加拿大一枝黄花生态适应机制研究

发布时间：2018-09-03 11:06

【摘要】：加拿大一枝黄花(Solidago canadensis L.)属菊科(Asteraceae)一枝黄花属(Solidago)的多年生草本植物,原产自北美,是世界性恶性杂草。由于其特有的生物学和生态学特性,该外来植物会造成入侵地生物多样性的损失、严重的经济损失和景观破坏等一系列危害。本研究首先从不同入侵梯度的加拿大一枝黄花群落的物种种类以及密度调查开始,再进一步的开展了加拿大一枝黄花有性繁殖、无性繁殖、化感作用以及对土壤理化性质的影响等研究,旨在解释加拿大一枝黄花的入侵优势,为其防除提供一定的理论依据。1.加拿大一枝黄花不同入侵程度群落物种种类及物种密度调查：本研究采用样方法对加拿大一枝黄花不同入侵程度群落内的植物组成以及物种密度进行调查,分析了不同入侵梯度群落内的物种多样性指数。结果表明：(1)随着加拿大一枝黄花入侵程度增加,群落内植物种类及相对密度降低,在轻度入侵的群落中有21种植物,加拿大一枝黄花的相对密度为0.057；而在加拿大一枝黄花重度入侵地区,本土植物仅有6种,加拿大一枝黄花的相对密度高达0.690。(2)加拿大一枝黄花降低被入侵群落的物种多样性,在轻度入侵区域,群落的Shannon-Wenner多样性指数较大,为2.67+0.28,而重度入侵群落的Shannon-Wenner多样性指数仅为0.93+0.81,不同入侵程度的群落的物种多样性指数之间有显著性差异。2.通过对加拿大一枝黄花有性繁殖的研究表明：(1)加拿大一枝黄花不同部位花序产生的种子活力不同,位于花序主干下部的花序产生种子的千粒重比中部和上部种子的千粒重大,为50.41mg。加拿大一枝黄花的种子萌发率较高,其中下部种子平均萌发率最高,为65.8%,明显高于中部与上部种子的萌发率,各部分种子萌发率存在显著性差异(P=0.05)；(2)加拿大一枝黄花种子的平均萌发率和发芽指数分别为61.00%、20.23,蒲公英(Taraxacum mongolicum)和黄鹌菜(Youngia Japonica)2种菊科植物的萌发率分别为38.80%、51.00%,发芽指数依次为8.54、7.33。与这2种菊科植物相比,加拿大一枝黄花的种子的活力指数大,萌发率和发芽指数存在显著性差异。3.通过对加拿大一枝黄花无性生殖的研究表明：(1)人工剪除等人为能够促进加拿大一枝黄花地上茎的应激性繁殖策略,使其在剪除部位附近萌发生成新的克隆分支。随着加拿大一枝黄花地上茎剪除后剩余高度的增加,剪除部位新生分支数增加,割除后剩余高度为130cm时新生分支数为9.5个,其他割除干扰后新生分支数均在4个以上；(2)人工割除干扰引起加拿大一枝黄花生物量分配的变化,自然条件下,加拿大一枝黄花在根、茎、叶、花的分配分别为0.145、0.491、0.209和0.155,人工割除干扰后加拿大一枝黄花更多的向有性生殖器官投资,有性生殖器官的比例平均在0.21以上,在根、茎器官的生物量投资相应减少,人工割除前后的加拿大一枝黄花生物量分配有明显差异。(3)加拿大一枝黄花的根状茎具有较强的无性繁殖能力。随着埋藏深度的增加,加拿大一枝黄花根状茎片段的发芽数随之降低,且随着该物种根状茎的节数的减少,其发芽率在降低,含有3个节的根状茎片段的发芽数在深度为3cm与15cm的处理中的发芽数分别为7.2个和4.6个,而有1个节的根状茎片段在深度为3cm与15cm的处理中的发芽数分别为2.4和0个；随着埋藏深度的增加,加拿大一枝黄花根状茎的初始萌发天数随之升高,深度为3cm和15cm的处理中加拿大一枝黄花根状茎初始萌发分别为第6.4天和第30.2天。4、采用不同浓度的加拿大一枝黄花地上部分浸提液分别对番茄(Lycopersicon esculentum Mill)、特矮青(Brassica chinensis var chinensis)、黑麦草(Lolium perenne L.)种子萌发实验进行处理,分别测定不同种子的终萌发率和发芽指数以及种子萌发动态。研究结果表明：(1)加拿大一枝黄花的地上部分能够分泌某些化感物质,对其他植物产生影响；(2)不同浓度的加拿大一枝黄花水浸提液对3种种子均有不同程度的抑制作用,且浓度越高,抑制作用越强。5、对加拿大一枝黄花不同入侵梯度区域的土壤理化性质的的测定,结果表明：(1)随着加拿大一枝黄花入侵程度的加深,入侵地土壤含水量呈上升趋势,在重度入侵区域,土壤含水量为0.24,比未入侵地区增加了20%左右,证明加拿大一枝黄花的入侵可以提高土壤的持水能力；(2)加拿大一枝黄花的入侵降低了被入侵地区的土壤养分,进而抑制本土植物的生长和发育。6、对加拿大一枝黄花不同部位叶片的叶绿素相对含量以及光合作用日变化进行测定,结果表明：(1)不同部位叶片的叶绿素相对含量不同,中部叶片最高,其数值为37.29±0.884SPAD;(2)加拿大一枝黄花不同部位叶片的净光合速率日变化趋势不同,其中中部叶片的光合作用能力最高,其最高值达到21.176μmolCO_2·m-2·S-1,上部叶片与中部叶片的光合作用存在午休现象。下部叶片的净光合速率日变化曲线为单峰型,其光合作用能力较弱,最高值为16.688μmolCO_2·m-2·S-1。
[Abstract]:Solidago canadensis L. is a perennial herb of Asteraceae, native to North America and a worldwide malignant weed. Due to its unique biological and ecological characteristics, the alien plant can cause loss of biodiversity, serious economic losses and landscape damage in invasive areas. This study begins with the investigation of species and density of Canadian yellow flower communities with different invasive gradients, and then further studies on the sexual reproduction, asexual reproduction, allelopathy and the effects on soil physical and chemical properties of Canadian yellow flower were carried out in order to explain the superiority of Canadian yellow flower invasion. 1. Investigation of species species species and density in communities with different invasive degrees of C. canadensis: The composition and density of species in communities with different invasive degrees of C. canadensis were investigated by sampling method, and the species diversity in communities with different invasive gradients was analyzed. The results showed that: (1) with the increase of the invasion degree, the species and relative density of plants in the community decreased. There were 21 species in the mild invasion community, and the relative density of Canadian yellow flower was 0.057. In the severe invasion area of Canadian yellow flower, there were only 6 native species and Canadian yellow flower. The relative density was as high as 0.690. (2) A. canadensis decreased the species diversity of the invaded communities. In the mild invasive areas, the Shannon-Wenner diversity index was 2.67+0.28, while the Shannon-Wenner diversity index of the severe invasive communities was only 0.93+0.81, and there were differences among the species diversity indices of different invasive communities. The results showed that: (1) The seed vigor of the inflorescence from different parts of a Canadian yellow flower was different. The 1000-seed weight of the inflorescence from the lower part of the main stem of a Canadian yellow flower was 50.41mg larger than that from the middle and upper parts of the inflorescence, and the seed germination