福州市长乐沿海木麻黄林下野生苗的根系形态特征

植物根系对环境的形态适应研究对准确揭示植物与环境的关系十分重要。为探索滨海恶劣环境条件下木麻黄林下植被天然更新特征,本研究以沿海木麻黄防护林林下野生苗为研究对象,比较不同高度级木麻黄野生苗根系的总根长、总根表面积、平均根系直径、总根体积和总根尖数,分析林下3种草本植物根系形态特征。结果表明：随着木麻黄野生苗高度级的增加,总根表面积、平均根系直径和总根体积显著增长（P<0.05）;高度级1的野生苗总根表面积随根系径级的增加显著减少,高度级2的野生苗总根表面积在0~2.0 mm随根系径级的增加而减少,但在>2.0 mm时显著增加（P<0.05）;与林下草本植物相比,木麻黄野生苗的根系生长不占优势,其平均根系直径是窃衣和一点红的2~3倍,但是总根尖数最少且显著少于天门冬（P<0.05）;此外,在根系径级>1.5 mm时,仅木麻黄有根尖存在,根尖数占总数的0.33%。研究结果为促进林下植被的更新和保持植物多样性提供参考。

Root Morphological Characteristics of Wild Seedings under Casuarina equisetifolia Forests at Changle,Fuzhou, Fujian

The study on root morphological adaptability plays an important role in exactly revealing the relationship between plant and environment. This study aims to explore the natural regeneration characteristics of the undergrowth of the Casuarina equisetifolia forest under the harsh coastal conditions, taking wild seedlings under the coastal Casuarina protective forest as the research objec. The total root length, total surface area, average root diameter, total root volume and total tips at different highness class and the root morphology characteristics of three herbaceous plants under the forest were compared. With the increase of the highness class of Casuarina, the total surface area, average root diameter, and total root volume increased significantly (P<0.05). The total root surface area of the wild seedlings of highness class 1 decreased significantly with the increase of root diameter class, and the total surface area of highness class 2 decreased from 0 to 2.0 mm, and increased significantly at >2.0 mm (P<0.05). Compared with undergrowth herbaceous plants, the root growth of Casuarina wild seedlings was not dominant, its average root diameter was 2 to 3 times that of Torilisscabra (Thunb.) DC. and Emilia sonchifolia (L.) DC., but the total tips were the smallest and significantly smaller than that of Asparagus cochinchinensis (Lour.) Merr. In addition, when the root diameter was >1.5 mm, only Casuarina seedlings had root tips accounting for 0.33% of the total. The results would provide references for promoting the regeneration and maintaining plant diversity of undergrowth vegetation.