NWIPB OpenIR
三江源区不同类型人工草地垂穗披碱草的生长与繁殖对策
付京晶
学位类型硕士
导师赵新全 ; 周华坤
2014-05
学位授予单位中国科学院研究生院
学位授予地点北京
学位专业生态学
关键词垂穗披碱草 克隆生长 繁殖分配 竞争 退化演替
摘要克隆性在植物界广泛存在,包括许多类群所拥有的克隆生长和一些类群所拥有的克隆生殖。克隆植物是众多生态系统的重要组成部分,其在不同生境中的地位和作用不同。克隆植物同时具有克隆生长和有性繁殖的能力。植物对这两种繁殖方式的投入可能随限制资源因子的不同而不同。目前,不同演替阶段人工草地类型中克隆植物的克隆生长与有性繁殖的权衡进化研究远远落后于不同干扰下植物繁殖分配研究。垂穗披碱草( Elymus nutans ) 为禾本科披碱草属多年生根茎疏丛型草本植物, 是构成高寒草甸根茎禾草层片的主要植物种。其以再生性和分蘖能力强, 茎叶茂盛, 产草量高, 耐牧性强, 适于晒制干草和放牧, 被作为青藏高原牧区人工草地建设的首选牧草之一。以垂穗披碱草为主要建植种建植的人工草地在次级演替中,一方面,垂穗披碱草作为根茎型克隆植物的代表种改良退化草地的土壤,改变区域生态环境,起到减缓草地退化的作用;另一方面,垂穗披碱草的生长与繁殖的资源分配格局、克隆生长与有性繁殖的繁殖策略面对退化生境存在一定响应。为了揭示这两个方面的问题,本研究选取了三江源区果洛不同龄期的垂穗披碱草人工草地和同德不同播种类型的人工草地,对克隆植物与非克隆植物的分布,垂穗披碱草生长和繁殖情况,分析不同干扰因子对根茎型克隆植物繁殖对策的影响,并阐述垂穗披碱草克隆生长特性在人工草地稳定性维持中的作用和贡献。本研究对揭示垂穗披碱草的形态可塑性变化及对异质性环境的适应机制具有重要意义,也对三江源区高寒草地退化过程和人工草地建植后生态稳定性和生产稳定性转化机制的认识有重要意义。
本研究结果如下:
①在同德和果洛人工草地中,克隆植物占植物总种数的比例低于非克隆植物。垂穗披碱草混播建植的人工草地的克隆植物丰度和相对重要值都高于垂穗披碱草单播人工草地。
②青海地区根茎型克隆植物的分布和相对重要值整体上比其他克隆生长型高。但部分样地中,分蘖型克隆植物的分布与根茎型相当。演替初期,根茎型克隆植物和分蘖型克隆植物都较多。而随着演替的进行,生境条件的改善,密集型克隆植物减少,而游击型克隆植物增加,并在群落中发挥重要作用。
③人工草地退化演替中期,单播的群落中垂穗披碱草相对重要值与优势度均显著小于混播。混播建植的人工草地对于逐渐退化的垂穗披碱草种群有减缓杂草入侵作用。因此,要延长人工草地的退化年限,提高垂穗披碱草的产量,最优是选择混播建植人工草地。而在人工草地退化演替中,2个种的混播可以促进对下一代的投资,增加种内的延续。
④人工建植的垂穗披碱草草地具有明显的龄级效应。垂穗披碱草建群的第二年或第三年植被盖度和生物量达最大值, 随后将出现退化。
⑤随着人工草地的退化,土壤理化性质也发生变化。垂穗披碱草的相对重要值与土壤容重、土壤水分成正相关,与土壤PH值成负相关;与土壤总有机碳成正相关,与速效磷、速效氮成负相关。因此,为了减缓建植的垂穗披碱草人工草地的退化演替,提高垂穗披碱草的产量,可通过提高土壤含水量、增加土壤有机碳。
⑥不同类型人工草地中垂穗披碱草各个营养器官(根、茎、叶)生物量投资无显著差异。与克隆植物“株丛中部死亡”的现象有关。
⑦垂穗披碱草的克隆生长和繁殖分配的负相关关系,说明了在人工草地退化演替中,垂穗披碱草克隆生长和繁殖分配存在“此消彼长”的权衡关系。这种关系同时受群落中克隆植物和非克隆植物相对重要值的影响。另外,垂穗披碱草的有性繁殖分配还受群落克隆植物丰度、分蘖型克隆植物相对重要值的影响。
其他摘要Clonality widespread in the plant kingdom, including many groups have clonal growth and some groups have clonal reproduction. Succession of different periods of the same community, clonal plants’ growth and distributions are not the same. Clonal plants have the ability of clonal growth and sexual reproductive. The inputs to these two plant reproduction may differ cause of limited resources factors. Currently, the trade-off between sexual reproduction and clonal growth of plants in different types of artificial grassland during succession is still far behind the study of Reproductive allocation under different disturbance. Elymus nutans, belongs to Elymus herbaceous, is sparse bundle type with perennial rhizome, and a major species of alpine meadow grass roots plies. To be a preferred Builder of the artificial pasture in Qinghai-Tibet Plateau, cause of its strong regeneration and tillering, leaf lush, high grass yield, resistance to animal and strong husbandry, suitable for making hay and grazing pasture. As the representative species of clonal plants, E. nutans could improve degraded grassland soil, and restore regional ecological environment, play a role in the slowing degenerated grassland. And certain responses could be made by resource allocation patterns between growth and reproduction (organs of vegetation and reproduction), clonal growth and sexual reproduction in the face of degraded habitats during the secondary succession of artificial pasture starting with single E. nutans and mixed plants. In order to reveal these two issues, the study selected two typical places of Three Rivers District (different seeding types of E. nutans artificial grassland in Tongde, and different ages artificial grassland in Guoluo), and investigated the distribution, growth and reproduction of clonal plants and non-clonal plants. Analyzed the influence of different factors on the rhizomatous clonal plant E. nutans’ reproductive strategies, and explained the role and contribution that E. nutans’ clonal growth characteristics made to maintain stability in artificial pasture. These are pretty meaningful which could reveal the adaptive mechanism of E. nutans’ morphological plasticity to the heterogeneous environments. And these are very helpful to understand degradation processes of alpine grassland in Three Rivers Area and ecological stability and transformation mechanism of production stability of artificial grassland.
