濒危植物裂叶沙参种群生殖力表的研究

本文分别以当年产种子数量和一年生幼苗数量为基础,编制了裂叶沙参种群(总和)和海拔2300-2400m, 2700-2900m, 2900-3100m, 3100-3400m 4个不同海拔区域种群的生殖力表,分析了不同种群两种生殖表的种群内禀增长率(r_m),周限增殖率(λ),净增长率(R₀),毛增长率(G)等动态参数与种群动态的关系;比较了两种生殖力表的特点和利弊;讨论了裂叶沙参种群生殖生态学特性和种群发展趋势及其与环境因素的关系。以种子数量为基础编制的生殖力表的各种群动态参数表明,裂叶沙参具有较强的产生种子的能力,特别是在生境条件较好的海拔2700-3100m区域,种群个体结实量可达到很高的水平。以一年生幼苗数量为基础编制的生殖力表表明,裂叶沙参种群从整体上呈衰退趋势。但不同种群间存在差异:在海拔2300-2400m,水份条件较好的特殊生境和海拔2900-3100m的种群呈稳定特征;而海拔2700-2900m,3100-3400m的种群呈缓慢衰退特征。以种子数量为基础编制的生殖力表可以反映裂叶沙参种群产生种子的能力和生殖生态学特征;而以一年生幼苗数量为基础编制的生殖力表包含了种子库的生态学过程,能较好的反映种群动态特征。在实践中,两种生殖力表应配合使用,才能全面刻划种群生殖生态学和种群动态特征。     

裂叶沙参分布区域和生物学生态学习性的调查

濒危植物裂叶沙参(Adenophora lobophylla Hong)已发现的天然分布区在四川西北部金川县的安宁、曾大、卡撒、马尔邦、观音桥五个乡,分布面积估计不超过5000km2,根据文献记载和50年代采集的标本分析,裂叶沙参的分布区正在缩小。裂叶沙参以有性生殖为主,在外界干挠和春旱严重的条件下也营无性生殖。在海拔2700m以下地区,裂叶沙参星散分布,生长发育不良,年龄结构老化,种群呈衰退趋势。在较为适生的海拔区间(2700-2900m),裂叶沙参生长正常,花果产量高,年龄结构合理。在海拔2900m以上地区,裂叶沙参分蘖数、花果量减少,个体寿命缩短。裂叶沙参所处群落可分为山杨、山棉花林;旱生多刺灌丛或灌丛;旱生灌草丛;和旱生草丛。裂叶沙参种群在各群落中均为伴生种,受到群落不同程度的影响。     

濒危种裂叶沙参种群生命表和存活曲线的研究及其与广布种泡沙参的对照

以近缘广布种泡沙参为对照,本文编制了濒危种裂叶沙参种群的标准生命表、存活曲线以及海拔２３００～２４００ｍ、２７００～２９００ｍ、２９００～３１００ｍ和３１００～３４００ｍ区域４个种群的生命表,存活曲线。根据其生活史,讨论了裂叶沙参各种群特定年龄的存活量、死亡量和死亡率等重要参数。裂叶沙参种群存活曲线属ＤｅｖｅｙＣ型,１～５年生死亡率最高,个体最长寿命２５年。而泡沙参种群的死亡高峰期是１～３年,个体最长寿命２１年。导致裂叶沙参种群幼龄个体死亡的内在原因是其较弱的抗逆性和适应能力;外在原因是严重的干旱、外界干扰和群落内的光照不足。裂叶沙参种群适应不良环境的能力较泡沙参弱：在海拔２７００ｍ以下地区,由于外界干扰和环境干旱,除水份条件较好的特殊生境,大多种群呈严重衰退趋势,不能满足编表条件,只有海拔２７００ｍ以上区域的种群呈稳定或扩展趋势;而泡沙参各种群在不同海拔区域均呈稳定或扩展趋势,满足编表条件。从海拔２３００ｍ到３４００ｍ,不同裂叶沙参种群个体寿命呈：短长短的格式,与外界严酷较好严酷的环境相对应。这表明裂叶沙参种群在严酷环境条件下改变了其生存对策,缩短了个体寿命。     

