KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 不同沙漠生境三种荒漠植物种内种子萌发差异及作用机制 | |
| Alternative Title | Intraspecific differentiation and their causes in seed germination of three species from different desert habitats of North China |
| 刘有军 | |
| Subtype | 博士 |
| Thesis Advisor | 徐新文 |
| 2019-06-30 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 理学博士 |
| Keyword | 种内种子萌发差异 荒漠植物 变化机制 不同沙漠生境 种皮纹饰 Intraspecific difference in seed germination desert plant variation mechanism of intraspcific seed germination different desert environments seed coat sculpture |
| Abstract | 种子萌发具有重要科学意义和应用价值，它不但影响种群动态，群落演替和植物生活史表达, 而且对育苗、造林等防护林建设关键技术制定具有指导意义。 同一植物在不同沙漠生境下会表现出不同种子萌发对策。我国各大沙漠环境因子（如降水、蒸发、气温等） 差异较大，那么，生长在不同沙漠生境同一种植物种子萌发会发生什么样变化？ 机制是什么？这个科学问题未见报道。沙葱（Allium mongolicum） 是一种沙生蔬菜，沙米（Agriophyllum squarrosum）是流动沙丘先锋植物，碟果虫实（Corispermum patelliforme） 是沙区一种优质饲料。它们均为广泛分布于我国沙区的草本植物，种子萌发完全受降水调控。因此，以它们在不同沙漠生境采集的种子为对象，采用实验生态学的方法，对其种内种子萌发特性、促进种内种子萌发方法、种皮切除前后种内种子吸水率变化和处理前后种皮超微结构和种子大小的比较研究， 探索不同沙漠生境 3 种植物种内种子萌发差异及作用机制。取得以下主要结果：（1）不同沙漠生境 3 种植物种内种子最适萌发温度存在差异。沙葱 SAW（阿拉善野生沙葱）最适萌发温度为恒温 20℃，沙葱 SAC（阿拉善栽培沙葱）为恒温 15℃，沙葱 SMW（民勤野生沙葱）为变温 15/25℃和 20/30℃、沙葱 SMC（民勤栽培沙葱）为变温 20/30℃；沙米 M（民勤野生沙米）最适萌发温度为变温 10/30℃，沙米 S（沙坡头野生沙米）为变温 10/30℃、 5/15℃和 15/35℃，沙米 D（敦煌野生沙米）为变温 10/30℃和 20/40℃。碟果虫实 DW（民勤野生碟果虫实）最适萌发温度为变温为 25/15℃， DC（民勤栽培碟果虫实）为变温25/5℃。（2） 3 种植物种子萌发均为嫌光型，且在 3 种光照条件下萌发率均为 G1（24h 黑暗） >G2（14h 黑暗/10h 光照） ≥G3（24h 光照）。它们种内种子萌发对光照的响应存在差异：在 24h 光照下萌发率为 SAC>SMC>SAW>SMW，沙米为 S>D=M，碟果虫实为 DC>DW。（3） 3 种植物种内种子萌发对水盐胁迫耐受性存在差异。沙葱忍受水分胁迫能力为 SAW>SAC>SMW>SMC，忍受盐分胁迫能力为 SMW> SAW> SAC>SMC，且忍受水分胁迫能力强于盐分胁迫；沙米种子萌发忍受水分胁迫能力为M>D>S，忍受盐分胁迫的能力为 D>S>M，且沙米种子忍受水分胁迫能力强于盐分胁迫。 2 种碟果虫实种子萌发忍受水盐胁迫的能力均为 DC>DW。（4） 3 种植物种子萌发均较缓慢，种内种子萌发休眠程度不同。沙葱种子休眠程度 SMW>SMC>SAW>SAC；沙米 M 种子休眠， S 和 D 种子不休眠；碟果虫实 DW 种子休眠， DC 不休眠；沙葱和碟果虫实休眠均属于物理休眠和化学休眠， 且以物理休眠为主； 沙米为物理休眠。（5） 3 种植物种内种子萌发差异均是由种子大小和种皮结构差异造成的，这些差异与种子采集地土壤含水量有关。而且， 每种生境种子具体原因不同。（6） 3 种植物种内种子大小与种子萌发率均呈现线性正相关关系。其中，沙葱种子大小与种子萌发率的关系为 y=29.07x-24.14（R2= 0.912）；沙米为y=223.6x-253.0（R2= 0.998），碟果虫实为 y=0.662x+0.541（R2= 1.0）。（7）造成 3 种植物种内种子萌发差异的种皮结构不同，而且种皮表面超微结构越粗糙，种子萌发越容易；颜色越浅，种子萌发越困难；种皮越疏松，种子萌发越容易，而且种皮颜色的影响大于种皮粗糙。沙葱主要是由种皮表面纹饰结构粗糙程度、颜色、种皮疏松程度和种子浸泡液对种子萌发抑制性差异造成。种皮纹饰粗糙度为 SAC>SAW>SMC>SMW，种皮纹饰颜色由浅到深依次为 SMW、 SMC、 SAW 和 SAC，种皮疏松程度为 SAC>SAW>SMC>SMW，种子浸泡液抑制性 SMW>SAW；沙米由种皮表面超微结构粗糙程度，颜色、种皮疏松程度和种子浸泡液对种子萌发促进作用差异造成。种皮粗糙程度为S>D>M，种皮疏松程度 S>M>D，种子浸泡液对种子萌发促进程度为 S>D>M；碟果虫实主要由种皮表面纹饰大小、颜色和水解性，萌发孔堵塞程度，堵塞物水溶性以及种皮浸泡液对种子萌发抑制性差异造成。碟果虫实种皮纹饰大小DC>DW，颜色 DC 较深， DW 较浅，纹饰水溶性 DC>DW，萌发孔堵塞 DW>DC，种皮浸泡液对种子萌发抑制性 DW>DC。（8） 阐明了野生碟果虫实种子休眠机制以及栽培后种子萌发休眠被打破的原因。野生碟果虫实种子休眠是由种皮透水性差和种皮中含有种子萌发抑制物引起。栽培后种子不休眠的原因是由种皮透水性增强和种皮中种子萌发抑制物消失所致。种皮透水性增强体现在种皮水溶性增强，萌发孔堵塞减弱，堵塞物水溶性增强。（9）获得了一种沙米种子浸泡液，种子在该浸泡液中进行催芽 2d，萌发率可达 100%. 该方法能克服现有技术种子萌发时间长，播种后保苗率低的缺点。（10）不同沙漠生境 3 种植物种内种子萌发存在差异。如果要在不同沙漠进行人工栽培，沙葱最好选择 SAC 或 SMC，沙米选择 S，碟果虫实选择 DC。 |
| Other Abstract | It was very important for seed germination in scientific research and agriculturalproduction and it not only affected the population dynamics, community successionand plant life history expression but also had an important guiding significance insome key technologies of seeding raising and afforestation in shelterbeltconstruction. The same species had the different seed germination strategies indifferent desert habitats. A significant difference of environment factors (rainfall,evaporation and air temperature, ete.)appeared in all deserts of our country, andconsequently which variation would happen in seed germination for the samespecies from different desert habitats and what was their mechanism? Thesescientific problems were ignored. Allium mongolicum was a wild vegetable indesert areas, Agriophyllum squarrosum was a pioneer plant species distributed inmobile sand dune of desert areas and Corispermum patelliforme was a fine foragefor camel and sheep in desert areas. These plants are all herbaceous plantsdistributed widely in desert areas of North and China and their seed germinationwas completely regulated by rainfall. Thus, we explored the differentiation and theircauses in intraspecific seed germination of three desert plants from the differentdesert