新疆短命植物小拟南芥(Arabidopsis pumila)种子萌发特性及其生态适应性

通过显微结构及不同处理条件下种子萌发率的观察,对早春短命植物小拟南芥(Arabidopsis pumila)种子萌发特性及影响因素进行了研究,并对其生态适应性进行了讨论。结果表明:(1)温度和光照变化对自然生境和温室收获种子的萌发率影响均不显著,说明此种群在前期萌发阶段对光、温不敏感;(2)自然生境中采收的小拟南芥种子萌发率显著低于温室收获种子,说明环境条件的变化对短命植物种子的发育具有重要作用,可显著改变种子的萌发行为;(3)赤霉素使自然生境收获种子胚活性增强从而对萌发有较大促进作用,可使萌发率增加50%以上;(4)对种皮进行各种机械损伤处理使得种皮松弛或透气,可以显著提高自然生境种子的萌发率(超过70%);(5)盐和干旱胁迫对种子萌发均具有明显的抑制作用,但复水后部分被抑制种子可重新萌发,显示盐和干旱胁迫可导致种子产生浅度休眠。结合小拟南芥自然生存环境及本研究的结果,显示其种子萌发特性与生境具有高度适应性。

Seed germination characteristics and ecological adaptability of Arabidopsis pumila, a Xinjiang-originated ephemeral plant species

Through observation of the microstructure of seeds and investigation of seed germination rate under various treatments, factors that influence germination and ecological adaptability of Arabidopsis pumila, a Xinjiang-originated ephemeral plant species were analyzed. Results showed: (1) temperature and light had little effects on seed germination rate (GR) of A. pumila, implying that the environmental sensitivity of the species in germination stage is relatively low; (2) The GR of seeds produced in natural habitat was significantly lower than those from green-house, suggesting that environmental conditions play a crucial role in seed development, and consequently influenced the germination of those seeds. (3) GA3 treatment promoted the germination of seeds produced from natural habitat by increasing the activity of embryos. GR of the GA-treated seeds was increased more than 50% over the untreated ones; (4)Mechanically altering the seed coat to make it loose, or permeable to gases, such as acupuncturing, or cutting, or peeling of seeds, could increase GR more than 70%. (5) Both NaCl and PEG-6000 treatments inhibited germination, however some non-germinable seeds germinated after rehydration, suggesting that salt and drought could induce seed dormancy of A. pumila in a low degree. Taken together, we conclude that the germination characteristics of A. pumila seeds are highly adapted to its habitat.