摘 要

为选出适合海启高速公路边坡防护的植物种类，本文对海启高速如东一标试验区内五种常用边坡防护植物（狗牙根、百喜草、胡枝子、紫穗槐、多花木兰）根系生长状况进行对比分析，通过测定植物根系生长状况和固土护坡效果存在关系的植物根长、根表面积、根体积、侧根数等指标，对比分析五种植物根系的生长状况，结合根系构型分析比较五种防护植物的固土护坡效益。主要研究结果如下：

（1）五种植物根系的形态特征表现为：狗牙根无明显主根，须根数多且较为顺直，但根系直径很小，标准株根系直径Dlt;1mm；百喜草是须根系植物，无明显主根，须根发达，根径较粗，标准株根系直径D在1～2mm范围内；紫穗槐具有明显的主根，标准株主根直径D约5mm，侧根丰富，分布较广，与主根呈一定角度，向斜下方伸展；胡枝子主根也较为粗壮，标准株主根直径D约在5mm左右，但侧根纤细，密集分布在主根周围；多花木兰有明显主根，侧根向两侧伸展，但整体发育滞缓，植株根系较小。

（2）五种植物根系根长、根表面积、根体积、侧根数等生长指标的对比：相同条件下，紫穗槐各项指标数据较其他几种植物均有明显优势，平均根长为399.536cm，约为胡枝子平均根长的3倍；平均根表面积为178.397cm，约为胡枝子平均根表面积的4倍；是较好的边坡防护植物的选。多花木兰的各项指标相对较差，根长指标与其他植物根长存在显著差异，均值仅有51.987cm，其他三项指标与紫穗槐有显著差异，与胡枝子、百喜草、狗牙根等差异不显著。对本次实验来说，多花木兰的固土护坡效果不太理想。胡枝子除侧根数指标平均约为28条/株，显著大于其他四种植物，其余三项指标与百喜草、狗牙根均无显著差异。狗牙根、百喜草在根长、根表面积、根体积、侧根数四项指标对比中均无显著差异。对五种防护植物的根系指标进行综合比较，紫穗槐＞胡枝子＞百喜草＞狗牙根＞多花木兰。

关键词：高速公路；边坡防护；根系；生长特征；

The Study on the Comparison of Five Highway Slope Protection plants’ root Growth

ABSTRACT

In order to select the most suitable plant species for the whole slope protection of Hai-Qi Expressway, this paper choose several common slope protection plants like Cynodon dactylon, Paspalum notatum, Amorpha fruticosa, Lespedeza bicolor and Magnolia multiflora in the test area of Rudong. The growth of roots of Magnolia growth cycle was about 90d. All the indicators we used were root length, root surface area, root volume and number of lateral roots. By comparing the above indexes which are closely related to the growth of plant roots and the effect of soil slope protection, the growth status of several plant roots was described. Combined with the root structure, the benefits of several plants on the slope of highway slope were analyzed and compared. The main findings are as follows:

(1) Morphological characteristics of the roots of five plant species: the roots of Cynodon dactylon have no obvious main roots, and the number of roots is relatively large and straight, but the diameter of roots is very small. The diameter of roots of standard plants is Dlt;1mm. The roots of Paspalum notatum are also roots and no obvious main roots. The roots are developed and the root diameter is relatively thick. The root diameter D of the standard plant is in the range of 1~2mm. The Amorpha fruticosa has obvious trunk roots. The diameter of the main root of the standard plant is about 5mm, the lateral roots are rich, and the distribution is wide. It is at an angle to the main root. The Lespedeza bicolor has obvious trunk roots, too. And the diameter of the main root of the standard plant is about 5 mm, but the lateral roots are slender and densely distributed around the main root. The magnolia has obvious main roots, and the lateral roots extend to both sides, but the overall development is delayed. Slow, the roots of the plants are small.

(2) Comparison of growth indexes such as root length, root surface area, root volume and number of lateral roots of the several plant roots, we learn that under the same conditions, the data of Amorpha fruticosa have obvious advantages compared with other plants. The average root length is 399.536cm, which is about 3 times of the average root length of Lespedeza bicolor. The average root surface area is 178.397cm, which is about 4 times of the average root surface area of Lespedeza bicolor. There is no doubt that Amorpha fruticosa is the preferred choice for slope protection plants. The indicators of Magnolia multiflora are relatively poor. The root length index is significantly different from other plant root lengths. The average value is only 51.987cm. The other three indicators are significantly different from Amorpha fruticosa, and the differences between the Cynodon dactylon and Paspalum notatum are not significant. For this experiment, the effect of multi-flower magnolia on soil slope protection is not ideal. The average number of lateral roots of Lespedeza bicolor was about 28 strain, which was significantly greater than that of the other four plants. The other three indicators were not significantly different from Cynodon dactylon and Paspalum notatum. There were no significant differences in the relationship between root length, root surface area, root volume and lateral root number of Cynodon dactylon and Paspalum notatum. A comprehensive comparison of the root indicators of five protective plants was Amorpha fruticosa gt; Lespedeza bicolor gt; Paspalum notatum gt; Cynodon dactylon gt; Magnolia multiflora.

Key words：Highway; Slope protection; Root system; Growth characteristics

目录

摘要...................................................................................……….................................................................Ⅰ

ABSTRACT......................................................................................……….................................................Ⅱ