The results of this study are as follows:
① Status and role of clonal plants in different habitats are imparity. The proportion of clonal plants in total number of species is lower than non-clonal plants in the artificial grasslands both at Tongde and Guoluo. Abundance and the relative importance value of clonal plants in mixed perennial artificial grassland are higher than that in E. nutans artificial grassland.
② As a whole, abundance and the relative importance of rhizomatous clonal plants are higher than other types of clonal growth in Qinghai. But the indexes of tillering clonal plants and rhizomatous are the same in part of the plot. Both rhizomatous and tillering clonal plants distributed widely during early succession. With the of succession, the habitat conditions improved, the number of intensive clonal plants decreased and guerilla clonal plants increased, and guerilla clonal plants played an important role in the community.
③ The relative importance value and dominance of E. nutans in monoculture are lower than that in mixture. Artificial Grassland succession mid unicast communities E. nutans relative importance value and dominance were significantly less than in mixed at the middle retrogressive succession in artificial grasslands. Mixed planting artificial grassland could fight for the gradual degradation of E. nutans populations. Therefore, in order to extend the life of artificial grassland degradation, improve E. nutans’ yield, the optimal choice is mixed planting. Two kinds of mixed culture can promote investment in the next generation, an increase in the continuation of species during retrogressive succession in artificial grasslands.
E. nutans in artificial planting have obvious effect of age class. Vegetation cover and biomass of E. nutans reached the maximum at second or third year, degradation would follow.
⑤ With artificial grassland degradation, soil properties also changed. The relative importance value of E. nutans had significant positive correlation with soil bulk density, soil water, and TOC, while had negative correlation with soil PH value, available nitrogen and available phosphorus. Therefore, in order to slow down the degradation succession and improve the production of E. nutans, we should increase soil moisture and increase soil organic carbon.
⑥ E. nutans did not make a significant difference on investments in various vegetative organs grass biomass (roots, stems, leaves) in different types of artificial grassland because of "centre cluster death" phenomenon in clonal plants.
⑦ The clonal growth tended to positive correlate to reproductive allocation of E. nutans significantly. It illustrates that the trade-off between clonal growth and reproductive allocation happened during retrogressive succession in artificial grasslands. In addition, sexual reproductive allocation E. nutans is also affected by the abundance of clonal plants and non-clonal plants, and the relative importance value of tillering clonal plants. Resource allocation on clonal growth had significant positive correlation with the relative importance value stolons and root biomass allocation, had significant negative correlation with stem biomass allocation.
文献类型学位论文
条目标识符http://210.75.249.4/handle/363003/4032
专题中国科学院西北高原生物研究所
推荐引用方式
GB/T 7714
付京晶. 三江源区不同类型人工草地垂穗披碱草的生长与繁殖对策[D]. 北京. 中国科学院研究生院,2014.
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