.Together,these results show that a low concentration of PEG can promote F .sinensis seed germination whereas high concentrations of PEG can decrease seed vigor.