沙化草地植被恢复过程中赖草地下根系发育影响因素研究

发布时间：2018-06-28 19:37

本文选题：植被恢复 + 赖草　；参考：《济南大学》2017年硕士论文

【摘要】：草地是陆地上面积仅次于森林的第二大绿色覆被层,约占全球植被生物量的36%、陆地面积的24%。我国草原面积约占国土面积的41%,其生态功能与经济价值均非常重要。退化和沙化一直是草地面临的严峻问题,我国退化、沙化草地面积已占草地总面积的三分之一。开展如何恢复沙化草地植被研究具有重要意义。赖草(Leymus secalinus)是多年生根茎型禾草,以克隆生殖为主要的繁殖方式,不仅具有很强的抗逆能力,而且具有较高的营养和经济价值,是用于植被恢复的优质牧草。本研究以赖草为实验材料,以沙土作为培养基质,探讨了在沙化草地植被恢复过程中不同影响因素对赖草地下根系发育的影响,通过野外实验和温室实验相结合的实验方法,对赖草种子萌发、幼苗根系发育和定植以及根茎生长的影响因素进行了探究,主要研究结果如下:1、赖草种子发芽受温度、光照、播种深度以及是否浸种的影响显著。(1)在一定温度范围内,赖草种子的发芽速度与温度呈正相关系,30℃条件下发芽速度最快;最终发芽率随着温度的升高呈现先升高后降低的趋势,25℃时发芽率最高,为28%,相对于高温情况,低温(温度20℃)不利于赖草种子的萌发。(2)光照显著影响赖草种子发芽速度和最终发芽率。有光的处理组中,种子的发芽时间比无光处理组提前2天,有光处理组的最终发芽率比无光处理组提高了9.33%,有光时,赖草长势更好。(3)在一定范围内,赖草最终发芽率与播种深度呈正相关,播种深度1cm时发芽率最高,为43.33%;播种深度0cm发芽率最低,为20%。说明适当的增加播种深度可以增加赖草种子的发芽率。(4)浸种处理的发芽率为39.33%,较不浸种处理的28%高,同时缩短了发芽周期,浸种处理比不浸种处理提前2天结束发芽。2、营养、干旱和光周期影响赖草幼苗根系发育。(1)高氮磷处理会抑制根系生长延伸和侧根发生,同时也抑制了根茎和分蘖的产生,降低了赖草幼苗对营养的吸收能力,导致地上生物量下降。氮对赖草幼苗的抑制作用显著强于磷,过量磷处理可以促进根系对营养和水分的吸收。营养梯度处理中,高营养浓度的处理能够促进赖草幼苗产生根茎和分蘖,幼苗更健壮。(2)间歇干旱处理赖草幼苗会抑制根延伸生长和侧根的发生,降低地上、地下生物量,但是对于赖草株高无明显影响。(3)12h光照处理显著增加了赖草生物量,植株更健壮,根系较8h光照更发达,促进根茎和分蘖发生,较8h光周期产生根茎时间更短。3、种植方向和单侧营养对赖草根茎生长的影响(1)田间实验发现,与东向和南向相比,根茎顶芽西向和北向移植时更利于赖草克隆片段根茎的延伸,移植克隆片段产生大量的分蘖、新芽、新根茎和发达的不定根,但没有发现会对根茎顶芽的生长方向性产生影响。移植克隆片段在每隔一天旋转90o处理下,赖草间隔子寿命会缩短,取而代之会产生发达的不定根。(2)单侧营养处理没有改变根茎顶芽的延伸方向,但是单侧营养能够促进根茎伸长和母株分蘖的产生。与田间实验相比,赖草地上株数、分蘖数、芽数和新生根茎的数量都很少或不产生,形态单薄。生长中的赖草根茎遭遇难以穿透的阻碍时,可以改变生长方向,绕过障碍物。研究结果为如何通过根茎型克隆植物播种和实生苗移植恢复沙化草地植物奠定了理论基础,同时也为植被恢复生产实践提供实验指导,研究结果具有很好的应用价值。
[Abstract]:Grassland is the second largest green overburden layer on land next to forest, which accounts for about 36% of the total vegetation biomass in the world. The land area of 24%. is about 41% of the land area. Its ecological function and economic value are very important. Degradation and desertification have been a serious problem facing the grassland. Our country has been degraded and the sandy grassland area has been occupied. The total area of the grassland is 1/3. It is of great significance to carry out the research on how to restore the vegetation of sandy grassland. Leymus secalinus is a perennial rhizomatous grass, which is the main reproductive mode of clone reproduction. It not only has strong anti inverse ability, but also has high nutritional and economic value. It is a high quality pasture for vegetation restoration. In this study, Leymus Leymus was used as the experimental material and sand soil was used as culture medium. The effects of different factors on the root system development of Leymus Leymus were discussed in the process of vegetation restoration in sandy grassland. The effects of the field experiment and greenhouse experiment on the seed germination, the root development and planting of the young seedlings and the rhizome growth were influenced by the field experiment and the greenhouse experiment. The main research results were as follows: 1, the seed germination of Leymus Leymus was significantly affected by temperature, light, sowing depth and seed soaking. (1) the germination speed of Leymus Leymus seeds was positively related to the temperature in a certain temperature range, and the germination rate was the fastest at 30 degrees C, and the final germination rate increased first and then decreased with the increase of temperature. The low trend, the highest germination rate at 25, was 28%. Compared with the high temperature, low temperature (temperature 20) was not conducive to the germination of Leymus Leymus seeds. (2) light significantly affected the germination speed and the final germination rate of Leymus Leymus. In the light treatment group, the germination time of seeds was 2 days ahead of the non light treatment