裂叶沙参和泡沙参种群有性生殖和无性繁殖的比较

通过对裂叶沙参(Adenophora lobophylla Hong)和泡沙参(A.potaninii Korsh.)种群有性生殖和无性繁殖特性的对比,揭示濒危植物裂叶沙参的种群内部致濒机制。结果表明:裂叶沙参种群幼苗抢占草本层上层空间能力弱于泡沙参种群;裂叶沙参种群是以相对长的生殖期和高产籽量来适应环境;裂叶沙参种群开花结实量虽高于泡沙参种群,但其中成熟种子少,种子质量差,致使其种群由种子到一年生幼苗的转化率极低,并且幼苗生活力弱,是导致其种群濒危的重要内部原因。裂叶沙参种群除有性生殖外还兼有较弱的无性繁殖,是对其有性生殖的一个重要补充。     

濒危种裂叶沙参种群生命表和存活曲线的研究及其与广布种泡沙参的 …

以近缘广布种泡沙参为对照,本文编制了濒危种裂叶沙参种群的标准生命表,存活曲线以及海拔２３００￣２４００ｍ、２７００￣２９００ｍ、２９００￣３１００ｍ和３１００￣３４００ｍ区域４个种各的生命表,存活曲线。根据其生活史,讨论了裂叶沙参各种群特定年龄的存活量,死亡量和死亡率等重要参数,裂叶沙参种群存活曲线属ＤｅｅｖｅｙＣ型,１￣５年生死亡率最高,个体最长寿命２５年,而泡沙参种群的死亡高峰期是１￣３年,个     

遮光条件下裂叶沙参和泡沙参气孔行为的对比研究

通过遮光实验研究了裂叶沙参（Ａｄｅｎｏｐｈｏｒａ ｌｏｂｏｐｈｙｌｌａ）和泡沙参（Ａ．ｐｏｔａｎｉｎｉｉ）叶片的气孔行为,比较了不同遮光处理对裂叶沙参和泡沙参气孔的生理特性以及生态适应的影响。结果表明：裂叶沙参对不同遮光处理的适应性较差,相反,泡沙参具有较强的适应性和抗逆性;在自然光照和轻度遮光条件下,中午时泡沙参叶片的孔开度逐渐减小和部分气关闭;裂叶沙参光合作用的非气孔限制占主要地位,泡沙参光合     

川西泡沙参种群地上生物量生长发育的研究

对川西泡沙参种群地上各器官,茎、叶、花-果的生物量生长发育过程进行了系统的研究,结果表明：（1）泡沙参种群（总和）个体地上总生物量和各器官的生长发育在1-5年生生长缓慢,5-15年生随年龄增长,年生物量增幅较大,此后,生长速度开始下降,直到死亡年龄,泡沙参种群（总和）地上生物量生长发育过程可程可用方程y=a0 a1x a2x^2表示。（2）不同海拔区间的泡沙参种群个体地上总生物量和各器官生物量生长发育与种群（总和）地上总生物量生长发育的趋势基本一致。生物量生长在幼年和老年时较低,大约在15年生时达到高峰。（3）不同海拔区域综合生境条件与种群的地上生物量生长,生长模式,生物量最高峰出现的年龄区段等有着密切联系。在较为适生的环境条件下,外界干扰少,水热条件适宜,种群各器官的生物量和个体总生物量可达到较高水平,在低海拔地区,外界干扰严重,或高海拔地区,低温条件来酷,个体总生物量和各器官生物量均较低。     

川西北泡沙参种群根系生长动态及其与环境因素关系研究

对川西北地区泡沙参种群根系生物量累积和形态发育过程及其与环境因素的关系进行了研究.结果表明,泡沙参种群根系生物量累积一般规律符合Logistic增长过程.较高的泡沙参根系生物量累积和形态发育时期可以持续到15～17年生以后,根系采收直径应在1.7cm以上.动物啃食、人为采挖、土壤、气候等环境条件与不同海拔各种群的根系生物量累积等有着密切联系,中海拔地区(2800～3300m)人为干扰少,土壤和水热条件适宜,根系生物量和形态发育达到较高水平,适合高产栽培.而低海拔和高海拔地区的不利环境条件限制了泡沙参根系生长.在进行野生资源保护利用以及人工栽培泡沙参时应充分考虑环境因素,努力减少放牧、采挖等人为破坏,有条件的地区应实行分区禁牧、禁采挖,为泡沙参种群恢复和药材品质提高创造条件.     

