Knowledge Resource Center for Ecological Environment in Arid Area
| 沙拐枣属（Calligonum L.）四种植物的繁殖生物学特性研究 | |
| 其他题名 | Study on Reproductive Characteristics of Four Species from Calligonum (Polygonaceae) |
| 康晓珊 | |
| 出版年 | 2011 |
| 学位类型 | 博士 |
| 导师 | 潘伯荣 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 本研究以在吐鲁番沙漠植物园生长三十多年的沙拐枣属（Calligonum L.）植物为研究对象，从该属四个组中各选取一个种作为代表：泡果组（Sect. Calliphysa）的泡果沙拐枣（C. calliphysa），翅果组（Sect. Pterococcus）的红皮沙拐枣(C. rubicundum)，基翅组（Sect. Calligonum）的密刺沙拐枣（C. densum），刺果组（Sect. Medusae）的艾比湖沙拐枣（C. ebinuricum），进行连续四年的观察和研究，对四个种的开花物候、繁育系统、传粉特性和结实结籽特性进行系统的研究，为该属植物的繁殖生物学研究和迁地保育策略提供必要的基础资料和信息。同时也针对艾比湖沙拐枣独特的两季开花现象进行了初步研究。主要结论如下：\n1. 开花物候特征表现为泡果沙拐枣（C. calliphysa）和红皮沙拐枣（C. rubicundum）相似，为“集中开花模式”，花期重叠指数较高，达79.99-100%，密刺沙拐枣（C. densum）和艾比湖沙拐枣（C. ebinuricum）相似，为“持续开花模式”，花期重叠指数较高为51.79-79.82%， 四个种的共有重叠期较短；四个种存在花期分化，但是分化不完全；结合气象数据， 4月中旬的温度是影响始花时间的主要因素。\n2. 四个种均呈现混合交配系统，表现为自交亲和，不能主动自交，偏于异交，杂交存在的可能性较小，不存在无融合生殖，生殖成功依赖传粉者，存在风媒。\n3. 四个种的主要传粉者是意大利蜂(Apis mellifera L.)，访花时间7:00-21:00，有两个访花高峰期：8:00-8:30和18:00-19:00，单花停留时间1-2s，意大利蜂单次拜访花粉移出率为80.1±29.7%，沉降花粉数目为3.3±1.7粒，传粉效率低。\n4. 四种沙拐枣结实率均不高，泡果沙拐枣和红皮沙拐枣开花前（20-37%）和开花后败育率均较高（34-77%）、大部分的密刺沙拐枣和艾比湖沙拐枣的花能正常开放，但开花后败育率较高（43-64%）；除艾比湖沙拐枣外（45-53.75%），其余三个种的果实有胚率均较高（71.25-98.25%），有胚的果实绝大多数都具有活性；经预处理后，四个种的种子均能较好的萌发（60.33-91.33%）。\n5. 艾比湖沙拐枣具有两个独立的花期：春花期（4月）和秋花期（8月）。（1）春花期比秋花期持续时间长，开花数目多；（2）春花期的花冠直径、花生物量、P/O等均大于秋花期；（3）春花期访花昆虫较多，秋花期极少，访花昆虫种类不同；（4）春花期的结实率（54.46-57.99%）和果实有胚率（45-53.75%）均高于秋花期的结实率（24.21-37.42%）和有胚率（21.85-22.28%。\n四个种的开花物候相遇，但是我们通过种间杂交试验，质疑了杂交的可能，因此即使生长在同一生境下，分享相同的传粉者，由于其杂交不育的特性，有利于种质资源保存；种子较高的萌发率也为种群的更新、扩大提供了保障。因此，该研究不仅为荒漠主要建群植物--沙拐枣属物种的迁地保护提供了理论支持，也为其它荒漠植物的引种保育工作提供指导。 |
| 英文摘要 | We selected four species from each of the four sections of Calligonum (C. calliphysa from C. Calliphysa; C. rubicundum from Sect. Pterococcus, C. densum from Sect. Calligonum and C. ebinuricum from Sect. Medusae) growing in Turpan Eremophyte Botanical Garden as research materials. We observed their flowering phenology, breeding system, pollination characters, fruiting and seed-set characteristics for four years to interpret their ecological adaptation mechainism.Our work provides some essential information and basic materials for the proliferation study and ex-situ conservation of Calligonum, as well as the protection and management of Calligonum germplasm resources. Meanwhile, we explored the unique bi-seasonal flowering phenomenon of C. ebinuricum. And the main results as follows:\n1. Analyzed the flowering phenology characteristics by observing the flowering phenology variation at population, individual, branch, branchlets and single flower levels. (1) At population, individual and branch levels, most of the flowering phenology characteristics of C. calliphysa and C. rubicundum were similar, exhibiting a so-called “mass-flowering” pattern with the overlap percentage 79.99–100%; the flowering phenology characteristics of C. densum and C. ebinuricum were similar, exhibiting an “extended-flowering” pattern with the overlap percentage 60.22–79.82%; the overlap period of four species was very narrow; (2)At branchlet level, the flower numbers, last time and the branchlet length of the four species showed significant differences among species and years; (3)At branchlet level, the first opening flower was located on different joint, C. Calliphysa, C. rubicundum and C. densum locating on 2, 3, and 4 joints, C. ebinuricum locating on 3, 4, and 5 joints; In the correlation analysis of the four species’ flowering time, flower amounts and fruit number, they all exhibited a high rate of fruit production during their flowering peak period, flower number showing an significant positive correlation to fruit number; To the relationship of fruit number and flowering point, the fruit number was more where flower number was more; The variation among species was significant, (4)The lasting time of flowering was different among the four species at single flower level, but all with a gradual pollen presentation. (5)The phenology parameters of the four species were similar during 2007-2009 combined with the climate information at the same period. But the phenology parameters of the four species were delayed in 2010. The initial flowering time was dependent on the mid-April temperature. The so-called “mass-flowering” or “extended-flowering” pattern exhibited by the four species were an adaptive strategy for the unpredictable disturbance in desert environment, also the “gradual pollen presentation” was an adaptive strategy to meet uncertain pollinators in terrible environment.