【作者】 杨远昭；

【导师】 王纯利； 张希明；

【作者基本信息】 新疆农业大学 ， 环境科学， 2007， 硕士

【摘要】 本文以盐角草(Salicornia europaea)鞑靼滨藜(Atriplex tatarica)小白藜(Chenopodium iljinii)为研究材料,对生长在新疆盐漠环境中的这三种盐生植物种子的萌发生态学进行了研究。同时,也研究了不同温度、盐分、水分胁迫等主要因子对三种盐生植物种子萌发的影响及萌发恢复情况。为当地的植被分布,植被格局研究以及荒漠地区植被自然更新、受损生态系统的恢复提供资料。三种盐生植物的种子在5-35℃的范围内均能萌发,最适宜萌发温度分别为30℃,25℃和25℃。低温和过高的温度都抑制了种子的萌发。三种盐生植物的种子萌发对NaCl盐度胁迫有相似的响应,即低浓度胁迫下种子的萌发受到的抑制较轻,种子萌发率随盐度的升高而逐渐降低,直至种子萌发被完全抑制。盐角草种子对盐生环境的适应能力最强,在1.0mol/L时仍然有少量萌发。低浓度下NaCl溶液刺激了小白藜种子的萌发,在0.1mol/L下其萌发率高达85%明显高于蒸馏水对照中的萌发率。水分胁迫对三种盐生植物的种子的抑制作用随着渗透压的增大而升高,而且萌发率低于同等渗透压下NaCl溶液中的萌发率。三种盐生植物的种子转入蒸馏水中后,均大量萌发。萌发恢复率随溶液浓度和渗透势的增加而增加。鞑靼滨藜种子的耐旱性最强,其次分别为盐角草和小白藜。三种盐生植物的种子均能在较低土壤含水量(1%)中萌发。盐角草和鞑靼滨藜种子萌发的适宜土壤含水量范围要宽于小白藜种子;并且这两个种子萌发的适宜土壤含水量均为4%～16%;而小白藜种子萌发相对适宜的土壤含水量为3%～8%,盐角草和鞑靼滨藜在相同土壤含水量下的萌发率均高于小白藜。这三种植物的种子对盐渍化环境有良好的生态适应机制,而且种子的萌发能够忍受一定的干旱胁迫,但是盐逆境和干旱逆境总体上仍然抑制种子的萌发。被逆境抑制的种子会选择合适的季节和环境待胁迫减轻后,恢复活力继续萌发。种子对不同温度、盐度和干旱水平的萌发策略反映了植物在种子萌发阶段对其环境形成的一种适应。正是这种适应性使盐生植物的种子能够选择适当的时机进行萌发,进而顺利完成生活史的萌发策略,使这三种盐生植物的种群得以在新疆的盐渍荒漠环境中不断繁衍生息。这三种盐生植物所表现出的对环境的适应性及萌发策略,为新疆广袤的干旱盐渍地区的盐生植物的引种驯化、增加荒漠系统植被覆盖度提供理论依据,对受损生态系统的恢复、盐碱土地的改良以及盐生资源植物的开发利用起到指导性的作用,因而具有重要的实际意义。更多还原

【Abstract】 In this paper, seed germination ecology of three halophytes Salicornia europaea, Atriplex tatarica and Chenopodium iljinii was studied by using the seeds of the three species collected from saline desert in North Xinjiang, including the effects of temperature stress, salt stress and water stress on seed germination and germination recovery after seeds were transferred to distilled water.The seeds of all the three species could germinate under the temperature of 5-35℃. The results indicated that the optimal temperatures for seed germination of Salicornia europaea, Atriplex tatarica and Chenopodium iljinii are 30℃,25℃and 25℃respectively. Both lower temperature and higher temperature repress the germination of the three species. The responses of the seeds to NaCl concentration among the three species were very similar. Lower concentrations of NaCl less inhibit seed germination and when the salinity above a certain concentration, seed germination decreased with the increase of salinity. In the end, germination was completely inhibited. However, the salinities of inhibit germination were different among the three species. The seed of Salicornia europaea has the highest adaptability to salty environment, even a few seeds germinated under the 1.0 mol/L NaCl. The seed of Chenopodium iljinii was stimulated by NaCl in 0.1 mol/L, under such salt concentration the germination rate was 85%, higher than distilled water control. The inhibiting effect of water stress by soaking the seeds in PEG-6000 solution increased with osmotic potential, whereas the germination was lower than in NaCl solution at the same osmotic potential. After the stresses were relieved by transferring the seeds of the three species to distilled water, the seeds still germinated greatly. All the three species seeds have higher germination recovery percentage, which increases with concentration and osmotic potential of NaCl and PEG solutions. Atriplex tatarica was the most tolerant to drought, then followed Salicornia europaea and Chenopodium iljinii.The results showed that the seeds of the species are with well adapted mechanism to the saline environment and as well the seed germinations are tolerant to certain drought stress, however, the salt and drought stresses repress the seed germination in general. The depressed seeds by the adverse conditions would recover to germination once the stresses relieved during the proper season and suitable environment. The three species were very salt tolerant. The ability of seeds when the salt stress was decreased is one of the special adaptive strategies for them to inhabit the salt desert environment. This adaptive strategy help the populations of three species successfully survive and reproduce in the salt desert of Xinjiang.更多还原