黄土丘陵区撂荒群落演替序列种根系对氮素施肥方式和水平的形态响应
发布时间：2018-11-11 19:55
【摘要】：采用盆栽试验,研究了黄土丘陵区撂荒群落演替序列种(即,黄土丘陵区摞荒群落演替主要阶段的优势种)根系对氮素施肥方式和水平的形态响应,对了解我国氮沉降增加背景下的群落生态效应及人为施肥干扰促进植被恢复具有较好的理论和实践意义。测试并分析了6个演替序列种在不同施氮方式(匀质和异质施氮)和水平(高、低和无氮对照)条件下植株个体生物量指标(地上及地下生物量和根冠比)、根系形态指标(根长、直径、表面积、比根长和比表面积)的变化及其差异显著性;并且利用根钻法和单样本T检验比较了异质施氮方式下施氮斑块与不施氮斑块根系形态指标的差异。结果表明:1)6种演替序列种地上、地下生物量和根冠比存在种间固有差别,施氮方式和水平整体上对三者无显著影响;施氮方式和植物种类对根冠比存在显著交互作用,说明个别种的根冠比对施氮方式响应明显,其中猪毛蒿根冠比在异质施氮方式下显著高于匀质施氮。2)6种演替序列种根系塑形指标包括比根长、比表面积和直径存在种间差别,并且施氮水平对比根长影响显著,高、低施氮水平下比根长都显著低于不施氮对照。3)狗尾草和铁杆蒿分别在异质高氮和异质低氮条件下施氮斑块根系生物量密度显著高于未施氮斑块;猪毛蒿在异质高氮条件下施氮斑块发生了更多的伸长生长,其根长、根表面积、比根长和比表面积在施氮斑块中的密度显著高于未施氮斑块;猪毛蒿和狗尾草在异质高氮条件下,以及白羊草在异质低氮条件下,其根系直径在施氮斑块显著小于未施氮斑块。从根系形态变化敏感性和施氮对促进植物生长来看,演替过程中演替序列种对施氮响应的敏感性总体上呈降低趋势,前期种对施氮响应更敏感,从施氮获利也更多,因而恢复前期进行人为干扰促进植被恢复效果也会更好。
[Abstract]:Pot experiment was carried out to study the morphological responses of root system of abandoned communities succession sequence species (i.e. dominant species in main stages of succession) to nitrogen fertilization patterns and levels in loess hilly region. It is of great theoretical and practical significance to understand the ecological effect of community and the disturbance of artificial fertilization to promote vegetation restoration under the background of increasing nitrogen deposition in China. The individual biomass indexes (aboveground and underground biomass and root / shoot ratio) of 6 succession sequence species under different nitrogen application patterns (homogeneous and heterogeneous nitrogen application) and levels (high, low and no nitrogen control) were tested and analyzed. The changes of root morphological indexes (root length, diameter, surface area, specific root length and specific surface area) and their differences were significant. Root drilling method and single sample T test were used to compare the root morphological indexes between different nitrogen application patterns and no nitrogen application patches. The results were as follows: 1) there were inherent differences in aboveground biomass and root-shoot ratio among 6 succession sequence species, but nitrogen application pattern and level had no significant effect on them; There was significant interaction between nitrogen application mode and plant species on root / shoot ratio, which indicated that root and shoot ratio of individual species had obvious response to nitrogen application mode. The root / shoot ratio of Artemisia annua was significantly higher than that of uniform nitrogen application in different nitrogen application modes. 2) the root shape-forming indexes of 6 succession sequence species included specific root length, specific surface area and diameter, and the effect of nitrogen application level on root length was significant and high. The specific root length at low nitrogen application level was significantly lower than that under no nitrogen application control. 3) the root biomass density of the root system in the condition of heterogeneity high nitrogen application and heterogenous low nitrogen application was significantly higher than that of no nitrogen patch. The root length, root surface area, specific root length and specific surface area of Artemisia pubescens were significantly higher in nitrogen patches than in those without nitrogen application. The root diameter of Artemisia hyacinth and Salvia chinensis were significantly smaller than that of non-nitrogen patches under heterogeneity and low nitrogen application conditions, and the root diameter of Artemisia annua was significantly smaller than that of non-nitrogen patches under the condition of heterogeneity and low nitrogen. According to the sensitivity of root morphological changes and nitrogen application to promote plant growth, the sensitivity of succession sequence species to nitrogen application showed a decreasing trend in general, and earlier species were more sensitive to nitrogen application and benefited more from nitrogen application. Therefore, the effect of artificial disturbance in the early stage of restoration to promote vegetation restoration will be better.
【作者单位】： 西北农林科技大学;中国科学院水利部水土保持研究所;中国科学院东北地理与农业生态研究所;
【基金】：国家自然科学基金项目(41271526)
【分类号】：S143.1
本文编号：2325963
[Abstract]:Pot experiment was carried out to study the morphological responses of root system of abandoned communities succession sequence species (i.e. dominant species in main stages of succession) to nitrogen fertilization patterns and levels in loess hilly region. It is of great theoretical and practical significance to understand the ecological effect of community and the disturbance of artificial fertilization to promote vegetation restoration under the background of increasing nitrogen deposition in China. The individual biomass indexes (aboveground and underground biomass and root / shoot ratio) of 6 succession sequence species under different nitrogen application patterns (homogeneous and heterogeneous nitrogen application) and levels (high, low and no nitrogen control) were tested and analyzed. The changes of root morphological indexes (root length, diameter, surface area, specific root length and specific surface area) and their differences were significant. Root drilling method and single sample T test were used to compare the root morphological indexes between different nitrogen application patterns and no nitrogen application patches. The results were as follows: 1) there were inherent differences in aboveground biomass and root-shoot ratio among 6 succession sequence species, but nitrogen application pattern and level had no significant effect on them; There was significant interaction between nitrogen application mode and plant species on root / shoot ratio, which indicated that root and shoot ratio of individual species had obvious response to nitrogen application mode. The root / shoot ratio of Artemisia annua was significantly higher than that of uniform nitrogen application in different nitrogen application modes. 2) the root shape-forming indexes of 6 succession sequence species included specific root length, specific surface area and diameter, and the effect of nitrogen application level on root length was significant and high. The specific root length at low nitrogen application level was significantly lower than that under no nitrogen application control. 3) the root biomass density of the root system in the condition of heterogeneity high nitrogen application and heterogenous low nitrogen application was significantly higher than that of no nitrogen patch. The root length, root surface area, specific root length and specific surface area of Artemisia pubescens were significantly higher in nitrogen patches than in those without nitrogen application. The root diameter of Artemisia hyacinth and Salvia chinensis were significantly smaller than that of non-nitrogen patches under heterogeneity and low nitrogen application conditions, and the root diameter of Artemisia annua was significantly smaller than that of non-nitrogen patches under the condition of heterogeneity and low nitrogen. According to the sensitivity of root morphological changes and nitrogen application to promote plant growth, the sensitivity of succession sequence species to nitrogen application showed a decreasing trend in general, and earlier species were more sensitive to nitrogen application and benefited more from nitrogen application. Therefore, the effect of artificial disturbance in the early stage of restoration to promote vegetation restoration will be better.
【作者单位】： 西北农林科技大学;中国科学院水利部水土保持研究所;中国科学院东北地理与农业生态研究所;
【基金】：国家自然科学基金项目(41271526)
【分类号】：S143.1
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