【作者】 宋兆伟；

【导师】 郝丽珍；

【作者基本信息】 内蒙古农业大学 ， 蔬菜学， 2010， 博士

【摘要】 沙芥属(Puionium Gaertn.)蔬菜植物属于十字花科(Cruciferae),为二年生草本植物,是亚洲中部蒙古高原沙地的特有属。沙芥(P. cornutum(L.)Gaertn.)和斧翅沙芥(P. dolabratum Maxim.)是沙芥属的两个种,生长于流动和半流动沙丘。通常此种生境下,具有高温、干旱、日夜温差大等特点,且多有盐分的积累,因此本试验从温度、不同沙埋深度和室内贮藏方式及NaCl和等渗PEG对沙芥和斧翅沙芥种子萌发的影响等方面,研究了沙芥属植物种子萌发的生态学适应。得出以下结论:1、在黑暗10～40℃恒温条件下,室内贮藏1年和2年的沙芥和斧翅沙芥种子在15～35℃范围内均可萌发,其种子分别在25℃和30℃达到最佳的萌发响应;在20~35℃下斧翅沙芥种子的萌发要优于沙芥种子,在此条件下斧翅沙芥种子的萌发特性优于沙芥种子。在黑暗变温条件下,沙芥和斧翅沙芥种子在20/30℃达到最佳的萌发响应,此处理下的萌发率高于其各自最佳恒温处理下的萌发率,其萌发后幼苗的下胚轴和胚根的长度较最佳恒温处理有明显的下降,但它们的干重却差异较小,说明变温处理有利于沙芥属植物种子的萌发和形成强壮的幼苗。在以上所有温度处理下,贮藏2年的沙芥和斧翅沙芥种子萌发均优于贮藏1年的种子。综上所述,沙芥和斧翅沙芥种子在黑暗条件下的20/30℃变温处理是种子的最佳萌发条件,并有利于种子萌发后幼苗建成。2、野外原生境下,0 cm、1 cm、2 cm和5 cm埋藏6个月和室内5℃恒温贮藏15个月的沙芥种子与室温贮藏2年的种子活力相当;所有室内贮藏种子的处理中,沙芥种子寿命均在2年以上;野外埋藏沙芥种子在50 cm埋藏处理下,种子库寿命最长也在2年以上,其次是0 cm埋藏处理种子库寿命可达15个月,在1~10 cm埋藏处理下沙芥种子库的寿命只有6个月。3、斧翅沙芥种子的综合耐盐性强于沙芥种子;沙芥和斧翅沙芥种子均在20/30℃下的耐盐性最强,种子最高能忍耐300 mmol?L-1的NaCl溶液,沙芥和斧翅沙芥种子在各温度下的耐盐强弱顺序为:20/30℃>25/35℃>15/25℃>10/20℃。沙芥和斧翅沙芥种子经各浓度的NaCl溶液前处理后,种子均在经200 mmol?L-1NaCl前处理时达到萌发率和萌发速率的最大值;而且在15/25℃、20/30℃和25/35℃下经200 mmol?L-1NaCl前处理后,种子的恢复萌发率的均超过90%,恢复萌发速率的均超过80,说明以上温度下种子恢复萌发快速而且整齐度高。4、斧翅沙芥种子的综合耐渗透胁迫的能力强于沙芥种子;其中沙芥和斧翅沙芥种子均在20/30℃处理下的耐渗透胁迫能力最强,种子最高能忍耐-1.0 MPa PEG;沙芥和斧翅沙芥种子在各温度下的耐渗透胁迫能力的强弱顺序为:20/30℃>15/25℃>25/35℃>10/20℃。沙芥和斧翅沙芥种子经不同PEG渗透势前处理后,种子均在经-1.0 MPa PEG前处理时达到萌发率和萌发速率的最大值;在20/30℃下经-1.0 MPa PEG前处理后,种子的恢复萌发率均能达到100%,恢复萌发速率均超过90,说明种子恢复萌发快速而且整齐度高。5、斧翅沙芥种子的抗氧化酶活性高于沙芥种子;NaCl前处理有提高沙芥属植物种子抗氧化酶活性的作用;其产生的离子效应和渗透调节效应可提高种子内APX、SOD和POD酶的活性,由PEG产生的单纯渗透效应也有提高种子内POD酶的活性和减少膜脂过氧化的作用。更多还原