遮光条件下裂叶沙参和泡沙参气孔行为的对比研究

通过遮光实验研究了裂叶沙参(Adenophora lobophylla)和泡沙参(A. potaninii)叶片的气孔行为,比较了不同遮光处理对裂叶沙参和泡沙参气孔的生理特性以及生态适应的影响。结果表明:裂叶沙参对不同遮光处理的适应性较差,相反,泡沙参具有较强的适应性和抗逆性;在自然光照和轻度遮光条件下,中午时泡沙参叶片的气孔开度逐渐减小和部分气孔关闭;裂叶沙参光合作用的非气孔限制占主要地位,泡沙参光合作用的气孔限制较明显。     

川西北泡沙参种群根系生长动态及其与环境因素关系研究

对川西北地区泡沙参种群根系生物量累积和形态发育过程及其与环境因素的关系进行了研究。结果表明,泡沙参种群根系生物量累积一般规律符合Logisticc增长过程。较高的泡沙参根系生物量累积和形态发育时期可以持续到15～17年生以后,根系采收直径应在1．7cm以上。动物啃食、人为采挖、土壤、气候等环境条件与不同海拔各种群的根系生物量累积等有着密切联系,中海拔地区(2800～3300m)人为干扰少,土壤和水热条件适宜,根系生物量和形态发育达到较高水平,适合高产栽培。而低海拔和高海拔地区的不利环境条件限制了泡沙参根系生长,在进行野生资源保护利用以及人工栽培泡沙参时应充分考虑环境因素,努力减少放牧、采挖等人为破坏,有条件的地区应实行分区禁牧、禁采挖,为泡沙参种群恢复和药材品质提高创造条件。     

Comparative Studies of Sexual Reproduction and Asexual Propagation Between Populations of Adenophora lobophylla and A. potaninii

To reveal the internal mechanism which lead to the endangerment of the AdenophoUa lobophylla Hong population, comparative studies of sexual reproduction and asexual propagation between the populations of A. lobophylla and A. potaninii Korsh were carried out. Young seedlings of A. lobophylla had less ability to occupy the uper space of the herbaceous layer than those of A. potaninii. The A. lobophylla population produced much more seeds and lived a long reproductive life to adapt the ambient environment. Though the number of flowers and fruits of A. lobophylla population was more than those of A.potaninii population, the number of its ripe seeds as well as the quality was less. Thus, the development rate from its seeds to one-year old seedlings was very low, and viability of its young seedlings was very poor. This could be the important factor causing the imminent population endangerment of A. lobophylla. Besides the sexual reproduction, the A. lobophylla population also had a comparatively tiny ability of asexual propagation, which was advantageously complementary to its sexual reproduction.     

Gas Exchange and Water Use Efficiency of Adenophora lobophylla (Campanulaceae) at Different Altitudes on the East Boundary of the Qing- Zang Plateau

Field measurements were made of leaf net photosynthetic rate (Pn), apparent quantum yield (AQY), dark respiration (Rd), transpiration (Tr), water use efficiency (WUE), stomatal conductance (Gs), intercellular CO2 concentration (Ci), leaf temperature (TI), stomatal density, air temperature (Ta) and relative soil water content (SWC) for Adenophora lobophylla Hong in August, 1996. The species grows in the region from an altitude of 2 300 m to 3 400 m on the eastern boundary of the Qing-Zang Plateau in Sichuan Province, China. Leaf gas exchange, water use efficiency and plasticity of populations in field were compared among different altitudes to evaluate the possible interactions between adaptation of A. lobophylla and environmental factors in these habitats. Pn and AQY at low altitudes were lower than those at high altitudes. They strongly responded to SWC and Ta. On the other hand, Rd at low altitudes was higher than that at high altitudes because of the higher air temperature there. The growth rates at low altitudes were associated with the increases in Rd and a relevant less Pn. Stomata showed strong responses to leaf-to-air vapor pressure deficit at the leaf surface (Vpdl) and Tl in these habitats. Increasing stomatal limitations to photosynthesis appeared to be responsible for the reduction in Pn at high Tl, Vpdl and low available soil water for A. lobophylla at low ahitudes. Nonstomatal limitation to photosynthesis also happened at extreme soil water deficits and high Tl and Vpdl at an altitude of 2 300 m. Tr had a close relationship with stomatal conductance and was also affected by leaf temperature and leaf-to-air vapor pressure deficit at the leaf surface among habitats grown in different ahitudes. WUE increased with altitude. Increasing stomatal densities showed different plasticity of A. lobophylla as altitude increased. SWC and Ta appeared to be important factors to limit carbon assimilation in A. lobophylla at low altitudes, primarily through the process of stomatal closure. The overall results are in consistence with the hypothesis that strong pressure from tmfavorable environmental factors to gas exchange and wateruse of A. lobophylla may prevent their population expansion at low altitudes, which indicate that the above-mentioned restrictions might lead to the endangerment of A. lobophylla.     