\n2. Analyzed the breeding system pattern and adaptibility and eveolutionary significance of mating system to desert habitat through bagging and artificial pollination experiments. Four species of Calligonum exhibited a mixed mating system: self-compatible, rare autonomous selfing, incline to outcrossing, no apomixis, hybridization is low possibility. Whether reproduction success or not relies on pollinators. Anemophily was an alternative way for reproduction. No self-fertility was to avoid inbreeding depression, but geitongamy is essential choice under unsure pollinators, hostile environment and the effect of the flowering patterns of Calligonum\n3. Examined the pollination characteristics through a series of comparison about pollinator species, foraging behavior, visition rate, rewards. The major pollinators were Apis mellifera L., of which Apis mellifera L.was dominant in number and visiting frequency. They visited flowers from 7:00 to 21:00 in sunny day, and had two visiting peak period: 8:00-8:30 and 18:00-19:00. The lasting time of each visit was 1-2s; After a single visit to virgin flowers, the pollen removal ratio from anthers were 80.1±29.7%, the pollen deposition on stigmas by a single visit to virgin flowers were 3.3±1.7. But “gradual pollen presentation” made Apis mellifera L. visit the same flower repeatedly to increase number of pollen deposition, decrease pollen discount and incresae reproductive success rate.\n4. Through detecting the reason of fruit abortion, we found the buds and flower abortion percentage were very high. C. Calliphysa and C. rubicundum both have high buds (20-37%) and flower abortion(34-77%),and most buds of C. densum and C. ebinuricum could open, but flower abortion was very high (43-64%). The four species except C. ebinuricum had higher embryo percent (60.33-91.33%). The seed germination rates of four species under two different pre-treatments were quite high.\n5. C. ebinuricum flowered twice a year, once in spring (from late April to late June), the other in autumn (from late August to late September). Spring flowering period had a visible peak, but autumn flowering period had none, and the discrepancy of two flowering period was nearly four months. Several significant differences between spring and autumn flowering and fruiting were found: (1) the autumn flowering period was shorter than that of spring; (2) the plants produced a larger amunnt of flowers in spring than in autumn; (3) plants produced smaller flowers, lower flower mass and lower P/O in autumn than in spring; (4) in spring plants had more pollinators and visitors than in antumn; (5) fruit set percentage was lower in autumn(24.21-37.42%)than in spring(54.46-57.99%), and the same with the non-embryo ratio and the weight of fruits; (6) the two flowering periods both had high seed germination (84-91.33%)which indicated the two flowering periods could supply sufficient seed bank for renewing population and conserving germplasm resource. The two-seasonal flowering was considered as a form of bet hedging that could lower the risk of mortality in the extreme environment of the Junggar Desert.\nHow to introduce plants and operate ex-situ protection in a botanical garden is a big challenge, since there is a hybridization risk of generating novel hybrid from artificial sympatry. Although the flowering phenology of four species were overlapped under ex-situ conservation, there were have low possibility of hybridization with each other. They showed normal healthy growth, yielded viable seeds, and were able to complete their life cycle in the environment of a botanic garden. Therefore, we concluded that they are suitable for ex situ conservation in TEBG. Furthermore, these results provide theoretical support for the construction of a national germplasm resource garden of Calligonum, and for the introduction and conservation of other eremophyte plants to Garden. |
| 中文关键词 | 沙拐枣属 ; 迁地保护 ; 开花物候 ; 繁育系统 ; 两季开花 |
| 英文关键词 | Calligonum L flowering phenology breeding system pollination characters |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院新疆生态与地理研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287001 |
| 推荐引用方式 GB/T 7714 | 康晓珊. 沙拐枣属（Calligonum L.）四种植物的繁殖生物学特性研究[D]. 中国科学院大学,2011. |
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