基于叶片解剖特征分析三种无患子科果树的亲缘关系

Analysis of relationship among three Sapindaceae fruit trees based on leaf anatomical characteristics

关键词:  无患子科果树, 叶片, 横切结构, 表皮结构, 聚类分析

Key words:  fruit tree of Sapindaceae, leaf, transection structure, epidermal structure, cluster analysis

摘要:

采用石蜡切片和组织离析法,对3种无患子科果树的10份种质叶片横切及表皮解剖特征进行观察,并采用聚类分析对其亲缘关系进行初步研究。结果表明:10份试材均为异面叶,叶横切结构分为表皮、叶肉和叶脉3部分。中脉厚度总体上龙眼最大、龙荔次之、荔枝最小,差异显著。荔枝的中脉横切面为圆三角形,龙眼近似半圆形,龙荔则近似扁圆形。不同试材的叶片、上表皮和下表皮、栅栏组织及海绵组织的厚度分别为175.23～318.84、11.18～25.13、7.49～20.43、50.01～124.59和84.0～173.64 μm,栅栏组织细胞有2～3层。此外,叶脉突起度、栅栏组织与海绵组织厚度之比、叶片组织结构紧密度和叶片组织结构疏松度分别为2.65～5.77、0.52～0.82、28.89%～39.95%和44.89%～55.57%。荔枝的表皮细胞较小、多边形,垂周壁为弧形,下表皮无表皮毛,气孔器呈长椭圆形; 龙眼的表皮细胞较大、不规则形,垂周壁深波状,下表皮具表皮毛,气孔椭圆形或近圆形; 龙荔的表皮细胞与龙眼相近,但垂周壁为波状。聚类分析显示,10份试材首先聚为两大类,其中第一类是荔枝属,第二类是龙眼属; 然后又分为4个亚类,三月红和龙荔各自单独聚为一个亚类。

Abstract:

Ten germplasms of three Sapindaceae fruit trees were analyzed by their leaf transection and epidermal structure,using paraffin method and tissue segregation procedure. On this basis, genetic relationship among these 10 germplasms was examined preliminarily by cluster analysis in SPSS. The results showed that the leaves of 10 accessions were bifacial type,and their leaf transection structures all consists of epidermis, mesophyll and vein. The midvein thickness had significantly different as longan was the greatest in three fruit trees, longli in the middle and litchi was the least. Midvein transverse of litchi was rounded triangular, longan approximate semicircle, and longli was approximately flat circular. Among the difference materials, the range of leaf thickness, upper and lower epidermis, palisade tissue and sponge tissue were 175.23-318.84, 11.18-25.13, 7.49-20.43, 50.01-124.59 and 84-173.64 μm, respectively. Palisade tissue cell had 2-3 layers in all materials. In addition, VDP, P/S, R_T and R_L were 2.65-5.77, 0.52-0.82, 28.89%-39.95% and 44.89%-55.57%, respectively. Epidermal cell of litchi was small, polygon, anticlinal wall arc, lower epidermal without trichomes, and stoma was long oval; epidermal cell of longan was big, irregular, anticlinal wall sinuate, lower epidermal with trichomes, and stoma was oval or suborbicular; epidermal cell morphology of longli was similar with longan, but its anticlinal wall was corrugated. The cluster analysis found that 10 accessions were firstly divided into 2 categories, which are Litchi and Dimocarpus. And then the Sanyuehong and longli were separated as subgroup in each category.