钠盐胁迫对河西走廊荒漠绿洲过渡带典型一年生草本植物种子萌发的影响

研究不同浓度盐分(NaCl和NaHCO₃,0、40、80、120、160和200 mmol·L^-1)对6种河西走廊荒漠绿洲边缘人工林典型一年生草本植物(禾本科:狗尾草、虎尾草和小画眉草;藜科:雾冰藜、刺沙蓬和蒙古虫实)种子在当年秋季和次年春季的萌发和复萌的影响。结果表明: NaCl和NaHCO₃对6种植物种子的萌发有显著影响,NaHCO₃对种子萌发的抑制作用大于NaCl。NaHCO₃浓度达到160 mmol·L^-1时,6种植物基本不萌发或萌发率较低;NaCl浓度达到200 mmol·L^-1时,6种植物仍能够保持相对较高的萌发率。种子当年秋季萌发率(2.8%～20.0%)远低于次年春季萌发率(21.7%～81.6%),秋季复萌率(3.3%～20.0%)低于春季复萌率(5.0%～41.1%),当年生种子秋季多保持休眠,次年春季休眠减弱。6种一年生草本植物种子的耐盐性为:虎尾草＞狗尾草＞刺沙蓬＞雾冰藜＞蒙古虫实＞小画眉草。

Effects of sodium salt stress on seed germination of typical annuals in a desert-oasis ecotone of Hexi Corridor,China

We assessed the effects of different concentrations of salts (0, 40, 80, 120, 160 and 200 mmol·L^-1) on the seed germination and re-germination of six typical annuals (Gramineae: Setaria viridis, Chloris virgata and Eragrostis minor; Chenopodiaceae: Bassia dasyphylla, Salsola ruthenica and Corispermum mongolicum) in autumn of current year and next spring, with NaCl and NaHCO₃ as neutral sodium salt and alkaline sodium salt. The results showed that NaCl and NaHCO₃ significantly affected seed germination of the six species. The inhibition effect of NaHCO₃ on seed germination was stronger than NaCl. When the concentration of NaHCO₃ reached to 160 mmol·L^-1, germination rates of the six species were low. However, when the concentration of NaCl reached to 200 mmol·L^-1, the germination rates of the six species were still high. The germination (2.8%-20.0%) and re-germination rates (3.3%-20.0%) in current autumn were much lower than those in next spring, with values of 21.7%-81.6% and 5.0%-41.1%, respectively. In autumn, most of the current year’s seeds kept dormancy, but the dormancy weakened in next spring. The salt tolerance of seeds of the six annual species was in the order of C. virgata > S. viridis > S. ruthenica > B. dasyphylla > C. mongolicum > E. minor.