group, and the final germination rate of the light treatment group was less than that of the light treatment group. The growth of Leymus Leymus was improved by 9.33%. (3) in a certain range, the final germination rate of Leymus Leymus was positively correlated with the depth of sowing, the germination rate was the highest when the sowing depth 1cm was 43.33%, and the seed depth 0cm germination rate was the lowest. It was 20%. that the appropriate increase of sowing depth could increase the germination rate of Leymus Leymus. (4) seed soaking treatment germination The rate of 39.33% was 28% higher than that of the non seed soaking treatment, and the germination period was shortened, and the germination period was shortened at the same time. The germination was.2 at 2 days earlier than that of the non soaking treatment. Nutrition, drought and photoperiod affected the root development of Leymus Leymus seedlings. (1) Gao Dan phosphorus treatment would inhibit the root growth and lateral root formation, and also inhibit the production of rhizomes and tillers, and reduced the Leymus Leymus. The ability of the seedlings to absorb nutrients leads to the decrease of the aboveground biomass. The inhibition of nitrogen to the seedlings of Leymus Leymus is significantly stronger than that of the phosphorus. Excessive phosphorus treatment can promote the absorption of nutrients and water. In the nutrient gradient treatment, the treatment of high nutrient concentration can promote the root and stem and the tillering of Leymus Leymus seedlings and the seedlings are more robust. (2) intermittent drought treatment. The seedlings of Leymus Leymus could inhibit the root elongation and lateral roots, decrease the aboveground and subsurface biomass, but have no obvious effect on the height of Leymus Leymus. (3) 12h light treatment significantly increased the biomass of Leymus, the plant was more robust, the root system was more developed than the 8h light, and the root and tiller were promoted, and the rhizome time was shorter than that of the 8h photoperiod, and the planting direction was higher than that of the rhizome. And the effects of unilateral nutrition on the Rhizome Growth of Leymus Leymus (1) field experiments found that compared with the East and south direction, the stem buds were more advantageous to the extension of rhizomes of the cloned cloned segments of the rhizome, and the cloned fragments produced a large number of tillers, new buds, new rhizomes and developed adventitious roots, but there was no direction for the growth direction of the rhizome buds. Transplanting cloned fragments can shorten the life span of the rhizome of Leymus and produce developed adventitious roots under the rotation of 90o every other day. (2) unilateral nutrition treatment does not change the extension direction of the root buds, but the unilateral nutrition can promote the root elongation and the production of the tillers of the mother plant. The number of plants, the number of tillers, the number of buds and the number of new rhizomes are very small or not, and the form is thin. The growth direction can be changed and the obstacles can be changed when the rhizome of the growth is difficult to penetrate. The results of the study have laid a theoretical foundation for how to restore the sandy grassland plants by sowing of rhizome type cloned plants and planting seedlings. At the same time, it also provides experimental guidance for the production practice of vegetation restoration, and the research results have very good application value.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X171.4;S543.9

【参考文献】