【作者】 黄修梅；

【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】 沙芥和斧形沙芥是十字花科(Cruciferae)沙芥属(Pugionium Gaertn)二年生草本植物,该属是亚洲中部蒙古高原沙地的特有属,其中沙芥为中国的特有种,斧形(翅)沙芥于1992年被列为濒危种。本论文以沙芥和斧形沙芥为试材,研究了水分、沙埋、高温对其萌发、出苗、成苗的影响及根系发育、生殖和传粉生物学,以期掌握其生理生态适应性,为沙芥和斧形沙芥的生存与繁衍机制的研究奠定理论基础,为恢复自然植被、保护和扩大野生资源及人工栽培提供实践指导。其主要研究结果如下：1.沙芥与斧形沙芥种子萌发对水分和沙埋的生理生态适应性(1)沙芥和斧形沙芥果实能够萌发的土壤含水量范围均为2～20%,适宜萌发的土壤含水量为6～12%；果实能够出苗的土壤含水量均为3～20%,果实适宜出苗的土壤含水量范围均为6～16%。说明极低的土壤含水量就能满足果实萌发与幼苗出土的适宜条件,其种子萌发机制表现了对沙生环境极强的适应性。(2)当土壤含水量为6～12%时,沙芥与斧形沙芥幼苗生物量显著高于其他处理,当土壤含水量为3～8%和4～8%时,二者根冠比分别达到最大。(3)沙芥与斧形沙芥最适宜的的供水量分别为：高于当地7月降雨量的50%和接近当地7月的降雨量；当降雨量为当地6月平均降雨量(50mm/month),沙埋深度1～4cm可以出苗；当降雨量为当地7月的降雨量(100mm/month),沙埋深度分别1-8cm、0～4cm均可出苗。最适宜的沙埋深度分别为2cm和lcm,说明斧形沙芥种子萌发期和幼苗出土期的抗旱性强于沙芥,但沙芥较斧形沙芥耐沙埋。2.沙芥与斧形沙芥幼苗生长对温度和沙埋深度的生理生态适应性(1)沙芥与斧形沙芥热处理出现轻微热害症状分别为：45℃/2h和40℃/24h；热处理直接导致植株死亡：沙芥50℃/24h、60℃/3h;斧形沙芥45℃/24h、50℃/8h和60℃/2h,说明沙芥比斧形沙芥耐高温。(2)不同温度对叶绿素荧光参数的影响分析,50℃显著影响沙芥光合作用,40℃显著影响斧形沙芥光合作用,60℃严重破坏沙芥与斧形沙芥的光合作用,说明沙芥比斧形沙芥耐高温。(3)当沙埋深度达沙芥与斧形沙芥幼苗高度的1/3时,有利于促进其生长；当沙埋深度达幼苗高度2/3时,抑制其生长,二者通过延长节间来适应沙埋。幼苗全部沙埋存活率为0%,沙埋2/3,存活率分别为80%、60%；沙埋1/2和1/3,存活率为100%。3.沙芥与斧形沙芥植株叶片水分生理和根系生长对生态的适应性(1)沙芥与斧形沙芥叶片的相对含水量、自然饱和亏、临界饱和亏和需水程度的各水分生理指标,虽然存在一定不同,但未形成显著差异；水势日变化呈现单峰曲线,在11:00-15:00均处于最低值。沙芥与斧形沙芥自然状态下脱水幅度变化相似,转折拐点分别12.77h和11.00h。(2)沙芥和斧形沙芥自然种群二年生植株根系周围的土壤含水量分别为3.13±0.46%、1.90±0.68%；一年生分别为2.68±0.11%、2.50±0.45%。(3)沙芥与斧形沙芥的主根垂直,水平根系发达；一年生(沙芥29片叶、斧形沙芥23片叶)侧根分布最大的土层深度为20-40cm、最大的区域均为：深度20-40cm、半径为0-40cm的范围内。二年生侧根分布最大的土层深度都为40-60cm、最大的区域均为：深度均为40-60cm、距主根0-40cm的半径范围内。沙芥和斧形沙芥侧根根量均随着距主根水平距离的增大分别呈对数函数和指数函数关系减少。4沙芥与斧形沙芥大小孢子的发生及雌雄配子体的发育(1)沙芥与斧形沙芥大小孢子的发生及雌雄配子体的发育基本一致；(2)小孢子母细胞减数分裂过程的胞质分裂属于同时型,四分体的排列方式为四面体型,成熟花粉为3细胞花粉。(3)花药具4个药室,花药壁发育为双子叶植物型,腺质绒毡层。(4)胚珠2室,每室1枚弯生胚珠,寥型胚囊。(5)胚珠发育开始略迟于花药发育。小孢子母细胞已进入减数分裂阶段,胚珠中才分化出孢原细胞。雄配子当形成功能大孢子之后,雌配子体发育相当迅速。5沙芥与斧形沙芥传粉生物学(1)沙芥与斧形沙芥开花呈单峰曲线,在自然生境区日开花高峰分别为18：00-19：00和19：00-20：00。(2)沙芥与斧形沙芥花粉萌发的最佳培养基分别为25%蔗糖+0.001%硼酸和30%蔗糖+0.005%硼酸；花粉萌发的温度范围均为15-38℃,最适萌发温度为25℃；从花冠松动到开花后16h花粉活力最高；花粉适宜的储藏期,在室温下为1d、在4℃下为7d；开花后24-48h、柱头可授性最强,是授粉的最佳时期。其开花日高峰和花粉萌发特性表现了对沙区环境的适应性。(3)沙芥传粉媒介中,风的飘移能力非常微弱。自然种群的访花昆虫,沙芥有19种,分属于6个目；斧形沙芥有7种,分属于4个目。沙芥与斧形沙芥自然种群主要传粉昆虫的访花频率呈双峰曲线,高峰时分别为7：00-11：00和15:00-20:00。全天传粉昆虫的访问单株频次沙芥可达150次以上、斧形沙芥不足7次,传粉媒介沙芥以蜂为主,斧形沙芥以风为主。更多还原

【Abstract】 Puionium Gaertn is a biennial herbaceous vegetable of cruciferous plants, a specially inhabiting in Mongolian plateau, including P.cornutum(L.)Gaertn.and P.dolabratum Maxim. P.cornutum(L.)Gaertn is a special species in China and P.dolabratum Maxim is listed an endangered species in 1992. In this thesis, in terms of seed germination, seedling growth, water physiology, pollination mechanism and reproductive development so on, the physiological and ecological adaptation of Puionium Gaertn was investigated and estimated, which can offer theoretical guidance and technical support for sand-fixing, provide theoretical basis for the survival and reproduction of the sand plants. The main findings are as follows:1. Physiological and ecological adaptation of seed germination(1) The soil moisture contents of P.cornutum and P.dolabratum fruit germination can range from 2% to 20%, the best suitable germination is 6% to 12%; the soil moisture content which the seedling of fruits can be grow can range from 3% to 20%, the seedling of seeds can be grow can range from 3% to 16%; the best suitable seedling growing of all fruit and seed can range from 6% to 16%.(2) P.cornutum and P.dolabratum have the biggest biomass in 6% to 12% of the soil water content, have the significantly highest Root-top ratio respectively in 3% to 8% and 4% to 8%.