habitats and to solve these problem, three research works were conductedincluded as follows, 1) Compared seed germination ability among intraspecificseeds at different temperature, light and moisture and salt stress among three species.2) Compared the response to the promoting intraspecific seed germination methodsin three species, and 3) Compared the water absorbed ability of intraspecific seedsafter seed coat primed, and the difference of microstructure of seed coat inintraspecific seeds after treated and the difference of intraspecific seed mass in threespecies, a few main results were obtained as follows:(1) The optimal temperature for seed germination was different amongintraspecific seeds in three species. For Allium mongolicum, the optimal value ofSAW (wild seeds from Alxa) was the constant temperature 20℃, the value of SAC (cultivated seeds from Alxa) was the constant temperature 20℃, the value of SMC(cultivated seeds from Minqin) was the alternative temperature 20/30℃and thevalues of SMW (wild seeds from Minqin) were the alternative temperature 15/25℃and 20/30℃. For Agriophyllum squarrosum, the value of M (wild seeds fromMinqin) was the alternative temperature 10/30℃, the value of S (wild seeds fromShapotou) were the alternative temperature 10/30℃, 5/15℃and 15/35℃and thevalue of D (wild seeds from Dunhuang) were the alternative temperature10/30℃and 20/40℃. For Corispermu patelliforme, the value of DW (wild seedsfrom Minqin) was the alternative temperature 25/15℃, the value of DC (cultivatedseeds from Minqin) was the alternative temperature 25/5℃.(2) Germination from different desert habitats seeds was very difficult for threespecies under light conditions and their germination percentage were all G1(24hdark)＞G2(14h light /10h dark)≥G3(24h light) under light conditions. There wassome significant difference of response to light appeared among intraspecific seed inthree species and the germination percentage under 24h light conditions follows, forAllium mongolicum, the germination value was SAC>SMC>SAW>SMW,respectively. For Agriophyllum squarrosum, the value was S>D=M, respectivelyand for Corispermu patelliforme, the value was DC>DW.(3) The ability to endure the moisture and salt stress for inspecific seeds in threespecies had a significant difference. The ability to endure moisture stress in Alliummongolicum was SAW>SAC>SMW>SMC respectively and the ability to enduresalt stress was SMW>SAW>SAC>SMC. Among them, there was a distinctdifference in enduring water and salt stress and the ability to endure water stress wasstronger than that of salt stress. The tolerant ability to moisture stress in threeAgriophyllum squarrosum seeds was M>D>S and the ability to salinity stress wasM=S>D. In general, the ability to endure water stress was stronger than that of saltstress for Agriophyllum squarrosum. The ability to endure moisture and salt stress oftwo Corispermum patelliforme seeds were both DC>DW.(4) Germination of intraspecific seeds was very slow in three species and theirdormancy level was also different. The dormancy appeared in four seeds of Alliummongolicum and their dormancy level was SMW>SMC>SAW>SAC, respectively.For Agriophyllum squarrosum, the M was dormancy and the S and D were not. ForCorispermum patelliforme, the DW was dormancy and the DC was not anddormancy types was physical dormancy and chemical dormancy in Alliummongolicum and Corispermum patelliforme and physical dormancy played adominant role in their dormancy, For Agriophyllum squarrosum, the dormancytypes was only physical dormancy.(5) The germination variation of intraspecific seeds in three species was causedby the difference of seed mass and seed coat structure and the differences wererelated to the soil moisture content of plant habitats. Moreover, every seeds fromdifferent habitats had the corresponding reasons about the differences.