Biosystematic studies on Adenophora potaninii Korsh.complex (Campanulaceae) V.A taxonomic treatment

Adenophora is an extremely variable genus,and its taxonomy is very controversial.Of the genus,Adenophora potaninii complex,including A.potaninii,A.bockiana,A.wawreana,A.lobophylla,A.biformifolia,A,polydentata,and A.wawreana var.lanceifolia,is a typical group with different taxonomical treatments due to high level of morphological diversity.We carried out extensive biosystematic studies based on population sampling,transplantation experiments and offspring tests,cluster analysis,and a crossing experiment.The results reveal four main findings.(i) Leaf forms of the A.potaninii complex were extremely polymorphic; the leaf form of A.potaninii and A.bockiana,and that ofA.wawreana and A.biformifolia could be found,respectively,on a single population or among the offsprings of a single plant.(ii) Cluster analysis and a crossing experiment indicated that A.bockiana and A.polydentata could not be separated from A.potaninii,nor d.biformifolia from A.wawreana.(iii) Adenophora potaninii and A.wawreana were gradational in morphology and their compatibility value was slightly reduced compared to that within each entity.(iv) Adenophora lobophylla was distinct from the other members of the complex in shape and size of corolla,relative length of style,and shape of capsule.This species was incompatible reproductively with the other members of the complex,but partly compatible with A.stenanthina,a species in another section.Therefore,we recognized only one species with two subspecies in the complex,A.potaninii subsp.potaninii and subsp,wawreana,moved A.lobophylla out of the complex,and reduced all the other names as new synonyms.     

裂叶沙参与泡沙参解剖生态学的比较研究

借助于光镜和扫描电镜,系统观察了濒危植物裂叶沙参(Adenophora lobo-phylla Hong.)的根、芦头、茎和叶的解剖特征及茎、叶、种子的表面形态特征,并将有关性状与广布种泡沙参(A.potaninii Korsh.)作了对比研究。结果表明,两种沙参在叶表皮细胞形状,垂周壁式样,角质层初级雕纹及次级雕纹;叶片气孔形状及外拱盖外缘纹饰及内缘形状,保卫细胞上角质层薄厚及蜡质纹饰;叶表毛状体形状及纹饰,茎中皮层占茎横切面的比例;茎中有无髓纤维等方面存在着明显差异。相对于泡沙参,裂叶沙参单株叶面积大,生物量高,表皮角质层薄,单位面积内被毛数量少,栅栏组织薄,气孔周围蜡质沉积颗粒少;茎的直径大,皮层较薄等。这些特征表明裂叶沙参对旱生生境适应能力弱,而泡沙参对旱生生境适应能力强。     

濒危物种裂叶沙参及其近缘广布种泡沙参的遗传多样性研究

根据对１２个形态性状的统计分析和１０个基因位点的等位酶检测,探讨了濒危植物裂叶沙参及其近缘广布种泡沙参的遗传多样性水平,对３个裂叶沙参和６个泡沙参天然群体的遗传分析表明,两种沙参属植物均具有很高的遗传变异水平,这种变异性既体现在形态学水平上,也体现在酶位点水平上,在２个茎叶形状以及１０个花果和种子形状上,濒危种裂叶沙参的变异性均与广布种相当,同样,根据７个酶系统１０个等位酶位点的度量,裂叶沙参群体