【Abstract】 Pugionium Gaerten. is a very important shrub species for sandy vegetable inhabilitation in Inner Mongolia of Inner Mongolia Autonomous Region China for its high ecological and economic values. P. cornutum (L.) Gaertn. and P. dolabratum Maxim. is its two species. They grew up in mobile and semi-mobile dunes. Usually in this habitat, there is a high temperature, drought, temperature difference between day and night and salt accumulation. Controlled experiments were conducted to investigate on seed germination of P. cornutum and its congeners P. dolabratum, for this experiment, the temperature, different sand burial depth and indoor storage means and osmotic NaCl and isotonic PEG, to better understanding how they adapt to desert habitats at seed germination stage. The results indicate:1. At constant incubating temperature and darkness, Storage for 1 and 2 years seed of P. cornutum and P. dolabratum can germinate at gradients from 15 to 35°C, and the germination percentages of P. cornutum were significantly higher than those of P. dolabratum at 15°C and 35°C respectively. The optimal germination temperature for P. cornutum and P. dolabratum were 25°C and 30°C respectively. Under alternating temperature and darkness conditions, the optimal temperature for seed germination of two congeners was both occurring at 20/30°C. Percentages of seed germination were higher at 20/30°C than their respective optimal constant temperatures of both species; In addition, seedling hypocotyl and radicel length of both species developed at 20/30°C were shorter than that at 25°C and 30°C respectively, but their dry weight were not obviously declined. Indicating alternating temperature has advantages for seed germination and seedling development of two congeners. In these temperature treatments, P. cornutum and P. dolabratum seeds were stored for 2 years than 1 year of seed storage.In summary, darkness and 20/30°C daily alternating temperatures are the favorable conditions for seed germination and seedling establishment of these two desert species.2. The original wild habitats, 0 cm, 1 cm, 2 cm and 5 cm buried for 6 months and 5°C room temperature storage for 15 months at room temperature storage of P. cornutum seeds and seed vigor quite 2 years; All indoor storage of seed processing, seed longevity this species were more than 2 years; Wild seeds buried 50 cm of treatments, P. cornutum seed was also the longest seed bank longevity expectancy more than 2 years, followed by the 0 cm burial treatment seed bank longevity were 15 months, in 1~10 cm burial treatment P. cornutum seed bank longevity span of only 6 months.3. P. dolabratum seeds had stronger salt tolerance than P. cornutum; Seeds had the strongest salt tolerance at 20/30°C, seeds could furthest tolerate 300 mmol·L-1 of NaCl solution. Salt tolerance in descending order of P. cornutum and P. dolabratum seeds was: 20/30°C >25/35°C >15/25°C >10/20°C. Seed of P. cornutum and P. dolabratum were the germination and germination rate reached the maximum by 200 mmol·L-1NaCl pre-treatment at 15/25°C, 20/30°C and 25/35°C; Seed recovery of germination rate was more than 90%, and germination rate of recovery was more than 80. In summary, NaCl pre-treatment seed germination of recovery was rapid and orderly in the temperature.4. The ability of resistance to osmotic stress of P. dolabratum seeds was stronger than that of P. cornutum seeds; the ability of P. cornutum and P. dolabratum seed germination were strongest at 20/30°C, Seeds were patient of -1.0 MPa PEG furthest; the descending order of capacity of osmotic adjustment in the temperature-resistant of P. cornutum and P. dolabratum seeds was: 20/30°C >15/25°C >25/35°C >10/20°C. Seed of P. cornutum and P. dolabratum were the germination and germination rate reached the maximum by -1.0 MPa PEG pre-treatment at 15/25°C, 20/30°C and 25/35°C; Seed recovery of germination rate was more than 90%, and germination rate of recovery was more than 80. In summary, PEG pre-treatment seed germination of recovery was rapid and orderly in the temperature.5. Antioxidant enzyme activity of P. dolabratum seeds was higher than P. cornutum seeds; NaCl pre-treatment had increased Pugionium Gaerten. plant seeds antioxidant enzyme system capacity; The resulting effect of ionic effects and osmotic adjustment increased APX , SOD and POD enzyme activity in seeds. Simply osmotic adjustment generated by the PEG had been improved POD enzyme activity and reduced the lipid peroxidation in seeds.更多还原