(6) Relationships between seed mass and germination percentage were a linearpositive correlation. Among them, seed mass of Allium mongolicum wasSAC>SAW>SMC> SMW, respectively and the equation of relationships betweenseed mass and germination percentage was y=29.07x-24.14(R2=0.912).Seed mass ofAgriophyllum squarrosum was S>D>M, respectively and the equation ofrelationships between seed mass and germination percentage was y=223.6x-253.0(R2= 0.998), Seed mass of Corispermu patelliforme was DC>DW, respectively, andthe equation of relationships between seed mass and germination percentage wasy=0.662x+0.541 (R2= 1.0).(7) There were some differences in seed coat structure which cause theintraspecific differences of seed germination in three species. The more rough inseed coat, the more easy in seed germination and the more shallow in seed coatcolor, the more difference and the effects of seed coat color was more than that ofseed coat rough. For Allium mongolicum, the difference of seed coat were includedin the degree of roughness of seed coat sculpture, the color of seed coat sculpture,the degree of seed coat loose and the inhibitory of seed soaked solution togermination. The roughness of seed coat sculpture was SAC>SAW>SMC>SMW,respectively, the color of seed coat sculpture from depth to shallow was SAC, SAW,SMC and SMW. the degree of seed coat loose was SAC>SAW>SMC>SMW,respectively, the inhibitory of seed soaked solution to seed germination wasSMW>SAW. For Agriophyllum squarrosum, the difference of seed coat wereincluded in the degree of roughness of seed coat, the color of seed coat, the degreeof seed coat loose and the promotion of seed soaked solution to germination. Theroughness of seed coat sculpture was S>D>M, respectively, the color of seed coatsculpture from depth to shallow was S, D and M, the degree of seed coat loose wasS>M>D, respectively, the promotion of soaking solution to seed germination wasS>D>M. For Corispermum patelliforme, the difference of seed coat were includedin the size, color and water solubility of seed coat sculpture, the degree of themicropyle jammed and the water solubility of the jammed substances and theinhibitory of seed coat soaked solution to germination. The roughness of seed coatsculpture was DC>DW, the color of seed coat sculpture from depth to shallow wasDC and DW, the degree of the micropyle jammed was DW>DC, the water solubilityof jammed substance near micropyle was DC>DW and the inhibitory of seed coatsoaked solution to seed germination itself was DW> DC.(8) We illuminated the dormancy mechanism of wild Corispermum patelliformeseeds and the cause of germination improved after the corresponding speciescultivated. Dormancy for wild seeds was caused by the poor water permeability inseed coat and by the substance of inhibiting seed germination found in seed coat.Dormancy was broken by the increase of water permeability and the disappearanceof inhibitive substance to seed germination in seed coat after cultivated and thevariation of water permeability was included in the increase of water solubility inseed coat, the release of jammed substance in micropyle and the increase of its watersolubility.(9) We obtained a soaked solution from Agriophyllum squarrosum seeds and ifseeds were cultured in the solution for two days in light incubators, germinationpercentage would quickly reached 100%. The technology can remedy the deficiency of the long days of seed germination and the low seedling preservation rate aftersowed in current technology for improving the germination of Agriophyllumsquarrosum seeds.(10) There was a significant difference in germination appeared amongintraspecific seeds of three desert plant species. Therefore, if we want to grow thesespecies in desert areas of our country, the SMC or SAC for Allium mongolicum, Sfor Agriophyllum squarrosum and DC for Corispermum patelliforme, as the bestseeds, should be firstly considered. |
| Subject Area | 生态学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/15344 |
| Collection | 中国科学院新疆生态与地理研究所 研究系统 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 刘有军. 不同沙漠生境三种荒漠植物种内种子萌发差异及作用机制[D]. 北京. 中国科学院大学,2019. |
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