金荞麦和荞麦的形态解剖学特征研究

Abstract

以金荞麦(Fagopyrum dibotrys (D. Don.) Hara.)和荞麦(F. esculentum Moench)为研究对象，利用石蜡切片法比较研究了两种植物的叶、叶柄、茎和根的解剖结构特征，在光学显微镜下对其解剖结构进行了观察和测定，并探讨了金荞麦的结构特征对其濒危的影响。观察显示，金荞麦和荞麦为典型的异面叶植物，荞麦叶上表皮与叶肉接触紧密，而金荞麦叶上表皮与叶肉之间具有空隙。叶柄外形马蹄状，由表皮、皮层和维管束组成；荞麦叶柄中央为由3~5层薄壁细胞隔开的2束维管束，而金荞麦叶柄中央为导管连成H状的2束维管束。茎中维管组织比例较小，韧皮纤维发达；中央为髓腔，髓腔随茎的年龄增大而增大。根由表皮、皮层和维管柱三部分组成，初生维管束四原型；金荞麦根的髓部由含有多种晶体的薄壁细胞组成。研究表明，金荞麦部分结构特征不利于其在逆境中生存，但这不能构成金荞麦濒危的主要原因。 The anatomical structure characteristics of vegetative organs (including leaf, petiole, stem and root) of Fagopyrum dibotrys (D. Don.) Hara. and F. esculentum Moench were observed using paraffin method, and the reason why F. dibotrys is endangered was also discussed based on its structure characteristics. The anatomical characters of F. dibotrys and F. esculentum are: Leaves typically dorsi-ventral; between upper epidermis and mesophyll cells in leaves structure there are gaps in F. dibotrys, but no gaps in F. esculentum. The transverse sec-tion of petioles made of epidermis, cortex and vascular bundle are U-shaped. The petiole of F. esculentum has two vascular bundles separated by three-five parenchyma cells in centre and the vessels in the centre of petiole of F. dibotrys link to H-shaped. The vascular tissue which has a small proportion in stem of F. dibotrys and F. esculen-tum contains developed phloem fibres; hollow pith of old stem is bigger than that of young. Roots are made of epidermis, cortex and vascular cylinder. Primary vascular bundles in root are tetrarch. There are many crystals in pith of root of F. dibotrys. It suggested that some structure characteristics are harmful for F. dibotrys to survive from environmental stress, but this is not the main reason for F. dibotrys to become endangered.