华中五味子根、茎次生木质部的比较解剖

Comparative Studies on Secondary Xylem in Root and Stem of Schisandra sphenanthera

对华中五味子根、茎次生木质部的观察表明,其根、茎次生木质部的解剖特征基本相同:散孔材;导管分子相对较长,其末端略倾斜,单穿孔;侧壁纹孔类型为梯状具缘纹孔和单纹孔,梯状、对列或互列;仅具纤维管胞,无韧型纤维;木薄壁组织离管型和傍管型;木射线均存在异形Ⅱ型.华中五味子次生木质部既表现出明显的原始特征,如散孔材,导管分子相对较长,单孔率高,梯状具缘纹孔,仅具纤维管胞,无韧型纤维,木射线为异形Ⅱ型;同时又表现出一些较为进化的特征,如导管分子以单穿孔为主,端壁倾斜度较小,单纹孔,木薄壁组织傍管型,说明五味子科是最原始类群中进化程度较高的类群.与根相比,华中五味子茎的次生木质部导管短宽,导管分布频率大,单孔率高,纤维短而窄,射线短而窄.茎次生木质部的这种“小型化”与其特定的功能和生境相适应.

Observation on secondary xylem in stem and root of Schisandra sphenanthera shown that both of them shared a great many anatomic charactenstics as follows：diffueporous wood,vessel element length were relativets long with simple perforation in slightly inclined end walis,both the borded and simple pits exist in one vessel element,arranged in the pattern of scalariform,opposite and alternate pitting;There were only tracheid-fibres and lacked libriform fibres in secondary xylem.Wood ray was Krib＇s heterogeneous Ⅱ type.The secondary xylem of S.sphenanthera not only had obvious primitive characteristics,such as diffuseporous wood,higher Percentage of single vessel,relatively longer vessel members,scalariform borded pits,only tracheid-fibres,etc.,but also had some evolutionary characteristics,such as imple perforation in slightly inclined end walls,simple pits,paratracheal parenchyma,etc.,thus indicated that Schisandraceae maybe the more evolved one of the primitive taxa.Compared to the roots,secondary xylem of the stem had shorter and wider vessel elements,more vessel frequency,shorter and thinner tracheid-fibres,and shorter and thinner rays,the miniaturization of stem secondary xylem adapt to its specified functions and environment.