(3) The best appropriate burial depth of P.cornutum and P.dolabratum are respectively 2cm and 1cm. The best suitable water supply are respectively 135ml and 90ml, then the best appropriate amount of monthly rainfall arel50ml and 100ml.The sand burial depth of seedling emergence:when the water supply for the 45ml, all are 1-4cm; when water supply are 90m, respectively are 1-8cm and 0-4cm; when the water supply of 135ml, respectively are 1-8cm and 0-8cm.2. Physiological and ecological adaption of seedling growing(1) P.cornutum and P.dolabratum have some flexibility to the high temperature, while a variety of symptoms of heat injury to P.cornutum always be later than P.dolabratum,about 1-3h later.(2) At a temperature of 25-50℃range, PS II reaction center not damaged or affected. when the temperature rises to 60℃, PSⅡreaction center by the damage has been increased significantly; heat should be 40-50℃.P.cornutum should be a very stronger heat resistance than P.dolabratum.(3) P.cornutum and P.dolabratum were buried 1/3 which promote its growth,2/3 which inhibit their growth; seedling survival rate of all burial was 0%,2/3 were respectively 80% and 60%,1/2 and 1/3 were respectively 100%.3. Physiological and ecological adaptation of the moisture physiology(1) The moisture Physiological indexes have’t significantly different between P.cornutum and P.dolabratum. Water potential changes in a single peak curve,11:00-15:00 in the lowest value.(2) P.cornutum and P.dolabratum dehydration rate degree of change in the state of nature is similar. The turning inflexion respectively is 12.77h and 11.00h.(3) The soil moisture around the biennial roots of P.cornutum and P.dolabratum were 3.13±0.46%,1.90±0.68%; the annual roots were 2.68±0.11%,2.50±0.45%.(4) The main roots of P.cornutum and P.dolabratum are vertical, horizontal roots system are very strong; the lateral roots distribution of the annual have maximum in the soil depth of 20-40cm; the largest regions for the distribution were the depth of 20-40cm, the radius within the range of 0-40cm; the lateral roots distribution of the biennial is largest in the soil depth of 40-60cm; the largest regions for the distribution is the depth of 40-60cm, the radius of 0-40cm away from the main root. The amount of lateral root of roots of P.cornutum is logarithmic decreased; the amount of lateral roots of P.dolabratum is exponential decreased, with increasing distance from the root.4. Megasporogenesis and microsporogenesis; Female and male gametophyte(1) The cytokinesis of the microspore mother cell is the successive type. The microspore tetrads are tetrahedron. The mature pollens are 3 cells.(2) The anther have 4chambers.The anther wall development type is dicotyledons. Tapetum is the secretory type.(3) Each locule contains the two ovules. The mature ovules are curve. The enlbryo sac is Polygonum type.(4) The female gametophyte is later than male gametophyte. The female inflorescence is beginning to grow when the male inflorescence is developing to monocyte microspore.5. Pollination Biology(1) P.cornutum and P.dolabratum reaches its full boom respectively in 18:00-19:00 and 19:00-20:00 in the natural population。(2) The pollen germinating percentage of P.cornutum and P.dolabratum reached the highest on the media supplemented respectively with 25% sucrose,0.001% Boric acid and 30% sucrose,0.005% Boric acid; The most congenial temperature of pollen germinating is 25℃,and effective temperature is 15-38℃;The pollen can reach highest peak from the biggest white flower bud to 16h after blooming; Low temperature (4℃) is advantage to pollen storaging. The stigma of P.cornutum and P.dolabratum had highest receptivitied from 24h to 48h after blooming.(3) Wind is very weak during pollinating for P.cornutum. Investigation showed that there are 19 and12 species flower visiting insects in the natural populations of P.cornutum and P.dolabratum. The frequency of pollinators in the natural populations was bimodal curve, the peak were 7:00-11:00 and 15:00-20:00.The visiting frequency of P.cornutum is up to 150 times every day, less than 7 times of P.dolabratum. The role of pollinating insects on P.dolabratum is very weak.更多还原