rate of a Canadian yellow flower was 50.41mg. The average germination rate of the lower part was 65.8%, which was significantly higher than that of the middle part and the upper part, and there was a significant difference in the germination rate of each part of the seeds (P = 0.05); (2) The average germination rate and germination index of the Canadian yellow flower seeds were 61.00%, 20.23, Taraxacum mongolicum and Youngia Japonicum, respectively. A) The germination rates of the two species of Compositae were 38.80%, 51.00% and the germination indices were 8.54, 7.33 respectively. Compared with the two species of Compositae, the vigor indices of the seeds of C. canadensis were higher, and the germination rates and germination indices of C. canadensis were significantly different. It can promote the stress propagation strategy of the aboveground stem of a Canadian yellow flower to germinate into a new clonal branch near the cutting site. With the increase of the remaining height after cutting off the aboveground stem of a Canadian yellow flower, the number of new branches in the cutting site increases. When the remaining height is 130cm after cutting, the number of new branches is 9.5, and other cutting disturbances are eliminated. The number of new branches was more than 4. (2) Artificial cutting disturbance caused changes in biomass allocation of C. canadensis. Under natural conditions, C. canadensis allocated 0.145, 0.491, 0.209 and 0.155 to roots, stems, leaves and flowers, respectively. The proportion of reproductive organs was above 0.21 on average, and the biomass investment in root and stem organs decreased accordingly. The biomass distribution of Canadian yellow flower was significantly different before and after artificial cutting. (3) The rhizome of Canadian yellow flower had strong asexual reproductive ability. The number of buds decreased with the decrease of the number of nodules in the rhizome. The number of buds in the treatment with 3 cm depth and 15 cm depth was 7.2 and 4.6 respectively. The number of buds in the treatment with 1 node was 2.4 and 0 respectively. With the increase of burial depth, the days of initial germination of Canadian yellow flower rhizome increased, and the days of initial germination of Canadian yellow flower rhizome were 6.4 days and 30.2 days and 4 days respectively in the treatments of 3 cm and 15 cm depth, respectively. The seed germination experiments of entum Mill, Brassica chinensis var. chinensis and Lolium perenne L. were carried out. The final germination rate, germination index and germination state of different seeds were determined respectively. The results showed that: (1) The aerial parts of A. canadensis could secrete some allelochemicals for other plants. The higher the concentration, the stronger the inhibition. 5. The physical and chemical properties of the soil in different invasive gradient regions were determined. The results showed that: (1) With the increase of the invasive degree of the Canadian crocus. The soil water content in the invaded area was 0.24, which was about 20% higher than that in the non-invaded area, indicating that the invasion of Canadian yellow flower could improve the soil water holding capacity. (2) The invasion of Canadian yellow flower reduced the soil nutrients in the invaded area and inhibited the native plants. Growth and development. 6. The relative chlorophyll content and diurnal variation of photosynthesis in different parts of the leaves of A. canadensis were measured. The results showed that: (1) The relative chlorophyll content was different in different parts of the leaves, and the highest value was 37.29 (+ 0.884 SPAD) in the middle part of the leaves; (2) The net photosynthetic rate in different parts of A. canadensis leaves. The diurnal variation trend was different, and the photosynthetic capacity of the middle leaves was the highest, with the highest value of 21.176 micron olCO_2.m-2.S-1. The photosynthesis of the upper leaves and the middle leaves had a midday recess. The diurnal variation curve of the net photosynthetic rate of the lower leaves was a single peak, and its photosynthetic capacity was weak, with the highest value of 16.688 micron olCO_2.m-2.S-1.
【学位授予单位】：安徽农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S451

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