高枝假木贼的胎生萌发特性及其生态适应  

The vivipary characteristic of Anabasis elatior and its ecological adaptation

作　　者：韩建欣[1] 魏岩[1] 严成[2] 安沙舟[1] 

机构地区：[1]新疆农业大学草业与环境科学学院,乌鲁木齐830052 [2]中国科学院新疆生态与地理研究所,乌鲁木齐830011

出　　处：《生态学报》2011年第10期2662-2668,共7页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(30770374);教育部高等学校博士学科点专项科研基金(20070758002)

摘　　要：对分布于准噶尔荒漠的超旱生小灌木高枝假木贼的繁殖特性进行研究。结果表明:①高枝假木贼具有胎生繁殖现象。果实于10月成熟后不脱落,冬季被积雪覆盖;种子长(4.175±0.132)mm,宽(3.146±0.109)mm,质量(3.727±0.137)g,胎生现象发生于翌年早春积雪融化时(3月上旬—4月上旬);胎生发生阶段空气最高温度为0—15℃,相对湿度为50%—60%。②胎生萌发时,胚根首先突破种皮后,下胚轴快速生长形成棒状胎生幼苗,长度为1—7 cm。③控制实验表明,高枝假木贼种子具有快速萌发特性,在30/15、25/15、20/10、15/5℃温度下,种子遇水6—7 h开始萌发。④高枝假木贼的幼苗具有忍受干燥并在下次水合后能够恢复生长的能力。幼根的长度和干燥时间影响幼苗的生长恢复率。长度在0—1 cm的幼苗通过14 d的干燥,有部分幼苗复水后能继续生长。结果表明:早春充足的雪水和种子快速萌发的特性共同促进了高枝假木贼的胎生繁殖。高枝假木贼的胎萌反映了干旱区荒漠灌木对不利环境的适应策略,在研究植物的生活史进化方面具有重要的理论意义。Vivipary,which is the germination of seeds before they are shed from the mother plant,is a remarkable condition because of its rarity in flowering plants involving complex ecophysiological processes.Anabasis elatior is a hyperxerophytic,viviparous subshrub that primarily occurs in the Junggar desert,which is situated between the Tian Shan and Altai mountain ranges in Xinjiang Province,north-western China.The plants are 30-50 cm tall,the woody stem is much branched,gray-brown to gray-white,and annual branches are erect or slightly obliquely spreading with 10-20 internodes.To better understand how A.elatior is adapted to the Junggar desert environment,we investigated seed morphs,germination traits,seedling desiccation tolerance and climatic variables（temperature and relative humidity）.Our main results were as follows.（1） Individuals of A.elatior were about 30-50 cm in height.Its fruits matured in October.The fruits had a lignified perianth with long wings and green utricles,thus they cannot easily be dispersed from the mother plant by wind.The seed was（4.175±0.132） mm in length,（3.146±0.109） mm in width and weighed（3.727±0.137） g.The fruits still adhered to the mother plant during winter and were covered by snow over this period.The snow melted in early spring（i.e.from early March to early April）,during which time the maximum air temperature was maintained at-15 ℃ and the relative humidity was 50%-60%,and the seeds germinated on the mother plants and developed into viviparous seedlings.（2） When vivipary occurred,the radicle emerged through the pericarp and the hypocotyl grew rapidly,developing into viviparous seedlings 1-7 cm in length.（3） The percentage seed germination was at least 78% after 15 days incubation at day/night temperatures of 30/15,25/15,20/10 and 15/5 ℃ under a 12 h photoperiod.Differences in germination percentage among the four temperature regimes were not significant.Seeds could germinate 6-7 h after imbibition at each temperature regime,with germination acc

关 键 词：高枝假木贼 胎生繁殖 环境因子 种子萌发 幼苗耐干燥特性 

分 类 号：Q948[生物学—植物学]