温度、光照、盐分和干旱胁迫对华北驼绒藜种子萌发的影响

Effects of temperature,light,salt and drought stress on seed germination of Ceratoides arborescens

通过测定温度、光照、盐分和干旱胁迫(Na Cl和PEG)对华北驼绒藜(Ceratoides arborescens)种子萌发的影响,探究该物种对荒漠生境的适应对策。结果表明,华北驼绒藜种皮具有透水性,吸水2 h后开始萌发,低温(5/15和5℃)条件下种子平均萌发时间(MGT)延长,萌发速率(GR)及发芽指数(GI)降低,但在不同光照和温度处理下,所有梯度均可达到较高最终萌发率(95%~100%),因此,该物种种子无休眠;种子初始萌发率随溶液渗透势降低而下降,渗透势高于-1.4 MPa的等渗溶液对种子初始萌发无显著影响,但是发芽指数(GI)显著降低;而在渗透势-2 MPa,种子仍保持10%~14%的萌发率,高渗透势溶液(0^-2.0 MPa)处理下的种子具有较高的萌发恢复率,而-2.7 MPa Na Cl处理下的种子死亡率高出与其等渗的PEG溶液处理的51%,高盐分胁迫会导致种子失去活力;华北驼绒藜种子具有快速的萌发特性及耐旱特性,有利于该物种在干旱荒漠环境的适应和种群维持。

We tested the effects of temperature, light and osmotic stresses （NaCl and PEG） on seed germination of C. arborescens to investigate the adaption strategy in desert habitat. The results showed that, seed coat of C. arborescens was water-permeable and the seed began to germinate after 2 hours of water absorption. The germination rate （GR） , germination index （GI） , and mean germination time （MGT） decreased more significantly in low temperature conditions （e. g. 5/15,5 ℃ ） than in the other temperature regimes, and its seed germination rate could reach an extremely high value （95% - 100% ） in all tested temperature regimes under both light and dark conditions. Therefore, C. arborescens was considered as a non-dormant species. With initial germination percentage decreased with the decrease of osmotic potential, germination was not affected by osmotic potential （NaCl and PEG） at concentrations higher than - 1.4 MPa; but the germination index was significantly reduced with the increase of osmotic potential ; The seed germination rate was decreased to 10% - 14% when osmotic potential was lower than 2.0 MPa. Germination percentage in high osmotic potentials concentrations （0 - - 2.0 MPa）has high recovery germination. But the seed mortality percentage under -2.7 MPa NaCl was higher than that under PEG with the same osmotic potential by 51% , which indicates that some seeds have lost their viability in high NaCl solution. Thus, C. arborescens owns relatively faster seed germination fraits and drought resistance that coutribute to the species adaption and persistence to the arid desert environment.